QEMU QMP Reference Manual

Introduction

This manual describes the commands and events supported by the QEMU Monitor Protocol (QMP).

For locating a particular item, please see the QMP Index.

The following notation is used in examples:

Example:

-> ... text sent by client (commands) ...
<- ... text sent by server (command responses and events) ...

Example text is formatted for readability. However, in real protocol usage, its commonly emitted as a single line.

Please refer to the QEMU Machine Protocol Specification for the general format of commands, responses, and events.

QMP errors

Enum QapiErrorClass (Since: 1.2)

QEMU error classes

Values:

  • GenericError – this is used for errors that don’t require a specific error class. This should be the default case for most errors

  • CommandNotFound – the requested command has not been found

  • DeviceNotActive – a device has failed to be become active

  • DeviceNotFound – the requested device has not been found

  • KVMMissingCap – the requested operation can’t be fulfilled because a required KVM capability is missing

Common data types

Enum IoOperationType (Since: 2.1)

An enumeration of the I/O operation types

Values:

  • read – read operation

  • write – write operation

Enum OnOffAuto (Since: 2.2)

An enumeration of three options: on, off, and auto

Values:

  • auto – QEMU selects the value between on and off

  • on – Enabled

  • off – Disabled

Enum OnOffSplit (Since: 2.6)

An enumeration of three values: on, off, and split

Values:

  • on – Enabled

  • off – Disabled

  • split – Mixed

Alternate StrOrNull (Since: 2.10)

This is a string value or the explicit lack of a string (null pointer in C). Intended for cases when ‘optional absent’ already has a different meaning.

Alternatives:

  • s (string) – the string value

  • n (null) – no string value

Enum OffAutoPCIBAR (Since: 2.12)

An enumeration of options for specifying a PCI BAR

Values:

  • off – The specified feature is disabled

  • auto – The PCI BAR for the feature is automatically selected

  • bar0 – PCI BAR0 is used for the feature

  • bar1 – PCI BAR1 is used for the feature

  • bar2 – PCI BAR2 is used for the feature

  • bar3 – PCI BAR3 is used for the feature

  • bar4 – PCI BAR4 is used for the feature

  • bar5 – PCI BAR5 is used for the feature

Enum PCIELinkSpeed (Since: 4.0)

An enumeration of PCIe link speeds in units of GT/s

Values:

  • 2_5 – 2.5GT/s

  • 5 – 5.0GT/s

  • 8 – 8.0GT/s

  • 16 – 16.0GT/s

  • 32 – 32.0GT/s (since 9.0)

  • 64 – 64.0GT/s (since 9.0)

Enum PCIELinkWidth (Since: 4.0)

An enumeration of PCIe link width

Values:

  • 1 – x1

  • 2 – x2

  • 4 – x4

  • 8 – x8

  • 12 – x12

  • 16 – x16

  • 32 – x32

Enum HostMemPolicy (Since: 2.1)

Host memory policy types

Values:

  • default – restore default policy, remove any nondefault policy

  • preferred – set the preferred host nodes for allocation

  • bind – a strict policy that restricts memory allocation to the host nodes specified

  • interleave – memory allocations are interleaved across the set of host nodes specified

Enum NetFilterDirection (Since: 2.5)

Indicates whether a netfilter is attached to a netdev’s transmit queue or receive queue or both.

Values:

  • all – the filter is attached both to the receive and the transmit queue of the netdev (default).

  • rx – the filter is attached to the receive queue of the netdev, where it will receive packets sent to the netdev.

  • tx – the filter is attached to the transmit queue of the netdev, where it will receive packets sent by the netdev.

Enum GrabToggleKeys (Since: 4.0)

Key combinations to toggle input-linux between host and guest.

Values:

  • ctrl-ctrl – left and right control key

  • alt-alt – left and right alt key

  • shift-shift – left and right shift key

  • meta-meta – left and right meta key

  • scrolllock – scroll lock key

  • ctrl-scrolllock – either control key and scroll lock key

Object HumanReadableText (Since: 6.2)
Members:

  • human-readable-text (string) – Formatted output intended for humans.

Enum EndianMode (Since: 10.0)
Values:

  • unspecified – Endianness not specified

  • little – Little endianness

  • big – Big endianness

Socket data types

Enum NetworkAddressFamily (Since: 2.1)

The network address family

Values:

  • ipv4 – IPV4 family

  • ipv6 – IPV6 family

  • unix – unix socket

  • vsock – vsock family (since 2.8)

  • unknown – otherwise

Object InetSocketAddressBase
Members:

  • host (string) – host part of the address

  • port (string) – port part of the address

Object InetSocketAddress (Since: 1.3)

Captures a socket address or address range in the Internet namespace.

Members:

  • numeric (boolean, optional) – true if the host/port are guaranteed to be numeric, false if name resolution should be attempted. Defaults to false. (Since 2.9)

  • to (int, optional) – If present, this is range of possible addresses, with port between port and to.

  • ipv4 (boolean, optional) – whether to accept IPv4 addresses, default try both IPv4 and IPv6

  • ipv6 (boolean, optional) – whether to accept IPv6 addresses, default try both IPv4 and IPv6

  • keep-alive (boolean, optional) – enable keep-alive when connecting to/listening on this socket. (Since 4.2, not supported for listening sockets until 10.1)

  • keep-alive-count (int, optional) – number of keep-alive packets sent before the connection is closed. Only supported for TCP sockets on systems where TCP_KEEPCNT socket option is defined (this includes Linux, Windows, macOS, FreeBSD, but not OpenBSD). When set to 0, system setting is used. (Since 10.1)

  • keep-alive-idle (int, optional) – time in seconds the connection needs to be idle before sending a keepalive packet. Only supported for TCP sockets on systems where TCP_KEEPIDLE socket option is defined (this includes Linux, Windows, macOS, FreeBSD, but not OpenBSD). When set to 0, system setting is used. (Since 10.1)

  • keep-alive-interval (int, optional) – time in seconds between keep-alive packets. Only supported for TCP sockets on systems where TCP_KEEPINTVL is defined (this includes Linux, Windows, macOS, FreeBSD, but not OpenBSD). When set to 0, system setting is used. (Since 10.1)

  • mptcp (boolean, optional) – enable multi-path TCP. (Since 6.1)

  • The members of InetSocketAddressBase.

Object UnixSocketAddress (Since: 1.3)

Captures a socket address in the local (“Unix socket”) namespace.

Members:

  • path (string) – filesystem path to use

  • abstract (boolean, optional) – if true, this is a Linux abstract socket address. path will be prefixed by a null byte, and optionally padded with null bytes. Defaults to false. (Since 5.1)

  • tight (boolean, optional) – if false, pad an abstract socket address with enough null bytes to make it fill struct sockaddr_un member sun_path. Defaults to true. (Since 5.1)

Object VsockSocketAddress (Since: 2.8)

Captures a socket address in the vsock namespace.

Members:

  • cid (string) – unique host identifier

  • port (string) – port

Note

String types are used to allow for possible future hostname or service resolution support.

Object FdSocketAddress (Since: 1.2)

A file descriptor name or number.

Members:

  • str (string) – decimal is for file descriptor number, otherwise it’s a file descriptor name. Named file descriptors are permitted in monitor commands, in combination with the getfd command. Decimal file descriptors are permitted at startup or other contexts where no monitor context is active.

Object InetSocketAddressWrapper (Since: 1.3)
Members:
Object UnixSocketAddressWrapper (Since: 1.3)
Members:
Object VsockSocketAddressWrapper (Since: 2.8)
Members:
Object FdSocketAddressWrapper (Since: 1.3)
Members:
Object SocketAddressLegacy (Since: 1.3)

Captures the address of a socket, which could also be a named file descriptor

Members:
Enum SocketAddressType (Since: 2.9)

Available SocketAddress types

Values:

  • inet – Internet address

  • unix – Unix domain socket

  • vsock – VMCI address

  • fd – Socket file descriptor

Object SocketAddress (Since: 2.9)

Captures the address of a socket, which could also be a socket file descriptor

Members:

VM run state

Enum RunState

An enumeration of VM run states.

Values:

  • debug – QEMU is running on a debugger

  • finish-migrate – guest is paused to finish the migration process

  • inmigrate – guest is paused waiting for an incoming migration. Note that this state does not tell whether the machine will start at the end of the migration. This depends on the command-line -S option and any invocation of stop or cont that has happened since QEMU was started.

  • internal-error – An internal error that prevents further guest execution has occurred

  • io-error – the last IOP has failed and the device is configured to pause on I/O errors

  • paused – guest has been paused via the ‘stop’ command

  • postmigrate – guest is paused following a successful ‘migrate’

  • prelaunch – QEMU was started with -S and guest has not started

  • restore-vm – guest is paused to restore VM state

  • running – guest is actively running

  • save-vm – guest is paused to save the VM state

  • shutdown – guest is shut down (and -no-shutdown is in use)

  • suspended – guest is suspended (ACPI S3)

  • watchdog – the watchdog action is configured to pause and has been triggered

  • guest-panicked – guest has been panicked as a result of guest OS panic

  • colo – guest is paused to save/restore VM state under colo checkpoint, VM can not get into this state unless colo capability is enabled for migration. (since 2.8)

Enum ShutdownCause

An enumeration of reasons for a shutdown.

Values:

  • none – No shutdown request pending

  • host-error – An error prevents further use of guest

  • host-qmp-quit – Reaction to the QMP command quit

  • host-qmp-system-reset – Reaction to the QMP command system_reset

  • host-signal – Reaction to a signal, such as SIGINT

  • host-ui – Reaction to a UI event, like window close

  • guest-shutdown – Guest shutdown/suspend request, via ACPI or other hardware-specific means

  • guest-reset – Guest reset request, and command line turns that into a shutdown

  • guest-panic – Guest panicked, and command line turns that into a shutdown

  • subsystem-reset – Partial guest reset that does not trigger QMP events and ignores –no-reboot. This is useful for sanitizing hypercalls on s390 that are used during kexec/kdump/boot

  • snapshot-load – A snapshot is being loaded by the record & replay subsystem. This value is used only within QEMU. It doesn’t occur in QMP. (since 7.2)

Object StatusInfo (Since: 0.14)

Information about VM run state

Members:

  • running (boolean) – true if all VCPUs are runnable, false if not runnable

  • status (RunState) – the virtual machine RunState

Command query-status (Since: 0.14)

Query the run status of the VM

Return:

StatusInfo

Example:

-> { "execute": "query-status" }
<- { "return": { "running": true,
                 "status": "running" } }
Event SHUTDOWN (Since: 0.12)

Emitted when the virtual machine has shut down, indicating that QEMU is about to exit.

Members:

  • guest (boolean) – If true, the shutdown was triggered by a guest request (such as a guest-initiated ACPI shutdown request or other hardware-specific action) rather than a host request (such as sending QEMU a SIGINT). (since 2.10)

  • reason (ShutdownCause) – The ShutdownCause which resulted in the SHUTDOWN. (since 4.0)

Note

If the command-line option -no-shutdown has been specified, QEMU will not exit, and a STOP event will eventually follow the SHUTDOWN event.

Example:

<- { "event": "SHUTDOWN",
     "data": { "guest": true, "reason": "guest-shutdown" },
     "timestamp": { "seconds": 1267040730, "microseconds": 682951 } }
Event POWERDOWN (Since: 0.12)

Emitted when the virtual machine is powered down through the power control system, such as via ACPI.

Example:

<- { "event": "POWERDOWN",
     "timestamp": { "seconds": 1267040730, "microseconds": 682951 } }
Event RESET (Since: 0.12)

Emitted when the virtual machine is reset

Members:

  • guest (boolean) – If true, the reset was triggered by a guest request (such as a guest-initiated ACPI reboot request or other hardware-specific action) rather than a host request (such as the QMP command system_reset). (since 2.10)

  • reason (ShutdownCause) – The ShutdownCause of the RESET. (since 4.0)

Example:

<- { "event": "RESET",
     "data": { "guest": false, "reason": "guest-reset" },
     "timestamp": { "seconds": 1267041653, "microseconds": 9518 } }
Event STOP (Since: 0.12)

Emitted when the virtual machine is stopped

Example:

<- { "event": "STOP",
     "timestamp": { "seconds": 1267041730, "microseconds": 281295 } }
Event RESUME (Since: 0.12)

Emitted when the virtual machine resumes execution

Example:

<- { "event": "RESUME",
     "timestamp": { "seconds": 1271770767, "microseconds": 582542 } }
Event SUSPEND (Since: 1.1)

Emitted when guest enters a hardware suspension state, for example, S3 state, which is sometimes called standby state

Example:

<- { "event": "SUSPEND",
     "timestamp": { "seconds": 1344456160, "microseconds": 309119 } }
Event SUSPEND_DISK (Since: 1.2)

Emitted when guest enters a hardware suspension state with data saved on disk, for example, S4 state, which is sometimes called hibernate state

Note

QEMU shuts down (similar to event SHUTDOWN) when entering this state.

Example:

<- { "event": "SUSPEND_DISK",
     "timestamp": { "seconds": 1344456160, "microseconds": 309119 } }
Event WAKEUP (Since: 1.1)

Emitted when the guest has woken up from suspend state and is running

Example:

<- { "event": "WAKEUP",
     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }
Event WATCHDOG (Since: 0.13)

Emitted when the watchdog device’s timer is expired

Members:

Note

If action is “reset”, “shutdown”, or “pause” the WATCHDOG event is followed respectively by the RESET, SHUTDOWN, or STOP events.

Note

This event is rate-limited.

Example:

<- { "event": "WATCHDOG",
     "data": { "action": "reset" },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }
Enum WatchdogAction (Since: 2.1)

An enumeration of the actions taken when the watchdog device’s timer is expired

Values:

  • reset – system resets

  • shutdown – system shutdown, note that it is similar to powerdown, which tries to set to system status and notify guest

  • poweroff – system poweroff, the emulator program exits

  • pause – system pauses, similar to stop

  • debug – system enters debug state

  • none – nothing is done

  • inject-nmi – a non-maskable interrupt is injected into the first VCPU (all VCPUS on x86) (since 2.4)

Enum RebootAction (Since: 6.0)

Possible QEMU actions upon guest reboot

Values:

  • reset – Reset the VM

  • shutdown – Shutdown the VM and exit, according to the shutdown action

Enum ShutdownAction (Since: 6.0)

Possible QEMU actions upon guest shutdown

Values:

  • poweroff – Shutdown the VM and exit

  • pause – pause the VM

Enum PanicAction (Since: 6.0)
Values:

  • none – Continue VM execution

  • pause – Pause the VM

  • shutdown – Shutdown the VM and exit, according to the shutdown action

  • exit-failure – Shutdown the VM and exit with nonzero status (since 7.1)

Command watchdog-set-action (Since: 2.11)

Set watchdog action.

Arguments:

Example:

-> { "execute": "watchdog-set-action",
     "arguments": { "action": "inject-nmi" } }
<- { "return": {} }
Command set-action (Since: 6.0)

Set the actions that will be taken by the emulator in response to guest events.

Arguments:

Example:

-> { "execute": "set-action",
     "arguments": { "reboot": "shutdown",
                    "shutdown" : "pause",
                    "panic": "pause",
                    "watchdog": "inject-nmi" } }
<- { "return": {} }
Event GUEST_PANICKED (Since: 1.5)

Emitted when guest OS panic is detected

Members:

Example:

<- { "event": "GUEST_PANICKED",
     "data": { "action": "pause" },
     "timestamp": { "seconds": 1648245231, "microseconds": 900001 } }
Event GUEST_CRASHLOADED (Since: 5.0)

Emitted when guest OS crash loaded is detected

Members:

Example:

<- { "event": "GUEST_CRASHLOADED",
     "data": { "action": "run" },
     "timestamp": { "seconds": 1648245259, "microseconds": 893771 } }
Event GUEST_PVSHUTDOWN (Since: 9.1)

Emitted when guest submits a shutdown request via pvpanic interface

Example:

<- { "event": "GUEST_PVSHUTDOWN",
     "timestamp": { "seconds": 1648245259, "microseconds": 893771 } }
Enum GuestPanicAction (Since: 2.1)

An enumeration of the actions taken when guest OS panic is detected

Values:

  • pause – system pauses

  • poweroff – system powers off (since 2.8)

  • run – system continues to run (since 5.0)

Enum GuestPanicInformationType (Since: 2.9)

An enumeration of the guest panic information types

Values:

  • hyper-v – hyper-v guest panic information type

  • s390 – s390 guest panic information type (Since: 2.12)

  • tdx – tdx guest panic information type (Since: 10.1)

  • sev – AMD SEV-ES guest termination information type (Since: 11.0)

Object GuestPanicInformation (Since: 2.9)

Information about a guest panic

Members:
Object GuestPanicInformationHyperV (Since: 2.9)

Hyper-V specific guest panic information (HV crash MSRs)

Members:

  • arg1 (int) – for Windows, STOP code for the guest crash. For Linux, an error code.

  • arg2 (int) – for Windows, first argument of the STOP. For Linux, the guest OS ID, which has the kernel version in bits 16-47 and 0x8100 in bits 48-63.

  • arg3 (int) – for Windows, second argument of the STOP. For Linux, the program counter of the guest.

  • arg4 (int) – for Windows, third argument of the STOP. For Linux, the RAX register (x86) or the stack pointer (aarch64) of the guest.

  • arg5 (int) – for Windows, fourth argument of the STOP. For x86 Linux, the stack pointer of the guest.

Enum S390CrashReason (Since: 2.12)

Reason why the CPU is in a crashed state.

Values:

  • unknown – no crash reason was set

  • disabled-wait – the CPU has entered a disabled wait state

  • extint-loop – clock comparator or cpu timer interrupt with new PSW enabled for external interrupts

  • pgmint-loop – program interrupt with BAD new PSW

  • opint-loop – operation exception interrupt with invalid code at the program interrupt new PSW

Object GuestPanicInformationS390 (Since: 2.12)

S390 specific guest panic information (PSW)

Members:

  • core (int) – core id of the CPU that crashed

  • psw-mask (int) – control fields of guest PSW

  • psw-addr (int) – guest instruction address

  • reason (S390CrashReason) – guest crash reason

Object GuestPanicInformationTdx (Since: 10.1)

TDX Guest panic information specific to TDX, as specified in the “Guest-Hypervisor Communication Interface (GHCI) Specification”, section TDG.VP.VMCALL<ReportFatalError>.

Members:

  • error-code (int) – TD-specific error code

  • message (string) – Human-readable error message provided by the guest. Not to be trusted.

  • gpa (int, optional) – guest-physical address of a page that contains more verbose error information, as zero-terminated string. Present when the “GPA valid” bit (bit 63) is set in error-code.

Object GuestPanicInformationSev (Since: 11.0)

Information for AMD SEV-specific termination request (GHCB MSR contents)

Members:

  • set (int) – The reason code set provided by the guest

  • code (int) – The reason code provided by the guest

Event MEMORY_FAILURE (Since: 5.2)

Emitted when a memory failure occurs on host side.

Members:

Example:

<- { "event": "MEMORY_FAILURE",
     "data": { "recipient": "hypervisor",
               "action": "fatal",
               "flags": { "action-required": false,
                          "recursive": false } },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }
Enum MemoryFailureRecipient (Since: 5.2)

Hardware memory failure occurs, handled by recipient.

Values:

  • hypervisor – memory failure at QEMU process address space. (none guest memory, but used by QEMU itself).

  • guest – memory failure at guest memory,

Enum MemoryFailureAction (Since: 5.2)

Actions taken by QEMU in response to a hardware memory failure.

Values:

  • ignore – the memory failure could be ignored. This will only be the case for action-optional failures.

  • inject – memory failure occurred in guest memory, the guest enabled MCE handling mechanism, and QEMU could inject the MCE into the guest successfully.

  • fatal – the failure is unrecoverable. This occurs for action-required failures if the recipient is the hypervisor; QEMU will exit.

  • reset – the failure is unrecoverable but confined to the guest. This occurs if the recipient is a guest guest which is not ready to handle memory failures.

Object MemoryFailureFlags (Since: 5.2)

Additional information on memory failures.

Members:

  • action-required (boolean) – whether a memory failure event is action-required or action-optional (e.g. a failure during memory scrub).

  • recursive (boolean) – whether the failure occurred while the previous failure was still in progress.

Enum NotifyVmexitOption (Since: 7.2)

An enumeration of the options specified when enabling notify VM exit

Values:

  • run – enable the feature, do nothing and continue if the notify VM exit happens.

  • internal-error – enable the feature, raise a internal error if the notify VM exit happens.

  • disable – disable the feature.

Cryptography

Enum QCryptoTLSCredsEndpoint (Since: 2.5)

The type of network endpoint that will be using the credentials. Most types of credential require different setup / structures depending on whether they will be used in a server versus a client.

Values:

  • client – the network endpoint is acting as the client

  • server – the network endpoint is acting as the server

Enum QCryptoSecretFormat (Since: 2.6)

The data format that the secret is provided in

Values:

  • raw – raw bytes. When encoded in JSON only valid UTF-8 sequences can be used

  • base64 – arbitrary base64 encoded binary data

Enum QCryptoHashAlgo (Since: 2.6)

The supported algorithms for computing content digests

Values:

  • md5 – MD5. Should not be used in any new code, legacy compat only

  • sha1 – SHA-1. Should not be used in any new code, legacy compat only

  • sha224 – SHA-224. (since 2.7)

  • sha256 – SHA-256. Current recommended strong hash.

  • sha384 – SHA-384. (since 2.7)

  • sha512 – SHA-512. (since 2.7)

  • ripemd160 – RIPEMD-160. (since 2.7)

  • sm3 – SM3. (since 9.2.0)

Enum QCryptoCipherAlgo (Since: 2.6)

The supported algorithms for content encryption ciphers

Values:

  • aes-128 – AES with 128 bit / 16 byte keys

  • aes-192 – AES with 192 bit / 24 byte keys

  • aes-256 – AES with 256 bit / 32 byte keys

  • des – DES with 56 bit / 8 byte keys. Do not use except in VNC. (since 6.1)

  • 3des – 3DES(EDE) with 192 bit / 24 byte keys (since 2.9)

  • cast5-128 – Cast5 with 128 bit / 16 byte keys

  • serpent-128 – Serpent with 128 bit / 16 byte keys

  • serpent-192 – Serpent with 192 bit / 24 byte keys

  • serpent-256 – Serpent with 256 bit / 32 byte keys

  • twofish-128 – Twofish with 128 bit / 16 byte keys

  • twofish-192 – Twofish with 192 bit / 24 byte keys

  • twofish-256 – Twofish with 256 bit / 32 byte keys

  • sm4 – SM4 with 128 bit / 16 byte keys (since 9.0)

Enum QCryptoCipherMode (Since: 2.6)

The supported modes for content encryption ciphers

Values:

  • ecb – Electronic Code Book

  • cbc – Cipher Block Chaining

  • xts – XEX with tweaked code book and ciphertext stealing

  • ctr – Counter (Since 2.8)

Enum QCryptoIVGenAlgo (Since: 2.6)

The supported algorithms for generating initialization vectors for full disk encryption. The ‘plain’ generator should not be used for disks with sector numbers larger than 2^32, except where compatibility with pre-existing Linux dm-crypt volumes is required.

Values:

  • plain – 64-bit sector number truncated to 32-bits

  • plain64 – 64-bit sector number

  • essiv – 64-bit sector number encrypted with a hash of the encryption key

Enum QCryptoBlockFormat (Since: 2.6)

The supported full disk encryption formats

Values:

  • qcow – QCow/QCow2 built-in AES-CBC encryption. Use only for liberating data from old images.

  • luks – LUKS encryption format. Recommended for new images

Object QCryptoBlockOptionsBase (Since: 2.6)

The common options that apply to all full disk encryption formats

Members:
Object QCryptoBlockOptionsQCow (Since: 2.6)

The options that apply to QCow/QCow2 AES-CBC encryption format

Members:

  • key-secret (string, optional) – the ID of a QCryptoSecret object providing the decryption key. Mandatory except when probing image for metadata only.

Object QCryptoBlockOptionsLUKS (Since: 2.6)

The options that apply to LUKS encryption format

Members:

  • key-secret (string, optional) – the ID of a QCryptoSecret object providing the decryption key. Mandatory except when probing image for metadata only.

Object QCryptoBlockCreateOptionsLUKS (Since: 2.6)

The options that apply to LUKS encryption format initialization

Members:

  • cipher-alg (QCryptoCipherAlgo, optional) – the cipher algorithm for data encryption. Currently defaults to ‘aes-256’.

  • cipher-mode (QCryptoCipherMode, optional) – the cipher mode for data encryption. Currently defaults to ‘xts’

  • ivgen-alg (QCryptoIVGenAlgo, optional) – the initialization vector generator. Currently defaults to ‘plain64’

  • ivgen-hash-alg (QCryptoHashAlgo, optional) – the initialization vector generator hash. Currently defaults to ‘sha256’

  • hash-alg (QCryptoHashAlgo, optional) – the master key hash algorithm. Currently defaults to ‘sha256’

  • iter-time (int, optional) – number of milliseconds to spend in PBKDF passphrase processing. Currently defaults to 2000. (since 2.8)

  • The members of QCryptoBlockOptionsLUKS.

Object QCryptoBlockOpenOptions (Since: 2.6)

The options that are available for all encryption formats when opening an existing volume

Members:
Object QCryptoBlockCreateOptions (Since: 2.6)

The options that are available for all encryption formats when initializing a new volume

Members:
Object QCryptoBlockInfoBase (Since: 2.7)

The common information that applies to all full disk encryption formats

Members:
Object QCryptoBlockInfoLUKSSlot (Since: 2.7)

Information about the LUKS block encryption key slot options

Members:

  • active (boolean) – whether the key slot is currently in use

  • key-offset (int) – offset to the key material in bytes

  • iters (int, optional) – number of PBKDF2 iterations for key material

  • stripes (int, optional) – number of stripes for splitting key material

Object QCryptoBlockInfoLUKS (Since: 2.7)

Information about the LUKS block encryption options

Members:

  • cipher-alg (QCryptoCipherAlgo) – the cipher algorithm for data encryption

  • cipher-mode (QCryptoCipherMode) – the cipher mode for data encryption

  • ivgen-alg (QCryptoIVGenAlgo) – the initialization vector generator

  • ivgen-hash-alg (QCryptoHashAlgo, optional) – the initialization vector generator hash

  • hash-alg (QCryptoHashAlgo) – the master key hash algorithm

  • detached-header (boolean) – whether the LUKS header is detached (Since 9.0)

  • payload-offset (int) – offset to the payload data in bytes

  • master-key-iters (int) – number of PBKDF2 iterations for key material

  • uuid (string) – unique identifier for the volume

  • slots ([QCryptoBlockInfoLUKSSlot]) – information about each key slot

Object QCryptoBlockInfo (Since: 2.7)

Information about the block encryption options

Members:
Enum QCryptoBlockLUKSKeyslotState (Since: 5.1)

Defines state of keyslots that are affected by the update

Values:

  • active – The slots contain the given password and marked as active

  • inactive – The slots are erased (contain garbage) and marked as inactive

Object QCryptoBlockAmendOptionsLUKS (Since: 5.1)

This struct defines the update parameters that activate/de-activate set of keyslots

Members:

  • state (QCryptoBlockLUKSKeyslotState) – the desired state of the keyslots

  • new-secret (string, optional) – The ID of a QCryptoSecret object providing the password to be written into added active keyslots

  • old-secret (string, optional) – Optional (for deactivation only). If given will deactivate all keyslots that match password located in QCryptoSecret with this ID

  • iter-time (int, optional) – Optional (for activation only). Number of milliseconds to spend in PBKDF passphrase processing for the newly activated keyslot. Currently defaults to 2000.

  • keyslot (int, optional) –

    Optional. ID of the keyslot to activate/deactivate. For keyslot activation, keyslot should not be active already (this is unsafe to update an active keyslot), but possible if ‘force’ parameter is given. If keyslot is not given, first free keyslot will be written.

    For keyslot deactivation, this parameter specifies the exact keyslot to deactivate

  • secret (string, optional) – Optional. The ID of a QCryptoSecret object providing the password to use to retrieve current master key. Defaults to the same secret that was used to open the image

Object QCryptoBlockAmendOptions (Since: 5.1)

The options that are available for all encryption formats when amending encryption settings

Members:
Object SecretCommonProperties (Since: 2.6)

Properties for objects of classes derived from secret-common.

Members:

  • format (QCryptoSecretFormat, optional) – the data format that the secret is provided in (default: raw)

  • keyid (string, optional) – the name of another secret that should be used to decrypt the provided data. If not present, the data is assumed to be unencrypted.

  • iv (string, optional) – the random initialization vector used for encryption of this particular secret. Should be a base64 encrypted string of the 16-byte IV. Mandatory if keyid is given. Ignored if keyid is absent.

Object SecretProperties (Since: 2.6)

Properties for secret objects.

Either data or file must be provided, but not both.

Members:

  • data (string, optional) – the associated with the secret from

  • file (string, optional) – the filename to load the data associated with the secret from

  • The members of SecretCommonProperties.

Object SecretKeyringProperties (Since: 5.1)
Availability: CONFIG_SECRET_KEYRING

Properties for secret_keyring objects.

Members:

  • serial (int) – serial number that identifies a key to get from the kernel

  • The members of SecretCommonProperties.

Object TlsCredsProperties (Since: 2.5)

Properties for objects of classes derived from tls-creds.

Members:

  • verify-peer (boolean, optional) – if true the peer credentials will be verified once the handshake is completed. This is a no-op for anonymous credentials. (default: true)

  • dir (string, optional) – the path of the directory that contains the credential files

  • endpoint (QCryptoTLSCredsEndpoint, optional) – whether the QEMU network backend that uses the credentials will be acting as a client or as a server (default: client)

  • priority (string, optional) – a gnutls priority string as described at https://gnutls.org/manual/html_node/Priority-Strings.html

Object TlsCredsAnonProperties (Since: 2.5)

Properties for tls-creds-anon objects.

Members:
Object TlsCredsPskProperties (Since: 3.0)

Properties for tls-creds-psk objects.

Members:

  • username (string, optional) – the username which will be sent to the server. For clients only. If absent, “qemu” is sent and the property will read back as an empty string.

  • The members of TlsCredsProperties.

Object TlsCredsX509Properties (Since: 2.5)

Properties for tls-creds-x509 objects.

Members:

  • sanity-check (boolean, optional) – if true, perform some sanity checks before using the credentials (default: true)

  • passwordid (string, optional) – For the server-key.pem and client-key.pem files which contain sensitive private keys, it is possible to use an encrypted version by providing the passwordid parameter. This provides the ID of a previously created secret object containing the password for decryption.

  • The members of TlsCredsProperties.

Enum QCryptoAkCipherAlgo (Since: 7.1)

The supported algorithms for asymmetric encryption ciphers

Values:

  • rsa – RSA algorithm

Enum QCryptoAkCipherKeyType (Since: 7.1)

The type of asymmetric keys.

Values:

  • public – public key

  • private – private key

Enum QCryptoRSAPaddingAlgo (Since: 7.1)

The padding algorithm for RSA.

Values:

  • raw – no padding used

  • pkcs1 – pkcs1#v1.5

Object QCryptoAkCipherOptionsRSA (Since: 7.1)

Specific parameters for RSA algorithm.

Members:
Object QCryptoAkCipherOptions (Since: 7.1)

The options that are available for all asymmetric key algorithms when creating a new QCryptoAkCipher.

Members:

Background jobs

Enum JobType (Since: 1.7)

Type of a background job.

Values:
Enum JobStatus (Since: 2.12)

Indicates the present state of a given job in its lifetime.

Values:

  • undefined – Erroneous, default state. Should not ever be visible.

  • created – The job has been created, but not yet started.

  • running – The job is currently running.

  • paused – The job is running, but paused. The pause may be requested by either the QMP user or by internal processes.

  • ready – The job is running, but is ready for the user to signal completion. This is used for long-running jobs like mirror that are designed to run indefinitely.

  • standby – The job is ready, but paused. This is nearly identical to paused. The job may return to ready or otherwise be canceled.

  • waiting – The job is waiting for other jobs in the transaction to converge to the waiting state. This status will likely not be visible for the last job in a transaction.

  • pending – The job has finished its work, but has finalization steps that it needs to make prior to completing. These changes will require manual intervention via job-finalize if auto-finalize was set to false. These pending changes may still fail.

  • aborting – The job is in the process of being aborted, and will finish with an error. The job will afterwards report that it is concluded. This status may not be visible to the management process.

  • concluded – The job has finished all work. If auto-dismiss was set to false, the job will remain in this state until it is dismissed via job-dismiss.

  • null – The job is in the process of being dismantled. This state should not ever be visible externally.

Enum JobVerb (Since: 2.12)

Represents command verbs that can be applied to a job.

Values:
Event JOB_STATUS_CHANGE (Since: 3.0)

Emitted when a job transitions to a different status.

Members:

  • id (string) – The job identifier

  • status (JobStatus) – The new job status

Command job-pause (Since: 3.0)

Pause an active job.

This command returns immediately after marking the active job for pausing. Pausing an already paused job is an error.

The job will pause as soon as possible, which means transitioning into the PAUSED state if it was RUNNING, or into STANDBY if it was READY. The corresponding JOB_STATUS_CHANGE event will be emitted.

Cancelling a paused job automatically resumes it.

Arguments:

  • id (string) – The job identifier.

Command job-resume (Since: 3.0)

Resume a paused job.

This command returns immediately after resuming a paused job. Resuming an already running job is an error.

This command also clears the error status for block-jobs (stream, commit, mirror, backup).

Arguments:

  • id (string) – The job identifier.

Command job-cancel (Since: 3.0)

Instruct an active background job to cancel at the next opportunity. This command returns immediately after marking the active job for cancellation.

The job will cancel as soon as possible and then emit a JOB_STATUS_CHANGE event. Usually, the status will change to ABORTING, but it is possible that a job successfully completes (e.g. because it was almost done and there was no opportunity to cancel earlier than completing the job) and transitions to PENDING instead.

Arguments:

  • id (string) – The job identifier.

Command job-complete (Since: 3.0)

Manually trigger completion of an active job in the READY or STANDBY state. Completing the job in any other state is an error.

This is supported only for drive mirroring, where it also switches the device to write to the target path only. Note that drive mirroring includes drive-mirror, blockdev-mirror and block-commit job (only in case of “active commit”, when the node being committed is used by the guest). The ability to complete is signaled with a BLOCK_JOB_READY event.

This command completes an active background block operation synchronously. The ordering of this command’s return with the BLOCK_JOB_COMPLETED event is not defined. Note that if an I/O error occurs during the processing of this command: 1) the command itself will fail; 2) the error will be processed according to the rerror/werror arguments that were specified when starting the operation.

Arguments:

  • id (string) – The job identifier.

Command job-dismiss (Since: 3.0)

Deletes a job that is in the CONCLUDED state. This command only needs to be run explicitly for jobs that don’t have automatic dismiss enabled. In turn, automatic dismiss may be enabled only for jobs that have auto-dismiss option, which are drive-backup, blockdev-backup, drive-mirror, blockdev-mirror, block-commit and block-stream. auto-dismiss is enabled by default for these jobs.

This command will refuse to operate on any job that has not yet reached its terminal state, CONCLUDED. For jobs that make use of the JOB_READY event, job-cancel or job-complete will still need to be used as appropriate.

Arguments:

  • id (string) – The job identifier.

Command job-finalize (Since: 3.0)

Instructs all jobs in a transaction (or a single job if it is not part of any transaction) to finalize any graph changes and do any necessary cleanup. This command requires that all involved jobs are in the PENDING state.

For jobs in a transaction, instructing one job to finalize will force ALL jobs in the transaction to finalize, so it is only necessary to instruct a single member job to finalize.

The command is applicable only to jobs which have auto-finalize option and only when this option is set to false.

Arguments:

  • id (string) – The identifier of any job in the transaction, or of a job that is not part of any transaction.

Object JobInfo (Since: 3.0)

Information about a job.

Members:

  • id (string) – The job identifier

  • type (JobType) – The kind of job that is being performed

  • status (JobStatus) – Current job state/status

  • current-progress (int) – Progress made until now. The unit is arbitrary and the value can only meaningfully be used for the ratio of current-progress to total-progress. The value is monotonically increasing.

  • total-progress (int) – Estimated current-progress value at the completion of the job. This value can arbitrarily change while the job is running, in both directions.

  • error (string, optional) –

    If this field is present, the job failed; if it is still missing in the CONCLUDED state, this indicates successful completion.

    The value is a human-readable error message to describe the reason for the job failure. It should not be parsed by applications.

Command query-jobs (Since: 3.0)

Return information about jobs.

Return:

[JobInfo] – a list with info for each active job

Accelerators

Object KvmInfo (Since: 0.14)

Information about support for KVM acceleration

Members:

  • enabled (boolean) – true if KVM acceleration is active

  • present (boolean) – true if KVM acceleration is built into this executable

Command query-kvm (Since: 0.14)

Return information about KVM acceleration

Return:

KvmInfo

Example:

-> { "execute": "query-kvm" }
<- { "return": { "enabled": true, "present": true } }
Command x-accel-stats (Since: 10.1)
This command is unstable/experimental.

Query accelerator statistics

Features:

  • unstable – This command is meant for debugging.

Return:

HumanReadableText – accelerator statistics

Enum Accelerator (Since: 10.2.0)

Information about support for MSHV acceleration

Values:

  • hvf – Apple Hypervisor.framework

  • kvm – KVM

  • mshv – Hyper-V

  • nvmm – NetBSD NVMM

  • qtest – QTest (dummy accelerator)

  • tcg – TCG (dynamic translation)

  • whpx – Windows Hypervisor Platform

  • xen – Xen

Object AcceleratorInfo (Since: 10.2.0)

Information about support for various accelerators

Members:

  • enabled (Accelerator) – the accelerator that is in use

  • present ([Accelerator]) – the list of accelerators that are built into this executable

Command query-accelerators (Since: 10.2.0)

Return information about accelerators

Return:

AcceleratorInfo – AcceleratorInfo

Example:

-> { "execute": "query-accelerators" }
<- { "return": { "enabled": "mshv", "present": ["kvm", "mshv", "qtest", "tcg"] } }

Block devices

Block core (VM unrelated)

Object SnapshotInfo (Since: 1.3)
Members:

  • id (string) – unique snapshot id

  • name (string) – user chosen name

  • vm-state-size (int) – size of the VM state

  • date-sec (int) – UTC date of the snapshot in seconds

  • date-nsec (int) – fractional part in nano seconds to be used with date-sec

  • vm-clock-sec (int) – VM clock relative to boot in seconds

  • vm-clock-nsec (int) – fractional part in nano seconds to be used with vm-clock-sec

  • icount (int, optional) – Current instruction count. Appears when execution record/replay is enabled. Used for “time-traveling” to match the moment in the recorded execution with the snapshots. This counter may be obtained through query-replay command (since 5.2)

Object ImageInfoSpecificQCow2EncryptionBase (Since: 2.10)
Members:
Object ImageInfoSpecificQCow2Encryption (Since: 2.10)
Members:
Object ImageInfoSpecificQCow2 (Since: 1.7)
Members:

  • compat (string) – compatibility level

  • data-file (string, optional) – the filename of the external data file that is stored in the image and used as a default for opening the image (since: 4.0)

  • data-file-raw (boolean, optional) – True if the external data file must stay valid as a standalone (read-only) raw image without looking at qcow2 metadata (since: 4.0)

  • extended-l2 (boolean, optional) – true if the image has extended L2 entries; only valid for compat >= 1.1 (since 5.2)

  • lazy-refcounts (boolean, optional) – on or off; only valid for compat >= 1.1

  • corrupt (boolean, optional) – true if the image has been marked corrupt; only valid for compat >= 1.1 (since 2.2)

  • refcount-bits (int) – width of a refcount entry in bits (since 2.3)

  • encrypt (ImageInfoSpecificQCow2Encryption, optional) – details about encryption parameters; only set if image is encrypted (since 2.10)

  • bitmaps ([Qcow2BitmapInfo], optional) – A list of qcow2 bitmap details (since 4.0)

  • compression-type (Qcow2CompressionType) – the image cluster compression method (since 5.1)

Object ImageInfoSpecificVmdk (Since: 1.7)
Members:

  • create-type (string) – The create type of VMDK image

  • cid (int) – Content id of image

  • parent-cid (int) – Parent VMDK image’s cid

  • extents ([VmdkExtentInfo]) – List of extent files

Object VmdkExtentInfo (Since: 8.0)

Information about a VMDK extent file

Members:

  • filename (string) – Name of the extent file

  • format (string) – Extent type (e.g. FLAT or SPARSE)

  • virtual-size (int) – Number of bytes covered by this extent

  • cluster-size (int, optional) – Cluster size in bytes (for non-flat extents)

  • compressed (boolean, optional) – Whether this extent contains compressed data

Object ImageInfoSpecificRbd (Since: 6.1)
Members:

  • encryption-format (RbdImageEncryptionFormat, optional) – Image encryption format. If encryption is enabled for the image (see encrypted in BlockNodeInfo), this is the actual format in which the image is accessed. If encryption is not enabled, this is the result of probing when the image was opened, to give a suggestion which encryption format could be enabled. Note that probing results can be changed by the guest by writing a (possibly partial) encryption format header to the image, so don’t treat this information as trusted if the guest is not trusted.

Object ImageInfoSpecificFile (Since: 8.0)
Members:

  • extent-size-hint (int, optional) – Extent size hint (if available)

Enum ImageInfoSpecificKind (Since: 1.7)
Values:

  • luks – Since 2.7

  • rbd – Since 6.1

  • file – Since 8.0

  • qcow2 – Not documented

  • vmdk – Not documented

Object ImageInfoSpecificQCow2Wrapper (Since: 1.7)
Members:
Object ImageInfoSpecificVmdkWrapper (Since: 6.1)
Members:
Object ImageInfoSpecificLUKSWrapper (Since: 2.7)
Members:
Object ImageInfoSpecificRbdWrapper (Since: 6.1)
Members:
Object ImageInfoSpecificFileWrapper (Since: 8.0)
Members:
Object ImageInfoSpecific (Since: 1.7)

A discriminated record of image format specific information structures.

Members:
Object BlockLimitsInfo
Members:

  • request-alignment (int) – Alignment requirement, in bytes, for offset/length of I/O requests.

  • max-discard (int, optional) – Maximum number of bytes that can be discarded at once. If not present, there is no specific maximum.

  • discard-alignment (int, optional) – Optimal alignment for discard requests in bytes. Note that this doesn’t have to be a power of two. If not present, discards don’t have a alignment requirement different from request-alignment.

  • max-write-zeroes (int, optional) – Maximum number of bytes that can be zeroed out at once. If not present, there is no specific maximum.

  • write-zeroes-alignment (int, optional) – Optimal alignment for write zeroes requests in bytes. Note that this doesn’t have to be a power of two. If not present, write_zeroes doesn’t have a alignment requirement different from request-alignment.

  • opt-transfer (int, optional) – Optimal transfer length in bytes. If not present, there is no preferred size.

  • max-transfer (int, optional) – Maximal transfer length in bytes. If not present, there is no specific maximum.

  • max-hw-transfer (int, optional) – Maximal hardware transfer length in bytes. Applies whenever transfers to the device bypass the kernel I/O scheduler, for example with SG_IO. If not present, there is no specific maximum.

  • max-iov (int) – Maximum number of scatter/gather elements

  • max-hw-iov (int, optional) – Maximum number of scatter/gather elements allowed by the hardware. Applies whenever transfers to the device bypass the kernel I/O scheduler, for example with SG_IO. If not present, the hardware limits is unknown and max-iov is always used.

  • min-mem-alignment (int) – Minimal required memory alignment in bytes for zero-copy I/O to succeed. For unaligned requests, a bounce buffer will be used.

  • opt-mem-alignment (int) – Optimal memory alignment in bytes. This is the alignment used for any buffer allocations QEMU performs internally.

Object BlockNodeInfo (Since: 8.0)

Information about a QEMU image file

Members:

  • filename (string) – name of the image file

  • format (string) – format of the image file

  • virtual-size (int) – maximum capacity in bytes of the image

  • actual-size (int, optional) – actual size on disk in bytes of the image

  • dirty-flag (boolean, optional) – true if image is not cleanly closed

  • cluster-size (int, optional) – size of a cluster in bytes

  • encrypted (boolean, optional) – true if the image is encrypted

  • compressed (boolean, optional) – true if the image is compressed (Since 1.7)

  • backing-filename (string, optional) – name of the backing file

  • full-backing-filename (string, optional) – full path of the backing file

  • backing-filename-format (string, optional) – the format of the backing file

  • snapshots ([SnapshotInfo], optional) – list of VM snapshots

  • limits (BlockLimitsInfo, optional) – block limits that are used for I/O on the node (Since 10.2)

  • format-specific (ImageInfoSpecific, optional) – structure supplying additional format-specific information (since 1.7)

Object ImageInfo (Since: 1.3)

Information about a QEMU image file, and potentially its backing image

Members:
Object BlockChildInfo (Since: 8.0)

Information about all nodes in the block graph starting at some node, annotated with information about that node in relation to its parent.

Members:

  • name (string) – Child name of the root node in the BlockGraphInfo struct, in its role as the child of some undescribed parent node

  • info (BlockGraphInfo) – Block graph information starting at this node

Object BlockGraphInfo (Since: 8.0)

Information about all nodes in a block (sub)graph in the form of BlockNodeInfo data. The base BlockNodeInfo struct contains the information for the (sub)graph’s root node.

Members:
Object ImageCheck (Since: 1.4)

Information about a QEMU image file check

Members:

  • filename (string) – name of the image file checked

  • format (string) – format of the image file checked

  • check-errors (int) – number of unexpected errors occurred during check

  • image-end-offset (int, optional) – offset (in bytes) where the image ends, this field is present if the driver for the image format supports it

  • corruptions (int, optional) – number of corruptions found during the check if any

  • leaks (int, optional) – number of leaks found during the check if any

  • corruptions-fixed (int, optional) – number of corruptions fixed during the check if any

  • leaks-fixed (int, optional) – number of leaks fixed during the check if any

  • total-clusters (int, optional) – total number of clusters, this field is present if the driver for the image format supports it

  • allocated-clusters (int, optional) – total number of allocated clusters, this field is present if the driver for the image format supports it

  • fragmented-clusters (int, optional) – total number of fragmented clusters, this field is present if the driver for the image format supports it

  • compressed-clusters (int, optional) – total number of compressed clusters, this field is present if the driver for the image format supports it

Object MapEntry (Since: 2.6)

Mapping information from a virtual block range to a host file range

Members:

  • start (int) – virtual (guest) offset of the first byte described by this entry

  • length (int) – the number of bytes of the mapped virtual range

  • data (boolean) – reading the image will actually read data from a file (in particular, if offset is present this means that the sectors are not simply preallocated, but contain actual data in raw format)

  • zero (boolean) – whether the virtual blocks read as zeroes

  • compressed (boolean) – true if the data is stored compressed (since 8.2)

  • depth (int) – number of layers (0 = top image, 1 = top image’s backing file, …, n - 1 = bottom image (where n is the number of images in the chain)) before reaching one for which the range is allocated

  • present (boolean) – true if this layer provides the data, false if adding a backing layer could impact this region (since 6.1)

  • offset (int, optional) – if present, the image file stores the data for this range in raw format at the given (host) offset

  • filename (string, optional) – filename that is referred to by offset

Object BlockdevCacheInfo (Since: 2.3)

Cache mode information for a block device

Members:

  • writeback (boolean) – true if writeback mode is enabled

  • direct (boolean) – true if the host page cache is bypassed (O_DIRECT)

  • no-flush (boolean) – true if flush requests are ignored for the device

Object BlockdevChild (Since: 10.1)
Members:

  • child (string) – The name of the child, for example ‘file’ or ‘backing’.

  • node-name (string) – The name of the child’s block driver node.

Object BlockDeviceInfo (Since: 0.14)

Information about the backing device for a block device.

Members:

  • file (string) – the filename of the backing device

  • node-name (string) – the name of the block driver node (Since 2.0)

  • ro (boolean) – true if the backing device was open read-only

  • drv (string) – the name of the block format used to open the backing device. As of 0.14 this can be: ‘blkdebug’, ‘bochs’, ‘cloop’, ‘cow’, ‘dmg’, ‘file’, ‘file’, ‘ftp’, ‘ftps’, ‘host_cdrom’, ‘host_device’, ‘http’, ‘https’, ‘luks’, ‘nbd’, ‘parallels’, ‘qcow’, ‘qcow2’, ‘raw’, ‘vdi’, ‘vmdk’, ‘vpc’, ‘vvfat’ 2.2: ‘archipelago’ added, ‘cow’ dropped 2.3: ‘host_floppy’ deprecated 2.5: ‘host_floppy’ dropped 2.6: ‘luks’ added 2.8: ‘replication’ added, ‘tftp’ dropped 2.9: ‘archipelago’ dropped

  • backing_file (string, optional) – the name of the backing file (for copy-on-write)

  • backing_file_depth (int) – number of files in the backing file chain (since: 1.2)

  • children ([BlockdevChild]) – Information about child block nodes. (since: 10.1)

  • active (boolean) – true if the backend is active; typical cases for inactive backends are on the migration source instance after migration completes and on the destination before it completes. (since: 10.0)

  • encrypted (boolean) – true if the backing device is encrypted

  • detect_zeroes (BlockdevDetectZeroesOptions) – detect and optimize zero writes (Since 2.1)

  • bps (int) – total throughput limit in bytes per second is specified

  • bps_rd (int) – read throughput limit in bytes per second is specified

  • bps_wr (int) – write throughput limit in bytes per second is specified

  • iops (int) – total I/O operations per second is specified

  • iops_rd (int) – read I/O operations per second is specified

  • iops_wr (int) – write I/O operations per second is specified

  • image (ImageInfo) – the info of image used (since: 1.6)

  • bps_max (int, optional) – total throughput limit during bursts, in bytes (Since 1.7)

  • bps_rd_max (int, optional) – read throughput limit during bursts, in bytes (Since 1.7)

  • bps_wr_max (int, optional) – write throughput limit during bursts, in bytes (Since 1.7)

  • iops_max (int, optional) – total I/O operations per second during bursts, in bytes (Since 1.7)

  • iops_rd_max (int, optional) – read I/O operations per second during bursts, in bytes (Since 1.7)

  • iops_wr_max (int, optional) – write I/O operations per second during bursts, in bytes (Since 1.7)

  • bps_max_length (int, optional) – maximum length of the bps_max burst period, in seconds. (Since 2.6)

  • bps_rd_max_length (int, optional) – maximum length of the bps_rd_max burst period, in seconds. (Since 2.6)

  • bps_wr_max_length (int, optional) – maximum length of the bps_wr_max burst period, in seconds. (Since 2.6)

  • iops_max_length (int, optional) – maximum length of the iops burst period, in seconds. (Since 2.6)

  • iops_rd_max_length (int, optional) – maximum length of the iops_rd_max burst period, in seconds. (Since 2.6)

  • iops_wr_max_length (int, optional) – maximum length of the iops_wr_max burst period, in seconds. (Since 2.6)

  • iops_size (int, optional) – an I/O size in bytes (Since 1.7)

  • group (string, optional) – throttle group name (Since 2.4)

  • cache (BlockdevCacheInfo) – the cache mode used for the block device (since: 2.3)

  • write_threshold (int) – configured write threshold for the device. 0 if disabled. (Since 2.3)

  • dirty-bitmaps ([BlockDirtyInfo], optional) – dirty bitmaps information (only present if node has one or more dirty bitmaps) (Since 4.2)

Enum BlockDeviceIoStatus (Since: 1.0)

An enumeration of block device I/O status.

Values:

  • ok – The last I/O operation has succeeded

  • failed – The last I/O operation has failed

  • nospace – The last I/O operation has failed due to a no-space condition

Object BlockDirtyInfo (Since: 1.3)

Block dirty bitmap information.

Members:

  • name (string, optional) – the name of the dirty bitmap (Since 2.4)

  • count (int) – number of dirty bytes according to the dirty bitmap

  • granularity (int) – granularity of the dirty bitmap in bytes (since 1.4)

  • recording (boolean) – true if the bitmap is recording new writes from the guest. (since 4.0)

  • busy (boolean) – true if the bitmap is in-use by some operation (NBD or jobs) and cannot be modified via QMP or used by another operation. (since 4.0)

  • persistent (boolean) – true if the bitmap was stored on disk, is scheduled to be stored on disk, or both. (since 4.0)

  • inconsistent (boolean, optional) – true if this is a persistent bitmap that was improperly stored. Implies persistent to be true; recording and busy to be false. This bitmap cannot be used. To remove it, use block-dirty-bitmap-remove. (Since 4.0)

Enum Qcow2BitmapInfoFlags (Since: 4.0)

An enumeration of flags that a bitmap can report to the user.

Values:

  • in-use – This flag is set by any process actively modifying the qcow2 file, and cleared when the updated bitmap is flushed to the qcow2 image. The presence of this flag in an offline image means that the bitmap was not saved correctly after its last usage, and may contain inconsistent data.

  • auto – The bitmap must reflect all changes of the virtual disk by any application that would write to this qcow2 file.

Object Qcow2BitmapInfo (Since: 4.0)

Qcow2 bitmap information.

Members:

  • name (string) – the name of the bitmap

  • granularity (int) – granularity of the bitmap in bytes

  • flags ([Qcow2BitmapInfoFlags]) – flags of the bitmap

Object BlockLatencyHistogramInfo (Since: 4.0)

Block latency histogram.

Members:

  • boundaries ([int]) – list of interval boundary values in nanoseconds, all greater than zero and in ascending order. For example, the list [10, 50, 100] produces the following histogram intervals: [0, 10), [10, 50), [50, 100), [100, +inf).

  • bins ([int]) –

    list of io request counts corresponding to histogram intervals, one more element than boundaries has. For the example above, bins may be something like [3, 1, 5, 2], and corresponding histogram looks like:

    5|           *
4|           *
3| *         *
2| *         *    *
1| *    *    *    *
 +------------------
     10   50   100

Object BlockInfo (Since: 0.14)

Block device information. This structure describes a virtual device and the backing device associated with it.

Members:

  • device (string) – The device name associated with the virtual device.

  • qdev (string, optional) – The qdev ID, or if no ID is assigned, the QOM path of the block device. (since 2.10)

  • type (string) – This field is returned only for compatibility reasons, it should not be used (always returns ‘unknown’)

  • removable (boolean) – True if the device supports removable media.

  • locked (boolean) – True if the guest has locked this device from having its media removed

  • tray_open (boolean, optional) – True if the device’s tray is open (only present if it has a tray)

  • io-status (BlockDeviceIoStatus, optional) – BlockDeviceIoStatus. Only present if the device supports it and the VM is configured to stop on errors (supported device models: virtio-blk, IDE, SCSI except scsi-generic)

  • inserted (BlockDeviceInfo, optional) – BlockDeviceInfo describing the device if media is present

Object BlockMeasureInfo (Since: 2.10)

Image file size calculation information. This structure describes the size requirements for creating a new image file.

The size requirements depend on the new image file format. File size always equals virtual disk size for the ‘raw’ format, even for sparse POSIX files. Compact formats such as ‘qcow2’ represent unallocated and zero regions efficiently so file size may be smaller than virtual disk size.

The values are upper bounds that are guaranteed to fit the new image file. Subsequent modification, such as internal snapshot or further bitmap creation, may require additional space and is not covered here.

Members:

  • required (int) – Size required for a new image file, in bytes, when copying just allocated guest-visible contents.

  • fully-allocated (int) – Image file size, in bytes, once data has been written to all sectors, when copying just guest-visible contents.

  • bitmaps (int, optional) – Additional size required if all the top-level bitmap metadata in the source image were to be copied to the destination, present only when source and destination both support persistent bitmaps. (since 5.1)

Command query-block (Since: 0.14)

Get a list of BlockInfo for all virtual block devices.

Arguments:

  • flat (boolean, optional) – Omit nested data about the backing image, i.e. BlockInfo member ‘inserted.image.backing-image’ will be absent. Default is false. (Since 11.0)

Return:

[BlockInfo] – a list describing each virtual block device. Filter nodes that were created implicitly are skipped over.

Example:

-> { "execute": "query-block" }
<- {
      "return":[
         {
            "io-status": "ok",
            "device":"ide0-hd0",
            "locked":false,
            "removable":false,
            "inserted":{
               "ro":false,
               "drv":"qcow2",
               "encrypted":false,
               "file":"disks/test.qcow2",
               "backing_file_depth":1,
               "bps":1000000,
               "bps_rd":0,
               "bps_wr":0,
               "iops":1000000,
               "iops_rd":0,
               "iops_wr":0,
               "bps_max": 8000000,
               "bps_rd_max": 0,
               "bps_wr_max": 0,
               "iops_max": 0,
               "iops_rd_max": 0,
               "iops_wr_max": 0,
               "iops_size": 0,
               "detect_zeroes": "on",
               "write_threshold": 0,
               "image":{
                  "filename":"disks/test.qcow2",
                  "format":"qcow2",
                  "virtual-size":2048000,
                  "backing_file":"base.qcow2",
                  "full-backing-filename":"disks/base.qcow2",
                  "backing-filename-format":"qcow2",
                  "snapshots":[
                     {
                        "id": "1",
                        "name": "snapshot1",
                        "vm-state-size": 0,
                        "date-sec": 10000200,
                        "date-nsec": 12,
                        "vm-clock-sec": 206,
                        "vm-clock-nsec": 30
                     }
                  ],
                  "backing-image":{
                      "filename":"disks/base.qcow2",
                      "format":"qcow2",
                      "virtual-size":2048000
                  }
               }
            },
            "qdev": "ide_disk",
            "type":"unknown"
         },
         {
            "io-status": "ok",
            "device":"ide1-cd0",
            "locked":false,
            "removable":true,
            "qdev": "/machine/unattached/device[23]",
            "tray_open": false,
            "type":"unknown"
         },
         {
            "device":"floppy0",
            "locked":false,
            "removable":true,
            "qdev": "/machine/unattached/device[20]",
            "type":"unknown"
         },
         {
            "device":"sd0",
            "locked":false,
            "removable":true,
            "type":"unknown"
         }
      ]
   }
Object BlockDeviceTimedStats (Since: 2.5)

Statistics of a block device during a given interval of time.

Members:

  • interval_length (int) – Interval used for calculating the statistics, in seconds.

  • min_rd_latency_ns (int) – Minimum latency of read operations in the defined interval, in nanoseconds.

  • min_wr_latency_ns (int) – Minimum latency of write operations in the defined interval, in nanoseconds.

  • min_zone_append_latency_ns (int) – Minimum latency of zone append operations in the defined interval, in nanoseconds (since 8.1)

  • min_flush_latency_ns (int) – Minimum latency of flush operations in the defined interval, in nanoseconds.

  • max_rd_latency_ns (int) – Maximum latency of read operations in the defined interval, in nanoseconds.

  • max_wr_latency_ns (int) – Maximum latency of write operations in the defined interval, in nanoseconds.

  • max_zone_append_latency_ns (int) – Maximum latency of zone append operations in the defined interval, in nanoseconds (since 8.1)

  • max_flush_latency_ns (int) – Maximum latency of flush operations in the defined interval, in nanoseconds.

  • avg_rd_latency_ns (int) – Average latency of read operations in the defined interval, in nanoseconds.

  • avg_wr_latency_ns (int) – Average latency of write operations in the defined interval, in nanoseconds.

  • avg_zone_append_latency_ns (int) – Average latency of zone append operations in the defined interval, in nanoseconds (since 8.1)

  • avg_flush_latency_ns (int) – Average latency of flush operations in the defined interval, in nanoseconds.

  • avg_rd_queue_depth (number) – Average number of pending read operations in the defined interval.

  • avg_wr_queue_depth (number) – Average number of pending write operations in the defined interval.

  • avg_zone_append_queue_depth (number) – Average number of pending zone append operations in the defined interval (since 8.1).

Object BlockDeviceStats (Since: 0.14)

Statistics of a virtual block device or a block backing device.

Members:

  • rd_bytes (int) – The number of bytes read by the device.

  • wr_bytes (int) – The number of bytes written by the device.

  • zone_append_bytes (int) – The number of bytes appended by the zoned devices (since 8.1)

  • unmap_bytes (int) – The number of bytes unmapped by the device (Since 4.2)

  • rd_operations (int) – The number of read operations performed by the device.

  • wr_operations (int) – The number of write operations performed by the device.

  • zone_append_operations (int) – The number of zone append operations performed by the zoned devices (since 8.1)

  • flush_operations (int) – The number of cache flush operations performed by the device (since 0.15)

  • unmap_operations (int) – The number of unmap operations performed by the device (Since 4.2)

  • rd_total_time_ns (int) – Total time spent on reads in nanoseconds (since 0.15)

  • wr_total_time_ns (int) – Total time spent on writes in nanoseconds (since 0.15)

  • zone_append_total_time_ns (int) – Total time spent on zone append writes in nanoseconds (since 8.1)

  • flush_total_time_ns (int) – Total time spent on cache flushes in nanoseconds (since 0.15).

  • unmap_total_time_ns (int) – Total time spent on unmap operations in nanoseconds (Since 4.2)

  • wr_highest_offset (int) – The offset after the greatest byte written to the device. The intended use of this information is for growable sparse files (like qcow2) that are used on top of a physical device.

  • rd_merged (int) – Number of read requests that have been merged into another request (Since 2.3).

  • wr_merged (int) – Number of write requests that have been merged into another request (Since 2.3).

  • zone_append_merged (int) – Number of zone append requests that have been merged into another request (since 8.1)

  • unmap_merged (int) – Number of unmap requests that have been merged into another request (Since 4.2)

  • idle_time_ns (int, optional) – Time since the last I/O operation, in nanoseconds. If the field is absent it means that there haven’t been any operations yet (Since 2.5).

  • failed_rd_operations (int) – The number of failed read operations performed by the device (Since 2.5)

  • failed_wr_operations (int) – The number of failed write operations performed by the device (Since 2.5)

  • failed_zone_append_operations (int) – The number of failed zone append write operations performed by the zoned devices (since 8.1)

  • failed_flush_operations (int) – The number of failed flush operations performed by the device (Since 2.5)

  • failed_unmap_operations (int) – The number of failed unmap operations performed by the device (Since 4.2)

  • invalid_rd_operations (int) – The number of invalid read operations performed by the device (Since 2.5)

  • invalid_wr_operations (int) – The number of invalid write operations performed by the device (Since 2.5)

  • invalid_zone_append_operations (int) – The number of invalid zone append operations performed by the zoned device (since 8.1)

  • invalid_flush_operations (int) – The number of invalid flush operations performed by the device (Since 2.5)

  • invalid_unmap_operations (int) – The number of invalid unmap operations performed by the device (Since 4.2)

  • account_invalid (boolean) – Whether invalid operations are included in the last access statistics (Since 2.5)

  • account_failed (boolean) – Whether failed operations are included in the latency and last access statistics (Since 2.5)

  • timed_stats ([BlockDeviceTimedStats]) – Statistics specific to the set of previously defined intervals of time (Since 2.5)

  • rd_latency_histogram (BlockLatencyHistogramInfo, optional) – BlockLatencyHistogramInfo. (Since 4.0)

  • wr_latency_histogram (BlockLatencyHistogramInfo, optional) – BlockLatencyHistogramInfo. (Since 4.0)

  • zone_append_latency_histogram (BlockLatencyHistogramInfo, optional) – BlockLatencyHistogramInfo. (since 8.1)

  • flush_latency_histogram (BlockLatencyHistogramInfo, optional) – BlockLatencyHistogramInfo. (Since 4.0)

Object BlockStatsSpecificFile (Since: 4.2)

File driver statistics

Members:

  • discard-nb-ok (int) – The number of successful discard operations performed by the driver.

  • discard-nb-failed (int) – The number of failed discard operations performed by the driver.

  • discard-bytes-ok (int) – The number of bytes discarded by the driver.

Object BlockStatsSpecificNvme (Since: 5.2)

NVMe driver statistics

Members:

  • completion-errors (int) – The number of completion errors.

  • aligned-accesses (int) – The number of aligned accesses performed by the driver.

  • unaligned-accesses (int) – The number of unaligned accesses performed by the driver.

Object BlockStatsSpecific (Since: 4.2)

Block driver specific statistics

Members:
Object BlockStats (Since: 0.14)

Statistics of a virtual block device or a block backing device.

Members:

  • device (string, optional) – If the stats are for a virtual block device, the name corresponding to the virtual block device.

  • node-name (string, optional) – The node name of the device. (Since 2.3)

  • qdev (string, optional) – The qdev ID, or if no ID is assigned, the QOM path of the block device. (since 3.0)

  • stats (BlockDeviceStats) – A BlockDeviceStats for the device.

  • driver-specific (BlockStatsSpecific, optional) – Optional driver-specific stats. (Since 4.2)

  • parent (BlockStats, optional) – This describes the file block device if it has one. Contains recursively the statistics of the underlying protocol (e.g. the host file for a qcow2 image). If there is no underlying protocol, this field is omitted

  • backing (BlockStats, optional) – This describes the backing block device if it has one. (Since 2.0)

Command query-blockstats (Since: 0.14)

Query the BlockStats for all virtual block devices.

Arguments:

  • query-nodes (boolean, optional) – If true, the command will query all the block nodes that have a node name, in a list which will include “parent” information, but not “backing”. If false or omitted, the behavior is as before - query all the device backends, recursively including their “parent” and “backing”. Filter nodes that were created implicitly are skipped over in this mode. (Since 2.3)

Return:

[BlockStats] – A list of statistics for each virtual block device.

Example:

-> { "execute": "query-blockstats" }
<- {
      "return":[
         {
            "device":"ide0-hd0",
            "parent":{
               "stats":{
                  "wr_highest_offset":3686448128,
                  "wr_bytes":9786368,
                  "wr_operations":751,
                  "rd_bytes":122567168,
                  "rd_operations":36772
                  "wr_total_times_ns":313253456
                  "rd_total_times_ns":3465673657
                  "flush_total_times_ns":49653
                  "flush_operations":61,
                  "rd_merged":0,
                  "wr_merged":0,
                  "idle_time_ns":2953431879,
                  "account_invalid":true,
                  "account_failed":false
               }
            },
            "stats":{
               "wr_highest_offset":2821110784,
               "wr_bytes":9786368,
               "wr_operations":692,
               "rd_bytes":122739200,
               "rd_operations":36604
               "flush_operations":51,
               "wr_total_times_ns":313253456
               "rd_total_times_ns":3465673657
               "flush_total_times_ns":49653,
               "rd_merged":0,
               "wr_merged":0,
               "idle_time_ns":2953431879,
               "account_invalid":true,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[23]"
         },
         {
            "device":"ide1-cd0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[24]"
         },
         {
            "device":"floppy0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[16]"
         },
         {
            "device":"sd0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            }
         }
      ]
   }
Enum BlockdevOnError (Since: 1.3)

An enumeration of possible behaviors for errors on I/O operations. The exact meaning depends on whether the I/O was initiated by a guest or by a block job

Values:

  • report – for guest operations, report the error to the guest; for jobs, cancel the job

  • ignore – ignore the error, only report a QMP event (BLOCK_IO_ERROR or BLOCK_JOB_ERROR). The backup, mirror and commit block jobs retry the failing request later and may still complete successfully. The stream block job continues to stream and will complete with an error.

  • enospc – same as stop on ENOSPC, same as report otherwise.

  • stop – for guest operations, stop the virtual machine; for jobs, pause the job

  • auto – inherit the error handling policy of the backend (since: 2.7)

Enum MirrorSyncMode (Since: 1.3)

An enumeration of possible behaviors for the initial synchronization phase of storage mirroring.

Values:

  • top – copies data in the topmost image to the destination

  • full – copies data from all images to the destination

  • none – only copy data written from now on

  • incremental – only copy data described by the dirty bitmap. (since: 2.4)

  • bitmap – only copy data described by the dirty bitmap. Behavior on completion is determined by the BitmapSyncMode. (since: 4.2)

Enum BitmapSyncMode (Since: 4.2)

An enumeration of possible behaviors for the synchronization of a bitmap when used for data copy operations.

Values:

  • on-success – The bitmap is only synced when the operation is successful. This is the behavior always used for incremental backups.

  • never – The bitmap is never synchronized with the operation, and is treated solely as a read-only manifest of blocks to copy.

  • always – The bitmap is always synchronized with the operation, regardless of whether or not the operation was successful.

Enum MirrorCopyMode (Since: 3.0)

An enumeration whose values tell the mirror block job when to trigger writes to the target.

Values:

  • background – copy data in background only.

  • write-blocking – when data is written to the source, write it (synchronously) to the target as well. In addition, data is copied in background just like in background mode.

Object BlockJobInfoMirror (Since: 8.2)

Information specific to mirror block jobs.

Members:

  • actively-synced (boolean) – Whether the source is actively synced to the target, i.e. same data and new writes are done synchronously to both.

Object BlockJobInfo (Since: 1.1)

Information about a long-running block device operation.

Members:

  • type (JobType) – the job type (‘stream’ for image streaming)

  • device (string) – The job identifier. Originally the device name but other values are allowed since QEMU 2.7

  • len (int) – Estimated offset value at the completion of the job. This value can arbitrarily change while the job is running, in both directions.

  • offset (int) – Progress made until now. The unit is arbitrary and the value can only meaningfully be used for the ratio of offset to len. The value is monotonically increasing.

  • busy (boolean) – false if the job is known to be in a quiescent state, with no pending I/O. (Since 1.3)

  • paused (boolean) – whether the job is paused or, if busy is true, will pause itself as soon as possible. (Since 1.3)

  • speed (int) – the rate limit, bytes per second

  • io-status (BlockDeviceIoStatus) – the status of the job (since 1.3)

  • ready (boolean) – true if the job may be completed (since 2.2)

  • status (JobStatus) – Current job state/status (since 2.12)

  • auto-finalize (boolean) – Job will finalize itself when PENDING, moving to the CONCLUDED state. (since 2.12)

  • auto-dismiss (boolean) – Job will dismiss itself when CONCLUDED, and disappear. (since 2.12)

  • error (string, optional) – Error information if the job did not complete successfully. Not set if the job completed successfully. (since 2.12.1)

  • When type is mirror: The members of BlockJobInfoMirror.

Command query-block-jobs (Since: 1.1)

Return information about long-running block device operations.

Return:

[BlockJobInfo] – a list of job info for each active block job

Command block_resize (Since: 0.14)

Resize a block image while a guest is running.

Either device or node-name must be set but not both.

Arguments:

  • device (string, optional) – the name of the device to get the image resized

  • node-name (string, optional) – graph node name to get the image resized (Since 2.0)

  • size (int) – new image size in bytes

Errors:

  • If device is not a valid block device, DeviceNotFound

Example:

-> { "execute": "block_resize",
     "arguments": { "device": "scratch", "size": 1073741824 } }
<- { "return": {} }
Enum NewImageMode (Since: 1.1)

An enumeration that tells QEMU how to set the backing file path in a new image file.

Values:

  • existing – QEMU should look for an existing image file.

  • absolute-paths – QEMU should create a new image with absolute paths for the backing file. If there is no backing file available, the new image will not be backed either.

Object BlockdevSnapshotSync

Either device or node-name must be set but not both.

Members:

  • device (string, optional) – the name of the device to take a snapshot of.

  • node-name (string, optional) – graph node name to generate the snapshot from (Since 2.0)

  • snapshot-file (string) – the target of the new overlay image. If the file exists, or if it is a device, the overlay will be created in the existing file/device. Otherwise, a new file will be created.

  • snapshot-node-name (string, optional) – the graph node name of the new image (Since 2.0)

  • format (string, optional) – the format of the overlay image, default is ‘qcow2’.

  • mode (NewImageMode, optional) – whether and how QEMU should create a new image, default is ‘absolute-paths’.

Object BlockdevSnapshot (Since: 2.5)
Members:

  • node (string) – device or node name that will have a snapshot taken.

  • overlay (string) – reference to the existing block device that will become the overlay of node, as part of taking the snapshot. It must not have a current backing file (this can be achieved by passing “backing”: null to blockdev-add).

Object BackupPerf (Since: 6.0)

Optional parameters for backup. These parameters don’t affect functionality, but may significantly affect performance.

Members:

  • use-copy-range (boolean, optional) – Use copy offloading. Default false.

  • max-workers (int, optional) – Maximum number of parallel requests for the sustained background copying process. Doesn’t influence copy-before-write operations. Default 64.

  • max-chunk (int, optional) – Maximum request length for the sustained background copying process. Doesn’t influence copy-before-write operations. 0 means unlimited. If max-chunk is non-zero then it should not be less than job cluster size which is calculated as maximum of target image cluster size and 64k. Default 0.

  • min-cluster-size (int, optional) – Minimum size of blocks used by copy-before-write and background copy operations. Has to be a power of 2. No effect if smaller than the maximum of the target’s cluster size and 64 KiB. Default 0. (Since 9.2)

Object BackupCommon (Since: 4.2)
Members:

  • job-id (string, optional) – identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

  • device (string) – the device name or node-name of a root node which should be copied.

  • sync (MirrorSyncMode) – what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, from a dirty bitmap, or only new I/O).

  • speed (int, optional) – the maximum speed, in bytes per second. The default is 0, for unlimited.

  • bitmap (string, optional) – The name of a dirty bitmap to use. Must be present if sync is “bitmap” or “incremental”. Can be present if sync is “full” or “top”. Must not be present otherwise. (Since 2.4 (drive-backup), 3.1 (blockdev-backup))

  • bitmap-mode (BitmapSyncMode, optional) – Specifies the type of data the bitmap should contain after the operation concludes. Must be present if a bitmap was provided, must not be present otherwise. (Since 4.2)

  • compress (boolean, optional) – true to compress data, if the target format supports it. (default: false) (since 2.8)

  • on-source-error (BlockdevOnError, optional) – the action to take on an error on the source, default ‘report’. ‘stop’ and ‘enospc’ can only be used if the block device supports io-status (see BlockInfo).

  • on-target-error (BlockdevOnError, optional) – the action to take on an error on the target, default ‘report’ (no limitations, since this applies to a different block device than device).

  • on-cbw-error (OnCbwError, optional) – policy defining behavior on I/O errors in copy-before-write jobs; defaults to break-guest-write. (Since 10.1)

  • auto-finalize (boolean, optional) – When false, this job will wait in a PENDING state after it has finished its work, waiting for job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 2.12)

  • auto-dismiss (boolean, optional) – When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits job-dismiss. When true, this job will automatically disappear without user intervention. Defaults to true. (Since 2.12)

  • filter-node-name (string, optional) – the node name that should be assigned to the filter driver that the backup job inserts into the graph above node specified by drive. If this option is not given, a node name is autogenerated. (Since: 4.2)

  • discard-source (boolean, optional) – Discard blocks on source which have already been copied to the target. (Since 9.1)

  • x-perf (BackupPerf, optional) – Performance options. (Since 6.0)

Features:

  • unstable – Member x-perf is experimental.

Note

on-source-error and on-target-error only affect background I/O. If an error occurs during a guest write request, the device’s rerror/werror actions will be used.

Object DriveBackup (Since: 1.6)
Members:

  • target (string) – the target of the new image. If the file exists, or if it is a device, the existing file/device will be used as the new destination. If it does not exist, a new file will be created.

  • format (string, optional) – the format of the new destination, default is to probe if mode is ‘existing’, else the format of the source

  • mode (NewImageMode, optional) – whether and how QEMU should create a new image, default is ‘absolute-paths’.

  • The members of BackupCommon.

Object BlockdevBackup (Since: 2.3)
Members:

  • target (string) – the device name or node-name of the backup target node.

  • The members of BackupCommon.

Command blockdev-snapshot-sync (Since: 0.14)

Takes a synchronous snapshot of a block device.

Arguments:
Errors:

  • If device is not a valid block device, DeviceNotFound

Example:

-> { "execute": "blockdev-snapshot-sync",
     "arguments": { "device": "ide-hd0",
                    "snapshot-file":
                    "/some/place/my-image",
                    "format": "qcow2" } }
<- { "return": {} }
Command blockdev-snapshot (Since: 2.5)

Takes a snapshot of a block device.

Take a snapshot, by installing ‘node’ as the backing image of ‘overlay’. Additionally, if ‘node’ is associated with a block device, the block device changes to using ‘overlay’ as its new active image.

Arguments:
Features:

  • allow-write-only-overlay – If present, the check whether this operation is safe was relaxed so that it can be used to change backing file of a destination of a blockdev-mirror. (since 5.0)

Example:

-> { "execute": "blockdev-add",
     "arguments": { "driver": "qcow2",
                    "node-name": "node1534",
                    "file": { "driver": "file",
                              "filename": "hd1.qcow2" },
                    "backing": null } }

<- { "return": {} }

-> { "execute": "blockdev-snapshot",
     "arguments": { "node": "ide-hd0",
                    "overlay": "node1534" } }
<- { "return": {} }
Command change-backing-file (Since: 2.1)

Change the backing file in the image file metadata. This does not cause QEMU to reopen the image file to reparse the backing filename (it may, however, perform a reopen to change permissions from r/o -> r/w -> r/o, if needed). The new backing file string is written into the image file metadata, and the QEMU internal strings are updated.

Arguments:

  • image-node-name (string) – The name of the block driver state node of the image to modify. The “device” argument is used to verify “image-node-name” is in the chain described by “device”.

  • device (string) – The device name or node-name of the root node that owns image-node-name.

  • backing-file (string) – The string to write as the backing file. This string is not validated, so care should be taken when specifying the string or the image chain may not be able to be reopened again.

Errors:

  • If “device” does not exist or cannot be determined, DeviceNotFound

Command block-commit (Since: 1.3)

Live commit of data from overlay image nodes into backing nodes - i.e., writes data between ‘top’ and ‘base’ into ‘base’.

If top == base, that is an error. If top has no overlays on top of it, or if it is in use by a writer, the job will not be completed by itself. The user needs to complete the job with the job-complete command after getting the ready event. (Since 2.0)

If the base image is smaller than top, then the base image will be resized to be the same size as top. If top is smaller than the base image, the base will not be truncated. If you want the base image size to match the size of the smaller top, you can safely truncate it yourself once the commit operation successfully completes.

Arguments:

  • job-id (string, optional) – identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

  • device (string) – the device name or node-name of a root node

  • base-node (string, optional) – The node name of the backing image to write data into. If not specified, this is the deepest backing image. (since: 3.1)

  • base (string, optional) – Same as base-node, except that it is a file name rather than a node name. This must be the exact filename string that was used to open the node; other strings, even if addressing the same file, are not accepted

  • top-node (string, optional) – The node name of the backing image within the image chain which contains the topmost data to be committed down. If not specified, this is the active layer. (since: 3.1)

  • top (string, optional) – Same as top-node, except that it is a file name rather than a node name. This must be the exact filename string that was used to open the node; other strings, even if addressing the same file, are not accepted

  • backing-file (string, optional) –

    The backing file string to write into the overlay image of ‘top’. If ‘top’ does not have an overlay image, or if ‘top’ is in use by a writer, specifying a backing file string is an error.

    This filename is not validated. If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.

    If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol. (Since 2.1)

  • backing-mask-protocol (boolean, optional) – If true, replace any protocol mentioned in the ‘backing file format’ with ‘raw’, rather than storing the protocol name as the backing format. Can be used even when no image header will be updated (default false; since 9.0).

  • speed (int, optional) – the maximum speed, in bytes per second

  • on-error (BlockdevOnError, optional) – the action to take on an error. ‘ignore’ means that the request should be retried. (default: report; since: 5.0)

  • filter-node-name (string, optional) – the node name that should be assigned to the filter driver that the commit job inserts into the graph above top. If this option is not given, a node name is autogenerated. (Since: 2.9)

  • auto-finalize (boolean, optional) – When false, this job will wait in a PENDING state after it has finished its work, waiting for job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 3.1)

  • auto-dismiss (boolean, optional) – When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits job-dismiss. When true, this job will automatically disappear without user intervention. Defaults to true. (Since 3.1)

Features:

  • deprecated – Members base and top are deprecated. Use base-node and top-node instead.

Errors:

  • If device does not exist, DeviceNotFound

Example:

-> { "execute": "block-commit",
     "arguments": { "device": "virtio0",
                    "top": "/tmp/snap1.qcow2" } }
<- { "return": {} }
Command drive-backup (Since: 1.6)
This command is deprecated.

Start a point-in-time copy of a block device to a new destination. The status of ongoing drive-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value ‘backup’. The operation can be stopped before it has completed using the job-cancel or block-job-cancel command.

Arguments:
Features:
Errors:

  • If device is not a valid block device, GenericError

Example:

-> { "execute": "drive-backup",
     "arguments": { "device": "drive0",
                    "sync": "full",
                    "target": "backup.img" } }
<- { "return": {} }
Command blockdev-backup (Since: 2.3)

Start a point-in-time copy of a block device to a new destination. The status of ongoing blockdev-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value ‘backup’. The operation can be stopped before it has completed using the job-cancel or block-job-cancel command.

Arguments:
Errors:

  • If device is not a valid block device, DeviceNotFound

Example:

-> { "execute": "blockdev-backup",
     "arguments": { "device": "src-id",
                    "sync": "full",
                    "target": "tgt-id" } }
<- { "return": {} }
Command query-named-block-nodes (Since: 2.0)

Get the named block driver list

Arguments:

  • flat (boolean, optional) – Omit the nested data about backing image (“backing-image” key) if true. Default is false (Since 5.0)

Return:

[BlockDeviceInfo]

Example:

-> { "execute": "query-named-block-nodes" }
<- { "return": [ { "ro":false,
                   "drv":"qcow2",
                   "encrypted":false,
                   "file":"disks/test.qcow2",
                   "node-name": "my-node",
                   "backing_file_depth":1,
                   "detect_zeroes":"off",
                   "bps":1000000,
                   "bps_rd":0,
                   "bps_wr":0,
                   "iops":1000000,
                   "iops_rd":0,
                   "iops_wr":0,
                   "bps_max": 8000000,
                   "bps_rd_max": 0,
                   "bps_wr_max": 0,
                   "iops_max": 0,
                   "iops_rd_max": 0,
                   "iops_wr_max": 0,
                   "iops_size": 0,
                   "write_threshold": 0,
                   "image":{
                      "filename":"disks/test.qcow2",
                      "format":"qcow2",
                      "virtual-size":2048000,
                      "backing_file":"base.qcow2",
                      "full-backing-filename":"disks/base.qcow2",
                      "backing-filename-format":"qcow2",
                      "snapshots":[
                         {
                            "id": "1",
                            "name": "snapshot1",
                            "vm-state-size": 0,
                            "date-sec": 10000200,
                            "date-nsec": 12,
                            "vm-clock-sec": 206,
                            "vm-clock-nsec": 30
                         }
                      ],
                      "backing-image":{
                          "filename":"disks/base.qcow2",
                          "format":"qcow2",
                          "virtual-size":2048000
                      }
                   } } ] }
Enum XDbgBlockGraphNodeType (Since: 4.0)
Values:

  • block-backend – corresponds to BlockBackend

  • block-job – corresponds to BlockJob

  • block-driver – corresponds to BlockDriverState

Object XDbgBlockGraphNode (Since: 4.0)
Members:

  • id (int) – Block graph node identifier. This id is generated only for x-debug-query-block-graph and does not relate to any other identifiers in QEMU.

  • type (XDbgBlockGraphNodeType) – Type of graph node. Can be one of block-backend, block-job or block-driver-state.

  • name (string) – Human readable name of the node. Corresponds to node-name for block-driver-state nodes; is not guaranteed to be unique in the whole graph (with block-jobs and block-backends).

Enum BlockPermission (Since: 4.0)

Enum of base block permissions.

Values:

  • consistent-read – A user that has the “permission” of consistent reads is guaranteed that their view of the contents of the block device is complete and self-consistent, representing the contents of a disk at a specific point. For most block devices (including their backing files) this is true, but the property cannot be maintained in a few situations like for intermediate nodes of a commit block job.

  • write – This permission is required to change the visible disk contents.

  • write-unchanged – This permission (which is weaker than BLK_PERM_WRITE) is both enough and required for writes to the block node when the caller promises that the visible disk content doesn’t change. As the BLK_PERM_WRITE permission is strictly stronger, either is sufficient to perform an unchanging write.

  • resize – This permission is required to change the size of a block node.

Object XDbgBlockGraphEdge (Since: 4.0)

Block Graph edge description for x-debug-query-block-graph.

Members:

  • parent (int) – parent id

  • child (int) – child id

  • name (string) – name of the relation (examples are ‘file’ and ‘backing’)

  • perm ([BlockPermission]) – granted permissions for the parent operating on the child

  • shared-perm ([BlockPermission]) – permissions that can still be granted to other users of the child while it is still attached to this parent

Object XDbgBlockGraph (Since: 4.0)

Block Graph - list of nodes and list of edges.

Members:
Command x-debug-query-block-graph (Since: 4.0)
This command is unstable/experimental.

Get the block graph.

Return:

XDbgBlockGraph

Features:

  • unstable – This command is meant for debugging.

Command drive-mirror (Since: 1.3)

Start mirroring a block device’s writes to a new destination. target specifies the target of the new image. If the file exists, or if it is a device, it will be used as the new destination for writes. If it does not exist, a new file will be created. format specifies the format of the mirror image, default is to probe if mode=’existing’, else the format of the source.

Arguments:
Errors:

  • If device is not a valid block device, GenericError

Example:

-> { "execute": "drive-mirror",
     "arguments": { "device": "ide-hd0",
                    "target": "/some/place/my-image",
                    "sync": "full",
                    "format": "qcow2" } }
<- { "return": {} }
Object DriveMirror (Since: 1.3)

A set of parameters describing drive mirror setup.

Members:

  • job-id (string, optional) – identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

  • device (string) – the device name or node-name of a root node whose writes should be mirrored.

  • target (string) – the target of the new image. If the file exists, or if it is a device, the existing file/device will be used as the new destination. If it does not exist, a new file will be created.

  • format (string, optional) – the format of the new destination, default is to probe if mode is ‘existing’, else the format of the source

  • node-name (string, optional) – the new block driver state node name in the graph (Since 2.1)

  • replaces (string, optional) – with sync=full graph node name to be replaced by the new image when a whole image copy is done. This can be used to repair broken Quorum files. By default, device is replaced, although implicitly created filters on it are kept. (Since 2.1)

  • mode (NewImageMode, optional) – whether and how QEMU should create a new image, default is ‘absolute-paths’.

  • speed (int, optional) – the maximum speed, in bytes per second

  • sync (MirrorSyncMode) – what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).

  • granularity (int, optional) – granularity of the dirty bitmap, default is 64K if the image format doesn’t have clusters, 4K if the clusters are smaller than that, else the cluster size. Must be a power of 2 between 512 and 64M (since 1.4).

  • buf-size (int, optional) – maximum amount of data in flight from source to target (since 1.4).

  • on-source-error (BlockdevOnError, optional) – the action to take on an error on the source, default ‘report’. ‘stop’ and ‘enospc’ can only be used if the block device supports io-status (see BlockInfo).

  • on-target-error (BlockdevOnError, optional) – the action to take on an error on the target, default ‘report’ (no limitations, since this applies to a different block device than device).

  • unmap (boolean, optional) – Whether to try to unmap target sectors where source has only zero. If true, and target unallocated sectors will read as zero, target image sectors will be unmapped; otherwise, zeroes will be written. Both will result in identical contents. Default is true. (Since 2.4)

  • copy-mode (MirrorCopyMode, optional) – when to copy data to the destination; defaults to ‘background’ (Since: 3.0)

  • auto-finalize (boolean, optional) – When false, this job will wait in a PENDING state after it has finished its work, waiting for job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 3.1)

  • auto-dismiss (boolean, optional) – When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits job-dismiss. When true, this job will automatically disappear without user intervention. Defaults to true. (Since 3.1)

Object BlockDirtyBitmap (Since: 2.4)
Members:

  • node (string) – name of device/node which the bitmap is tracking

  • name (string) – name of the dirty bitmap

Object BlockDirtyBitmapAdd (Since: 2.4)
Members:

  • node (string) – name of device/node which the bitmap is tracking

  • name (string) – name of the dirty bitmap (must be less than 1024 bytes)

  • granularity (int, optional) – the bitmap granularity, default is 64k for block-dirty-bitmap-add

  • persistent (boolean, optional) – the bitmap is persistent, i.e. it will be saved to the corresponding block device image file on its close. For now only Qcow2 disks support persistent bitmaps. Default is false for block-dirty-bitmap-add. (Since: 2.10)

  • disabled (boolean, optional) – the bitmap is created in the disabled state, which means that it will not track drive changes. The bitmap may be enabled with block-dirty-bitmap-enable. Default is false. (Since: 4.0)

Alternate BlockDirtyBitmapOrStr (Since: 4.1)
Alternatives:

  • local (string) – name of the bitmap, attached to the same node as target bitmap.

  • external (BlockDirtyBitmap) – bitmap with specified node

Object BlockDirtyBitmapMerge (Since: 4.0)
Members:

  • node (string) – name of device/node which the target bitmap is tracking

  • target (string) – name of the destination dirty bitmap

  • bitmaps ([BlockDirtyBitmapOrStr]) – name(s) of the source dirty bitmap(s) at node and/or fully specified BlockDirtyBitmap elements. The latter are supported since 4.1.

Command block-dirty-bitmap-add (Since: 2.4)

Create a dirty bitmap with a name on the node, and start tracking the writes.

Arguments:
Errors:

  • If node is not a valid block device or node, DeviceNotFound

  • If name is already taken, GenericError

Example:

-> { "execute": "block-dirty-bitmap-add",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }
Command block-dirty-bitmap-remove (Since: 2.4)

Stop write tracking and remove the dirty bitmap that was created with block-dirty-bitmap-add. If the bitmap is persistent, remove it from its storage too.

Arguments:
Errors:

  • If node is not a valid block device or node, DeviceNotFound

  • If name is not found, GenericError

  • if name is frozen by an operation, GenericError

Example:

-> { "execute": "block-dirty-bitmap-remove",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }
Command block-dirty-bitmap-clear (Since: 2.4)

Clear (reset) a dirty bitmap on the device, so that an incremental backup from this point in time forward will only backup clusters modified after this clear operation.

Arguments:
Errors:

  • If node is not a valid block device, DeviceNotFound

  • If name is not found, GenericError

Example:

-> { "execute": "block-dirty-bitmap-clear",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }
Command block-dirty-bitmap-enable (Since: 4.0)

Enables a dirty bitmap so that it will begin tracking disk changes.

Arguments:
Errors:

  • If node is not a valid block device, DeviceNotFound

  • If name is not found, GenericError

Example:

-> { "execute": "block-dirty-bitmap-enable",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }
Command block-dirty-bitmap-disable (Since: 4.0)

Disables a dirty bitmap so that it will stop tracking disk changes.

Arguments:
Errors:

  • If node is not a valid block device, DeviceNotFound

  • If name is not found, GenericError

Example:

-> { "execute": "block-dirty-bitmap-disable",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }
Command block-dirty-bitmap-merge (Since: 4.0)

Merge dirty bitmaps listed in bitmaps to the target dirty bitmap. Dirty bitmaps in bitmaps will be unchanged, except if it also appears as the target bitmap. Any bits already set in target will still be set after the merge, i.e., this operation does not clear the target. On error, target is unchanged.

The resulting bitmap will count as dirty any clusters that were dirty in any of the source bitmaps. This can be used to achieve backup checkpoints, or in simpler usages, to copy bitmaps.

Arguments:
Errors:

  • If node is not a valid block device, DeviceNotFound

  • If any bitmap in bitmaps or target is not found, GenericError

  • If any of the bitmaps have different sizes or granularities, GenericError

Example:

-> { "execute": "block-dirty-bitmap-merge",
     "arguments": { "node": "drive0", "target": "bitmap0",
                    "bitmaps": ["bitmap1"] } }
<- { "return": {} }
Object BlockDirtyBitmapSha256 (Since: 2.10)

SHA256 hash of dirty bitmap data

Members:

  • sha256 (string) – ASCII representation of SHA256 bitmap hash

Command x-debug-block-dirty-bitmap-sha256 (Since: 2.10)
This command is unstable/experimental.

Get bitmap SHA256.

Arguments:
Features:

  • unstable – This command is meant for debugging.

Return:

BlockDirtyBitmapSha256

Errors:

  • If node is not a valid block device, DeviceNotFound

  • If name is not found or if hashing has failed, GenericError

Command blockdev-mirror (Since: 2.6)

Start mirroring a block device’s writes to a new destination.

Arguments:

  • job-id (string, optional) – identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

  • device (string) – The device name or node-name of a root node whose writes should be mirrored.

  • target (string) – the id or node-name of the block device to mirror to. This mustn’t be attached to guest.

  • replaces (string, optional) – with sync=full graph node name to be replaced by the new image when a whole image copy is done. This can be used to repair broken Quorum files. By default, device is replaced, although implicitly created filters on it are kept.

  • speed (int, optional) – the maximum speed, in bytes per second

  • sync (MirrorSyncMode) – what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).

  • granularity (int, optional) – granularity of the dirty bitmap, default is 64K if the image format doesn’t have clusters, 4K if the clusters are smaller than that, else the cluster size. Must be a power of 2 between 512 and 64M

  • buf-size (int, optional) – maximum amount of data in flight from source to target

  • on-source-error (BlockdevOnError, optional) – the action to take on an error on the source, default ‘report’. ‘stop’ and ‘enospc’ can only be used if the block device supports io-status (see BlockInfo).

  • on-target-error (BlockdevOnError, optional) – the action to take on an error on the target, default ‘report’ (no limitations, since this applies to a different block device than device).

  • filter-node-name (string, optional) – the node name that should be assigned to the filter driver that the mirror job inserts into the graph above device. If this option is not given, a node name is autogenerated. (Since: 2.9)

  • copy-mode (MirrorCopyMode, optional) – when to copy data to the destination; defaults to ‘background’ (Since: 3.0)

  • auto-finalize (boolean, optional) – When false, this job will wait in a PENDING state after it has finished its work, waiting for job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 3.1)

  • auto-dismiss (boolean, optional) – When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits job-dismiss. When true, this job will automatically disappear without user intervention. Defaults to true. (Since 3.1)

  • target-is-zero (boolean, optional) – Assume the destination reads as all zeroes before the mirror started. Setting this to true can speed up the mirror. Setting this to true when the destination is not actually all zero can corrupt the destination. (Since 10.1)

Example:

-> { "execute": "blockdev-mirror",
     "arguments": { "device": "ide-hd0",
                    "target": "target0",
                    "sync": "full" } }
<- { "return": {} }
Object BlockIOThrottle (Since: 1.1)

A set of parameters describing block throttling.

Members:

  • device (string, optional) – Block device name

  • id (string, optional) – The name or QOM path of the guest device (since: 2.8)

  • bps (int) – total throughput limit in bytes per second

  • bps_rd (int) – read throughput limit in bytes per second

  • bps_wr (int) – write throughput limit in bytes per second

  • iops (int) – total I/O operations per second

  • iops_rd (int) – read I/O operations per second

  • iops_wr (int) – write I/O operations per second

  • bps_max (int, optional) – total throughput limit during bursts, in bytes (Since 1.7)

  • bps_rd_max (int, optional) – read throughput limit during bursts, in bytes (Since 1.7)

  • bps_wr_max (int, optional) – write throughput limit during bursts, in bytes (Since 1.7)

  • iops_max (int, optional) – total I/O operations per second during bursts, in bytes (Since 1.7)

  • iops_rd_max (int, optional) – read I/O operations per second during bursts, in bytes (Since 1.7)

  • iops_wr_max (int, optional) – write I/O operations per second during bursts, in bytes (Since 1.7)

  • bps_max_length (int, optional) – maximum length of the bps_max burst period, in seconds. It must only be set if bps_max is set as well. Defaults to 1. (Since 2.6)

  • bps_rd_max_length (int, optional) – maximum length of the bps_rd_max burst period, in seconds. It must only be set if bps_rd_max is set as well. Defaults to 1. (Since 2.6)

  • bps_wr_max_length (int, optional) – maximum length of the bps_wr_max burst period, in seconds. It must only be set if bps_wr_max is set as well. Defaults to 1. (Since 2.6)

  • iops_max_length (int, optional) – maximum length of the iops burst period, in seconds. It must only be set if iops_max is set as well. Defaults to 1. (Since 2.6)

  • iops_rd_max_length (int, optional) – maximum length of the iops_rd_max burst period, in seconds. It must only be set if iops_rd_max is set as well. Defaults to 1. (Since 2.6)

  • iops_wr_max_length (int, optional) – maximum length of the iops_wr_max burst period, in seconds. It must only be set if iops_wr_max is set as well. Defaults to 1. (Since 2.6)

  • iops_size (int, optional) – an I/O size in bytes (Since 1.7)

  • group (string, optional) – throttle group name (Since 2.4)

Features:

  • deprecated – Member device is deprecated. Use id instead.

Object ThrottleLimits (Since: 2.11)

Limit parameters for throttling. Since some limit combinations are illegal, limits should always be set in one transaction. All fields are optional. When setting limits, if a field is missing the current value is not changed.

Members:

  • iops-total (int, optional) – limit total I/O operations per second

  • iops-total-max (int, optional) – I/O operations burst

  • iops-total-max-length (int, optional) – length of the iops-total-max burst period, in seconds. It must only be set if iops-total-max is set as well.

  • iops-read (int, optional) – limit read operations per second

  • iops-read-max (int, optional) – I/O operations read burst

  • iops-read-max-length (int, optional) – length of the iops-read-max burst period, in seconds. It must only be set if iops-read-max is set as well.

  • iops-write (int, optional) – limit write operations per second

  • iops-write-max (int, optional) – I/O operations write burst

  • iops-write-max-length (int, optional) – length of the iops-write-max burst period, in seconds. It must only be set if iops-write-max is set as well.

  • bps-total (int, optional) – limit total bytes per second

  • bps-total-max (int, optional) – total bytes burst

  • bps-total-max-length (int, optional) – length of the bps-total-max burst period, in seconds. It must only be set if bps-total-max is set as well.

  • bps-read (int, optional) – limit read bytes per second

  • bps-read-max (int, optional) – total bytes read burst

  • bps-read-max-length (int, optional) – length of the bps-read-max burst period, in seconds. It must only be set if bps-read-max is set as well.

  • bps-write (int, optional) – limit write bytes per second

  • bps-write-max (int, optional) – total bytes write burst

  • bps-write-max-length (int, optional) – length of the bps-write-max burst period, in seconds. It must only be set if bps-write-max is set as well.

  • iops-size (int, optional) – when limiting by iops max size of an I/O in bytes

Object ThrottleGroupProperties (Since: 2.11)

Properties for throttle-group objects.

Members:

  • limits (ThrottleLimits, optional) – limits to apply for this throttle group

  • x-iops-total (int, optional) – Not documented

  • x-iops-total-max (int, optional) – Not documented

  • x-iops-total-max-length (int, optional) – Not documented

  • x-iops-read (int, optional) – Not documented

  • x-iops-read-max (int, optional) – Not documented

  • x-iops-read-max-length (int, optional) – Not documented

  • x-iops-write (int, optional) – Not documented

  • x-iops-write-max (int, optional) – Not documented

  • x-iops-write-max-length (int, optional) – Not documented

  • x-bps-total (int, optional) – Not documented

  • x-bps-total-max (int, optional) – Not documented

  • x-bps-total-max-length (int, optional) – Not documented

  • x-bps-read (int, optional) – Not documented

  • x-bps-read-max (int, optional) – Not documented

  • x-bps-read-max-length (int, optional) – Not documented

  • x-bps-write (int, optional) – Not documented

  • x-bps-write-max (int, optional) – Not documented

  • x-bps-write-max-length (int, optional) – Not documented

  • x-iops-size (int, optional) – Not documented

Features:

  • unstable – All members starting with x- are aliases for the same key without x- in the limits object. This is not a stable interface and may be removed or changed incompatibly in the future. Use limits for a supported stable interface.

Command block-stream (Since: 1.1)

Copy data from a backing file into a block device.

The block streaming operation is performed in the background until the entire backing file has been copied. This command returns immediately once streaming has started. The status of ongoing block streaming operations can be checked with query-block-jobs. The operation can be stopped before it has completed using the job-cancel or block-job-cancel command.

The node that receives the data is called the top image, can be located in any part of the chain (but always above the base image; see below) and can be specified using its device or node name. Earlier QEMU versions only allowed ‘device’ to name the top level node; presence of the ‘base-node’ parameter during introspection can be used as a witness of the enhanced semantics of ‘device’.

If a base file is specified then sectors are not copied from that base file and its backing chain. This can be used to stream a subset of the backing file chain instead of flattening the entire image. When streaming completes the image file will have the base file as its backing file, unless that node was changed while the job was running. In that case, base’s parent’s backing (or filtered, whichever exists) child (i.e., base at the beginning of the job) will be the new backing file.

On successful completion the image file is updated to drop the backing file and the BLOCK_JOB_COMPLETED event is emitted.

In case device is a filter node, block-stream modifies the first non-filter overlay node below it to point to the new backing node instead of modifying device itself.

Arguments:

  • job-id (string, optional) – identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

  • device (string) – the device or node name of the top image

  • base (string, optional) – the common backing file name. It cannot be set if base-node or bottom is also set.

  • base-node (string, optional) – the node name of the backing file. It cannot be set if base or bottom is also set. (Since 2.8)

  • bottom (string, optional) – the last node in the chain that should be streamed into top. It cannot be set if base or base-node is also set. It cannot be filter node. (Since 6.0)

  • backing-file (string, optional) –

    The backing file string to write into the top image. This filename is not validated.

    If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.

    If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol. (Since 2.1)

  • backing-mask-protocol (boolean, optional) – If true, replace any protocol mentioned in the ‘backing file format’ with ‘raw’, rather than storing the protocol name as the backing format. Can be used even when no image header will be updated (default false; since 9.0).

  • speed (int, optional) – the maximum speed, in bytes per second

  • on-error (BlockdevOnError, optional) – the action to take on an error (default report). ‘stop’ and ‘enospc’ can only be used if the block device supports io-status (see BlockInfo). (Since 1.3)

  • filter-node-name (string, optional) – the node name that should be assigned to the filter driver that the stream job inserts into the graph above device. If this option is not given, a node name is autogenerated. (Since: 6.0)

  • auto-finalize (boolean, optional) – When false, this job will wait in a PENDING state after it has finished its work, waiting for job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 3.1)

  • auto-dismiss (boolean, optional) – When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits job-dismiss. When true, this job will automatically disappear without user intervention. Defaults to true. (Since 3.1)

Errors:

  • If device does not exist, DeviceNotFound.

Example:

-> { "execute": "block-stream",
     "arguments": { "device": "virtio0",
                    "base": "/tmp/master.qcow2" } }
<- { "return": {} }
Command block-job-set-speed (Since: 1.1)

Set maximum speed for a background block operation.

This command can only be issued when there is an active block job.

Throttling can be disabled by setting the speed to 0.

Arguments:

  • device (string) – The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

  • speed (int) – the maximum speed, in bytes per second, or 0 for unlimited. Defaults to 0.

Errors:

  • If no background operation is active on this device, DeviceNotActive

Command block-job-cancel (Since: 1.1)

Stop an active background block operation.

This command returns immediately after marking the active background block operation for cancellation. It is an error to call this command if no operation is in progress.

The operation will cancel as soon as possible and then emit the BLOCK_JOB_CANCELLED event. Before that happens the job is still visible when enumerated using query-block-jobs.

Note that if you issue block-job-cancel after drive-mirror has indicated (via the event BLOCK_JOB_READY) that the source and destination are synchronized, then the event triggered by this command changes to BLOCK_JOB_COMPLETED, to indicate that the mirroring has ended and the destination now has a point-in-time copy tied to the time of the cancellation.

For streaming, the image file retains its backing file unless the streaming operation happens to complete just as it is being cancelled. A new streaming operation can be started at a later time to finish copying all data from the backing file.

Arguments:

  • device (string) – The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

  • force (boolean, optional) – If true, and the job has already emitted the event BLOCK_JOB_READY, abandon the job immediately (even if it is paused) instead of waiting for the destination to complete its final synchronization (since 1.3)

Errors:

  • If no background operation is active on this device, DeviceNotActive

Command block-job-pause (Since: 1.3)
This command is deprecated.

Pause an active background block operation.

This command returns immediately after marking the active job for pausing. Pausing an already paused job is an error.

The job will pause as soon as possible, which means transitioning into the PAUSED state if it was RUNNING, or into STANDBY if it was READY. The corresponding JOB_STATUS_CHANGE event will be emitted.

Cancelling a paused job automatically resumes it.

Arguments:

  • device (string) – The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Features:

  • deprecated – This command is deprecated. Use job-pause instead.

Errors:

  • If no background operation is active on this device, DeviceNotActive

Command block-job-resume (Since: 1.3)
This command is deprecated.

Resume an active background block operation.

This command returns immediately after resuming a paused job. Resuming an already running job is an error.

This command also clears the error status of the job.

Arguments:

  • device (string) – The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Features:

  • deprecated – This command is deprecated. Use job-resume instead.

Errors:

  • If no background operation is active on this device, DeviceNotActive

Command block-job-complete (Since: 1.3)
This command is deprecated.

Manually trigger completion of an active job in the READY or STANDBY state. Completing the job in any other state is an error.

This is supported only for drive mirroring, where it also switches the device to write to the target path only. Note that drive mirroring includes drive-mirror, blockdev-mirror and block-commit job (only in case of “active commit”, when the node being committed is used by the guest). The ability to complete is signaled with a BLOCK_JOB_READY event.

This command completes an active background block operation synchronously. The ordering of this command’s return with the BLOCK_JOB_COMPLETED event is not defined. Note that if an I/O error occurs during the processing of this command: 1) the command itself will fail; 2) the error will be processed according to the rerror/werror arguments that were specified when starting the operation.

Arguments:

  • device (string) – The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Features:

  • deprecated – This command is deprecated. Use job-complete instead.

Errors:

  • If no background operation is active on this device, DeviceNotActive

Command block-job-dismiss (Since: 2.12)
This command is deprecated.

Deletes a job that is in the CONCLUDED state. This command only needs to be run explicitly for jobs that don’t have automatic dismiss enabled. In turn, automatic dismiss may be enabled only for jobs that have auto-dismiss option, which are drive-backup, blockdev-backup, drive-mirror, blockdev-mirror, block-commit and block-stream. auto-dismiss is enabled by default for these jobs.

This command will refuse to operate on any job that has not yet reached its terminal state, CONCLUDED. For jobs that make use of the BLOCK_JOB_READY event, job-cancel, block-job-cancel or job-complete will still need to be used as appropriate.

Arguments:

  • id (string) – The job identifier.

Features:

  • deprecated – This command is deprecated. Use job-dismiss instead.

Command block-job-finalize (Since: 2.12)
This command is deprecated.

Instructs all jobs in a transaction (or a single job if it is not part of any transaction) to finalize any graph changes and do any necessary cleanup. This command requires that all involved jobs are in the PENDING state.

For jobs in a transaction, instructing one job to finalize will force ALL jobs in the transaction to finalize, so it is only necessary to instruct a single member job to finalize.

The command is applicable only to jobs which have auto-finalize option and only when this option is set to false.

Arguments:

  • id (string) – The job identifier.

Features:

  • deprecated – This command is deprecated. Use job-finalize instead.

Object BlockJobChangeOptionsMirror (Since: 8.2)
Members:

  • copy-mode (MirrorCopyMode) – Switch to this copy mode. Currently, only the switch from ‘background’ to ‘write-blocking’ is implemented.

Object BlockJobChangeOptions (Since: 8.2)

Block job options that can be changed after job creation.

Members:
Command block-job-change (Since: 8.2)

Change the block job’s options.

Arguments:
Enum BlockdevDiscardOptions (Since: 2.9)

Determines how to handle discard requests.

Values:

  • ignore – Ignore the request

  • unmap – Forward as an unmap request

Enum BlockdevDetectZeroesOptions (Since: 2.1)

Describes the operation mode for the automatic conversion of plain zero writes by the OS to driver specific optimized zero write commands.

Values:

  • off – Disabled (default)

  • on – Enabled

  • unmap – Enabled and even try to unmap blocks if possible. This requires also that BlockdevDiscardOptions is set to unmap for this device.

Enum BlockdevAioOptions (Since: 2.9)

Selects the AIO backend to handle I/O requests

Values:

  • threads – Use QEMU’s thread pool

  • native – Use native AIO backend (only Linux and Windows)

  • io_uring – Use linux io_uring (since 5.0)

Object BlockdevCacheOptions (Since: 2.9)

Includes cache-related options for block devices

Members:

  • direct (boolean, optional) – enables use of O_DIRECT (bypass the host page cache; default: false)

  • no-flush (boolean, optional) – ignore any flush requests for the device (default: false)

Enum BlockdevDriver (Since: 2.9)

Drivers that are supported in block device operations.

Values:

  • throttle – Since 2.11

  • nvme – Since 2.12

  • copy-on-read – Since 3.0

  • blklogwrites – Since 3.0

  • blkreplay – Since 4.2

  • compress – Since 5.0

  • copy-before-write – Since 6.2

  • snapshot-access – Since 7.0

  • blkdebug – Not documented

  • blkverify – Not documented

  • bochs – Not documented

  • cloop – Not documented

  • dmg – Not documented

  • file – Not documented

  • ftp – Not documented

  • ftps – Not documented

  • gluster – Not documented

  • host_cdrom – Not documented

  • host_device – Not documented

  • http – Not documented

  • https – Not documented

  • io_uring – Not documented

  • iscsi – Not documented

  • luks – Not documented

  • nbd – Not documented

  • nfs – Not documented

  • null-aio – Not documented

  • null-co – Not documented

  • nvme-io_uring – Not documented

  • parallels – Not documented

  • preallocate – Not documented

  • qcow – Not documented

  • qcow2 – Not documented

  • qed – Not documented

  • quorum – Not documented

  • raw – Not documented

  • rbd – Not documented

  • replication – Not documented

  • ssh – Not documented

  • vdi – Not documented

  • vhdx – Not documented

  • virtio-blk-vfio-pci – Not documented

  • virtio-blk-vhost-user – Not documented

  • virtio-blk-vhost-vdpa – Not documented

  • vmdk – Not documented

  • vpc – Not documented

  • vvfat – Not documented

Features:

  • deprecated – Member gluster is deprecated because GlusterFS development ceased.

Object BlockdevOptionsFile (Since: 2.9)

Driver specific block device options for the file backend.

Members:

  • filename (string) – path to the image file

  • pr-manager (string, optional) – the id for the object that will handle persistent reservations for this device (default: none, forward the commands via SG_IO; since 2.11)

  • aio (BlockdevAioOptions, optional) – AIO backend (default: threads) (since: 2.8)

  • aio-max-batch (int, optional) – maximum number of requests to batch together into a single submission in the AIO backend. The smallest value between this and the aio-max-batch value of the IOThread object is chosen. 0 means that the AIO backend will handle it automatically. (default: 0, since 6.2)

  • locking (OnOffAuto, optional) – whether to enable file locking. If set to ‘auto’, only enable when Open File Descriptor (OFD) locking API is available (default: auto, since 2.10)

  • drop-cache (boolean, optional) – invalidate page cache during live migration. This prevents stale data on the migration destination with cache.direct=off. Currently only supported on Linux hosts. (default: on, since: 4.0)

  • x-check-cache-dropped (boolean, optional) – whether to check that page cache was dropped on live migration. May cause noticeable delays if the image file is large, do not use in production. (default: off) (since: 3.0)

Features:

  • dynamic-auto-read-only – If present, enabled auto-read-only means that the driver will open the image read-only at first, dynamically reopen the image file read-write when the first writer is attached to the node and reopen read-only when the last writer is detached. This allows giving QEMU write permissions only on demand when an operation actually needs write access.

  • unstable – Member x-check-cache-dropped is meant for debugging.

Object BlockdevOptionsNull (Since: 2.9)

Driver specific block device options for the null backend.

Members:

  • size (int, optional) – size of the device in bytes.

  • latency-ns (int, optional) – emulated latency (in nanoseconds) in processing requests. Default to zero which completes requests immediately. (Since 2.4)

  • read-zeroes (boolean, optional) – if true, reads from the device produce zeroes; if false, the buffer is left unchanged. (default: false; since: 4.1)

Object BlockdevOptionsNVMe (Since: 2.12)

Driver specific block device options for the NVMe backend.

Members:

  • device (string) – PCI controller address of the NVMe device in format hhhh:bb:ss.f (host:bus:slot.function)

  • namespace (int) – namespace number of the device, starting from 1.

Note that the PCI device must have been unbound from any host kernel driver before instructing QEMU to add the blockdev.

Object BlockdevOptionsVVFAT (Since: 2.9)

Driver specific block device options for the vvfat protocol.

Members:

  • dir (string) – directory to be exported as FAT image

  • fat-type (int, optional) – FAT type: 12, 16 or 32

  • floppy (boolean, optional) – whether to export a floppy image (true) or partitioned hard disk (false; default)

  • label (string, optional) – set the volume label, limited to 11 bytes. FAT16 and FAT32 traditionally have some restrictions on labels, which are ignored by most operating systems. Defaults to “QEMU VVFAT”. (since 2.4)

  • rw (boolean, optional) – whether to allow write operations (default: false)

Object BlockdevOptionsGenericFormat (Since: 2.9)

Driver specific block device options for image format that have no option besides their data source.

Members:

  • file (BlockdevRef) – reference to or definition of the data source block device

Object BlockdevOptionsLUKS (Since: 2.9)

Driver specific block device options for LUKS.

Members:

  • key-secret (string, optional) – the ID of a QCryptoSecret object providing the decryption key. Mandatory except when doing a metadata-only probe of the image. (since 2.6)

  • header (BlockdevRef, optional) – block device holding a detached LUKS header. (since 9.0)

  • The members of BlockdevOptionsGenericFormat.

Object BlockdevOptionsGenericCOWFormat (Since: 2.9)

Driver specific block device options for image format that have no option besides their data source and an optional backing file.

Members:

  • backing (BlockdevRefOrNull, optional) – reference to or definition of the backing file block device, null disables the backing file entirely. Defaults to the backing file stored the image file.

  • The members of BlockdevOptionsGenericFormat.

Enum Qcow2OverlapCheckMode (Since: 2.9)

General overlap check modes.

Values:

  • none – Do not perform any checks

  • constant – Perform only checks which can be done in constant time and without reading anything from disk

  • cached – Perform only checks which can be done without reading anything from disk

  • all – Perform all available overlap checks

Object Qcow2OverlapCheckFlags (Since: 2.9)

Structure of flags for each metadata structure. Setting a field to ‘true’ makes QEMU guard that Qcow2 format structure against unintended overwriting. See Qcow2 format specification for detailed information on these structures. The default value is chosen according to the template given.

Members:

  • template (Qcow2OverlapCheckMode, optional) – Specifies a template mode which can be adjusted using the other flags, defaults to ‘cached’

  • main-header (boolean, optional) – Qcow2 format header

  • active-l1 (boolean, optional) – Qcow2 active L1 table

  • active-l2 (boolean, optional) – Qcow2 active L2 table

  • refcount-table (boolean, optional) – Qcow2 refcount table

  • refcount-block (boolean, optional) – Qcow2 refcount blocks

  • snapshot-table (boolean, optional) – Qcow2 snapshot table

  • inactive-l1 (boolean, optional) – Qcow2 inactive L1 tables

  • inactive-l2 (boolean, optional) – Qcow2 inactive L2 tables

  • bitmap-directory (boolean, optional) – Qcow2 bitmap directory (since 3.0)

Alternate Qcow2OverlapChecks (Since: 2.9)

Specifies which metadata structures should be guarded against unintended overwriting.

Alternatives:
Enum BlockdevQcowEncryptionFormat (Since: 2.10)
Values:

  • aes – AES-CBC with plain64 initialization vectors

Object BlockdevQcowEncryption (Since: 2.10)
Members:
Object BlockdevOptionsQcow (Since: 2.10)

Driver specific block device options for qcow.

Members:
Enum BlockdevQcow2EncryptionFormat (Since: 2.10)
Values:

  • aes – AES-CBC with plain64 initialization vectors

  • luks – Not documented

Object BlockdevQcow2Encryption (Since: 2.10)
Members:
Object BlockdevOptionsPreallocate (Since: 6.0)

Filter driver intended to be inserted between format and protocol node and do preallocation in protocol node on write.

Members:

  • prealloc-align (int, optional) – on preallocation, align file length to this number, default 1048576 (1M)

  • prealloc-size (int, optional) – how much to preallocate, default 134217728 (128M)

  • The members of BlockdevOptionsGenericFormat.

Object BlockdevOptionsQcow2 (Since: 2.9)

Driver specific block device options for qcow2.

Members:

  • lazy-refcounts (boolean, optional) – whether to enable the lazy refcounts feature (default is taken from the image file)

  • pass-discard-request (boolean, optional) – whether discard requests to the qcow2 device should be forwarded to the data source

  • pass-discard-snapshot (boolean, optional) – whether discard requests for the data source should be issued when a snapshot operation (e.g. deleting a snapshot) frees clusters in the qcow2 file

  • pass-discard-other (boolean, optional) – whether discard requests for the data source should be issued on other occasions where a cluster gets freed

  • discard-no-unref (boolean, optional) – when enabled, data clusters will remain preallocated when they are no longer used, e.g. because they are discarded or converted to zero clusters. As usual, whether the old data is discarded or kept on the protocol level (i.e. in the image file) depends on the setting of the pass-discard-request option. Keeping the clusters preallocated prevents qcow2 fragmentation that would otherwise be caused by freeing and re-allocating them later. Besides potential performance degradation, such fragmentation can lead to increased allocation of clusters past the end of the image file, resulting in image files whose file length can grow much larger than their guest disk size would suggest. If image file length is of concern (e.g. when storing qcow2 images directly on block devices), you should consider enabling this option. (since 8.1)

  • overlap-check (Qcow2OverlapChecks, optional) – which overlap checks to perform for writes to the image, defaults to ‘cached’ (since 2.2)

  • cache-size (int, optional) – the maximum total size of the L2 table and refcount block caches in bytes (since 2.2)

  • l2-cache-size (int, optional) – the maximum size of the L2 table cache in bytes (since 2.2)

  • l2-cache-entry-size (int, optional) – the size of each entry in the L2 cache in bytes. It must be a power of two between 512 and the cluster size. The default value is the cluster size (since 2.12)

  • refcount-cache-size (int, optional) – the maximum size of the refcount block cache in bytes (since 2.2)

  • cache-clean-interval (int, optional) – clean unused entries in the L2 and refcount caches. The interval is in seconds. The default value is 600 on supporting platforms, and 0 on other platforms. 0 disables this feature. (since 2.5)

  • encrypt (BlockdevQcow2Encryption, optional) – Image decryption options. Mandatory for encrypted images, except when doing a metadata-only probe of the image. (since 2.10)

  • data-file (BlockdevRef, optional) – reference to or definition of the external data file. This may only be specified for images that require an external data file. If it is not specified for such an image, the data file name is loaded from the image file. (since 4.0)

  • The members of BlockdevOptionsGenericCOWFormat.

Enum SshHostKeyCheckMode (Since: 2.12)
Values:

  • none – Don’t check the host key at all

  • hash – Compare the host key with a given hash

  • known_hosts – Check the host key against the known_hosts file

Enum SshHostKeyCheckHashType (Since: 2.12)
Values:

  • md5 – The given hash is an md5 hash

  • sha1 – The given hash is an sha1 hash

  • sha256 – The given hash is an sha256 hash

Object SshHostKeyHash (Since: 2.12)
Members:

  • type (SshHostKeyCheckHashType) – The hash algorithm used for the hash

  • hash (string) – The expected hash value

Object SshHostKeyCheck (Since: 2.12)
Members:
Object BlockdevOptionsSsh (Since: 2.9)
Members:

  • server (InetSocketAddress) – host address

  • path (string) – path to the image on the host

  • user (string, optional) – user as which to connect, defaults to current local user name

  • host-key-check (SshHostKeyCheck, optional) – Defines how and what to check the host key against (default: known_hosts)

Enum BlkdebugEvent (Since: 2.9)

Trigger events supported by blkdebug.

Values:

  • l1_shrink_write_table – write zeros to the l1 table to shrink image. (since 2.11)

  • l1_shrink_free_l2_clusters – discard the l2 tables. (since 2.11)

  • cor_write – a write due to copy-on-read (since 2.11)

  • cluster_alloc_space – an allocation of file space for a cluster (since 4.1)

  • none – triggers once at creation of the blkdebug node (since 4.1)

  • l1_update – Not documented

  • l1_grow_alloc_table – Not documented

  • l1_grow_write_table – Not documented

  • l1_grow_activate_table – Not documented

  • l2_load – Not documented

  • l2_update – Not documented

  • l2_update_compressed – Not documented

  • l2_alloc_cow_read – Not documented

  • l2_alloc_write – Not documented

  • read_aio – Not documented

  • read_backing_aio – Not documented

  • read_compressed – Not documented

  • write_aio – Not documented

  • write_compressed – Not documented

  • vmstate_load – Not documented

  • vmstate_save – Not documented

  • cow_read – Not documented

  • cow_write – Not documented

  • reftable_load – Not documented

  • reftable_grow – Not documented

  • reftable_update – Not documented

  • refblock_load – Not documented

  • refblock_update – Not documented

  • refblock_update_part – Not documented

  • refblock_alloc – Not documented

  • refblock_alloc_hookup – Not documented

  • refblock_alloc_write – Not documented

  • refblock_alloc_write_blocks – Not documented

  • refblock_alloc_write_table – Not documented

  • refblock_alloc_switch_table – Not documented

  • cluster_alloc – Not documented

  • cluster_alloc_bytes – Not documented

  • cluster_free – Not documented

  • flush_to_os – Not documented

  • flush_to_disk – Not documented

  • pwritev_rmw_head – Not documented

  • pwritev_rmw_after_head – Not documented

  • pwritev_rmw_tail – Not documented

  • pwritev_rmw_after_tail – Not documented

  • pwritev – Not documented

  • pwritev_zero – Not documented

  • pwritev_done – Not documented

  • empty_image_prepare – Not documented

Enum BlkdebugIOType (Since: 4.1)

Kinds of I/O that blkdebug can inject errors in.

Values:

  • read – .bdrv_co_preadv()

  • write – .bdrv_co_pwritev()

  • write-zeroes – .bdrv_co_pwrite_zeroes()

  • discard – .bdrv_co_pdiscard()

  • flush – .bdrv_co_flush_to_disk()

  • block-status – .bdrv_co_block_status()

Object BlkdebugInjectErrorOptions (Since: 2.9)

Describes a single error injection for blkdebug.

Members:

  • event (BlkdebugEvent) – trigger event

  • state (int, optional) – the state identifier blkdebug needs to be in to actually trigger the event; defaults to “any”

  • iotype (BlkdebugIOType, optional) – the type of I/O operations on which this error should be injected; defaults to “all read, write, write-zeroes, discard, and flush operations” (since: 4.1)

  • errno (int, optional) – error identifier (errno) to be returned; defaults to EIO

  • delay-ns (int, optional) – request delay before completion in nanoseconds (default: 0, since: 11.1)

  • sector (int, optional) – specifies the sector index which has to be affected in order to actually trigger the event; defaults to “any sector”

  • once (boolean, optional) – disables further events after this one has been triggered; defaults to false

  • immediately (boolean, optional) – fail immediately; defaults to false

Object BlkdebugSetStateOptions (Since: 2.9)

Describes a single state-change event for blkdebug.

Members:

  • event (BlkdebugEvent) – trigger event

  • state (int, optional) – the current state identifier blkdebug needs to be in; defaults to “any”

  • new_state (int) – the state identifier blkdebug is supposed to assume if this event is triggered

Object BlockdevOptionsBlkdebug (Since: 2.9)

Driver specific block device options for blkdebug.

Members:

  • image (BlockdevRef) – underlying raw block device (or image file)

  • config (string, optional) – filename of the configuration file

  • align (int, optional) – required alignment for requests in bytes, must be positive power of 2, or 0 for default

  • max-transfer (int, optional) – maximum size for I/O transfers in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

  • opt-write-zero (int, optional) – preferred alignment for write zero requests in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

  • max-write-zero (int, optional) – maximum size for write zero requests in bytes, must be positive multiple of align, of opt-write-zero, and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

  • opt-discard (int, optional) – preferred alignment for discard requests in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

  • max-discard (int, optional) – maximum size for discard requests in bytes, must be positive multiple of align, of opt-discard, and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

  • inject-error ([BlkdebugInjectErrorOptions], optional) – array of error injection descriptions

  • set-state ([BlkdebugSetStateOptions], optional) – array of state-change descriptions

  • take-child-perms ([BlockPermission], optional) – Permissions to take on image in addition to what is necessary anyway (which depends on how the blkdebug node is used). Defaults to none. (since 5.0)

  • unshare-child-perms ([BlockPermission], optional) – Permissions not to share on image in addition to what cannot be shared anyway (which depends on how the blkdebug node is used). Defaults to none. (since 5.0)

Object BlockdevOptionsBlklogwrites (Since: 3.0)

Driver specific block device options for blklogwrites.

Members:

  • file (BlockdevRef) – block device

  • log (BlockdevRef) – block device used to log writes to file

  • log-sector-size (int, optional) – sector size used in logging writes to file, determines granularity of offsets and sizes of writes (default: 512)

  • log-append (boolean, optional) – append to an existing log (default: false)

  • log-super-update-interval (int, optional) – interval of write requests after which the log super block is updated to disk (default: 4096)

Object BlockdevOptionsBlkverify (Since: 2.9)

Driver specific block device options for blkverify.

Members:
Object BlockdevOptionsBlkreplay (Since: 4.2)

Driver specific block device options for blkreplay.

Members:

  • image (BlockdevRef) – disk image which should be controlled with blkreplay

Enum QuorumReadPattern (Since: 2.9)

An enumeration of quorum read patterns.

Values:

  • quorum – read all the children and do a quorum vote on reads

  • fifo – read only from the first child that has not failed

Object BlockdevOptionsQuorum (Since: 2.9)

Driver specific block device options for Quorum

Members:

  • blkverify (boolean, optional) – true if the driver must print content mismatch set to false by default

  • children ([BlockdevRef]) – the children block devices to use

  • vote-threshold (int) – the vote limit under which a read will fail

  • rewrite-corrupted (boolean, optional) – rewrite corrupted data when quorum is reached (Since 2.1)

  • read-pattern (QuorumReadPattern, optional) – choose read pattern and set to quorum by default (Since 2.2)

Object BlockdevOptionsGluster (Since: 2.9)

Driver specific block device options for Gluster

Members:

  • volume (string) – name of gluster volume where VM image resides

  • path (string) – absolute path to image file in gluster volume

  • server ([SocketAddress]) – gluster servers description

  • debug (int, optional) – libgfapi log level (default ‘4’ which is Error) (Since 2.8)

  • logfile (string, optional) – libgfapi log file (default /dev/stderr) (Since 2.8)

Object BlockdevOptionsIoUring (Since: 7.2)
Availability: CONFIG_BLKIO

Driver specific block device options for the io_uring backend.

Members:

  • filename (string) – path to the image file

Object BlockdevOptionsNvmeIoUring (Since: 7.2)
Availability: CONFIG_BLKIO

Driver specific block device options for the nvme-io_uring backend.

Members:

  • path (string) – path to the NVMe namespace’s character device (e.g. /dev/ng0n1).

Object BlockdevOptionsVirtioBlkVfioPci (Since: 7.2)
Availability: CONFIG_BLKIO

Driver specific block device options for the virtio-blk-vfio-pci backend.

Members:

  • path (string) – path to the PCI device’s sysfs directory (e.g. /sys/bus/pci/devices/0000:00:01.0).

Object BlockdevOptionsVirtioBlkVhostUser (Since: 7.2)
Availability: CONFIG_BLKIO

Driver specific block device options for the virtio-blk-vhost-user backend.

Members:

  • path (string) – path to the vhost-user UNIX domain socket.

Object BlockdevOptionsVirtioBlkVhostVdpa (Since: 7.2)
Availability: CONFIG_BLKIO

Driver specific block device options for the virtio-blk-vhost-vdpa backend.

Members:

  • path (string) – path to the vhost-vdpa character device.

Features:

  • fdset – Member path supports the special “/dev/fdset/N” path (since 8.1)

Enum IscsiTransport (Since: 2.9)

An enumeration of libiscsi transport types

Values:

  • tcp – Not documented

  • iser – Not documented

Enum IscsiHeaderDigest (Since: 2.9)

An enumeration of header digests supported by libiscsi

Values:

  • crc32c – Not documented

  • none – Not documented

  • crc32c-none – Not documented

  • none-crc32c – Not documented

Object BlockdevOptionsIscsi (Since: 2.9)

Driver specific block device options for iscsi

Members:

  • transport (IscsiTransport) – The iscsi transport type

  • portal (string) – The address of the iscsi portal

  • target (string) – The target iqn name

  • lun (int, optional) – LUN to connect to. Defaults to 0.

  • user (string, optional) – User name to log in with. If omitted, no CHAP authentication is performed.

  • password-secret (string, optional) – The ID of a QCryptoSecret object providing the password for the login. This option is required if user is specified.

  • initiator-name (string, optional) – The iqn name we want to identify to the target as. If this option is not specified, an initiator name is generated automatically.

  • header-digest (IscsiHeaderDigest, optional) – The desired header digest. Defaults to none-crc32c.

  • timeout (int, optional) – Timeout in seconds after which a request will timeout. 0 means no timeout and is the default.

Enum RbdAuthMode (Since: 3.0)
Values:

  • cephx – Not documented

  • none – Not documented

Enum RbdImageEncryptionFormat (Since: 6.1)
Values:

  • luks-any – Used for opening either luks or luks2 (Since 8.0)

  • luks – Not documented

  • luks2 – Not documented

Object RbdEncryptionOptionsLUKSBase (Since: 6.1)
Members:

  • key-secret (string) – ID of a QCryptoSecret object providing a passphrase for unlocking the encryption

Object RbdEncryptionCreateOptionsLUKSBase (Since: 6.1)
Members:
Object RbdEncryptionOptionsLUKS (Since: 6.1)
Members:
Object RbdEncryptionOptionsLUKS2 (Since: 6.1)
Members:
Object RbdEncryptionOptionsLUKSAny (Since: 8.0)
Members:
Object RbdEncryptionCreateOptionsLUKS (Since: 6.1)
Members:
Object RbdEncryptionCreateOptionsLUKS2 (Since: 6.1)
Members:
Object RbdEncryptionOptions (Since: 6.1)
Members:
Object RbdEncryptionCreateOptions (Since: 6.1)
Members:
Object BlockdevOptionsRbd (Since: 2.9)
Members:

  • pool (string) – Ceph pool name.

  • namespace (string, optional) – Rados namespace name in the Ceph pool. (Since 5.0)

  • image (string) – Image name in the Ceph pool.

  • conf (string, optional) – path to Ceph configuration file. Values in the configuration file will be overridden by options specified via QAPI.

  • snapshot (string, optional) – Ceph snapshot name.

  • encrypt (RbdEncryptionOptions, optional) – Image encryption options. (Since 6.1)

  • user (string, optional) – Ceph id name.

  • auth-client-required ([RbdAuthMode], optional) – Acceptable authentication modes. This maps to Ceph configuration option “auth_client_required”. (Since 3.0)

  • key-secret (string, optional) – ID of a QCryptoSecret object providing a key for cephx authentication. This maps to Ceph configuration option “key”. (Since 3.0)

  • server ([InetSocketAddressBase], optional) – Monitor host address and port. This maps to the “mon_host” Ceph option.

Enum ReplicationMode (Since: 2.9)
Availability: CONFIG_REPLICATION

An enumeration of replication modes.

Values:

  • primary – Primary mode, the vm’s state will be sent to secondary QEMU.

  • secondary – Secondary mode, receive the vm’s state from primary QEMU.

Object BlockdevOptionsReplication (Since: 2.9)
Availability: CONFIG_REPLICATION

Driver specific block device options for replication

Members:

  • mode (ReplicationMode) – the replication mode

  • top-id (string, optional) – In secondary mode, node name or device ID of the root node who owns the replication node chain. Must not be given in primary mode.

  • The members of BlockdevOptionsGenericFormat.

Enum NFSTransport (Since: 2.9)

An enumeration of NFS transport types

Values:

  • inet – TCP transport

Object NFSServer (Since: 2.9)

Captures the address of the socket

Members:

  • type (NFSTransport) – transport type used for NFS (only TCP supported)

  • host (string) – host address for NFS server

Object BlockdevOptionsNfs (Since: 2.9)

Driver specific block device option for NFS

Members:

  • server (NFSServer) – host address

  • path (string) – path of the image on the host

  • user (int, optional) – UID value to use when talking to the server (defaults to 65534 on Windows and getuid() on unix)

  • group (int, optional) – GID value to use when talking to the server (defaults to 65534 on Windows and getgid() in unix)

  • tcp-syn-count (int, optional) – number of SYNs during the session establishment (defaults to libnfs default)

  • readahead-size (int, optional) – set the readahead size in bytes (defaults to libnfs default)

  • page-cache-size (int, optional) – set the pagecache size in bytes (defaults to libnfs default)

  • debug (int, optional) – set the NFS debug level (max 2) (defaults to libnfs default)

Object BlockdevOptionsCurlBase (Since: 2.9)

Driver specific block device options shared by all protocols supported by the curl backend.

Members:

  • url (string) – URL of the image file

  • readahead (int, optional) – Size of the read-ahead cache; must be a multiple of 512 (defaults to 256 kB)

  • timeout (int, optional) – Timeout for connections, in seconds (defaults to 5)

  • username (string, optional) – Username for authentication (defaults to none)

  • password-secret (string, optional) – ID of a QCryptoSecret object providing a password for authentication (defaults to no password)

  • proxy-username (string, optional) – Username for proxy authentication (defaults to none)

  • proxy-password-secret (string, optional) – ID of a QCryptoSecret object providing a password for proxy authentication (defaults to no password)

Object BlockdevOptionsCurlHttp (Since: 2.9)

Driver specific block device options for HTTP connections over the curl backend. URLs must start with “http://”.

Members:

  • cookie (string, optional) – List of cookies to set; format is “name1=content1; name2=content2;” as explained by CURLOPT_COOKIE(3). Defaults to no cookies.

  • cookie-secret (string, optional) – ID of a QCryptoSecret object providing the cookie data in a secure way. See cookie for the format. (since 2.10)

  • force-range (boolean, optional) – Don’t issue a HEAD HTTP request to discover if the http server supports range requests and rely only on GET requests. This is especially useful for S3 presigned URLs where HEAD requests are unauthorized. (default: false; since 11.0)

  • The members of BlockdevOptionsCurlBase.

Object BlockdevOptionsCurlHttps (Since: 2.9)

Driver specific block device options for HTTPS connections over the curl backend. URLs must start with “https://”.

Members:

  • sslverify (boolean, optional) – Whether to verify the SSL certificate’s validity (defaults to true)

  • The members of BlockdevOptionsCurlHttp.

Object BlockdevOptionsCurlFtp (Since: 2.9)

Driver specific block device options for FTP connections over the curl backend. URLs must start with “ftp://”.

Members:
Object BlockdevOptionsCurlFtps (Since: 2.9)

Driver specific block device options for FTPS connections over the curl backend. URLs must start with “ftps://”.

Members:

  • sslverify (boolean, optional) – Whether to verify the SSL certificate’s validity (defaults to true)

  • The members of BlockdevOptionsCurlBase.

Object BlockdevOptionsNbd (Since: 2.9)

Driver specific block device options for NBD.

Members:

  • server (SocketAddress) – NBD server address

  • export (string, optional) – export name

  • tls-creds (string, optional) – TLS credentials ID

  • tls-hostname (string, optional) – TLS hostname override for certificate validation (Since 7.0)

  • x-dirty-bitmap (string, optional) – A metadata context name such as “qemu:dirty-bitmap:NAME” or “qemu:allocation-depth” to query in place of the traditional “base:allocation” block status (see NBD_OPT_LIST_META_CONTEXT in the NBD protocol; and yes, naming this option x-context would have made more sense) (since 3.0)

  • reconnect-delay (int, optional) – On an unexpected disconnect, the nbd client tries to connect again until succeeding or encountering a serious error. During the first reconnect-delay seconds, all requests are paused and will be rerun on a successful reconnect. After that time, any delayed requests and all future requests before a successful reconnect will immediately fail. Default 0 (Since 4.2)

  • open-timeout (int, optional) – In seconds. If zero, the nbd driver tries the connection only once, and fails to open if the connection fails. If non-zero, the nbd driver will repeat connection attempts until successful or until open-timeout seconds have elapsed. Default 0 (Since 7.0)

Features:

  • unstable – Member x-dirty-bitmap is experimental.

Object BlockdevOptionsRaw (Since: 2.9)

Driver specific block device options for the raw driver.

Members:

  • offset (int, optional) – position where the block device starts

  • size (int, optional) – the assumed size of the device

  • The members of BlockdevOptionsGenericFormat.

Object BlockdevOptionsThrottle (Since: 2.11)

Driver specific block device options for the throttle driver

Members:

  • throttle-group (string) – the name of the throttle-group object to use. It must already exist.

  • file (BlockdevRef) – reference to or definition of the data source block device

Object BlockdevOptionsCor (Since: 6.0)

Driver specific block device options for the copy-on-read driver.

Members:

  • bottom (string, optional) – The name of a non-filter node (allocation-bearing layer) that limits the COR operations in the backing chain (inclusive), so that no data below this node will be copied by this filter. If option is absent, the limit is not applied, so that data from all backing layers may be copied.

  • The members of BlockdevOptionsGenericFormat.

Enum OnCbwError (Since: 7.1)

An enumeration of possible behaviors for copy-before-write operation failures.

Values:

  • break-guest-write – report the error to the guest. This way, the guest will not be able to overwrite areas that cannot be backed up, so the backup process remains valid.

  • break-snapshot – continue guest write. Doing so will make the provided snapshot state invalid and any backup or export process based on it will finally fail.

Object BlockdevOptionsCbw (Since: 6.2)

Driver specific block device options for the copy-before-write driver, which does so called copy-before-write operations: when data is written to the filter, the filter first reads corresponding blocks from its file child and copies them to target child. After successfully copying, the write request is propagated to file child. If copying fails, the original write request is failed too and no data is written to file child.

Members:

  • target (BlockdevRef) – The target for copy-before-write operations.

  • bitmap (BlockDirtyBitmap, optional) – If specified, copy-before-write filter will do copy-before-write operations only for dirty regions of the bitmap. Bitmap size must be equal to length of file and target child of the filter. Note also, that bitmap is used only to initialize internal bitmap of the process, so further modifications (or removing) of specified bitmap doesn’t influence the filter. (Since 7.0)

  • on-cbw-error (OnCbwError, optional) – Behavior on failure of copy-before-write operation. Default is break-guest-write. (Since 7.1)

  • cbw-timeout (int, optional) – Zero means no limit. Non-zero sets the timeout in seconds for copy-before-write operation. When a timeout occurs, the respective copy-before-write operation will fail, and the on-cbw-error parameter will decide how this failure is handled. Default 0. (Since 7.1)

  • min-cluster-size (int, optional) – Minimum size of blocks used by copy-before-write operations. Has to be a power of 2. No effect if smaller than the maximum of the target’s cluster size and 64 KiB. Default 0. (Since 9.2)

  • The members of BlockdevOptionsGenericFormat.

Object BlockdevOptions (Since: 2.9)

Options for creating a block device. Many options are available for all block devices, independent of the block driver:

Members:
Alternate BlockdevRef (Since: 2.9)

Reference to a block device.

Alternatives:

  • definition (BlockdevOptions) – defines a new block device inline

  • reference (string) – references the ID of an existing block device

Alternate BlockdevRefOrNull (Since: 2.9)

Reference to a block device.

Alternatives:

  • definition (BlockdevOptions) – defines a new block device inline

  • reference (string) – references the ID of an existing block device. An empty string means that no block device should be referenced. Deprecated; use null instead.

  • null (null) – No block device should be referenced (since 2.10)

Command blockdev-add (Since: 2.9)

Creates a new block device.

Arguments:

Example:

-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "test1",
          "file": {
              "driver": "file",
              "filename": "test.qcow2"
           }
      }
    }
<- { "return": {} }

Example:

-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "node0",
          "discard": "unmap",
          "cache": {
             "direct": true
           },
           "file": {
             "driver": "file",
             "filename": "/tmp/test.qcow2"
           },
           "backing": {
              "driver": "raw",
              "file": {
                 "driver": "file",
                 "filename": "/dev/fdset/4"
               }
           }
       }
     }

<- { "return": {} }
Command blockdev-reopen (Since: 6.1)

Reopens one or more block devices using the given set of options. Any option not specified will be reset to its default value regardless of its previous status. If an option cannot be changed or a particular driver does not support reopening then the command will return an error. All devices in the list are reopened in one transaction, so if one of them fails then the whole transaction is cancelled.

The command receives a list of block devices to reopen. For each one of them, the top-level node-name option (from BlockdevOptions) must be specified and is used to select the block device to be reopened. Other node-name options must be either omitted or set to the current name of the appropriate node. This command won’t change any node name and any attempt to do it will result in an error.

In the case of options that refer to child nodes, the behavior of this command depends on the value:

  1. A set of options (BlockdevOptions): the child is reopened with the specified set of options.

  2. A reference to the current child: the child is reopened using its existing set of options.

  3. A reference to a different node: the current child is replaced with the specified one.

  4. null: the current child (if any) is detached.

Options (1) and (2) are supported in all cases. Option (3) is supported for file and backing, and option (4) for backing only.

Unlike with blockdev-add, the backing option must always be present unless the node being reopened does not have a backing file and its image does not have a default backing file name as part of its metadata.

Arguments:
Command blockdev-del (Since: 2.9)

Deletes a block device that has been added using blockdev-add. The command will fail if the node is attached to a device or is otherwise being used.

Arguments:

  • node-name (string) – Name of the graph node to delete.

Example:

-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "node0",
          "file": {
              "driver": "file",
              "filename": "test.qcow2"
          }
     }
   }
<- { "return": {} }

-> { "execute": "blockdev-del",
     "arguments": { "node-name": "node0" }
   }
<- { "return": {} }
Command blockdev-set-active (Since: 10.0)

Activate or deactivate a block device. Use this to manage the handover of block devices on migration with qemu-storage-daemon.

Activating a node automatically activates all of its child nodes first. Deactivating a node automatically deactivates any of its child nodes that are not in use by a still active node.

Arguments:

  • node-name (string, optional) – Name of the graph node to activate or deactivate. By default, all nodes are affected by the operation.

  • active (boolean) – true if the nodes should be active when the command returns success, false if they should be inactive.

Example:

-> { "execute": "blockdev-set-active",
     "arguments": {
          "node-name": "node0",
          "active": false
     }
   }
<- { "return": {} }
Object BlockdevCreateOptionsFile (Since: 2.12)

Driver specific image creation options for file.

Members:

  • filename (string) – Filename for the new image file

  • size (int) – Size of the virtual disk in bytes

  • preallocation (PreallocMode, optional) – Preallocation mode for the new image (default: off; allowed values: off, falloc (if CONFIG_POSIX_FALLOCATE), full (if CONFIG_POSIX))

  • nocow (boolean, optional) – Turn off copy-on-write (valid only on btrfs; default: off)

  • extent-size-hint (int, optional) – Extent size hint to add to the image file; 0 for not adding an extent size hint (default: 1 MB, since 5.1)

Object BlockdevCreateOptionsGluster (Since: 2.12)

Driver specific image creation options for gluster.

Members:

  • location (BlockdevOptionsGluster) – Where to store the new image file

  • size (int) – Size of the virtual disk in bytes

  • preallocation (PreallocMode, optional) – Preallocation mode for the new image (default: off; allowed values: off, falloc (if CONFIG_GLUSTERFS_FALLOCATE), full (if CONFIG_GLUSTERFS_ZEROFILL))

Object BlockdevCreateOptionsLUKS (Since: 2.12)

Driver specific image creation options for LUKS.

Members:

  • file (BlockdevRef, optional) – Node to create the image format on, mandatory except when ‘preallocation’ is not requested

  • header (BlockdevRef, optional) – Block device holding a detached LUKS header. (since 9.0)

  • size (int) – Size of the virtual disk in bytes

  • preallocation (PreallocMode, optional) – Preallocation mode for the new image (since: 4.2) (default: off; allowed values: off, metadata, falloc, full)

  • The members of QCryptoBlockCreateOptionsLUKS.

Object BlockdevCreateOptionsNfs (Since: 2.12)

Driver specific image creation options for NFS.

Members:

  • location (BlockdevOptionsNfs) – Where to store the new image file

  • size (int) – Size of the virtual disk in bytes

Object BlockdevCreateOptionsParallels (Since: 2.12)

Driver specific image creation options for parallels.

Members:

  • file (BlockdevRef) – Node to create the image format on

  • size (int) – Size of the virtual disk in bytes

  • cluster-size (int, optional) – Cluster size in bytes (default: 1 MB)

Object BlockdevCreateOptionsQcow (Since: 2.12)

Driver specific image creation options for qcow.

Members:

  • file (BlockdevRef) – Node to create the image format on

  • size (int) – Size of the virtual disk in bytes

  • backing-file (string, optional) – File name of the backing file if a backing file should be used

  • encrypt (QCryptoBlockCreateOptions, optional) – Encryption options if the image should be encrypted

Enum BlockdevQcow2Version (Since: 2.12)
Values:

  • v2 – The original QCOW2 format as introduced in QEMU 0.10 (version 2)

  • v3 – The extended QCOW2 format as introduced in QEMU 1.1 (version 3)

Enum Qcow2CompressionType (Since: 5.1)

Compression type used in qcow2 image file

Values:
Object BlockdevCreateOptionsQcow2 (Since: 2.12)

Driver specific image creation options for qcow2.

Members:

  • file (BlockdevRef) – Node to create the image format on

  • data-file (BlockdevRef, optional) – Node to use as an external data file in which all guest data is stored so that only metadata remains in the qcow2 file (since: 4.0)

  • data-file-raw (boolean, optional) – True if the external data file must stay valid as a standalone (read-only) raw image without looking at qcow2 metadata (default: false; since: 4.0)

  • extended-l2 (boolean, optional) – True to make the image have extended L2 entries (default: false; since 5.2)

  • size (int) – Size of the virtual disk in bytes

  • version (BlockdevQcow2Version, optional) – Compatibility level (default: v3)

  • backing-file (string, optional) – File name of the backing file if a backing file should be used

  • backing-fmt (BlockdevDriver, optional) – Name of the block driver to use for the backing file

  • encrypt (QCryptoBlockCreateOptions, optional) – Encryption options if the image should be encrypted

  • cluster-size (int, optional) – qcow2 cluster size in bytes (default: 65536)

  • preallocation (PreallocMode, optional) – Preallocation mode for the new image (default: off; allowed values: off, falloc, full, metadata)

  • lazy-refcounts (boolean, optional) – True if refcounts may be updated lazily (default: off)

  • refcount-bits (int, optional) – Width of reference counts in bits (default: 16)

  • compression-type (Qcow2CompressionType, optional) – The image cluster compression method (default: zlib, since 5.1)

Object BlockdevCreateOptionsQed (Since: 2.12)

Driver specific image creation options for qed.

Members:

  • file (BlockdevRef) – Node to create the image format on

  • size (int) – Size of the virtual disk in bytes

  • backing-file (string, optional) – File name of the backing file if a backing file should be used

  • backing-fmt (BlockdevDriver, optional) – Name of the block driver to use for the backing file

  • cluster-size (int, optional) – Cluster size in bytes (default: 65536)

  • table-size (int, optional) – L1/L2 table size (in clusters)

Object BlockdevCreateOptionsRbd (Since: 2.12)

Driver specific image creation options for rbd/Ceph.

Members:

  • location (BlockdevOptionsRbd) – Where to store the new image file. This location cannot point to a snapshot.

  • size (int) – Size of the virtual disk in bytes

  • cluster-size (int, optional) – RBD object size

  • encrypt (RbdEncryptionCreateOptions, optional) – Image encryption options. (Since 6.1)

Enum BlockdevVmdkSubformat (Since: 4.0)

Subformat options for VMDK images

Values:

  • monolithicSparse – Single file image with sparse cluster allocation

  • monolithicFlat – Single flat data image and a descriptor file

  • twoGbMaxExtentSparse – Data is split into 2GB (per virtual LBA) sparse extent files, in addition to a descriptor file

  • twoGbMaxExtentFlat – Data is split into 2GB (per virtual LBA) flat extent files, in addition to a descriptor file

  • streamOptimized – Single file image sparse cluster allocation, optimized for streaming over network.

Enum BlockdevVmdkAdapterType (Since: 4.0)

Adapter type info for VMDK images

Values:

  • ide – Not documented

  • buslogic – Not documented

  • lsilogic – Not documented

  • legacyESX – Not documented

Object BlockdevCreateOptionsVmdk (Since: 4.0)

Driver specific image creation options for VMDK.

Members:

  • file (BlockdevRef) – Where to store the new image file. This refers to the image file for monolithcSparse and streamOptimized format, or the descriptor file for other formats.

  • size (int) – Size of the virtual disk in bytes

  • extents ([BlockdevRef], optional) – Where to store the data extents. Required for monolithcFlat, twoGbMaxExtentSparse and twoGbMaxExtentFlat formats. For monolithicFlat, only one entry is required; for twoGbMaxExtent* formats, the number of entries required is calculated as extent_number = virtual_size / 2GB. Providing more extents than will be used is an error.

  • subformat (BlockdevVmdkSubformat, optional) – The subformat of the VMDK image. Default: “monolithicSparse”.

  • backing-file (string, optional) – The path of backing file. Default: no backing file is used.

  • adapter-type (BlockdevVmdkAdapterType, optional) – The adapter type used to fill in the descriptor. Default: ide.

  • hwversion (string, optional) – Hardware version. The meaningful options are “4” or “6”. Default: “4”.

  • toolsversion (string, optional) – VMware guest tools version. Default: “2147483647” (Since 6.2)

  • zeroed-grain (boolean, optional) – Whether to enable zeroed-grain feature for sparse subformats. Default: false.

Object BlockdevCreateOptionsSsh (Since: 2.12)

Driver specific image creation options for SSH.

Members:

  • location (BlockdevOptionsSsh) – Where to store the new image file

  • size (int) – Size of the virtual disk in bytes

Object BlockdevCreateOptionsVdi (Since: 2.12)

Driver specific image creation options for VDI.

Members:

  • file (BlockdevRef) – Node to create the image format on

  • size (int) – Size of the virtual disk in bytes

  • preallocation (PreallocMode, optional) – Preallocation mode for the new image (default: off; allowed values: off, metadata)

Enum BlockdevVhdxSubformat (Since: 2.12)
Values:

  • dynamic – Growing image file

  • fixed – Preallocated fixed-size image file

Object BlockdevCreateOptionsVhdx (Since: 2.12)

Driver specific image creation options for vhdx.

Members:

  • file (BlockdevRef) – Node to create the image format on

  • size (int) – Size of the virtual disk in bytes

  • log-size (int, optional) – Log size in bytes, must be a multiple of 1 MB (default: 1 MB)

  • block-size (int, optional) – Block size in bytes, must be a multiple of 1 MB and not larger than 256 MB (default: automatically choose a block size depending on the image size)

  • subformat (BlockdevVhdxSubformat, optional) – vhdx subformat (default: dynamic)

  • block-state-zero (boolean, optional) – Force use of payload blocks of type ‘ZERO’. Non-standard, but default. Do not set to ‘off’ when using ‘qemu-img convert’ with subformat=dynamic.

Enum BlockdevVpcSubformat (Since: 2.12)
Values:

  • dynamic – Growing image file

  • fixed – Preallocated fixed-size image file

Object BlockdevCreateOptionsVpc (Since: 2.12)

Driver specific image creation options for vpc (VHD).

Members:

  • file (BlockdevRef) – Node to create the image format on

  • size (int) – Size of the virtual disk in bytes

  • subformat (BlockdevVpcSubformat, optional) – vhdx subformat (default: dynamic)

  • force-size (boolean, optional) – Force use of the exact byte size instead of rounding to the next size that can be represented in CHS geometry (default: false)

Object BlockdevCreateOptions (Since: 2.12)

Options for creating an image format on a given node.

Members:
Command blockdev-create (Since: 3.0)

Starts a job to create an image format on a given node. The job is automatically finalized, but a manual job-dismiss is required.

Arguments:

  • job-id (string) – Identifier for the newly created job.

  • options (BlockdevCreateOptions) – Options for the image creation.

Object BlockdevAmendOptionsLUKS (Since: 5.1)

Driver specific image amend options for LUKS.

Members:
Object BlockdevAmendOptionsQcow2 (Since: 5.1)

Driver specific image amend options for qcow2. For now, only encryption options can be amended

Members:
Object BlockdevAmendOptions (Since: 5.1)

Options for amending an image format

Members:
Command x-blockdev-amend (Since: 5.1)
This command is unstable/experimental.

Starts a job to amend format specific options of an existing open block device. The job is automatically finalized, but a manual job-dismiss is required.

Arguments:

  • job-id (string) – Identifier for the newly created job.

  • node-name (string) – Name of the block node to work on

  • options (BlockdevAmendOptions) – Options (driver specific)

  • force (boolean, optional) – Allow unsafe operations, format specific. For luks that allows erase of the last active keyslot (permanent loss of data), and replacement of an active keyslot (possible loss of data if IO error happens)

Features:

  • unstable – This command is experimental.

Enum BlockErrorAction (Since: 2.1)

An enumeration of action that has been taken when a DISK I/O occurs

Values:

  • ignore – error has been ignored

  • report – error has been reported to the device

  • stop – error caused VM to be stopped

Event BLOCK_IMAGE_CORRUPTED (Since: 1.7)

Emitted when a disk image is being marked corrupt. The image can be identified by its device or node name. The ‘device’ field is always present for compatibility reasons, but it can be empty (“”) if the image does not have a device name associated.

Members:

  • device (string) – device name. This is always present for compatibility reasons, but it can be empty (“”) if the image does not have a device name associated.

  • node-name (string, optional) – node name (Since: 2.4)

  • msg (string) – informative message for human consumption, such as the kind of corruption being detected. It should not be parsed by machine as it is not guaranteed to be stable

  • offset (int, optional) – if the corruption resulted from an image access, this is the host’s access offset into the image

  • size (int, optional) – if the corruption resulted from an image access, this is the access size

  • fatal (boolean) – if set, the image is marked corrupt and therefore unusable after this event and must be repaired (Since 2.2; before, every BLOCK_IMAGE_CORRUPTED event was fatal)

Note

If action is “stop”, a STOP event will eventually follow the BLOCK_IO_ERROR event.

Example:

<- { "event": "BLOCK_IMAGE_CORRUPTED",
     "data": { "device": "", "node-name": "drive", "fatal": false,
               "msg": "L2 table offset 0x2a2a2a00 unaligned (L1 index: 0)" },
     "timestamp": { "seconds": 1648243240, "microseconds": 906060 } }
Event BLOCK_IO_ERROR (Since: 0.13)

Emitted when a disk I/O error occurs

Members:

  • qom-path (string) – path to the device object in the QOM tree (since 9.2)

  • device (string) – device name. This is always present for compatibility reasons, but it can be empty (“”) if the image does not have a device name associated.

  • node-name (string, optional) – node name. Note that errors may be reported for the root node that is directly attached to a guest device rather than for the node where the error occurred. The node name is not present if the drive is empty. (Since: 2.8)

  • operation (IoOperationType) – I/O operation

  • action (BlockErrorAction) – action that has been taken

  • nospace (boolean, optional) – true if I/O error was caused due to a no-space condition. This key is only present if query-block’s io-status is present, please see query-block documentation for more information (since: 2.2)

  • reason (string) – human readable string describing the error cause. (This field is a debugging aid for humans, it should not be parsed by applications) (since: 2.2)

Note

If action is “stop”, a STOP event will eventually follow the BLOCK_IO_ERROR event.

Note

This event is rate-limited, except if action is “stop”.

Example:

<- { "event": "BLOCK_IO_ERROR",
     "data": { "qom-path": "/machine/unattached/device[0]",
               "device": "ide0-hd1",
               "node-name": "#block212",
               "operation": "write",
               "action": "stop",
               "reason": "No space left on device" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
Event BLOCK_JOB_COMPLETED (Since: 1.1)

Emitted when a block job has completed

Members:

  • type (JobType) – job type

  • device (string) – The job identifier. Originally the device name but other values are allowed since QEMU 2.7

  • len (int) – maximum progress value

  • offset (int) – current progress value. On success this is equal to len. On failure this is less than len

  • speed (int) – rate limit, bytes per second

  • error (string, optional) – error message. Only present on failure. This field contains a human-readable error message. There are no semantics other than that streaming has failed and clients should not try to interpret the error string

Example:

<- { "event": "BLOCK_JOB_COMPLETED",
     "data": { "type": "stream", "device": "virtio-disk0",
               "len": 10737418240, "offset": 10737418240,
               "speed": 0 },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }
Event BLOCK_JOB_CANCELLED (Since: 1.1)

Emitted when a block job has been cancelled

Members:

  • type (JobType) – job type

  • device (string) – The job identifier. Originally the device name but other values are allowed since QEMU 2.7

  • len (int) – maximum progress value

  • offset (int) – current progress value. On success this is equal to len. On failure this is less than len

  • speed (int) – rate limit, bytes per second

Example:

<- { "event": "BLOCK_JOB_CANCELLED",
     "data": { "type": "stream", "device": "virtio-disk0",
               "len": 10737418240, "offset": 134217728,
               "speed": 0 },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }
Event BLOCK_JOB_ERROR (Since: 1.3)

Emitted when a block job encounters an error

Members:

  • device (string) – The job identifier. Originally the device name but other values are allowed since QEMU 2.7

  • operation (IoOperationType) – I/O operation

  • action (BlockErrorAction) – action that has been taken

Example:

<- { "event": "BLOCK_JOB_ERROR",
     "data": { "device": "ide0-hd1",
               "operation": "write",
               "action": "stop" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
Event BLOCK_JOB_READY (Since: 1.3)

Emitted when a block job is ready to complete

Members:

  • type (JobType) – job type

  • device (string) – The job identifier. Originally the device name but other values are allowed since QEMU 2.7

  • len (int) – maximum progress value

  • offset (int) – current progress value. On success this is equal to len. On failure this is less than len

  • speed (int) – rate limit, bytes per second

Note

The “ready to complete” status is always reset by a BLOCK_JOB_ERROR event.

Example:

<- { "event": "BLOCK_JOB_READY",
     "data": { "device": "drive0", "type": "mirror", "speed": 0,
               "len": 2097152, "offset": 2097152 },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
Event BLOCK_JOB_PENDING (Since: 2.12)

Emitted when a block job is awaiting explicit authorization to finalize graph changes via job-finalize. If this job is part of a transaction, it will not emit this event until the transaction has converged first.

Members:

  • type (JobType) – job type

  • id (string) – The job identifier.

Example:

<- { "event": "BLOCK_JOB_PENDING",
     "data": { "type": "mirror", "id": "backup_1" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
Enum PreallocMode (Since: 2.2)

Preallocation mode of QEMU image file

Values:

  • off – no preallocation

  • metadata – preallocate only for metadata

  • falloc – like full preallocation but allocate disk space by posix_fallocate() rather than writing data.

  • full – preallocate all data by writing it to the device to ensure disk space is really available. This data may or may not be zero, depending on the image format and storage. full preallocation also sets up metadata correctly.

Event BLOCK_WRITE_THRESHOLD (Since: 2.3)

Emitted when writes on block device reaches or exceeds the configured write threshold. For thin-provisioned devices, this means the device should be extended to avoid pausing for disk exhaustion. The event is one shot. Once triggered, it needs to be re-registered with another block-set-write-threshold command.

Members:

  • node-name (string) – graph node name on which the threshold was exceeded.

  • amount-exceeded (int) – amount of data which exceeded the threshold, in bytes.

  • write-threshold (int) – last configured threshold, in bytes.

Command block-set-write-threshold (Since: 2.3)

Change the write threshold for a block drive. An event will be delivered if a write to this block drive crosses the configured threshold. The threshold is an offset, thus must be non-negative. Default is no write threshold. Setting the threshold to zero disables it.

This is useful to transparently resize thin-provisioned drives without the guest OS noticing.

Arguments:

  • node-name (string) – graph node name on which the threshold must be set.

  • write-threshold (int) – configured threshold for the block device, bytes. Use 0 to disable the threshold.

Example:

-> { "execute": "block-set-write-threshold",
     "arguments": { "node-name": "mydev",
                    "write-threshold": 17179869184 } }
<- { "return": {} }
Command x-blockdev-change (Since: 2.7)
This command is unstable/experimental.

Dynamically reconfigure the block driver state graph.

Currently only supports adding and deleting quorum children. A child will be added at the end of the list of children. Its contents must be consistent with the other childrens’ contents. Deleting a child that is not last in the list of children is problematic, because it “renumbers” the children following it.

Arguments:

  • parent (string) – the id or name of the parent node.

  • child (string, optional) – the name of a child to be deleted. Mutually exclusive with node.

  • node (string, optional) – the name of the node to be added. Mutually exclusive with child.

Features:

  • unstable – This command is experimental.

Example: Add a new node to a quorum

 -> { "execute": "blockdev-add",
      "arguments": {
          "driver": "raw",
          "node-name": "new_node",
          "file": { "driver": "file",
                    "filename": "test.raw" } } }
 <- { "return": {} }
 -> { "execute": "x-blockdev-change",
      "arguments": { "parent": "disk1",
                     "node": "new_node" } }
 <- { "return": {} }

Example: Delete a quorum’s node

 -> { "execute": "x-blockdev-change",
      "arguments": { "parent": "disk1",
                     "child": "children.1" } }
 <- { "return": {} }
Command x-blockdev-set-iothread (Since: 2.12)
This command is unstable/experimental.

Move node and its children into the iothread. If iothread is null then move node and its children into the main loop.

The node must not be attached to a BlockBackend.

Arguments:

  • node-name (string) – the name of the block driver node

  • iothread (StrOrNull) – the name of the IOThread object or null for the main loop

  • force (boolean, optional) – true if the node and its children should be moved when a BlockBackend is already attached

Features:

  • unstable – This command is experimental and intended for test cases that need control over IOThreads only.

Example: Move a node into an IOThread

 -> { "execute": "x-blockdev-set-iothread",
      "arguments": { "node-name": "disk1",
                     "iothread": "iothread0" } }
 <- { "return": {} }

Example: Move a node into the main loop

 -> { "execute": "x-blockdev-set-iothread",
      "arguments": { "node-name": "disk1",
                     "iothread": null } }
 <- { "return": {} }
Enum QuorumOpType (Since: 2.6)

An enumeration of the quorum operation types

Values:

  • read – read operation

  • write – write operation

  • flush – flush operation

Event QUORUM_FAILURE (Since: 2.0)

Emitted by the Quorum block driver if it fails to establish a quorum

Members:

  • reference (string) – device name if defined else node name

  • sector-num (int) – number of the first sector of the failed read operation

  • sectors-count (int) – failed read operation sector count

Note

This event is rate-limited.

Example:

<- { "event": "QUORUM_FAILURE",
     "data": { "reference": "usr1", "sector-num": 345435, "sectors-count": 5 },
     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }
Event QUORUM_REPORT_BAD (Since: 2.0)

Emitted to report a corruption of a Quorum file

Members:

  • type (QuorumOpType) – quorum operation type (Since 2.6)

  • error (string, optional) – error message. Only present on failure. This field contains a human-readable error message. There are no semantics other than that the block layer reported an error and clients should not try to interpret the error string.

  • node-name (string) – the graph node name of the block driver state

  • sector-num (int) – number of the first sector of the failed read operation

  • sectors-count (int) – failed read operation sector count

Note

This event is rate-limited.

Example: Read operation

 <- { "event": "QUORUM_REPORT_BAD",
      "data": { "node-name": "node0", "sector-num": 345435, "sectors-count": 5,
                "type": "read" },
      "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

Example: Flush operation

 <- { "event": "QUORUM_REPORT_BAD",
      "data": { "node-name": "node0", "sector-num": 0, "sectors-count": 2097120,
                "type": "flush", "error": "Broken pipe" },
      "timestamp": { "seconds": 1456406829, "microseconds": 291763 } }
Object BlockdevSnapshotInternal (Since: 1.7)
Members:

  • device (string) – the device name or node-name of a root node to generate the snapshot from

  • name (string) – the name of the internal snapshot to be created

Command blockdev-snapshot-internal-sync (Since: 1.7)

Synchronously take an internal snapshot of a block device, when the format of the image used supports it. If the name is an empty string, or a snapshot with name already exists, the operation will fail.

Arguments:
Errors:

  • If device is not a valid block device, GenericError

  • If any snapshot matching name exists, or name is empty, GenericError

  • If the format of the image used does not support it, GenericError

Note

Only some image formats such as qcow2 and rbd support internal snapshots.

Example:

-> { "execute": "blockdev-snapshot-internal-sync",
     "arguments": { "device": "ide-hd0",
                    "name": "snapshot0" }
   }
<- { "return": {} }
Command blockdev-snapshot-delete-internal-sync (Since: 1.7)

Synchronously delete an internal snapshot of a block device, when the format of the image used support it. The snapshot is identified by name or id or both. One of the name or id is required. Return SnapshotInfo for the successfully deleted snapshot.

Arguments:

  • device (string) – the device name or node-name of a root node to delete the snapshot from

  • id (string, optional) – optional the snapshot’s ID to be deleted

  • name (string, optional) – optional the snapshot’s name to be deleted

Return:

SnapshotInfo

Errors:

  • If device is not a valid block device, GenericError

  • If snapshot not found, GenericError

  • If the format of the image used does not support it, GenericError

  • If id and name are both not specified, GenericError

Example:

-> { "execute": "blockdev-snapshot-delete-internal-sync",
     "arguments": { "device": "ide-hd0",
                    "name": "snapshot0" }
   }
<- { "return": {
                   "id": "1",
                   "name": "snapshot0",
                   "vm-state-size": 0,
                   "date-sec": 1000012,
                   "date-nsec": 10,
                   "vm-clock-sec": 100,
                   "vm-clock-nsec": 20,
                   "icount": 220414
     }
   }
Object DummyBlockCoreForceArrays (Since: 8.0)

Not used by QMP; hack to let us use BlockGraphInfoList internally

Members:

Block device exports

Object NbdServerOptionsBase
Members:

  • handshake-max-seconds (int, optional) – Time limit, in seconds, at which a client that has not completed the negotiation handshake will be disconnected, or 0 for no limit (since 10.0; default: 10).

  • tls-creds (string, optional) – ID of the TLS credentials object (since 2.6).

  • tls-authz (string, optional) – ID of the QAuthZ authorization object used to validate the client’s x509 distinguished name. This object is is only resolved at time of use, so can be deleted and recreated on the fly while the NBD server is active. If missing, it will default to denying access (since 4.0).

  • max-connections (int, optional) – The maximum number of connections to allow at the same time, 0 for unlimited. Setting this to 1 also stops the server from advertising multiple client support (since 5.2; default: 100).

Object NbdServerOptions

Keep this type consistent with the NbdServerOptionsLegacy type. The only intended difference is using SocketAddress instead of SocketAddressLegacy.

Members:
Object NbdServerOptionsLegacy

Keep this type consistent with the NbdServerOptions type. The only intended difference is using SocketAddressLegacy instead of SocketAddress.

Members:
Command nbd-server-start (Since: 1.3)

Start an NBD server listening on the given host and port. Block devices can then be exported using nbd-server-add. The NBD server will present them as named exports; for example, another QEMU instance could refer to them as “nbd:HOST:PORT:exportname=NAME”.

Arguments:
Errors:

  • if the server is already running

Object BlockExportOptionsNbdBase (Since: 5.0)

An NBD block export (common options shared between nbd-server-add and the NBD branch of block-export-add).

Members:

  • name (string, optional) – Export name. If unspecified, the device parameter is used as the export name. (Since 2.12)

  • description (string, optional) – Free-form description of the export, up to 4096 bytes. (Since 5.0)

Object BlockExportOptionsNbd (Since: 5.2)

An NBD block export (distinct options used in the NBD branch of block-export-add).

Members:

  • bitmaps ([BlockDirtyBitmapOrStr], optional) – Also export each of the named dirty bitmaps reachable from device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with the metadata context name “qemu:dirty-bitmap:BITMAP” to inspect each bitmap. Since 7.1 bitmap may be specified by node/name pair.

  • allocation-depth (boolean, optional) – Also export the allocation depth map for device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with the metadata context name “qemu:allocation-depth” to inspect allocation details. (since 5.2)

  • The members of BlockExportOptionsNbdBase.

Object BlockExportOptionsVhostUserBlk (Since: 5.2)

A vhost-user-blk block export.

Members:

  • addr (SocketAddress) – The vhost-user socket on which to listen. Both ‘unix’ and ‘fd’ SocketAddress types are supported. Passed fds must be UNIX domain sockets.

  • logical-block-size (int, optional) – Logical block size in bytes. Defaults to 512 bytes.

  • num-queues (int, optional) – Number of request virtqueues. Must be greater than 0. Defaults to 1.

Enum FuseExportAllowOther (Since: 6.1)

Possible allow_other modes for FUSE exports.

Values:

  • off – Do not pass allow_other as a mount option.

  • on – Pass allow_other as a mount option.

  • auto – Try mounting with allow_other first, and if that fails, retry without allow_other.

Object BlockExportOptionsFuse (Since: 6.0)
Availability: CONFIG_FUSE

Options for exporting a block graph node on some (file) mountpoint as a raw image.

Multi-threading note: The FUSE export supports multi-threading. Currently, requests are distributed across these threads in a round-robin fashion, i.e. independently of the CPU core from which a request originates.

Members:

  • mountpoint (string) – Path on which to export the block device via FUSE. This must point to an existing regular file.

  • growable (boolean, optional) – Whether writes beyond the EOF should grow the block node accordingly. (default: false)

  • allow-other (FuseExportAllowOther, optional) – If this is off, only QEMU’s user is allowed access to this export. That cannot be changed even with chmod or chown. Enabling this option will allow other users access to the export with the FUSE mount option “allow_other”. Note that using allow_other as a non-root user requires user_allow_other to be enabled in the global fuse.conf configuration file. In auto mode (the default), the FUSE export driver will first attempt to mount the export with allow_other, and if that fails, try again without. (since 6.1; default: auto)

Object BlockExportOptionsVduseBlk (Since: 7.1)

A vduse-blk block export.

Members:

  • name (string) – the name of VDUSE device (must be unique across the host).

  • num-queues (int, optional) – the number of virtqueues. Defaults to 1.

  • queue-size (int, optional) – the size of virtqueue. Defaults to 256.

  • logical-block-size (int, optional) – Logical block size in bytes. Range [512, PAGE_SIZE] and must be power of 2. Defaults to 512 bytes.

  • serial (string, optional) – the serial number of virtio block device. Defaults to empty string.

Object NbdServerAddOptions (Since: 5.0)

An NBD block export, per legacy nbd-server-add command.

Members:

  • device (string) – The device name or node name of the node to be exported

  • writable (boolean, optional) – Whether clients should be able to write to the device via the NBD connection (default false).

  • bitmap (string, optional) – Also export a single dirty bitmap reachable from device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with the metadata context name “qemu:dirty-bitmap:BITMAP” to inspect the bitmap (since 4.0).

  • The members of BlockExportOptionsNbdBase.

Command nbd-server-add (Since: 1.3)
This command is deprecated.

Export a block node to QEMU’s embedded NBD server.

The export name will be used as the id for the resulting block export.

Arguments:
Features:
Errors:

  • if the server is not running

  • if an export with the same name already exists

Enum BlockExportRemoveMode (Since: 2.12)

Mode for removing a block export.

Values:

  • safe – Remove export if there are no existing connections, fail otherwise.

  • hard – Drop all connections immediately and remove export.

Command nbd-server-remove (Since: 2.12)
This command is deprecated.

Remove NBD export by name.

Arguments:
Features:
Errors:

  • if the server is not running

  • if export is not found

  • if mode is ‘safe’ and there are existing connections

Command nbd-server-stop (Since: 1.3)

Stop QEMU’s embedded NBD server, and unregister all devices previously added via nbd-server-add.

Enum BlockExportType (Since: 4.2)

An enumeration of block export types

Values:

  • nbd – NBD export

  • vhost-user-blk – vhost-user-blk export (since 5.2)

  • fuse – FUSE export (since: 6.0)

  • vduse-blk – vduse-blk export (since 7.1)

Object BlockExportOptions (Since: 4.2)

Describes a block export, i.e. how single node should be exported on an external interface.

Members:

  • type (BlockExportType) – Block export type

  • id (string) – A unique identifier for the block export (across all export types)

  • node-name (string) – The node name of the block node to be exported (since: 5.2)

  • writable (boolean, optional) – True if clients should be able to write to the export (default false)

  • writethrough (boolean, optional) – If true, caches are flushed after every write request to the export before completion is signalled. (since: 5.2; default: false)

  • iothread (BlockExportIothreads, optional) – The name(s) of one or more iothread object(s) where the export will run. The default is to use the thread currently associated with the block node. (since: 5.2; multi-threading since 10.1)

  • fixed-iothread (boolean, optional) – True prevents the block node from being moved to another thread while the export is active. If true and iothread is given, export creation fails if the block node cannot be moved to the iothread. Must not be true when giving multiple iothreads for iothread. The default is false. (since: 5.2)

  • allow-inactive (boolean, optional) – If true, the export allows the exported node to be inactive. If it is created for an inactive block node, the node remains inactive. If the export type doesn’t support running on an inactive node, an error is returned. If false, inactive block nodes are automatically activated before creating the export and trying to inactivate them later fails. (since: 10.0; default: false)

  • When type is nbd: The members of BlockExportOptionsNbd.

  • When type is vhost-user-blk: The members of BlockExportOptionsVhostUserBlk.

  • When type is fuse: The members of BlockExportOptionsFuse.

  • When type is vduse-blk: The members of BlockExportOptionsVduseBlk.

Alternate BlockExportIothreads (Since: 10.1)

Specify a single or multiple I/O threads in which to run a block export’s I/O.

Alternatives:

  • single (string) – Run the export’s I/O in the given single I/O thread.

  • multi ([string]) – Use multi-threading across the given set of I/O threads, which must not be empty. Note: Passing a single I/O thread via this variant is still treated as multi-threading, which is different from using the single variant. In particular, even if there only is a single I/O thread in the set, export types that do not support multi-threading will generally reject this variant, and BlockExportOptions.fixed-iothread is always incompatible with it.

Command block-export-add (Since: 5.2)

Creates a new block export.

Arguments:
Command block-export-del (Since: 5.2)

Request to remove a block export. This drops the user’s reference to the export, but the export may still stay around after this command returns until the shutdown of the export has completed.

Arguments:
Errors:

  • if the export is not found

  • if mode is ‘safe’ and the export is still in use (e.g. by existing client connections)

Event BLOCK_EXPORT_DELETED (Since: 5.2)

Emitted when a block export is removed and its id can be reused.

Members:

  • id (string) – Block export id.

Object BlockExportInfo (Since: 5.2)

Information about a single block export.

Members:

  • id (string) – The unique identifier for the block export

  • type (BlockExportType) – The block export type

  • node-name (string) – The node name of the block node that is exported

  • shutting-down (boolean) – True if the export is shutting down (e.g. after a block-export-del command, but before the shutdown has completed)

Command query-block-exports (Since: 5.2)
Return:

[BlockExportInfo] – A list describing all block exports

Character devices

Object ChardevInfo (Since: 0.14)

Information about a character device.

Members:

  • label (string) – the label of the character device

  • filename (string) – the filename of the character device

  • frontend-open (boolean) – shows whether the frontend device attached to this backend (e.g. with the chardev=… option) is in open or closed state (since 2.1)

Note

filename is encoded using the QEMU command line character device encoding. See the QEMU man page for details.

Command query-chardev (Since: 0.14)

Return information about current character devices.

Return:

[ChardevInfo]

Example:

-> { "execute": "query-chardev" }
<- {
      "return": [
         {
            "label": "charchannel0",
            "filename": "unix:/var/lib/libvirt/qemu/seabios.rhel6.agent,server=on",
            "frontend-open": false
         },
         {
            "label": "charmonitor",
            "filename": "unix:/var/lib/libvirt/qemu/seabios.rhel6.monitor,server=on",
            "frontend-open": true
         },
         {
            "label": "charserial0",
            "filename": "pty:/dev/pts/2",
            "frontend-open": true
         }
      ]
   }
Object ChardevBackendInfo (Since: 2.0)

Information about a character device backend

Members:

  • name (string) – The backend name

Command query-chardev-backends (Since: 2.0)

Return information about character device backends.

Return:

[ChardevBackendInfo]

Example:

-> { "execute": "query-chardev-backends" }
<- {
      "return":[
         {
            "name":"udp"
         },
         {
            "name":"tcp"
         },
         {
            "name":"unix"
         },
         {
            "name":"spiceport"
         }
      ]
   }
Enum DataFormat (Since: 1.4)

An enumeration of data format.

Values:

  • utf8 – Data is a UTF-8 string (RFC 3629)

  • base64 – Data is Base64 encoded binary (RFC 3548)

Command ringbuf-write (Since: 1.4)

Write to a ring buffer character device.

Arguments:

  • device (string) – the ring buffer character device name

  • data (string) – data to write

  • format (DataFormat, optional) –

    data encoding (default ‘utf8’).

    • base64: data must be base64 encoded text. Its binary decoding gets written.

    • utf8: data’s UTF-8 encoding is written

    • data itself is always Unicode regardless of format, like any other string.

Example:

-> { "execute": "ringbuf-write",
     "arguments": { "device": "foo",
                    "data": "abcdefgh",
                    "format": "utf8" } }
<- { "return": {} }
Command ringbuf-read (Since: 1.4)

Read from a ring buffer character device.

Arguments:

  • device (string) – the ring buffer character device name

  • size (int) – how many bytes to read at most

  • format (DataFormat, optional) –

    data encoding (default ‘utf8’).

    • base64: the data read is returned in base64 encoding.

    • utf8: the data read is interpreted as UTF-8. Bug: can screw up when the buffer contains invalid UTF-8 sequences, NUL characters, after the ring buffer lost data, and when reading stops because the size limit is reached.

    • The return value is always Unicode regardless of format, like any other string.

Return:

string – data read from the device

Example:

-> { "execute": "ringbuf-read",
     "arguments": { "device": "foo",
                    "size": 1000,
                    "format": "utf8" } }
<- { "return": "abcdefgh" }
Object ChardevCommon (Since: 2.6)

Configuration shared across all chardev backends

Members:

  • logfile (string, optional) – The name of a logfile to save output

  • logappend (boolean, optional) – true to append instead of truncate (default to false to truncate)

  • logtimestamp (boolean, optional) – true to insert timestamps into logfile (default false) (since 11.0)

Object ChardevFile (Since: 1.4)

Configuration info for file chardevs.

Members:

  • in (string, optional) – The name of the input file

  • out (string) – The name of the output file

  • append (boolean, optional) – Open the file in append mode (default false to truncate) (Since 2.6)

  • The members of ChardevCommon.

Object ChardevHostdev (Since: 1.4)

Configuration info for device and pipe chardevs.

Members:

  • device (string) – The name of the special file for the device, i.e. /dev/ttyS0 on Unix or COM1: on Windows

  • The members of ChardevCommon.

Object ChardevSocket (Since: 1.4)

Configuration info for (stream) socket chardevs.

Members:

  • addr (SocketAddressLegacy) – socket address to listen on (server=true) or connect to (server=false)

  • tls-creds (string, optional) – the ID of the TLS credentials object (since 2.6)

  • tls-authz (string, optional) – the ID of the QAuthZ authorization object against which the client’s x509 distinguished name will be validated. This object is only resolved at time of use, so can be deleted and recreated on the fly while the chardev server is active. If missing, it will default to denying access (since 4.0)

  • server (boolean, optional) – create server socket (default: true)

  • wait (boolean, optional) – wait for incoming connection on server sockets (default: false). Silently ignored with server: false. This use is deprecated.

  • nodelay (boolean, optional) – set TCP_NODELAY socket option (default: false)

  • telnet (boolean, optional) – enable telnet protocol on server sockets (default: false)

  • tn3270 (boolean, optional) – enable tn3270 protocol on server sockets (default: false) (Since: 2.10)

  • websocket (boolean, optional) – enable websocket protocol on server sockets (default: false) (Since: 3.1)

  • reconnect-ms (int, optional) – For a client socket, if a socket is disconnected, then attempt a reconnect after the given number of milliseconds. Setting this to zero disables this function. (default: 0) (Since: 9.2)

  • The members of ChardevCommon.

Object ChardevUdp (Since: 1.5)

Configuration info for datagram socket chardevs.

Members:
Object ChardevMux (Since: 1.5)

Configuration info for mux chardevs.

Members:

  • chardev (string) – name of the base chardev.

  • The members of ChardevCommon.

Object ChardevHub (Since: 10.0)

Configuration info for hub chardevs.

Members:

  • chardevs ([string]) – IDs to be added to this hub (maximum 4 devices).

  • The members of ChardevCommon.

Object ChardevStdio (Since: 1.5)

Configuration info for stdio chardevs.

Members:

  • signal (boolean, optional) – Allow signals (such as SIGINT triggered by ^C) be delivered to QEMU. Default: true.

  • The members of ChardevCommon.

Object ChardevSpiceChannel (Since: 1.5)
Availability: CONFIG_SPICE

Configuration info for spice vm channel chardevs.

Members:

  • type (string) – kind of channel (for example vdagent).

  • The members of ChardevCommon.

Object ChardevSpicePort (Since: 1.5)
Availability: CONFIG_SPICE

Configuration info for spice port chardevs.

Members:

  • fqdn (string) – name of the channel (see docs/spice-port-fqdn.txt)

  • The members of ChardevCommon.

Object ChardevDBus (Since: 7.0)
Availability: CONFIG_DBUS_DISPLAY

Configuration info for DBus chardevs.

Members:

  • name (string) – name of the channel (following docs/spice-port-fqdn.txt)

  • The members of ChardevCommon.

Object ChardevVC (Since: 1.5)

Configuration info for virtual console chardevs.

Members:

  • width (int, optional) – console width, in pixels

  • height (int, optional) – console height, in pixels

  • cols (int, optional) – console width, in chars

  • rows (int, optional) – console height, in chars

  • The members of ChardevCommon.

Note

The options are only effective when the VNC or SDL graphical display backend is active. They are ignored with the GTK, Spice, VNC and D-Bus display backends.

Object ChardevRingbuf (Since: 1.5)

Configuration info for ring buffer chardevs.

Members:

  • size (int, optional) – ring buffer size, must be power of two, default is 65536

  • The members of ChardevCommon.

Object ChardevQemuVDAgent (Since: 6.1)
Availability: CONFIG_SPICE_PROTOCOL

Configuration info for QEMU vdagent implementation.

Members:

  • mouse (boolean, optional) – enable/disable mouse, default is enabled.

  • clipboard (boolean, optional) – enable/disable clipboard, default is disabled.

  • The members of ChardevCommon.

Object ChardevPty (Since: 9.2)

Configuration info for pty implementation.

Members:

  • path (string, optional) – optional path to create a symbolic link that points to the allocated PTY

  • The members of ChardevCommon.

Enum ChardevBackendKind (Since: 1.4)
Values:

  • file – regular files

  • serial – serial host device

  • parallel – parallel host device

  • pipe – pipes (since 1.5)

  • socket – stream socket

  • udp – datagram socket (since 1.5)

  • pty – pseudo-terminal

  • null – provides no input, throws away output

  • mux – (since 1.5)

  • hub – (since 10.0)

  • msmouse – emulated Microsoft serial mouse (since 1.5)

  • wctablet – emulated Wacom Penpartner serial tablet (since 2.9)

  • braille – Baum Braille device (since 1.5)

  • testdev – device for test-suite control (since 2.2)

  • stdio – standard I/O (since 1.5)

  • console – Windows console (since 1.5)

  • spicevmc – spice vm channel (since 1.5)

  • spiceport – Spice port channel (since 1.5)

  • qemu-vdagent – Spice vdagent (since 6.1)

  • dbus – D-Bus channel (since 7.0)

  • vc – virtual console (since 1.5)

  • ringbuf – memory ring buffer (since 1.6)

  • memory – synonym for ringbuf (since 1.5)

Features:

  • deprecated – Member memory is deprecated. Use ringbuf instead.

Object ChardevFileWrapper (Since: 1.4)
Members:

  • data (ChardevFile) – Configuration info for file chardevs

Object ChardevHostdevWrapper (Since: 1.4)
Members:

  • data (ChardevHostdev) – Configuration info for device and pipe chardevs

Object ChardevSocketWrapper (Since: 1.4)
Members:

  • data (ChardevSocket) – Configuration info for (stream) socket chardevs

Object ChardevUdpWrapper (Since: 1.5)
Members:

  • data (ChardevUdp) – Configuration info for datagram socket chardevs

Object ChardevCommonWrapper (Since: 2.6)
Members:

  • data (ChardevCommon) – Configuration shared across all chardev backends

Object ChardevMuxWrapper (Since: 1.5)
Members:

  • data (ChardevMux) – Configuration info for mux chardevs

Object ChardevHubWrapper (Since: 10.0)
Members:

  • data (ChardevHub) – Configuration info for hub chardevs

Object ChardevStdioWrapper (Since: 1.5)
Members:

  • data (ChardevStdio) – Configuration info for stdio chardevs

Object ChardevSpiceChannelWrapper (Since: 1.5)
Availability: CONFIG_SPICE
Members:
Object ChardevSpicePortWrapper (Since: 1.5)
Availability: CONFIG_SPICE
Members:
Object ChardevQemuVDAgentWrapper (Since: 6.1)
Availability: CONFIG_SPICE_PROTOCOL
Members:
Object ChardevDBusWrapper (Since: 7.0)
Availability: CONFIG_DBUS_DISPLAY
Members:

  • data (ChardevDBus) – Configuration info for DBus chardevs

Object ChardevVCWrapper (Since: 1.5)
Members:

  • data (ChardevVC) – Configuration info for virtual console chardevs

Object ChardevRingbufWrapper (Since: 1.5)
Members:

  • data (ChardevRingbuf) – Configuration info for ring buffer chardevs

Object ChardevPtyWrapper (Since: 9.2)
Members:

  • data (ChardevPty) – Configuration info for pty chardevs

Object ChardevBackend (Since: 1.4)

Configuration info for the new chardev backend.

Members:
Object ChardevReturn (Since: 1.4)

Return info about the chardev backend just created.

Members:

  • pty (string, optional) – name of the slave pseudoterminal device, present if and only if a chardev of type ‘pty’ was created

Command chardev-add (Since: 1.4)

Add a character device backend

Arguments:

  • id (string) – the chardev’s ID, must be unique

  • backend (ChardevBackend) – backend type and parameters

Return:

ChardevReturn

Example:

-> { "execute" : "chardev-add",
     "arguments" : { "id" : "foo",
                     "backend" : { "type" : "null", "data" : {} } } }
<- { "return": {} }

Example:

-> { "execute" : "chardev-add",
     "arguments" : { "id" : "bar",
                     "backend" : { "type" : "file",
                                   "data" : { "out" : "/tmp/bar.log" } } } }
<- { "return": {} }

Example:

-> { "execute" : "chardev-add",
     "arguments" : { "id" : "baz",
                     "backend" : { "type" : "pty", "data" : {} } } }
<- { "return": { "pty" : "/dev/pty/42" } }
Command chardev-change (Since: 2.10)

Change a character device backend

Arguments:

  • id (string) – the chardev’s ID, must exist

  • backend (ChardevBackend) – new backend type and parameters

Return:

ChardevReturn

Example:

-> { "execute" : "chardev-change",
     "arguments" : { "id" : "baz",
                     "backend" : { "type" : "pty", "data" : {} } } }
<- { "return": { "pty" : "/dev/pty/42" } }

Example:

-> {"execute" : "chardev-change",
    "arguments" : {
        "id" : "charchannel2",
        "backend" : {
            "type" : "socket",
            "data" : {
                "addr" : {
                    "type" : "unix" ,
                    "data" : {
                        "path" : "/tmp/charchannel2.socket"
                    }
                 },
                 "server" : true,
                 "wait" : false }}}}
<- {"return": {}}
Command chardev-remove (Since: 1.4)

Remove a character device backend

Arguments:

  • id (string) – the chardev’s ID, must exist and not be in use

Example:

-> { "execute": "chardev-remove", "arguments": { "id" : "foo" } }
<- { "return": {} }
Command chardev-send-break (Since: 2.10)

Send a break to a character device

Arguments:

  • id (string) – the chardev’s ID, must exist

Example:

-> { "execute": "chardev-send-break", "arguments": { "id" : "foo" } }
<- { "return": {} }
Event VSERPORT_CHANGE (Since: 2.1)

Emitted when the guest opens or closes a virtio-serial port.

Members:

  • id (string) – device identifier of the virtio-serial port

  • open (boolean) – true if the guest has opened the virtio-serial port

Note

This event is rate-limited.

Example:

<- { "event": "VSERPORT_CHANGE",
     "data": { "id": "channel0", "open": true },
     "timestamp": { "seconds": 1401385907, "microseconds": 422329 } }

Dump guest memory

Enum DumpGuestMemoryFormat (Since: 2.0)

An enumeration of guest-memory-dump’s format.

Values:

  • elf – elf format

  • kdump-zlib – makedumpfile flattened, kdump-compressed format with zlib compression

  • kdump-lzo – makedumpfile flattened, kdump-compressed format with lzo compression

  • kdump-snappy – makedumpfile flattened, kdump-compressed format with snappy compression

  • kdump-raw-zlib – raw assembled kdump-compressed format with zlib compression (since 8.2)

  • kdump-raw-lzo – raw assembled kdump-compressed format with lzo compression (since 8.2)

  • kdump-raw-snappy – raw assembled kdump-compressed format with snappy compression (since 8.2)

  • win-dmp – Windows full crashdump format, can be used instead of ELF converting (since 2.13)

Command dump-guest-memory (Since: 1.2)

Dump guest’s memory to vmcore. It is a synchronous operation that can take very long depending on the amount of guest memory.

Arguments:

  • paging (boolean) –

    if true, do paging to get guest’s memory mapping. This allows using gdb to process the core file.

    Important: this option can make QEMU allocate several gigabytes of RAM. This can happen for a large guest, or a malicious guest pretending to be large.

    Also, paging=true has the following limitations:

    1. The guest may be in a catastrophic state or can have corrupted memory, which cannot be trusted

    2. The guest can be in real-mode even if paging is enabled. For example, the guest uses ACPI to sleep, and ACPI sleep state goes in real-mode

    3. Currently only supported on i386 and x86_64.

  • protocol (string) –

    the filename or file descriptor of the vmcore. The supported protocols are:

    1. file: the protocol starts with “file:”, and the following string is the file’s path.

    2. fd: the protocol starts with “fd:”, and the following string is the fd’s name.

  • detach (boolean, optional) – if true, QMP will return immediately rather than waiting for the dump to finish. The user can track progress using query-dump. (since 2.6).

  • begin (int, optional) – if specified, the starting physical address.

  • length (int, optional) – if specified, the memory size, in bytes. If you don’t want to dump all guest’s memory, please specify the start begin and length

  • format (DumpGuestMemoryFormat, optional) – if specified, the format of guest memory dump. But non-elf format is conflict with paging and filter, ie. paging, begin and length is not allowed to be specified with non-elf format at the same time (since 2.0)

Note

All boolean arguments default to false.

Example:

-> { "execute": "dump-guest-memory",
     "arguments": { "paging": false, "protocol": "fd:dump" } }
<- { "return": {} }
Enum DumpStatus (Since: 2.6)

Describe the status of a long-running background guest memory dump.

Values:

  • none – no dump-guest-memory has started yet.

  • active – there is one dump running in background.

  • completed – the last dump has finished successfully.

  • failed – the last dump has failed.

Object DumpQueryResult (Since: 2.6)

The result format for query-dump.

Members:

  • status (DumpStatus) – enum of DumpStatus, which shows current dump status

  • completed (int) – bytes written in latest dump (uncompressed)

  • total (int) – total bytes to be written in latest dump (uncompressed)

Command query-dump (Since: 2.6)

Query latest dump status.

Return:

DumpQueryResult – An object showing the dump status.

Example:

-> { "execute": "query-dump" }
<- { "return": { "status": "active", "completed": 1024000,
                 "total": 2048000 } }
Event DUMP_COMPLETED (Since: 2.6)

Emitted when background dump has completed

Members:

  • result (DumpQueryResult) – final dump status

  • error (string, optional) – human-readable error string that provides hint on why dump failed. Only presents on failure. The user should not try to interpret the error string.

Example:

<- { "event": "DUMP_COMPLETED",
     "data": { "result": { "total": 1090650112, "status": "completed",
                           "completed": 1090650112 } },
     "timestamp": { "seconds": 1648244171, "microseconds": 950316 } }
Object DumpGuestMemoryCapability (Since: 2.0)
Members:
Command query-dump-guest-memory-capability (Since: 2.0)

Return the available formats for dump-guest-memory

Return:

DumpGuestMemoryCapability – An object listing available formats for dump-guest-memory

Example:

-> { "execute": "query-dump-guest-memory-capability" }
<- { "return": { "formats":
                 ["elf", "kdump-zlib", "kdump-lzo", "kdump-snappy"] } }

Net devices

Sets the link status of a virtual network adapter.

Arguments:

  • name (string) – the device name of the virtual network adapter

  • up (boolean) – true to set the link status to be up

Errors:

  • If name is not a valid network device, DeviceNotFound

Note

Not all network adapters support setting link status. This command will succeed even if the network adapter does not support link status notification.

Example:

-> { "execute": "set_link",
     "arguments": { "name": "e1000.0", "up": false } }
<- { "return": {} }
Command netdev_add (Since: 0.14)

Add a network backend.

Additional arguments depend on the type.

Arguments:
Errors:

  • If type is not a valid network backend, DeviceNotFound

Example:

-> { "execute": "netdev_add",
     "arguments": { "type": "user", "id": "netdev1",
                    "dnssearch": [ { "str": "example.org" } ] } }
<- { "return": {} }
Command netdev_del (Since: 0.14)

Remove a network backend.

Arguments:

  • id (string) – the name of the network backend to remove

Errors:

  • If id is not a valid network backend, DeviceNotFound

Example:

-> { "execute": "netdev_del", "arguments": { "id": "netdev1" } }
<- { "return": {} }
Object NetLegacyNicOptions (Since: 1.2)

Create a new Network Interface Card.

Members:

  • netdev (string, optional) – id of -netdev to connect to

  • macaddr (string, optional) – MAC address

  • model (string, optional) – device model (e1000, rtl8139, virtio etc.)

  • addr (string, optional) – PCI device address

  • vectors (int, optional) – number of MSI-x vectors, 0 to disable MSI-X

Object String (Since: 1.2)

A fat type wrapping ‘str’, to be embedded in lists.

Members:

  • str (string) – Not documented

Object NetDevPasstOptions (Since: 10.1)
Availability: CONFIG_PASST

Unprivileged user-mode network connectivity using passt

Members:

  • path (string, optional) – Filename of the passt program to run (by default ‘passt’, and use PATH)

  • quiet (boolean, optional) – don’t print informational messages (default, passed as ‘–quiet’)

  • vhost-user (boolean, optional) – enable vhost-user

  • mtu (int, optional) – assign MTU via DHCP/NDP

  • address (string, optional) – IPv4 or IPv6 address

  • netmask (string, optional) – IPv4 mask

  • mac (string, optional) – source MAC address

  • gateway (string, optional) – IPv4 or IPv6 address as gateway

  • interface (string, optional) – interface for addresses and routes

  • outbound (string, optional) – bind to address as outbound source

  • outbound-if4 (string, optional) – bind to outbound interface for IPv4

  • outbound-if6 (string, optional) – bind to outbound interface for IPv6

  • dns (string, optional) – IPv4 or IPv6 address as DNS

  • search ([String], optional) – search domains

  • fqdn (string, optional) – FQDN to configure client with

  • dhcp-dns (boolean, optional) – enable/disable DNS list in DHCP/DHCPv6/NDP

  • dhcp-search (boolean, optional) – enable/disable list in DHCP/DHCPv6/NDP

  • map-host-loopback (string, optional) – addresse to refer to host

  • map-guest-addr (string, optional) – addr to translate to guest’s address

  • dns-forward (string, optional) – forward DNS queries sent to

  • dns-host (string, optional) – host nameserver to direct queries to

  • tcp (boolean, optional) – enable/disable TCP

  • udp (boolean, optional) – enable/disable UDP

  • icmp (boolean, optional) – enable/disable ICMP

  • dhcp (boolean, optional) – enable/disable DHCP

  • ndp (boolean, optional) – enable/disable NDP

  • dhcpv6 (boolean, optional) – enable/disable DHCPv6

  • ra (boolean, optional) – enable/disable route advertisements

  • freebind (boolean, optional) – bind to any address for forwarding

  • ipv4 (boolean, optional) – enable/disable IPv4

  • ipv6 (boolean, optional) – enable/disable IPv6

  • tcp-ports ([String], optional) – TCP ports to forward

  • udp-ports ([String], optional) – UDP ports to forward

  • param ([String], optional) – parameter to pass to passt command

Object NetdevUserOptions (Since: 1.2)

Use the user mode network stack which requires no administrator privilege to run.

Members:

  • hostname (string, optional) – client hostname reported by the builtin DHCP server

  • restrict (boolean, optional) – isolate the guest from the host

  • ipv4 (boolean, optional) – whether to support IPv4, default true for enabled (since 2.6)

  • ipv6 (boolean, optional) – whether to support IPv6, default true for enabled (since 2.6)

  • ip (string, optional) – legacy parameter, use net= instead

  • net (string, optional) – IP network address that the guest will see, in the form addr[/netmask] The netmask is optional, and can be either in the form a.b.c.d or as a number of valid top-most bits. Default is 10.0.2.0/24.

  • host (string, optional) – guest-visible address of the host

  • tftp (string, optional) – root directory of the built-in TFTP server

  • bootfile (string, optional) – BOOTP filename, for use with tftp=

  • dhcpstart (string, optional) – the first of the 16 IPs the built-in DHCP server can assign

  • dns (string, optional) – guest-visible address of the virtual nameserver

  • dnssearch ([String], optional) – list of DNS suffixes to search, passed as DHCP option to the guest

  • domainname (string, optional) – guest-visible domain name of the virtual nameserver (since 3.0)

  • ipv6-prefix (string, optional) – IPv6 network prefix (default is fec0::). The network prefix is given in the usual hexadecimal IPv6 address notation. (since 2.6)

  • ipv6-prefixlen (int, optional) – IPv6 network prefix length (default is 64) (since 2.6)

  • ipv6-host (string, optional) – guest-visible IPv6 address of the host (since 2.6)

  • ipv6-dns (string, optional) – guest-visible IPv6 address of the virtual nameserver (since 2.6)

  • smb (string, optional) – root directory of the built-in SMB server

  • smbserver (string, optional) – IP address of the built-in SMB server

  • hostfwd ([String], optional) – redirect incoming TCP, UDP or UNIX host connections to guest endpoints

  • guestfwd ([String], optional) – forward guest TCP connections

  • tftp-server-name (string, optional) – RFC2132 “TFTP server name” string (Since 3.1)

Object NetdevTapOptions (Since: 1.2)

Used to configure a host TAP network interface backend.

Members:

  • ifname (string, optional) – interface name

  • fd (string, optional) – file descriptor of an already opened tap

  • fds (string, optional) – multiple file descriptors of already opened multiqueue capable tap

  • script (string, optional) – script to initialize the interface

  • downscript (string, optional) – script to shut down the interface

  • br (string, optional) – bridge name (since 2.8)

  • helper (string, optional) – command to execute to configure bridge

  • sndbuf (int, optional) – send buffer limit. Understands [TGMKkb] suffixes.

  • vnet_hdr (boolean, optional) – enable the IFF_VNET_HDR flag on the tap interface

  • vhost (boolean, optional) – enable vhost-net network accelerator

  • vhostfd (string, optional) – file descriptor of an already opened vhost net device

  • vhostfds (string, optional) – file descriptors of multiple already opened vhost net devices

  • vhostforce (boolean, optional) – vhost on for non-MSIX virtio guests

  • queues (int, optional) – number of queues to be created for multiqueue capable tap

  • poll-us (int, optional) – maximum number of microseconds that could be spent on busy polling for tap (since 2.7)

Object NetdevSocketOptions (Since: 1.2)

Socket netdevs are used to establish a network connection to another QEMU virtual machine via a TCP socket.

Members:

  • fd (string, optional) – file descriptor of an already opened socket

  • listen (string, optional) – port number, and optional hostname, to listen on

  • connect (string, optional) – port number, and optional hostname, to connect to

  • mcast (string, optional) – UDP multicast address and port number

  • localaddr (string, optional) – source address and port for multicast and udp packets

  • udp (string, optional) – UDP unicast address and port number

Object NetdevL2TPv3Options (Since: 2.1)

Configure an Ethernet over L2TPv3 tunnel.

Members:

  • src (string) – source address

  • dst (string) – destination address

  • srcport (string, optional) – source port - mandatory for udp, optional for ip

  • dstport (string, optional) – destination port - mandatory for udp, optional for ip

  • ipv6 (boolean, optional) – force the use of ipv6

  • udp (boolean, optional) – use the udp version of l2tpv3 encapsulation

  • cookie64 (boolean, optional) – use 64 bit cookies

  • counter (boolean, optional) – have sequence counter

  • pincounter (boolean, optional) – pin sequence counter to zero - workaround for buggy implementations or networks with packet reorder

  • txcookie (int, optional) – 32 or 64 bit transmit cookie

  • rxcookie (int, optional) – 32 or 64 bit receive cookie

  • txsession (int) – 32 bit transmit session

  • rxsession (int, optional) – 32 bit receive session - if not specified set to the same value as transmit

  • offset (int, optional) – additional offset - allows the insertion of additional application-specific data before the packet payload

Object NetdevVdeOptions (Since: 1.2)

Connect to a vde switch running on the host.

Members:

  • sock (string, optional) – socket path

  • port (int, optional) – port number

  • group (string, optional) – group owner of socket

  • mode (int, optional) – permissions for socket

Object NetdevBridgeOptions (Since: 1.2)

Connect a host TAP network interface to a host bridge device.

Members:

  • br (string, optional) – bridge name

  • helper (string, optional) – command to execute to configure bridge

Object NetdevHubPortOptions (Since: 1.2)

Connect two or more net clients through a software hub.

Members:

  • hubid (int) – hub identifier number

  • netdev (string, optional) – used to connect hub to a netdev instead of a device (since 2.12)

Object NetdevNetmapOptions (Since: 2.0)

Connect a client to a netmap-enabled NIC or to a VALE switch port

Members:

  • ifname (string) – Either the name of an existing network interface supported by netmap, or the name of a VALE port (created on the fly). A VALE port name is in the form ‘valeXXX:YYY’, where XXX and YYY are non-negative integers. XXX identifies a switch and YYY identifies a port of the switch. VALE ports having the same XXX are therefore connected to the same switch.

  • devname (string, optional) – path of the netmap device (default: ‘/dev/netmap’).

Enum AFXDPMode (Since: 8.2)
Availability: CONFIG_AF_XDP

Attach mode for a default XDP program

Values:

  • skb – generic mode, no driver support necessary

  • native – DRV mode, program is attached to a driver, packets are passed to the socket without allocation of skb.

Object NetdevAFXDPOptions (Since: 8.2)
Availability: CONFIG_AF_XDP

AF_XDP network backend

Members:

  • ifname (string) – The name of an existing network interface.

  • mode (AFXDPMode, optional) – Attach mode for a default XDP program. If not specified, then ‘native’ will be tried first, then ‘skb’.

  • force-copy (boolean, optional) – Force XDP copy mode even if device supports zero-copy. (default: false)

  • queues (int, optional) – number of queues to be used for multiqueue interfaces (default: 1).

  • start-queue (int, optional) – Use queues starting from this queue number (default: 0).

  • inhibit (boolean, optional) – Don’t load a default XDP program, use one already loaded to the interface (default: false). Requires sock-fds or map-path.

  • sock-fds (string, optional) – A colon (:) separated list of file descriptors for already open but not bound AF_XDP sockets in the queue order. One fd per queue. These descriptors should already be added into XDP socket map for corresponding queues. sock-fds and map-path are mutually exclusive. Requires inhibit.

  • map-path (string, optional) – The path to a pinned xsk map to push file descriptors for bound AF_XDP sockets into. map-path and sock-fds are mutually exclusive. Requires inhibit. (Since 10.1)

  • map-start-index (int, optional) – Use map-path to insert xsk sockets starting from this index number (default: 0). Requires map-path. (Since 10.1)

Object NetdevVhostUserOptions (Since: 2.1)

Vhost-user network backend

Members:

  • chardev (string) – name of a unix socket chardev

  • vhostforce (boolean, optional) – vhost on for non-MSIX virtio guests (default: false).

  • queues (int, optional) – number of queues to be created for multiqueue vhost-user (default: 1) (Since 2.5)

Object NetdevVhostVDPAOptions (Since: 5.1)

Vhost-vdpa network backend

vDPA device is a device that uses a datapath which complies with the virtio specifications with a vendor specific control path.

Members:

  • vhostdev (string, optional) – path of vhost-vdpa device (default:’/dev/vhost-vdpa-0’)

  • vhostfd (string, optional) – file descriptor of an already opened vhost vdpa device

  • queues (int, optional) – number of queues to be created for multiqueue vhost-vdpa (default: 1)

  • x-svq (boolean, optional) – Start device with (experimental) shadow virtqueue. (Since 7.1) (default: false)

Features:

  • unstable – Member x-svq is experimental.

Object NetdevVmnetHostOptions (Since: 7.1)
Availability: CONFIG_VMNET

vmnet (host mode) network backend.

Allows the vmnet interface to communicate with other vmnet interfaces that are in host mode and also with the host.

Members:

  • start-address (string, optional) – The starting IPv4 address to use for the interface. Must be in the private IP range (RFC 1918). Must be specified along with end-address and subnet-mask. This address is used as the gateway address. The subsequent address up to and including end-address are placed in the DHCP pool.

  • end-address (string, optional) – The DHCP IPv4 range end address to use for the interface. Must be in the private IP range (RFC 1918). Must be specified along with start-address and subnet-mask.

  • subnet-mask (string, optional) – The IPv4 subnet mask to use on the interface. Must be specified along with start-address and subnet-mask.

  • isolated (boolean, optional) – Enable isolation for this interface. Interface isolation ensures that vmnet interface is not able to communicate with any other vmnet interfaces. Only communication with host is allowed. Requires at least macOS Big Sur 11.0.

  • net-uuid (string, optional) – The identifier (UUID) to uniquely identify the isolated network vmnet interface should be added to. If set, no DHCP service is provided for this interface and network communication is allowed only with other interfaces added to this network identified by the UUID. Requires at least macOS Big Sur 11.0.

Object NetdevVmnetSharedOptions (Since: 7.1)
Availability: CONFIG_VMNET

vmnet (shared mode) network backend.

Allows traffic originating from the vmnet interface to reach the Internet through a network address translator (NAT). The vmnet interface can communicate with the host and with other shared mode interfaces on the same subnet. If no DHCP settings, subnet mask and IPv6 prefix specified, the interface can communicate with any of other interfaces in shared mode.

Members:

  • start-address (string, optional) – The starting IPv4 address to use for the interface. Must be in the private IP range (RFC 1918). Must be specified along with end-address and subnet-mask. This address is used as the gateway address. The subsequent address up to and including end-address are placed in the DHCP pool.

  • end-address (string, optional) – The DHCP IPv4 range end address to use for the interface. Must be in the private IP range (RFC 1918). Must be specified along with start-address and subnet-mask.

  • subnet-mask (string, optional) – The IPv4 subnet mask to use on the interface. Must be specified along with start-address and subnet-mask.

  • isolated (boolean, optional) – Enable isolation for this interface. Interface isolation ensures that vmnet interface is not able to communicate with any other vmnet interfaces. Only communication with host is allowed. Requires at least macOS Big Sur 11.0.

  • nat66-prefix (string, optional) – The IPv6 prefix to use into guest network. Must be a unique local address i.e. start with fd00::/8 and have length of 64.

Object NetdevVmnetBridgedOptions (Since: 7.1)
Availability: CONFIG_VMNET

vmnet (bridged mode) network backend.

Bridges the vmnet interface with a physical network interface.

Members:

  • ifname (string) – The name of the physical interface to be bridged.

  • isolated (boolean, optional) – Enable isolation for this interface. Interface isolation ensures that vmnet interface is not able to communicate with any other vmnet interfaces. Only communication with host is allowed. Requires at least macOS Big Sur 11.0.

Object NetdevStreamOptions (Since: 7.2)

Configuration info for stream socket netdev

Members:

  • addr (SocketAddress) – socket address to listen on (server=true) or connect to (server=false)

  • server (boolean, optional) – create server socket (default: false)

  • reconnect-ms (int, optional) – For a client socket, if a socket is disconnected, then attempt a reconnect after the given number of milliseconds. Setting this to zero disables this function. (default: 0) (Since: 9.2)

Only SocketAddress types ‘unix’, ‘inet’ and ‘fd’ are supported.

Object NetdevDgramOptions (Since: 7.2)

Configuration info for datagram socket netdev.

Members:

Only SocketAddress types ‘unix’, ‘inet’ and ‘fd’ are supported.

If remote address is present and it’s a multicast address, local address is optional. Otherwise local address is required and remote address is optional.

Valid parameters combination table

remote

local

okay?

absent

absent

no

absent

not fd

no

absent

fd

yes

multicast

absent

yes

multicast

present

yes

not multicast

absent

no

not multicast

present

yes
Enum NetClientDriver (Since: 2.7)

Available netdev drivers.

Values:

  • l2tpv3 – since 2.1

  • vhost-vdpa – since 5.1

  • vmnet-host – since 7.1

  • vmnet-shared – since 7.1

  • vmnet-bridged – since 7.1

  • stream – since 7.2

  • dgram – since 7.2

  • af-xdp – since 8.2

  • passt – since 10.1

  • none – Not documented

  • nic – Not documented

  • user – Not documented

  • tap – Not documented

  • socket – Not documented

  • vde – Not documented

  • bridge – Not documented

  • hubport – Not documented

  • netmap – Not documented

  • vhost-user – Not documented

Object Netdev (Since: 1.2)

Captures the configuration of a network device.

Members:
Enum RxState (Since: 1.6)

Packets receiving state

Values:

  • normal – filter assigned packets according to the mac-table

  • none – don’t receive any assigned packet

  • all – receive all assigned packets

Object RxFilterInfo (Since: 1.6)

Rx-filter information for a NIC.

Members:

  • name (string) – net client name

  • promiscuous (boolean) – whether promiscuous mode is enabled

  • multicast (RxState) – multicast receive state

  • unicast (RxState) – unicast receive state

  • vlan (RxState) – vlan receive state (Since 2.0)

  • broadcast-allowed (boolean) – whether to receive broadcast

  • multicast-overflow (boolean) – multicast table is overflowed or not

  • unicast-overflow (boolean) – unicast table is overflowed or not

  • main-mac (string) – the main macaddr string

  • vlan-table ([int]) – a list of active vlan id

  • unicast-table ([string]) – a list of unicast macaddr string

  • multicast-table ([string]) – a list of multicast macaddr string

Command query-rx-filter (Since: 1.6)

Return rx-filter information for all NICs (or for the given NIC).

Arguments:

  • name (string, optional) – net client name

Return:

[RxFilterInfo] – list of info for all NICs (or for the given NIC).

Errors:

  • if the given name doesn’t exist

  • if the given NIC doesn’t support rx-filter querying

  • if the given net client isn’t a NIC

Example:

-> { "execute": "query-rx-filter", "arguments": { "name": "vnet0" } }
<- { "return": [
        {
            "promiscuous": true,
            "name": "vnet0",
            "main-mac": "52:54:00:12:34:56",
            "unicast": "normal",
            "vlan": "normal",
            "vlan-table": [
                4,
                0
            ],
            "unicast-table": [
            ],
            "multicast": "normal",
            "multicast-overflow": false,
            "unicast-overflow": false,
            "multicast-table": [
                "01:00:5e:00:00:01",
                "33:33:00:00:00:01",
                "33:33:ff:12:34:56"
            ],
            "broadcast-allowed": false
        }
      ]
   }
Event NIC_RX_FILTER_CHANGED (Since: 1.6)

Emitted once until the query-rx-filter command is executed, the first event will always be emitted

Members:

  • name (string, optional) – net client name

  • path (string) – device path

Example:

<- { "event": "NIC_RX_FILTER_CHANGED",
     "data": { "name": "vnet0",
               "path": "/machine/peripheral/vnet0/virtio-backend" },
     "timestamp": { "seconds": 1368697518, "microseconds": 326866 } }
Object AnnounceParameters (Since: 4.0)

Parameters for self-announce timers

Members:

  • initial (int) – Initial delay (in ms) before sending the first GARP/RARP announcement

  • max (int) – Maximum delay (in ms) between GARP/RARP announcement packets

  • rounds (int) – Number of self-announcement attempts

  • step (int) – Delay increase (in ms) after each self-announcement attempt

  • interfaces ([string], optional) – An optional list of interface names, which restricts the announcement to the listed interfaces. (Since 4.1)

  • id (string, optional) – A name to be used to identify an instance of announce-timers and to allow it to modified later. Not for use as part of the migration parameters. (Since 4.1)

Command announce-self (Since: 4.0)

Trigger generation of broadcast RARP frames to update network switches. This can be useful when network bonds fail-over the active slave.

Arguments:

Example:

-> { "execute": "announce-self",
     "arguments": {
         "initial": 50, "max": 550, "rounds": 10, "step": 50,
         "interfaces": ["vn2", "vn3"], "id": "bob" } }
<- { "return": {} }
Event FAILOVER_NEGOTIATED (Since: 4.2)

Emitted when VIRTIO_NET_F_STANDBY was enabled during feature negotiation. Failover primary devices which were hidden (not hotplugged when requested) before will now be hotplugged by the virtio-net standby device.

Members:

  • device-id (string) – QEMU device id of the unplugged device

Example:

<- { "event": "FAILOVER_NEGOTIATED",
     "data": { "device-id": "net1" },
     "timestamp": { "seconds": 1368697518, "microseconds": 326866 } }
Event NETDEV_STREAM_CONNECTED (Since: 7.2)

Emitted when the netdev stream backend is connected

Members:

  • netdev-id (string) – QEMU netdev id that is connected

  • addr (SocketAddress) – The destination address

Example:

<- { "event": "NETDEV_STREAM_CONNECTED",
     "data": { "netdev-id": "netdev0",
               "addr": { "port": "47666", "ipv6": true,
                         "host": "::1", "type": "inet" } },
     "timestamp": { "seconds": 1666269863, "microseconds": 311222 } }

Example:

<- { "event": "NETDEV_STREAM_CONNECTED",
     "data": { "netdev-id": "netdev0",
               "addr": { "path": "/tmp/qemu0", "type": "unix" } },
     "timestamp": { "seconds": 1666269706, "microseconds": 413651 } }
Event NETDEV_STREAM_DISCONNECTED (Since: 7.2)

Emitted when the netdev stream backend is disconnected

Members:

  • netdev-id (string) – QEMU netdev id that is disconnected

Example:

<- { "event": "NETDEV_STREAM_DISCONNECTED",
     "data": {"netdev-id": "netdev0"},
     "timestamp": {"seconds": 1663330937, "microseconds": 526695} }
Event NETDEV_VHOST_USER_CONNECTED (Since: 10.0)

Emitted when the vhost-user chardev is connected

Members:

  • netdev-id (string) – QEMU netdev id that is connected

  • chardev-id (string) – The character device id used by the QEMU netdev

Example:

<- { "timestamp": {"seconds": 1739538638, "microseconds": 354181 },
     "event": "NETDEV_VHOST_USER_CONNECTED",
     "data": { "netdev-id": "netdev0", "chardev-id": "chr0" } }
Event NETDEV_VHOST_USER_DISCONNECTED (Since: 10.0)

Emitted when the vhost-user chardev is disconnected

Members:

  • netdev-id (string) – QEMU netdev id that is disconnected

Example:

<- { "timestamp": { "seconds": 1739538634, "microseconds": 920450 },
     "event": "NETDEV_VHOST_USER_DISCONNECTED",
     "data": { "netdev-id": "netdev0" } }

eBPF Objects

eBPF object is an ELF binary that contains the eBPF program and eBPF map description(BTF). Overall, eBPF object should contain the program and enough metadata to create/load eBPF with libbpf. As the eBPF maps/program should correspond to QEMU, the eBPF can’t be used from different QEMU build.

Currently, there is a possible eBPF for receive-side scaling (RSS).

Object EbpfObject (Since: 9.0)
Availability: CONFIG_EBPF

An eBPF ELF object.

Members:

  • object (string) – the eBPF object encoded in base64

Enum EbpfProgramID (Since: 9.0)
Availability: CONFIG_EBPF

The eBPF programs that can be gotten with request-ebpf.

Values:

  • rss – Receive side scaling, technology that allows steering traffic between queues by calculation hash. Users may set up indirection table and hash/packet types configurations. Used with virtio-net.

Command request-ebpf (Since: 9.0)
Availability: CONFIG_EBPF

Retrieve an eBPF object that can be loaded with libbpf. Management applications (e.g. libvirt) may load it and pass file descriptors to QEMU, so they can run running QEMU without BPF capabilities.

Arguments:
Return:

EbpfObject – eBPF object encoded in base64.

Rocker switch device

Object RockerSwitch (Since: 2.4)

Rocker switch information.

Members:

  • name (string) – switch name

  • id (int) – switch ID

  • ports (int) – number of front-panel ports

Command query-rocker (Since: 2.4)

Return rocker switch information.

Arguments:

  • name (string) – switch name

Return:

RockerSwitch

Example:

-> { "execute": "query-rocker", "arguments": { "name": "sw1" } }
<- { "return": {"name": "sw1", "ports": 2, "id": 1327446905938}}
Enum RockerPortDuplex (Since: 2.4)

An enumeration of port duplex states.

Values:

  • half – half duplex

  • full – full duplex

Enum RockerPortAutoneg (Since: 2.4)

An enumeration of port autoneg states.

Values:

  • off – autoneg is off

  • on – autoneg is on

Object RockerPort (Since: 2.4)

Rocker switch port information.

Members:

  • name (string) – port name

  • enabled (boolean) – port is enabled for I/O

  • link-up (boolean) – physical link is UP on port

  • speed (int) – port link speed in Mbps

  • duplex (RockerPortDuplex) – port link duplex

  • autoneg (RockerPortAutoneg) – port link autoneg

Command query-rocker-ports (Since: 2.4)

Return rocker switch port information.

Arguments:

  • name (string) – port name

Return:

[RockerPort]

Example:

-> { "execute": "query-rocker-ports", "arguments": { "name": "sw1" } }
<- { "return": [ {"duplex": "full", "enabled": true, "name": "sw1.1",
                  "autoneg": "off", "link-up": true, "speed": 10000},
                 {"duplex": "full", "enabled": true, "name": "sw1.2",
                  "autoneg": "off", "link-up": true, "speed": 10000}
   ]}
Object RockerOfDpaFlowKey (Since: 2.4)

Rocker switch OF-DPA flow key

Members:

  • priority (int) – key priority, 0 being lowest priority

  • tbl-id (int) – flow table ID

  • in-pport (int, optional) – physical input port

  • tunnel-id (int, optional) – tunnel ID

  • vlan-id (int, optional) – VLAN ID

  • eth-type (int, optional) – Ethernet header type

  • eth-src (string, optional) – Ethernet header source MAC address

  • eth-dst (string, optional) – Ethernet header destination MAC address

  • ip-proto (int, optional) – IP Header protocol field

  • ip-tos (int, optional) – IP header TOS field

  • ip-dst (string, optional) – IP header destination address

Note

Optional members may or may not appear in the flow key depending if they’re relevant to the flow key.

Object RockerOfDpaFlowMask (Since: 2.4)

Rocker switch OF-DPA flow mask

Members:

  • in-pport (int, optional) – physical input port

  • tunnel-id (int, optional) – tunnel ID

  • vlan-id (int, optional) – VLAN ID

  • eth-src (string, optional) – Ethernet header source MAC address

  • eth-dst (string, optional) – Ethernet header destination MAC address

  • ip-proto (int, optional) – IP Header protocol field

  • ip-tos (int, optional) – IP header TOS field

Note

Optional members may or may not appear in the flow mask depending if they’re relevant to the flow mask.

Object RockerOfDpaFlowAction (Since: 2.4)

Rocker switch OF-DPA flow action

Members:

  • goto-tbl (int, optional) – next table ID

  • group-id (int, optional) – group ID

  • tunnel-lport (int, optional) – tunnel logical port ID

  • vlan-id (int, optional) – VLAN ID

  • new-vlan-id (int, optional) – new VLAN ID

  • out-pport (int, optional) – physical output port

Note

Optional members may or may not appear in the flow action depending if they’re relevant to the flow action.

Object RockerOfDpaFlow (Since: 2.4)

Rocker switch OF-DPA flow

Members:
Command query-rocker-of-dpa-flows (Since: 2.4)

Return rocker OF-DPA flow information.

Arguments:

  • name (string) – switch name

  • tbl-id (int, optional) – flow table ID. If tbl-id is not specified, returns flow information for all tables.

Return:

[RockerOfDpaFlow] – rocker OF-DPA flow information

Example:

-> { "execute": "query-rocker-of-dpa-flows",
     "arguments": { "name": "sw1" } }
<- { "return": [ {"key": {"in-pport": 0, "priority": 1, "tbl-id": 0},
                  "hits": 138,
                  "cookie": 0,
                  "action": {"goto-tbl": 10},
                  "mask": {"in-pport": 4294901760}
                 },
                 ...
   ]}
Object RockerOfDpaGroup (Since: 2.4)

Rocker switch OF-DPA group

Members:

  • id (int) – group unique ID

  • type (int) – group type

  • vlan-id (int, optional) – VLAN ID

  • pport (int, optional) – physical port number

  • index (int, optional) – group index, unique with group type

  • out-pport (int, optional) – output physical port number

  • group-id (int, optional) – next group ID

  • set-vlan-id (int, optional) – VLAN ID to set

  • pop-vlan (int, optional) – pop VLAN headr from packet

  • group-ids ([int], optional) – list of next group IDs

  • set-eth-src (string, optional) – set source MAC address in Ethernet header

  • set-eth-dst (string, optional) – set destination MAC address in Ethernet header

  • ttl-check (int, optional) – perform TTL check

Note

Optional members may or may not appear in the group depending if they’re relevant to the group type.

Command query-rocker-of-dpa-groups (Since: 2.4)

Return rocker OF-DPA group information.

Arguments:

  • name (string) – switch name

  • type (int, optional) – group type. If type is not specified, returns group information for all group types.

Return:

[RockerOfDpaGroup] – rocker OF-DPA group information

Example:

-> { "execute": "query-rocker-of-dpa-groups",
     "arguments": { "name": "sw1" } }
<- { "return": [ {"type": 0, "out-pport": 2,
                  "pport": 2, "vlan-id": 3841,
                  "pop-vlan": 1, "id": 251723778},
                 {"type": 0, "out-pport": 0,
                  "pport": 0, "vlan-id": 3841,
                  "pop-vlan": 1, "id": 251723776},
                 {"type": 0, "out-pport": 1,
                  "pport": 1, "vlan-id": 3840,
                  "pop-vlan": 1, "id": 251658241},
                 {"type": 0, "out-pport": 0,
                  "pport": 0, "vlan-id": 3840,
                  "pop-vlan": 1, "id": 251658240}
   ]}

TPM (trusted platform module) devices

Enum TpmModel (Since: 1.5)
Availability: CONFIG_TPM

An enumeration of TPM models

Values:

  • tpm-tis – TPM TIS model

  • tpm-crb – TPM CRB model (since 2.12)

  • tpm-spapr – TPM SPAPR model (since 5.0)

Command query-tpm-models (Since: 1.5)
Availability: CONFIG_TPM

Return a list of supported TPM models

Return:

[TpmModel]

Example:

-> { "execute": "query-tpm-models" }
<- { "return": [ "tpm-tis", "tpm-crb", "tpm-spapr" ] }
Enum TpmType (Since: 1.5)
Availability: CONFIG_TPM

An enumeration of TPM types

Values:

  • passthrough – TPM passthrough type

  • emulator – Software Emulator TPM type (since 2.11)

Command query-tpm-types (Since: 1.5)
Availability: CONFIG_TPM

Return a list of supported TPM types

Return:

[TpmType]

Example:

-> { "execute": "query-tpm-types" }
<- { "return": [ "passthrough", "emulator" ] }
Object TPMPassthroughOptions (Since: 1.5)
Availability: CONFIG_TPM

Information about the TPM passthrough type

Members:

  • path (string, optional) – string describing the path used for accessing the TPM device

  • cancel-path (string, optional) – string showing the TPM’s sysfs cancel file for cancellation of TPM commands while they are executing

Object TPMEmulatorOptions (Since: 2.11)
Availability: CONFIG_TPM

Information about the TPM emulator type

Members:

  • chardev (string) – Name of a unix socket chardev

Object TPMPassthroughOptionsWrapper (Since: 1.5)
Availability: CONFIG_TPM
Members:
Object TPMEmulatorOptionsWrapper (Since: 2.11)
Availability: CONFIG_TPM
Members:
Object TpmTypeOptions (Since: 1.5)
Availability: CONFIG_TPM

A union referencing different TPM backend types’ configuration options

Members:

  • type (TpmType) –

    • ‘passthrough’ The configuration options for the TPM passthrough type

    • ’emulator’ The configuration options for TPM emulator backend type

  • When type is passthrough: The members of TPMPassthroughOptionsWrapper.

  • When type is emulator: The members of TPMEmulatorOptionsWrapper.

Object TPMInfo (Since: 1.5)
Availability: CONFIG_TPM

Information about the TPM

Members:

  • id (string) – The Id of the TPM

  • model (TpmModel) – The TPM frontend model

  • options (TpmTypeOptions) – The TPM (backend) type configuration options

Command query-tpm (Since: 1.5)
Availability: CONFIG_TPM

Return information about the TPM device

Return:

[TPMInfo]

Example:

-> { "execute": "query-tpm" }
<- { "return":
     [
       { "model": "tpm-tis",
         "options":
           { "type": "passthrough",
             "data":
               { "cancel-path": "/sys/class/misc/tpm0/device/cancel",
                 "path": "/dev/tpm0"
               }
           },
         "id": "tpm0"
       }
     ]
   }

Remote desktop

Enum DisplayProtocol (Since: 7.0)

Display protocols which support changing password options.

Values:

  • vnc – Not documented

  • spice – Not documented

Enum SetPasswordAction (Since: 7.0)

An action to take on changing a password on a connection with active clients.

Values:

  • keep – maintain existing clients

  • fail – fail the command if clients are connected

  • disconnect – disconnect existing clients

Object SetPasswordOptions (Since: 7.0)

Options for set_password.

Members:

  • protocol (DisplayProtocol) –

    • ‘vnc’ to modify the VNC server password

    • ’spice’ to modify the Spice server password

  • password (string) – the new password

  • connected (SetPasswordAction, optional) – How to handle existing clients when changing the password. If nothing is specified, defaults to ‘keep’. For VNC, only ‘keep’ is currently implemented.

  • When protocol is vnc: The members of SetPasswordOptionsVnc.

Object SetPasswordOptionsVnc (Since: 7.0)

Options for set_password specific to the VNC protocol.

Members:

  • display (string, optional) – The id of the display where the password should be changed. Defaults to the first.

Command set_password (Since: 0.14)

Set the password of a remote display server.

Arguments:
Errors:

  • If Spice is not enabled, DeviceNotFound

Example:

-> { "execute": "set_password", "arguments": { "protocol": "vnc",
                                               "password": "secret" } }
<- { "return": {} }
Object ExpirePasswordOptions (Since: 7.0)

General options for expire_password.

Members:

  • protocol (DisplayProtocol) –

    • ‘vnc’ to modify the VNC server expiration

    • ’spice’ to modify the Spice server expiration

  • time (string) –

    when to expire the password.

    • ’now’ to expire the password immediately

    • ’never’ to cancel password expiration

    • ’+INT’ where INT is the number of seconds from now (integer)

    • ’INT’ where INT is the absolute time in seconds

  • When protocol is vnc: The members of ExpirePasswordOptionsVnc.

Note

Time is relative to the server and currently there is no way to coordinate server time with client time. It is not recommended to use the absolute time version of the time parameter unless you’re sure you are on the same machine as the QEMU instance.

Object ExpirePasswordOptionsVnc (Since: 7.0)

Options for expire_password specific to the VNC protocol.

Members:

  • display (string, optional) – The id of the display where the expiration should be changed. Defaults to the first.

Command expire_password (Since: 0.14)

Expire the password of a remote display server.

Arguments:
Errors:

  • If protocol is ‘spice’ and Spice is not active, DeviceNotFound

Example:

-> { "execute": "expire_password", "arguments": { "protocol": "vnc",
                                                  "time": "+60" } }
<- { "return": {} }
Enum ImageFormat (Since: 7.1)

Supported image format types.

Values:

  • png – PNG format

  • ppm – PPM format

Command screendump (Since: 0.14)
Availability: CONFIG_PIXMAN

Capture the contents of a screen and write it to a file.

Arguments:

  • filename (string) – the path of a new file to store the image

  • device (string, optional) – ID of the display device that should be dumped. If this parameter is missing, the primary display will be used. (Since 2.12)

  • head (int, optional) – head to use in case the device supports multiple heads. If this parameter is missing, head #0 will be used. Also note that the head can only be specified in conjunction with the device ID. (Since 2.12)

  • format (ImageFormat, optional) – image format for screendump. (default: ppm) (Since 7.1)

Example:

-> { "execute": "screendump",
     "arguments": { "filename": "/tmp/image" } }
<- { "return": {} }

Spice

Object SpiceBasicInfo (Since: 2.1)
Availability: CONFIG_SPICE

The basic information for SPICE network connection

Members:

  • host (string) – IP address

  • port (string) – port number

  • family (NetworkAddressFamily) – address family

Object SpiceServerInfo (Since: 2.1)
Availability: CONFIG_SPICE

Information about a SPICE server

Members:

  • auth (string, optional) – authentication method

  • The members of SpiceBasicInfo.

Object SpiceChannel (Since: 0.14)
Availability: CONFIG_SPICE

Information about a SPICE client channel.

Members:

  • connection-id (int) – SPICE connection id number. All channels with the same id belong to the same SPICE session.

  • channel-type (int) – SPICE channel type number. “1” is the main control channel, filter for this one if you want to track spice sessions only

  • channel-id (int) – SPICE channel ID number. Usually “0”, might be different when multiple channels of the same type exist, such as multiple display channels in a multihead setup

  • tls (boolean) – true if the channel is encrypted, false otherwise.

  • The members of SpiceBasicInfo.

Enum SpiceQueryMouseMode (Since: 1.1)
Availability: CONFIG_SPICE

An enumeration of Spice mouse states.

Values:

  • client – Mouse cursor position is determined by the client.

  • server – Mouse cursor position is determined by the server.

  • unknown – No information is available about mouse mode used by the spice server.

Object SpiceInfo (Since: 0.14)
Availability: CONFIG_SPICE

Information about the SPICE session.

Members:

  • enabled (boolean) – true if the SPICE server is enabled, false otherwise

  • migrated (boolean) – true if the last guest migration completed and spice migration had completed as well, false otherwise (since 1.4)

  • host (string, optional) – The hostname the SPICE server is bound to. This depends on the name resolution on the host and may be an IP address.

  • port (int, optional) – The SPICE server’s port number.

  • compiled-version (string, optional) – SPICE server version.

  • tls-port (int, optional) – The SPICE server’s TLS port number.

  • auth (string, optional) –

    the current authentication type used by the server

    • ’none’ if no authentication is being used

    • ’spice’ uses SASL or direct TLS authentication, depending on command line options

  • mouse-mode (SpiceQueryMouseMode) – The mode in which the mouse cursor is displayed currently. Can be determined by the client or the server, or unknown if spice server doesn’t provide this information. (since: 1.1)

  • channels ([SpiceChannel], optional) – a list of SpiceChannel for each active spice channel

Command query-spice (Since: 0.14)
Availability: CONFIG_SPICE

Return information about the current SPICE server

Return:

SpiceInfo

Example:

-> { "execute": "query-spice" }
<- { "return": {
         "enabled": true,
         "auth": "spice",
         "port": 5920,
         "migrated":false,
         "tls-port": 5921,
         "host": "0.0.0.0",
         "mouse-mode":"client",
         "channels": [
            {
               "port": "54924",
               "family": "ipv4",
               "channel-type": 1,
               "connection-id": 1804289383,
               "host": "127.0.0.1",
               "channel-id": 0,
               "tls": true
            },
            {
               "port": "36710",
               "family": "ipv4",
               "channel-type": 4,
               "connection-id": 1804289383,
               "host": "127.0.0.1",
               "channel-id": 0,
               "tls": false
            },
            ...
         ]
      }
   }
Event SPICE_CONNECTED (Since: 0.14)
Availability: CONFIG_SPICE

Emitted when a SPICE client establishes a connection

Members:

Example:

<- { "timestamp": {"seconds": 1290688046, "microseconds": 388707},
     "event": "SPICE_CONNECTED",
     "data": {
       "server": { "port": "5920", "family": "ipv4", "host": "127.0.0.1"},
       "client": {"port": "52873", "family": "ipv4", "host": "127.0.0.1"}
   }}
Event SPICE_INITIALIZED (Since: 0.14)
Availability: CONFIG_SPICE

Emitted after initial handshake and authentication takes place (if any) and the SPICE channel is up and running

Members:

Example:

<- { "timestamp": {"seconds": 1290688046, "microseconds": 417172},
     "event": "SPICE_INITIALIZED",
     "data": {"server": {"auth": "spice", "port": "5921",
                         "family": "ipv4", "host": "127.0.0.1"},
              "client": {"port": "49004", "family": "ipv4", "channel-type": 3,
                         "connection-id": 1804289383, "host": "127.0.0.1",
                         "channel-id": 0, "tls": true}
   }}
Event SPICE_DISCONNECTED (Since: 0.14)
Availability: CONFIG_SPICE

Emitted when the SPICE connection is closed

Members:

Example:

<- { "timestamp": {"seconds": 1290688046, "microseconds": 388707},
     "event": "SPICE_DISCONNECTED",
     "data": {
       "server": { "port": "5920", "family": "ipv4", "host": "127.0.0.1"},
       "client": {"port": "52873", "family": "ipv4", "host": "127.0.0.1"}
   }}
Event SPICE_MIGRATE_COMPLETED (Since: 1.3)
Availability: CONFIG_SPICE

Emitted when SPICE migration has completed

Example:

<- { "timestamp": {"seconds": 1290688046, "microseconds": 417172},
     "event": "SPICE_MIGRATE_COMPLETED" }

VNC

Object VncBasicInfo (Since: 2.1)
Availability: CONFIG_VNC

The basic information for vnc network connection

Members:

  • host (string) – IP address

  • service (string) – The service name of the vnc port. This may depend on the host system’s service database so symbolic names should not be relied on.

  • family (NetworkAddressFamily) – address family

  • websocket (boolean) – true in case the socket is a websocket (since 2.3).

Object VncServerInfo (Since: 2.1)
Availability: CONFIG_VNC

The network connection information for server

Members:

  • auth (string, optional) – authentication method used for the plain (non-websocket) VNC server

  • The members of VncBasicInfo.

Object VncClientInfo (Since: 0.14)
Availability: CONFIG_VNC

Information about a connected VNC client.

Members:

  • x509_dname (string, optional) – If x509 authentication is in use, the Distinguished Name of the client.

  • sasl_username (string, optional) – If SASL authentication is in use, the SASL username used for authentication.

  • The members of VncBasicInfo.

Object VncInfo (Since: 0.14)
Availability: CONFIG_VNC

Information about the VNC session.

Members:

  • enabled (boolean) – true if the VNC server is enabled, false otherwise

  • host (string, optional) – The hostname the VNC server is bound to. This depends on the name resolution on the host and may be an IP address.

  • family (NetworkAddressFamily, optional) –

    • ‘ipv6’ if the host is listening for IPv6 connections

    • ’ipv4’ if the host is listening for IPv4 connections

    • ’unix’ if the host is listening on a unix domain socket

    • ’unknown’ otherwise

  • service (string, optional) – The service name of the server’s port. This may depends on the host system’s service database so symbolic names should not be relied on.

  • auth (string, optional) –

    the current authentication type used by the server

    • ’none’ if no authentication is being used

    • ’vnc’ if VNC authentication is being used

    • ’vencrypt+plain’ if VEncrypt is used with plain text authentication

    • ’vencrypt+tls+none’ if VEncrypt is used with TLS and no authentication

    • ’vencrypt+tls+vnc’ if VEncrypt is used with TLS and VNC authentication

    • ’vencrypt+tls+plain’ if VEncrypt is used with TLS and plain text auth

    • ’vencrypt+x509+none’ if VEncrypt is used with x509 and no auth

    • ’vencrypt+x509+vnc’ if VEncrypt is used with x509 and VNC auth

    • ’vencrypt+x509+plain’ if VEncrypt is used with x509 and plain text auth

    • ’vencrypt+tls+sasl’ if VEncrypt is used with TLS and SASL auth

    • ’vencrypt+x509+sasl’ if VEncrypt is used with x509 and SASL auth

  • clients ([VncClientInfo], optional) – a list of VncClientInfo of all currently connected clients

Enum VncPrimaryAuth (Since: 2.3)
Availability: CONFIG_VNC

vnc primary authentication method.

Values:

  • none – Not documented

  • vnc – Not documented

  • ra2 – Not documented

  • ra2ne – Not documented

  • tight – Not documented

  • ultra – Not documented

  • tls – Not documented

  • vencrypt – Not documented

  • sasl – Not documented

Enum VncVencryptSubAuth (Since: 2.3)
Availability: CONFIG_VNC

vnc sub authentication method with vencrypt.

Values:

  • plain – Not documented

  • tls-none – Not documented

  • x509-none – Not documented

  • tls-vnc – Not documented

  • x509-vnc – Not documented

  • tls-plain – Not documented

  • x509-plain – Not documented

  • tls-sasl – Not documented

  • x509-sasl – Not documented

Object VncServerInfo2 (Since: 2.9)
Availability: CONFIG_VNC

The network connection information for server

Members:

  • auth (VncPrimaryAuth) – The current authentication type used by the servers

  • vencrypt (VncVencryptSubAuth, optional) – The vencrypt sub authentication type used by the servers, only specified in case auth == vencrypt.

  • The members of VncBasicInfo.

Object VncInfo2 (Since: 2.3)
Availability: CONFIG_VNC

Information about a vnc server

Members:

  • id (string) – vnc server name.

  • server ([VncServerInfo2]) – A list of VncBasicInfo describing all listening sockets. The list can be empty (in case the vnc server is disabled). It also may have multiple entries: normal + websocket, possibly also ipv4 + ipv6 in the future.

  • clients ([VncClientInfo]) – A list of VncClientInfo of all currently connected clients. The list can be empty, for obvious reasons.

  • auth (VncPrimaryAuth) – The current authentication type used by the non-websockets servers

  • vencrypt (VncVencryptSubAuth, optional) – The vencrypt authentication type used by the servers, only specified in case auth == vencrypt.

  • display (string, optional) – The display device the vnc server is linked to.

Command query-vnc (Since: 0.14)
Availability: CONFIG_VNC

Return information about the current VNC server

Return:

VncInfo

Example:

-> { "execute": "query-vnc" }
<- { "return": {
         "enabled":true,
         "host":"0.0.0.0",
         "service":"50402",
         "auth":"vnc",
         "family":"ipv4",
         "clients":[
            {
               "host":"127.0.0.1",
               "service":"50401",
               "family":"ipv4",
               "websocket":false
            }
         ]
      }
   }
Command query-vnc-servers (Since: 2.3)
Availability: CONFIG_VNC

Return a list of vnc servers. The list can be empty.

Return:

[VncInfo2]

Command change-vnc-password (Since: 1.1)
Availability: CONFIG_VNC

Change the VNC server password.

Arguments:

  • password (string) – the new password to use with VNC authentication

Note

An empty password in this command will set the password to the empty string. Existing clients are unaffected by executing this command.

Event VNC_CONNECTED (Since: 0.13)
Availability: CONFIG_VNC

Emitted when a VNC client establishes a connection

Members:

Note

This event is emitted before any authentication takes place, thus the authentication ID is not provided.

Example:

<- { "event": "VNC_CONNECTED",
     "data": {
           "server": { "auth": "sasl", "family": "ipv4", "websocket": false,
                       "service": "5901", "host": "0.0.0.0" },
           "client": { "family": "ipv4", "service": "58425",
                       "host": "127.0.0.1", "websocket": false } },
     "timestamp": { "seconds": 1262976601, "microseconds": 975795 } }
Event VNC_INITIALIZED (Since: 0.13)
Availability: CONFIG_VNC

Emitted after authentication takes place (if any) and the VNC session is made active

Members:

Example:

<-  { "event": "VNC_INITIALIZED",
      "data": {
           "server": { "auth": "sasl", "family": "ipv4", "websocket": false,
                       "service": "5901", "host": "0.0.0.0"},
           "client": { "family": "ipv4", "service": "46089", "websocket": false,
                       "host": "127.0.0.1", "sasl_username": "luiz" } },
      "timestamp": { "seconds": 1263475302, "microseconds": 150772 } }
Event VNC_DISCONNECTED (Since: 0.13)
Availability: CONFIG_VNC

Emitted when the connection is closed

Members:

Example:

<- { "event": "VNC_DISCONNECTED",
     "data": {
           "server": { "auth": "sasl", "family": "ipv4", "websocket": false,
                       "service": "5901", "host": "0.0.0.0" },
           "client": { "family": "ipv4", "service": "58425", "websocket": false,
                       "host": "127.0.0.1", "sasl_username": "luiz" } },
     "timestamp": { "seconds": 1262976601, "microseconds": 975795 } }

Input

Object MouseInfo (Since: 0.14)

Information about a mouse device.

Members:

  • name (string) – the name of the mouse device

  • index (int) – the index of the mouse device

  • current (boolean) – true if this device is currently receiving mouse events

  • absolute (boolean) – true if this device supports absolute coordinates as input

Command query-mice (Since: 0.14)

Return information about each active mouse device

Return:

[MouseInfo] – a list of info for each device

Example:

-> { "execute": "query-mice" }
<- { "return": [
         {
            "name":"QEMU Microsoft Mouse",
            "index":0,
            "current":false,
            "absolute":false
         },
         {
            "name":"QEMU PS/2 Mouse",
            "index":1,
            "current":true,
            "absolute":true
         }
      ]
   }
Enum QKeyCode (Since: 1.3)

An enumeration of key name.

This is used by the send-key command.

Values:

  • unmapped – since 2.0

  • pause – since 2.0

  • ro – since 2.4

  • kp_comma – since 2.4

  • kp_equals – since 2.6

  • power – since 2.6

  • hiragana – since 2.9

  • henkan – since 2.9

  • yen – since 2.9

  • sleep – since 2.10

  • wake – since 2.10

  • audionext – since 2.10

  • audioprev – since 2.10

  • audiostop – since 2.10

  • audioplay – since 2.10

  • audiomute – since 2.10

  • volumeup – since 2.10

  • volumedown – since 2.10

  • mediaselect – since 2.10

  • mail – since 2.10

  • calculator – since 2.10

  • computer – since 2.10

  • ac_home – since 2.10

  • ac_back – since 2.10

  • ac_forward – since 2.10

  • ac_refresh – since 2.10

  • ac_bookmarks – since 2.10

  • muhenkan – since 2.12

  • katakanahiragana – since 2.12

  • lang1 – since 6.1

  • lang2 – since 6.1

  • f13 – since 8.0

  • f14 – since 8.0

  • f15 – since 8.0

  • f16 – since 8.0

  • f17 – since 8.0

  • f18 – since 8.0

  • f19 – since 8.0

  • f20 – since 8.0

  • f21 – since 8.0

  • f22 – since 8.0

  • f23 – since 8.0

  • f24 – since 8.0

  • shift – Not documented

  • shift_r – Not documented

  • alt – Not documented

  • alt_r – Not documented

  • ctrl – Not documented

  • ctrl_r – Not documented

  • menu – Not documented

  • esc – Not documented

  • 1 – Not documented

  • 2 – Not documented

  • 3 – Not documented

  • 4 – Not documented

  • 5 – Not documented

  • 6 – Not documented

  • 7 – Not documented

  • 8 – Not documented

  • 9 – Not documented

  • 0 – Not documented

  • minus – Not documented

  • equal – Not documented

  • backspace – Not documented

  • tab – Not documented

  • q – Not documented

  • w – Not documented

  • e – Not documented

  • r – Not documented

  • t – Not documented

  • y – Not documented

  • u – Not documented

  • i – Not documented

  • o – Not documented

  • p – Not documented

  • bracket_left – Not documented

  • bracket_right – Not documented

  • ret – Not documented

  • a – Not documented

  • s – Not documented

  • d – Not documented

  • f – Not documented

  • g – Not documented

  • h – Not documented

  • j – Not documented

  • k – Not documented

  • l – Not documented

  • semicolon – Not documented

  • apostrophe – Not documented

  • grave_accent – Not documented

  • backslash – Not documented

  • z – Not documented

  • x – Not documented

  • c – Not documented

  • v – Not documented

  • b – Not documented

  • n – Not documented

  • m – Not documented

  • comma – Not documented

  • dot – Not documented

  • slash – Not documented

  • asterisk – Not documented

  • spc – Not documented

  • caps_lock – Not documented

  • f1 – Not documented

  • f2 – Not documented

  • f3 – Not documented

  • f4 – Not documented

  • f5 – Not documented

  • f6 – Not documented

  • f7 – Not documented

  • f8 – Not documented

  • f9 – Not documented

  • f10 – Not documented

  • num_lock – Not documented

  • scroll_lock – Not documented

  • kp_divide – Not documented

  • kp_multiply – Not documented

  • kp_subtract – Not documented

  • kp_add – Not documented

  • kp_enter – Not documented

  • kp_decimal – Not documented

  • sysrq – Not documented

  • kp_0 – Not documented

  • kp_1 – Not documented

  • kp_2 – Not documented

  • kp_3 – Not documented

  • kp_4 – Not documented

  • kp_5 – Not documented

  • kp_6 – Not documented

  • kp_7 – Not documented

  • kp_8 – Not documented

  • kp_9 – Not documented

  • less – Not documented

  • f11 – Not documented

  • f12 – Not documented

  • print – Not documented

  • home – Not documented

  • pgup – Not documented

  • pgdn – Not documented

  • end – Not documented

  • left – Not documented

  • up – Not documented

  • down – Not documented

  • right – Not documented

  • insert – Not documented

  • delete – Not documented

  • stop – Not documented

  • again – Not documented

  • props – Not documented

  • undo – Not documented

  • front – Not documented

  • copy – Not documented

  • open – Not documented

  • paste – Not documented

  • find – Not documented

  • cut – Not documented

  • lf – Not documented

  • help – Not documented

  • meta_l – Not documented

  • meta_r – Not documented

  • compose – Not documented

‘sysrq’ was mistakenly added to hack around the fact that the ps2 driver was not generating correct scancodes sequences when ‘alt+print’ was pressed. This flaw is now fixed and the ‘sysrq’ key serves no further purpose. Any further use of ‘sysrq’ will be transparently changed to ‘print’, so they are effectively synonyms.

Enum KeyValueKind (Since: 1.3)
Values:

  • number – Not documented

  • qcode – Not documented

Object IntWrapper (Since: 1.3)
Members:

  • data (int) – a numeric key code

Object QKeyCodeWrapper (Since: 1.3)
Members:

  • data (QKeyCode) – An enumeration of key name

Object KeyValue (Since: 1.3)

Represents a keyboard key.

Members:
Command send-key (Since: 1.3)

Send keys to guest.

Arguments:

  • keys ([KeyValue]) – An array of KeyValue elements. All KeyValues in this array are simultaneously sent to the guest. A KeyValue.number value is sent directly to the guest, while KeyValue.qcode must be a valid QKeyCode value

  • hold-time (int, optional) – time to delay key up events, milliseconds. Defaults to 100

Errors:

  • If key is unknown or redundant, GenericError

Example:

-> { "execute": "send-key",
     "arguments": { "keys": [ { "type": "qcode", "data": "ctrl" },
                              { "type": "qcode", "data": "alt" },
                              { "type": "qcode", "data": "delete" } ] } }
<- { "return": {} }
Enum InputButton (Since: 2.0)

Button of a pointer input device (mouse, tablet).

Values:

  • side – front side button of a 5-button mouse (since 2.9)

  • extra – rear side button of a 5-button mouse (since 2.9)

  • touch – screen contact on a multi-touch device (since 8.1)

  • left – Not documented

  • middle – Not documented

  • right – Not documented

  • wheel-up – Not documented

  • wheel-down – Not documented

  • wheel-left – Not documented

  • wheel-right – Not documented

Enum InputAxis (Since: 2.0)

Position axis of a pointer input device (mouse, tablet).

Values:

  • x – Not documented

  • y – Not documented

Enum InputMultiTouchType (Since: 8.1)

Type of a multi-touch event.

Values:

  • begin – A new touch event sequence has just started.

  • update – A touch event sequence has been updated.

  • end – A touch event sequence has finished.

  • cancel – A touch event sequence has been canceled.

  • data – Absolute position data.

Object InputKeyEvent (Since: 2.0)

Keyboard input event.

Members:

  • key (KeyValue) – Which key this event is for.

  • down (boolean) – True for key-down and false for key-up events.

Object InputBtnEvent (Since: 2.0)

Pointer button input event.

Members:

  • button (InputButton) – Which button this event is for.

  • down (boolean) – True for key-down and false for key-up events.

Object InputMoveEvent (Since: 2.0)

Pointer motion input event.

Members:

  • axis (InputAxis) – Which axis is referenced by value.

  • value (int) – Pointer position. For absolute coordinates the valid range is 0 to 0x7fff.

Object InputMultiTouchEvent (Since: 8.1)

MultiTouch input event.

Members:

  • type (InputMultiTouchType) – The type of multi-touch event.

  • slot (int) – Which slot has generated the event.

  • tracking-id (int) – ID to correlate this event with previously generated events.

  • axis (InputAxis) – Which axis is referenced by value.

  • value (int) – Contact position.

Enum InputEventKind (Since: 2.0)
Values:

  • key – a keyboard input event

  • btn – a pointer button input event

  • rel – a relative pointer motion input event

  • abs – an absolute pointer motion input event

  • mtt – a multi-touch input event

Object InputKeyEventWrapper (Since: 2.0)
Members:
Object InputBtnEventWrapper (Since: 2.0)
Members:
Object InputMoveEventWrapper (Since: 2.0)
Members:
Object InputMultiTouchEventWrapper (Since: 8.1)
Members:
Object InputEvent (Since: 2.0)

Input event union.

Members:
Command input-send-event (Since: 2.6)

Send input event(s) to guest.

The device and head parameters can be used to send the input event to specific input devices in case (a) multiple input devices of the same kind are added to the virtual machine and (b) you have configured input routing (see docs/multiseat.txt) for those input devices. The parameters work exactly like the device and head properties of input devices. If device is missing, only devices that have no input routing config are admissible. If device is specified, both input devices with and without input routing config are admissible, but devices with input routing config take precedence.

Arguments:

  • device (string, optional) – display device to send event(s) to.

  • head (int, optional) – head to send event(s) to, in case the display device supports multiple scanouts.

  • events ([InputEvent]) – List of InputEvent union.

Note

The consoles are visible in the qom tree, under /backend/console[$index]. They have a device link and head property, so it is possible to map which console belongs to which device and display.

Example: Press left mouse button

 -> { "execute": "input-send-event",
     "arguments": { "device": "video0",
                    "events": [ { "type": "btn",
                    "data" : { "down": true, "button": "left" } } ] } }
 <- { "return": {} }

 -> { "execute": "input-send-event",
     "arguments": { "device": "video0",
                    "events": [ { "type": "btn",
                    "data" : { "down": false, "button": "left" } } ] } }
 <- { "return": {} }

Example: Press ctrl-alt-del

 -> { "execute": "input-send-event",
      "arguments": { "events": [
         { "type": "key", "data" : { "down": true,
           "key": {"type": "qcode", "data": "ctrl" } } },
         { "type": "key", "data" : { "down": true,
           "key": {"type": "qcode", "data": "alt" } } },
         { "type": "key", "data" : { "down": true,
           "key": {"type": "qcode", "data": "delete" } } } ] } }
 <- { "return": {} }

Example: Move mouse pointer to absolute coordinates

 -> { "execute": "input-send-event" ,
   "arguments": { "events": [
                { "type": "abs", "data" : { "axis": "x", "value" : 20000 } },
                { "type": "abs", "data" : { "axis": "y", "value" : 400 } } ] } }
 <- { "return": {} }
Object DisplayGTK (Since: 2.12)

GTK display options.

Members:

  • grab-on-hover (boolean, optional) – Grab keyboard input on mouse hover.

  • zoom-to-fit (boolean, optional) – Zoom guest display to fit into the host window. When turned off the host window will be resized instead. In case the display device can notify the guest on window resizes (virtio-gpu) this will default to “on”, assuming the guest will resize the display to match the window size then. Otherwise it defaults to “off”. (Since 3.1)

  • show-tabs (boolean, optional) – Display the tab bar for switching between the various graphical interfaces (e.g. VGA and virtual console character devices) by default. (Since 7.1)

  • show-menubar (boolean, optional) – Display the main window menubar. Defaults to “on”. (Since 8.0)

  • keep-aspect-ratio (boolean, optional) – Keep width/height aspect ratio of guest content when resizing host window. Defaults to “on”. (Since 10.1)

  • scale (number, optional) – Set preferred scale of the display. Defaults to 1.0. (Since 10.1)

Object DisplayEGLHeadless (Since: 3.1)

EGL headless display options.

Members:

  • rendernode (string, optional) – Which DRM render node should be used. Default is the first available node on the host.

Object DisplayDBus (Since: 7.0)

DBus display options.

Members:

  • addr (string, optional) – The D-Bus bus address (default to the session bus).

  • rendernode (string, optional) – Which DRM render node should be used. Default is the first available node on the host.

  • p2p (boolean, optional) – Whether to use peer-to-peer connections (accepted through add_client).

  • audiodev (string, optional) – Use the specified DBus audiodev to export audio.

Enum DisplayGLMode (Since: 3.0)

Display OpenGL mode.

Values:

  • off – Disable OpenGL (default).

  • on – Use OpenGL, pick context type automatically. Would better be named ‘auto’ but is called ‘on’ for backward compatibility with bool type.

  • core – Use OpenGL with Core (desktop) Context.

  • es – Use OpenGL with ES (embedded systems) Context.

Object DisplayCurses (Since: 4.0)

Curses display options.

Members:

  • charset (string, optional) – Font charset used by guest (default: CP437).

Object DisplayCocoa (Since: 7.0)

Cocoa display options.

Members:

  • left-command-key (boolean, optional) – Enable/disable forwarding of left command key to guest. Allows command-tab window switching on the host without sending this key to the guest when “off”. Defaults to “on”

  • full-grab (boolean, optional) – Capture all key presses, including system combos. This requires accessibility permissions, since it performs a global grab on key events. (default: off) See https://support.apple.com/en-in/guide/mac-help/mh32356/mac

  • swap-opt-cmd (boolean, optional) – Swap the Option and Command keys so that their key codes match their position on non-Mac keyboards and you can use Meta/Super and Alt where you expect them. (default: off)

  • zoom-to-fit (boolean, optional) – Zoom guest display to fit into the host window. When turned off the host window will be resized instead. Defaults to “off”. (Since 8.2)

  • zoom-interpolation (boolean, optional) – Apply interpolation to smooth output when zoom-to-fit is enabled. Defaults to “off”. (Since 9.0)

Enum HotKeyMod (Since: 7.1)

Set of modifier keys that need to be held for shortcut key actions.

Values:

  • lctrl-lalt – Not documented

  • lshift-lctrl-lalt – Not documented

  • rctrl – Not documented

Object DisplaySDL (Since: 7.1)

SDL2 display options.

Members:

  • grab-mod (HotKeyMod, optional) – Modifier keys that should be pressed together with the “G” key to release the mouse grab.

Enum DisplayType (Since: 2.12)

Display (user interface) type.

Values:

  • default – The default user interface, selecting from the first available of gtk, sdl, cocoa, and vnc.

  • none – No user interface or video output display. The guest will still see an emulated graphics card, but its output will not be displayed to the QEMU user.

  • gtk – The GTK user interface.

  • sdl – The SDL user interface.

  • egl-headless – No user interface, offload GL operations to a local DRI device. Graphical display need to be paired with VNC or Spice. (Since 3.1)

  • curses – Display video output via curses. For graphics device models which support a text mode, QEMU can display this output using a curses/ncurses interface. Nothing is displayed when the graphics device is in graphical mode or if the graphics device does not support a text mode. Generally only the VGA device models support text mode.

  • cocoa – The Cocoa user interface.

  • spice-app – Set up a Spice server and run the default associated application to connect to it. The server will redirect the serial console and QEMU monitors. (Since 4.0)

  • dbus – Start a D-Bus service for the display. (Since 7.0)

Object DisplayOptions (Since: 2.12)

Display (user interface) options.

Members:

  • type (DisplayType) – Which DisplayType QEMU should use.

  • full-screen (boolean, optional) – Start user interface in fullscreen mode (default: off).

  • window-close (boolean, optional) – Allow to quit QEMU with window close button (default: on).

  • show-cursor (boolean, optional) – Force showing the mouse cursor (default: off). (since: 5.0)

  • gl (DisplayGLMode, optional) – Enable OpenGL support (default: off).

  • When type is gtk: The members of DisplayGTK.

  • When type is cocoa: The members of DisplayCocoa.

  • When type is curses: The members of DisplayCurses.

  • When type is egl-headless: The members of DisplayEGLHeadless.

  • When type is dbus: The members of DisplayDBus.

  • When type is sdl: The members of DisplaySDL.

Command query-display-options (Since: 3.1)

Return information about display configuration

Return:

DisplayOptions

Enum DisplayReloadType (Since: 6.0)

Available DisplayReload types.

Values:

  • vnc – VNC display

Object DisplayReloadOptionsVNC (Since: 6.0)

Specify the VNC reload options.

Members:

  • tls-certs (boolean, optional) – reload tls certs or not.

Object DisplayReloadOptions (Since: 6.0)

Options of the display configuration reload.

Members:
Command display-reload (Since: 6.0)

Reload display configuration.

Arguments:

Example:

-> { "execute": "display-reload",
     "arguments": { "type": "vnc", "tls-certs": true  } }
<- { "return": {} }
Enum DisplayUpdateType (Since: 7.1)

Available DisplayUpdate types.

Values:

  • vnc – VNC display

Object DisplayUpdateOptionsVNC (Since: 7.1)

Specify the VNC reload options.

Members:

  • addresses ([SocketAddress], optional) – If specified, change set of addresses to listen for connections. Addresses configured for websockets are not touched.

Object DisplayUpdateOptions (Since: 7.1)

Options of the display configuration reload.

Members:
Command display-update (Since: 7.1)

Update display configuration.

Arguments:

Example:

-> { "execute": "display-update",
     "arguments": { "type": "vnc", "addresses":
                    [ { "type": "inet", "host": "0.0.0.0",
                        "port": "5901" } ] } }
<- { "return": {} }
Command client_migrate_info (Since: 0.14)

Set migration information for remote display. This makes the server ask the client to automatically reconnect using the new parameters once migration finished successfully. Only implemented for SPICE.

Arguments:

  • protocol (string) – must be “spice”

  • hostname (string) – migration target hostname

  • port (int, optional) – spice tcp port for plaintext channels

  • tls-port (int, optional) – spice tcp port for tls-secured channels

  • cert-subject (string, optional) – server certificate subject

Example:

-> { "execute": "client_migrate_info",
     "arguments": { "protocol": "spice",
                    "hostname": "virt42.lab.kraxel.org",
                    "port": 1234 } }
<- { "return": {} }

User authorization

Enum QAuthZListPolicy (Since: 4.0)

The authorization policy result

Values:

  • deny – deny access

  • allow – allow access

Enum QAuthZListFormat (Since: 4.0)

The authorization policy match format

Values:

  • exact – an exact string match

  • glob – string with ? and * shell wildcard support

Object QAuthZListRule (Since: 4.0)

A single authorization rule.

Members:

  • match (string) – a string or glob to match against a user identity

  • policy (QAuthZListPolicy) – the result to return if match evaluates to true

  • format (QAuthZListFormat, optional) – the format of the match rule (default ‘exact’)

Object AuthZListProperties (Since: 4.0)

Properties for authz-list objects.

Members:

  • policy (QAuthZListPolicy, optional) – Default policy to apply when no rule matches (default: deny)

  • rules ([QAuthZListRule], optional) – Authorization rules based on matching user

Object AuthZListFileProperties (Since: 4.0)

Properties for authz-listfile objects.

Members:

  • filename (string) – File name to load the configuration from. The file must contain valid JSON for AuthZListProperties.

  • refresh (boolean, optional) – If true, inotify is used to monitor the file, automatically reloading changes. If an error occurs during reloading, all authorizations will fail until the file is next successfully loaded. (default: true if the binary was built with CONFIG_INOTIFY1, false otherwise)

Object AuthZPAMProperties (Since: 4.0)

Properties for authz-pam objects.

Members:

  • service (string) – PAM service name to use for authorization

Object AuthZSimpleProperties (Since: 4.0)

Properties for authz-simple objects.

Members:

  • identity (string) – Identifies the allowed user. Its format depends on the network service that authorization object is associated with. For authorizing based on TLS x509 certificates, the identity must be the x509 distinguished name.

Migration

Object MigrationStats (Since: 0.14)

Detailed migration status.

Members:

  • transferred (int) – amount of bytes already transferred to the target VM

  • remaining (int) – amount of bytes remaining to be transferred to the target VM

  • total (int) – total amount of bytes involved in the migration process

  • duplicate (int) – number of duplicate (zero) pages (since 1.2)

  • normal (int) – number of normal pages (since 1.2)

  • normal-bytes (int) – number of normal bytes sent (since 1.2)

  • dirty-pages-rate (int) – number of pages dirtied by second by the guest (since 1.3)

  • mbps (number) – throughput in megabits/sec. (since 1.6)

  • dirty-sync-count (int) – number of times that dirty ram was synchronized (since 2.1)

  • postcopy-requests (int) – The number of page requests received from the destination (since 2.7)

  • page-size (int) – The number of bytes per page for the various page-based statistics (since 2.10)

  • multifd-bytes (int) – The number of bytes sent through multifd (since 3.0)

  • pages-per-second (int) – the number of memory pages transferred per second (Since 4.0)

  • precopy-bytes (int) – The number of bytes sent in the pre-copy phase (since 7.0).

  • downtime-bytes (int) – The number of bytes sent while the guest is paused (since 7.0).

  • postcopy-bytes (int) – The number of bytes sent during the post-copy phase (since 7.0).

  • dirty-sync-missed-zero-copy (int) – Number of times dirty RAM synchronization could not avoid copying dirty pages. This is between 0 and dirty-sync-count * multifd-channels. (since 7.1)

Object XBZRLECacheStats (Since: 1.2)

Detailed XBZRLE migration cache statistics

Members:

  • cache-size (int) – XBZRLE cache size

  • bytes (int) – amount of bytes already transferred to the target VM

  • pages (int) – amount of pages transferred to the target VM

  • cache-miss (int) – number of cache miss

  • cache-miss-rate (number) – rate of cache miss (since 2.1)

  • encoding-rate (number) – rate of encoded bytes (since 5.1)

  • overflow (int) – number of overflows

Object CompressionStats (Since: 3.1)

Detailed migration compression statistics

Members:

  • pages (int) – amount of pages compressed and transferred to the target VM

  • busy (int) – count of times that no free thread was available to compress data

  • busy-rate (number) – rate of thread busy

  • compressed-size (int) – amount of bytes after compression

  • compression-rate (number) – rate of compressed size

Enum MigrationStatus (Since: 2.3)

An enumeration of migration status.

Values:

  • none – no migration has ever happened.

  • setup – migration process has been initiated.

  • cancelling – in the process of cancelling migration.

  • cancelled – cancelling migration is finished.

  • active – in the process of doing migration.

  • postcopy-active – like active, but now in postcopy mode. (since 2.5)

  • postcopy-device – like postcopy-active, but the destination is still loading device state and is not running yet. If migration fails during this state, the source side will resume. If there is no return-path from destination to source, this state is skipped. (since 10.2)

  • postcopy-paused – during postcopy but paused. (since 3.0)

  • postcopy-recover-setup – setup phase for a postcopy recovery process, preparing for a recovery phase to start. (since 9.1)

  • postcopy-recover – trying to recover from a paused postcopy. (since 3.0)

  • completed – migration is finished.

  • failing – error occurred during migration, clean-up underway. (since 11.0)

  • failed – error occurred during migration, clean-up done.

  • colo – VM is in the process of fault tolerance, VM can not get into this state unless colo capability is enabled for migration. (since 2.8)

  • pre-switchover – Paused before device serialisation. (since 2.11)

  • device – During device serialisation (also known as switchover phase). Before 9.2, this is only used when (1) in precopy, and (2) when pre-switchover capability is enabled. After 10.0, this state will always be present for every migration procedure as the switchover phase. (since 2.11)

  • wait-unplug – wait for device unplug request by guest OS to be completed. (since 4.2)

Object VfioStats (Since: 5.2)

Detailed VFIO devices migration statistics

Members:

  • transferred (int) – amount of bytes transferred to the target VM by VFIO devices

Object MigrationInfo (Since: 0.14)

Information about current migration process.

Members:

  • status (MigrationStatus, optional) – MigrationStatus describing the current migration status. If this field is not returned, no migration process has been initiated

  • ram (MigrationStats, optional) – MigrationStats containing detailed migration status, only returned if status is ‘active’ or ‘completed’(since 1.2)

  • xbzrle-cache (XBZRLECacheStats, optional) – XBZRLECacheStats containing detailed XBZRLE migration statistics, only returned if XBZRLE feature is on and status is ‘active’ or ‘completed’ (since 1.2)

  • total-time (int, optional) – total amount of milliseconds since migration started. If migration has ended, it returns the total migration time. (since 1.2)

  • downtime (int, optional) – only present when migration finishes correctly total downtime in milliseconds for the guest. (since 1.3)

  • expected-downtime (int, optional) – only present while migration is active expected downtime in milliseconds for the guest in last walk of the dirty bitmap. (since 1.3)

  • setup-time (int, optional) – amount of setup time in milliseconds before the iterations begin but after the QMP command is issued. This is designed to provide an accounting of any activities (such as RDMA pinning) which may be expensive, but do not actually occur during the iterative migration rounds themselves. (since 1.6)

  • cpu-throttle-percentage (int, optional) – percentage of time guest cpus are being throttled during auto-converge. This is only present when auto-converge has started throttling guest cpus. (Since 2.7)

  • error-desc (string, optional) – the human readable error description string. Clients should not attempt to parse the error strings. (Since 2.7)

  • postcopy-blocktime (int, optional) – total time when all vCPU were blocked during postcopy live migration. This is only present when the postcopy-blocktime migration capability is enabled. (Since 3.0)

  • postcopy-vcpu-blocktime ([int], optional) – list of the postcopy blocktime per vCPU. This is only present when the postcopy-blocktime migration capability is enabled. (Since 3.0)

  • postcopy-latency (int, optional) – average remote page fault latency (in ns). Note that this doesn’t include all faults, but only the ones that require a remote page request. So it should be always bigger than the real average page fault latency. This is only present when the postcopy-blocktime migration capability is enabled. (Since 10.1)

  • postcopy-latency-dist ([int], optional) – remote page fault latency distributions. Each element of the array is the number of faults that fall into the bucket period. For the N-th bucket (N>=0), the latency window is [2^Nus, 2^(N+1)us). For example, the 8th element stores how many remote faults got resolved within [256us, 512us) window. This is only present when the postcopy-blocktime migration capability is enabled. (Since 10.1)

  • postcopy-vcpu-latency ([int], optional) – average remote page fault latency per vCPU (in ns). It has the same definition of postcopy-latency, but instead this is the per-vCPU statistics. This is only present when the postcopy-blocktime migration capability is enabled. (Since 10.1)

  • postcopy-non-vcpu-latency (int, optional) – average remote page fault latency for all faults happend in non-vCPU threads (in ns). It has the same definition of postcopy-latency but this only provides statistics to non-vCPU faults. This is only present when the postcopy-blocktime migration capability is enabled. (Since 10.1)

  • socket-address ([SocketAddress], optional) – Only used for tcp, to know what the real port is (Since 4.0)

  • vfio (VfioStats, optional) – VfioStats containing detailed VFIO devices migration statistics, only returned if VFIO device is present, migration is supported by all VFIO devices and status is ‘active’ or ‘completed’ (since 5.2)

  • blocked-reasons ([string], optional) – A list of reasons an outgoing migration is blocked. Present and non-empty when migration is blocked. (since 6.0)

  • dirty-limit-throttle-time-per-round (int, optional) – Maximum throttle time (in microseconds) of virtual CPUs each dirty ring full round, which shows how MigrationCapability dirty-limit affects the guest during live migration. (Since 8.1)

  • dirty-limit-ring-full-time (int, optional) – Estimated average dirty ring full time (in microseconds) for each dirty ring full round. The value equals the dirty ring memory size divided by the average dirty page rate of the virtual CPU, which can be used to observe the average memory load of the virtual CPU indirectly. Note that zero means guest doesn’t dirty memory. (Since 8.1)

Features:

  • unstable – Members postcopy-latency, postcopy-vcpu-latency, postcopy-latency-dist, postcopy-non-vcpu-latency are experimental.

Command query-migrate (Since: 0.14)

Return information about current migration process. If migration is active there will be another json-object with RAM migration status.

Return:

MigrationInfo

Example: Before the first migration

 -> { "execute": "query-migrate" }
 <- { "return": {} }

Example: Migration is done and has succeeded

 -> { "execute": "query-migrate" }
 <- { "return": {
         "status": "completed",
         "total-time":12345,
         "setup-time":12345,
         "downtime":12345,
         "ram":{
           "transferred":123,
           "remaining":123,
           "total":246,
           "duplicate":123,
           "normal":123,
           "normal-bytes":123456,
           "dirty-sync-count":15
         }
      }
    }

Example: Migration is done and has failed

 -> { "execute": "query-migrate" }
 <- { "return": { "status": "failed" } }

Example: Migration is being performed

 -> { "execute": "query-migrate" }
 <- {
       "return":{
          "status":"active",
          "total-time":12345,
          "setup-time":12345,
          "expected-downtime":12345,
          "ram":{
             "transferred":123,
             "remaining":123,
             "total":246,
             "duplicate":123,
             "normal":123,
             "normal-bytes":123456,
             "dirty-sync-count":15
          }
       }
    }

Example: Migration is being performed and XBZRLE is active

 -> { "execute": "query-migrate" }
 <- {
       "return":{
          "status":"active",
          "total-time":12345,
          "setup-time":12345,
          "expected-downtime":12345,
          "ram":{
             "total":1057024,
             "remaining":1053304,
             "transferred":3720,
             "duplicate":10,
             "normal":3333,
             "normal-bytes":3412992,
             "dirty-sync-count":15
          },
          "xbzrle-cache":{
             "cache-size":67108864,
             "bytes":20971520,
             "pages":2444343,
             "cache-miss":2244,
             "cache-miss-rate":0.123,
             "encoding-rate":80.1,
             "overflow":34434
          }
       }
    }
Enum MigrationCapability (Since: 1.2)

Migration capabilities enumeration

Values:

  • xbzrle – Migration supports xbzrle (Xor Based Zero Run Length Encoding). This feature allows us to minimize migration traffic for certain work loads, by sending compressed difference of the pages

  • rdma-pin-all – Controls whether or not the entire VM memory footprint is mlock()’d on demand or all at once. Refer to docs/rdma.txt for usage. Disabled by default. (since 2.0)

  • events – generate events for each migration state change (since 2.4)

  • auto-converge – If enabled, QEMU will automatically throttle down the guest to speed up convergence of RAM migration. (since 1.6)

  • postcopy-ram – Start executing on the migration target before all of RAM has been migrated, pulling the remaining pages along as needed. The capacity must have the same setting on both source and target or migration will not even start. Note: if the migration fails during postcopy the VM will fail. (since 2.6)

  • x-colo – If enabled, migration will never end, and the state of the VM on the primary side will be migrated continuously to the VM on secondary side, this process is called COarse-Grain LOck Stepping (COLO) for Non-stop Service. (since 2.8)

  • release-ram – if enabled, QEMU will free the migrated ram pages on the source during postcopy-ram migration. (since 2.9)

  • return-path – If enabled, migration will use the return path even for precopy. (since 2.10)

  • pause-before-switchover – Pause outgoing migration before serialising device state and before disabling block IO (since 2.11)

  • multifd – Use more than one fd for migration (since 4.0)

  • dirty-bitmaps – If enabled, QEMU will migrate named dirty bitmaps. (since 2.12)

  • postcopy-blocktime – Calculate downtime for postcopy live migration (since 3.0)

  • late-block-activate – If enabled, the destination will not activate block devices (and thus take locks) immediately at the end of migration. (since 3.0)

  • x-ignore-shared – If enabled, QEMU will not migrate shared memory that is accessible on the destination machine. (since 4.0)

  • validate-uuid – Send the UUID of the source to allow the destination to ensure it is the same. (since 4.2)

  • background-snapshot – If enabled, the migration stream will be a snapshot of the VM exactly at the point when the migration procedure starts. The VM RAM is saved with running VM. (since 6.0)

  • zero-copy-send – Controls behavior on sending memory pages on migration. When true, enables a zero-copy mechanism for sending memory pages, if host supports it. Requires that QEMU be permitted to use locked memory for guest RAM pages. (since 7.1)

  • postcopy-preempt – If enabled, the migration process will allow postcopy requests to preempt precopy stream, so postcopy requests will be handled faster. This is a performance feature and should not affect the correctness of postcopy migration. (since 7.1)

  • switchover-ack – If enabled, migration will not stop the source VM and complete the migration until an ACK is received from the destination that it’s OK to do so. Exactly when this ACK is sent depends on the migrated devices that use this feature. For example, a device can use it to make sure some of its data is sent and loaded in the destination before doing switchover. This can reduce downtime if devices that support this capability are present. ‘return-path’ capability must be enabled to use it. (since 8.1)

  • dirty-limit – If enabled, migration will throttle vCPUs as needed to keep their dirty page rate within vcpu-dirty-limit. This can improve responsiveness of large guests during live migration, and can result in more stable read performance. Requires KVM with accelerator property “dirty-ring-size” set. (Since 8.1)

  • mapped-ram – Migrate using fixed offsets in the migration file for each RAM page. Requires a migration URI that supports seeking, such as a file. (since 9.0)

Features:

  • unstable – Members x-colo and x-ignore-shared are experimental.

Object MigrationCapabilityStatus (Since: 1.2)

Migration capability information

Members:

  • capability (MigrationCapability) – capability enum

  • state (boolean) – capability state bool

Command migrate-set-capabilities (Since: 1.2)

Enable/Disable the following migration capabilities (like xbzrle)

Arguments:

Example:

-> { "execute": "migrate-set-capabilities" , "arguments":
     { "capabilities": [ { "capability": "xbzrle", "state": true } ] } }
<- { "return": {} }
Command query-migrate-capabilities (Since: 1.2)

Return information about the current migration capabilities status

Return:

[MigrationCapabilityStatus]

Example:

-> { "execute": "query-migrate-capabilities" }
<- { "return": [
      {"state": false, "capability": "xbzrle"},
      {"state": false, "capability": "rdma-pin-all"},
      {"state": false, "capability": "auto-converge"},
      {"state": true, "capability": "events"},
      {"state": false, "capability": "postcopy-ram"},
      {"state": false, "capability": "x-colo"}
   ]}
Enum MultiFDCompression (Since: 5.0)

An enumeration of multifd compression methods.

Values:

  • none – no compression.

  • zlib – use zlib compression method.

  • zstd – use zstd compression method.

  • qatzip – use qatzip compression method. (Since 9.2)

  • qpl – use qpl compression method. Query Processing Library(qpl) is based on the deflate compression algorithm and use the Intel In-Memory Analytics Accelerator(IAA) accelerated compression and decompression. (Since 9.1)

  • uadk – use UADK library compression method. (Since 9.1)

Enum MigMode
Values:

  • normal – the original form of migration. (since 8.2)

  • cpr-reboot –

    The migrate command stops the VM and saves state to the URI. After quitting QEMU, the user resumes by running QEMU -incoming.

    This mode allows the user to quit QEMU, optionally update and reboot the OS, and restart QEMU. If the user reboots, the URI must persist across the reboot, such as by using a file.

    Unlike normal mode, the use of certain local storage options does not block the migration, but the user must not modify the contents of guest block devices between the quit and restart.

    This mode supports VFIO devices provided the user first puts the guest in the suspended runstate, such as by issuing guest-suspend-ram to the QEMU guest agent.

    Best performance is achieved when the memory backend is shared and the x-ignore-shared migration capability is set, but this is not required. Further, if the user reboots before restarting such a configuration, the shared memory must persist across the reboot, such as by backing it with a dax device.

    cpr-reboot may not be used with postcopy, background-snapshot, or COLO.

    (since 8.2)

  • cpr-transfer –

    This mode allows the user to transfer a guest to a new QEMU instance on the same host with minimal guest pause time by preserving guest RAM in place.

    Devices and their pinned pages are also preserved for VFIO and IOMMUFD. (since 10.1)

    The user starts new QEMU on the same host as old QEMU, with command-line arguments to create the same machine, plus the -incoming option for the main migration channel, like normal live migration. In addition, the user adds a second -incoming option with channel type “cpr”. This CPR channel must support file descriptor transfer with SCM_RIGHTS, i.e. it must be a UNIX domain socket.

    To initiate CPR, the user issues a migrate command to old QEMU, adding a second migration channel of type “cpr” in the channels argument. Old QEMU stops the VM, saves state to the migration channels, and enters the postmigrate state. Execution resumes in new QEMU.

    New QEMU reads the CPR channel before opening a monitor, hence the CPR channel cannot be specified in the list of channels for a migrate-incoming command. It may only be specified on the command line.

    The main channel address cannot be a file type, and for an inet socket, the port cannot be 0 (meaning dynamically choose a port).

    Memory-backend objects must have the share=on attribute, but memory-backend-epc is not supported. The VM must be started with the ‘-machine aux-ram-share=on’ option.

    When using -incoming defer, you must issue the migrate command to old QEMU before issuing any monitor commands to new QEMU. However, new QEMU does not open and read the migration stream until you issue the migrate-incoming command.

    (since 10.0)

  • cpr-exec –

    The migrate command stops the VM, saves state to the migration channel, directly exec’s a new version of QEMU on the same host, replacing the original process while retaining its PID, and loads state from the channel. Guest RAM is preserved in place. Devices and their pinned pages are also preserved for VFIO and IOMMUFD.

    Old QEMU starts new QEMU by exec’ing the command specified by the cpr-exec-command parameter. The command may be a direct invocation of new QEMU, or may be a wrapper that exec’s the new QEMU binary.

    Because old QEMU terminates when new QEMU starts, one cannot stream data between the two, so the channel must be a type, such as a file, that accepts all data before old QEMU exits. Otherwise, old QEMU may quietly block writing to the channel.

    Memory-backend objects must have the share=on attribute, but memory-backend-epc is not supported. The VM must be started with the ‘-machine aux-ram-share=on’ option.

    (since 10.2)

Enum ZeroPageDetection (Since: 9.0)
Values:

  • none – Do not perform zero page checking.

  • legacy – Perform zero page checking in main migration thread.

  • multifd – Perform zero page checking in multifd sender thread if multifd migration is enabled, else in the main migration thread as for legacy.

Object BitmapMigrationBitmapAliasTransform (Since: 6.0)
Members:

  • persistent (boolean, optional) – If present, the bitmap will be made persistent or transient depending on this parameter.

Object BitmapMigrationBitmapAlias (Since: 5.2)
Members:

  • name (string) – The name of the bitmap.

  • alias (string) – An alias name for migration (for example the bitmap name on the opposite site).

  • transform (BitmapMigrationBitmapAliasTransform, optional) – Allows the modification of the migrated bitmap. (since 6.0)

Object BitmapMigrationNodeAlias (Since: 5.2)

Maps a block node name and the bitmaps it has to aliases for dirty bitmap migration.

Members:

  • node-name (string) – A block node name.

  • alias (string) – An alias block node name for migration (for example the node name on the opposite site).

  • bitmaps ([BitmapMigrationBitmapAlias]) – Mappings for the bitmaps on this node.

Enum MigrationParameter (Since: 2.4)

Migration parameters enumeration. The enumeration values mirror the members of MigrationParameters.

Values:

  • cpr-exec-command – Command to start the new QEMU process when mode is cpr-exec. The first list element is the program’s filename, the remainder its arguments. (Since 10.2)

  • announce-initial – Not documented

  • announce-max – Not documented

  • announce-rounds – Not documented

  • announce-step – Not documented

  • throttle-trigger-threshold – Not documented

  • cpu-throttle-initial – Not documented

  • cpu-throttle-increment – Not documented

  • cpu-throttle-tailslow – Not documented

  • tls-creds – Not documented

  • tls-hostname – Not documented

  • tls-authz – Not documented

  • max-bandwidth – Not documented

  • avail-switchover-bandwidth – Not documented

  • downtime-limit – Not documented

  • x-checkpoint-delay – Not documented

  • multifd-channels – Not documented

  • xbzrle-cache-size – Not documented

  • max-postcopy-bandwidth – Not documented

  • max-cpu-throttle – Not documented

  • multifd-compression – Not documented

  • multifd-zlib-level – Not documented

  • multifd-zstd-level – Not documented

  • multifd-qatzip-level – Not documented

  • block-bitmap-mapping – Not documented

  • x-vcpu-dirty-limit-period – Not documented

  • vcpu-dirty-limit – Not documented

  • mode – Not documented

  • zero-page-detection – Not documented

  • direct-io – Not documented

Features:

  • unstable – Members x-checkpoint-delay and x-vcpu-dirty-limit-period are experimental.

Command migrate-set-parameters (Since: 2.4)

Set migration parameters. All arguments are optional.

Arguments:

Example:

-> { "execute": "migrate-set-parameters" ,
     "arguments": { "multifd-channels": 5 } }
<- { "return": {} }
Object MigrationParameters (Since: 2.4)
Members:

  • announce-initial (int, optional) – Initial delay (in milliseconds) before sending the first announce (Since 4.0)

  • announce-max (int, optional) – Maximum delay (in milliseconds) between packets in the announcement (Since 4.0)

  • announce-rounds (int, optional) – Number of self-announce packets sent after migration (Since 4.0)

  • announce-step (int, optional) – Increase in delay (in milliseconds) between subsequent packets in the announcement (Since 4.0)

  • throttle-trigger-threshold (int, optional) – The ratio of bytes_dirty_period and bytes_xfer_period to trigger throttling. It is expressed as percentage. The default value is 50. (Since 5.0)

  • cpu-throttle-initial (int, optional) – Initial percentage of time guest cpus are throttled when migration auto-converge is activated. The default value is 20. (Since 2.7)

  • cpu-throttle-increment (int, optional) – throttle percentage increase each time auto-converge detects that migration is not making progress. The default value is 10. (Since 2.7)

  • cpu-throttle-tailslow (boolean, optional) – Make CPU throttling slower at tail stage. At the tail stage of throttling, the Guest is very sensitive to CPU percentage while the cpu-throttle -increment is excessive usually at tail stage. If this parameter is true, we will compute the ideal CPU percentage used by the Guest, which may exactly make the dirty rate match the dirty rate threshold. Then we will choose a smaller throttle increment between the one specified by cpu-throttle-increment and the one generated by ideal CPU percentage. Therefore, it is compatible to traditional throttling, meanwhile the throttle increment won’t be excessive at tail stage. The default value is false. (Since 5.1)

  • tls-creds (StrOrNull, optional) – ID of the ‘tls-creds’ object that provides credentials for establishing a TLS connection over the migration data channel. On the outgoing side of the migration, the credentials must be for a ‘client’ endpoint, while for the incoming side the credentials must be for a ‘server’ endpoint. Setting this to a non-empty string enables TLS for all migrations. An empty string means that QEMU will use plain text mode for migration, rather than TLS. This is the default. (Since 2.7)

  • tls-hostname (StrOrNull, optional) –

    migration target’s hostname for validating the server’s x509 certificate identity. If empty, QEMU will use the hostname from the migration URI, if any. A non-empty value is required when using x509 based TLS credentials and the migration URI does not include a hostname, such as fd: or exec: based migration. (Since 2.7)

    Note: empty value works only since 2.9.

  • tls-authz (StrOrNull, optional) – ID of the ‘authz’ object subclass that provides access control checking of the TLS x509 certificate distinguished name. This object is only resolved at time of use, so can be deleted and recreated on the fly while the migration server is active. If missing, it will default to denying access (Since 4.0)

  • max-bandwidth (int, optional) – maximum speed for migration, in bytes per second. (Since 2.8)

  • avail-switchover-bandwidth (int, optional) – to set the available bandwidth that migration can use during switchover phase. Note: this does not limit the bandwidth during switchover, but only for calculations when making decisions to switchover. By default, this value is zero, which means QEMU will estimate the bandwidth automatically. This can be set when the estimated value is not accurate, while the user is able to guarantee such bandwidth is available when switching over. When specified correctly, this can make the switchover decision much more accurate. (Since 8.2)

  • downtime-limit (int, optional) – set maximum tolerated downtime for migration. maximum downtime in milliseconds (Since 2.8)

  • x-checkpoint-delay (int, optional) – The delay time (in ms) between two COLO checkpoints in periodic mode. (Since 2.8)

  • multifd-channels (int, optional) – Number of channels used to migrate data in parallel. This is the same number that the number of sockets used for migration. The default value is 2 (since 4.0)

  • xbzrle-cache-size (int, optional) – cache size to be used by XBZRLE migration. It needs to be a multiple of the target page size and a power of 2 (Since 2.11)

  • max-postcopy-bandwidth (int, optional) – Background transfer bandwidth during postcopy. Defaults to 0 (unlimited). In bytes per second. (Since 3.0)

  • max-cpu-throttle (int, optional) – maximum cpu throttle percentage. Defaults to 99. (Since 3.1)

  • multifd-compression (MultiFDCompression, optional) – Which compression method to use. Defaults to none. (Since 5.0)

  • multifd-zlib-level (int, optional) – Set the compression level to be used in live migration, the compression level is an integer between 0 and 9, where 0 means no compression, 1 means the best compression speed, and 9 means best compression ratio which will consume more CPU. Defaults to 1. (Since 5.0)

  • multifd-qatzip-level (int, optional) – Set the compression level to be used in live migration. The level is an integer between 1 and 9, where 1 means the best compression speed, and 9 means the best compression ratio which will consume more CPU. Defaults to 1. (Since 9.2)

  • multifd-zstd-level (int, optional) – Set the compression level to be used in live migration, the compression level is an integer between 0 and 20, where 0 means no compression, 1 means the best compression speed, and 20 means best compression ratio which will consume more CPU. Defaults to 1. (Since 5.0)

  • block-bitmap-mapping ([BitmapMigrationNodeAlias], optional) – Maps block nodes and bitmaps on them to aliases for the purpose of dirty bitmap migration. Such aliases may for example be the corresponding names on the opposite site. The mapping must be one-to-one, but not necessarily complete: On the source, unmapped bitmaps and all bitmaps on unmapped nodes will be ignored. On the destination, encountering an unmapped alias in the incoming migration stream will result in a report, and all further bitmap migration data will then be discarded. Note that the destination does not know about bitmaps it does not receive, so there is no limitation or requirement regarding the number of bitmaps received, or how they are named, or on which nodes they are placed. By default (when this parameter has never been set), bitmap names are mapped to themselves. Nodes are mapped to their block device name if there is one, and to their node name otherwise. (Since 5.2)

  • x-vcpu-dirty-limit-period (int, optional) – Periodic time (in milliseconds) of dirty limit during live migration. Should be in the range 1 to 1000ms. Defaults to 1000ms. (Since 8.1)

  • vcpu-dirty-limit (int, optional) – Dirtyrate limit (MB/s) during live migration. Defaults to 1. (Since 8.1)

  • mode (MigMode, optional) – Migration mode. See description in MigMode. Default is ‘normal’. (Since 8.2)

  • zero-page-detection (ZeroPageDetection, optional) – Whether and how to detect zero pages. See description in ZeroPageDetection. Default is ‘multifd’. (since 9.0)

  • direct-io (boolean, optional) – Open migration files with O_DIRECT when possible. This only has effect if the mapped-ram capability is enabled. (Since 9.1)

  • cpr-exec-command ([string], optional) – Command to start the new QEMU process when mode is cpr-exec. The first list element is the program’s filename, the remainder its arguments. (Since 10.2)

Features:

  • unstable – Members x-checkpoint-delay and x-vcpu-dirty-limit-period are experimental.

Command query-migrate-parameters (Since: 2.4)

Return information about the current migration parameters. Optional members of the return value are always present, except block-bitmap-mapping, which is only present if it has been previously set.

Return:

MigrationParameters

Example:

-> { "execute": "query-migrate-parameters" }
<- { "return": {
         "multifd-channels": 2,
         "cpu-throttle-increment": 10,
         "cpu-throttle-initial": 20,
         "max-bandwidth": 33554432,
         "downtime-limit": 300
      }
   }
Command migrate-start-postcopy (Since: 2.5)

Followup to a migration command to switch the migration to postcopy mode. The postcopy-ram capability must be set on both source and destination before the original migration command.

Example:

-> { "execute": "migrate-start-postcopy" }
<- { "return": {} }
Event MIGRATION (Since: 2.4)

Emitted when a migration event happens

Members:

Example:

<- {"timestamp": {"seconds": 1432121972, "microseconds": 744001},
    "event": "MIGRATION",
    "data": {"status": "completed"} }
Event MIGRATION_PASS (Since: 2.6)

Emitted from the source side of a migration at the start of each pass (when it syncs the dirty bitmap)

Members:

  • pass (int) – An incrementing count (starting at 1 on the first pass)

Example:

<- { "timestamp": {"seconds": 1449669631, "microseconds": 239225},
      "event": "MIGRATION_PASS", "data": {"pass": 2} }
Enum COLOMessage (Since: 2.8)

The message transmission between Primary side and Secondary side.

Values:

  • checkpoint-ready – Secondary VM (SVM) is ready for checkpointing

  • checkpoint-request – Primary VM (PVM) tells SVM to prepare for checkpointing

  • checkpoint-reply – SVM gets PVM’s checkpoint request

  • vmstate-send – VM’s state will be sent by PVM.

  • vmstate-size – The total size of VMstate.

  • vmstate-received – VM’s state has been received by SVM.

  • vmstate-loaded – VM’s state has been loaded by SVM.

Enum COLOMode (Since: 2.8)

The COLO current mode.

Values:

  • none – COLO is disabled.

  • primary – COLO node in primary side.

  • secondary – COLO node in slave side.

Enum FailoverStatus (Since: 2.8)

An enumeration of COLO failover status

Values:

  • none – no failover has ever happened

  • require – got failover requirement but not handled

  • active – in the process of doing failover

  • completed – finish the process of failover

  • relaunch – restart the failover process, from ‘none’ -> ‘completed’ (Since 2.9)

Event COLO_EXIT (Since: 3.1)

Emitted when VM finishes COLO mode due to some errors happening or at the request of users.

Members:

  • mode (COLOMode) – report COLO mode when COLO exited.

  • reason (COLOExitReason) – describes the reason for the COLO exit.

Example:

<- { "timestamp": {"seconds": 2032141960, "microseconds": 417172},
     "event": "COLO_EXIT", "data": {"mode": "primary", "reason": "request" } }
Enum COLOExitReason (Since: 3.1)

The reason for a COLO exit.

Values:

  • none – failover has never happened. This state does not occur in the COLO_EXIT event, and is only visible in the result of query-colo-status.

  • request – COLO exit is due to an external request.

  • error – COLO exit is due to an internal error.

  • processing – COLO is currently handling a failover (since 4.0).

Command x-colo-lost-heartbeat (Since: 2.8)
This command is unstable/experimental.
Availability: CONFIG_REPLICATION

Tell QEMU that heartbeat is lost, request it to do takeover procedures. If this command is sent to the PVM, the Primary side will exit COLO mode. If sent to the Secondary, the Secondary side will run failover work, then takes over server operation to become the service VM.

Features:

  • unstable – This command is experimental.

Example:

-> { "execute": "x-colo-lost-heartbeat" }
<- { "return": {} }
Command migrate_cancel (Since: 0.14)

Cancel the currently executing migration process. Allows a new migration to be started right after. When postcopy-ram is in use, cancelling is not allowed after the postcopy phase has started.

Note

This command succeeds even if there is no migration process running.

Example:

-> { "execute": "migrate_cancel" }
<- { "return": {} }
Command migrate-continue (Since: 2.11)

Continue migration when it’s in a paused state.

Arguments:

  • state (MigrationStatus) – The state the migration is currently expected to be in

Example:

-> { "execute": "migrate-continue" , "arguments":
     { "state": "pre-switchover" } }
<- { "return": {} }
Enum MigrationAddressType (Since: 8.2)

The migration stream transport mechanisms.

Values:

  • socket – Migrate via socket.

  • exec – Direct the migration stream to another process.

  • rdma – Migrate via RDMA.

  • file – Direct the migration stream to a file.

Object FileMigrationArgs (Since: 8.2)
Members:

  • filename (string) – The file to receive the migration stream

  • offset (int) – The file offset where the migration stream will start

Object MigrationExecCommand (Since: 8.2)
Members:

  • args ([string]) – command (list head) and arguments to execute.

Object MigrationAddress (Since: 8.2)

Migration endpoint configuration.

Members:
Enum MigrationChannelType (Since: 8.1)

The migration channel-type request options.

Values:

  • main – Main outbound migration channel.

  • cpr – Checkpoint and restart state channel.

Object MigrationChannel (Since: 8.1)

Migration stream channel parameters.

Members:
Command migrate (Since: 0.14)

Migrates the current running guest to another Virtual Machine.

Arguments:

  • uri (string, optional) – the Uniform Resource Identifier of the destination VM

  • channels ([MigrationChannel], optional) – list of migration stream channels with each stream in the list connected to a destination interface endpoint.

  • resume (boolean, optional) – when set, use the new uri/channels specified to resume paused postcopy migration. This flag should only be used if the previous postcopy migration was interrupted. The command will fail unless migration is in “postcopy-paused” state. (default: false, since 3.0)

Notes

  1. The query-migrate command should be used to check migration’s progress and final result (this information is provided by the ‘status’ member).

  2. The uri argument should have the Uniform Resource Identifier of default destination VM. This connection will be bound to default network.

  3. For now, number of migration streams is restricted to one, i.e. number of items in ‘channels’ list is just 1.

  4. The ‘uri’ and ‘channels’ arguments are mutually exclusive; exactly one of the two should be present.

Example:

-> { "execute": "migrate", "arguments": { "uri": "tcp:0:4446" } }
<- { "return": {} }

-> { "execute": "migrate",
     "arguments": {
         "channels": [ { "channel-type": "main",
                         "addr": { "transport": "socket",
                                   "type": "inet",
                                   "host": "10.12.34.9",
                                   "port": "1050" } } ] } }
<- { "return": {} }

-> { "execute": "migrate",
     "arguments": {
         "channels": [ { "channel-type": "main",
                         "addr": { "transport": "exec",
                                   "args": [ "/bin/nc", "-p", "6000",
                                             "/some/sock" ] } } ] } }
<- { "return": {} }

-> { "execute": "migrate",
     "arguments": {
         "channels": [ { "channel-type": "main",
                         "addr": { "transport": "rdma",
                                   "host": "10.12.34.9",
                                   "port": "1050" } } ] } }
<- { "return": {} }

-> { "execute": "migrate",
     "arguments": {
         "channels": [ { "channel-type": "main",
                         "addr": { "transport": "file",
                                   "filename": "/tmp/migfile",
                                   "offset": "0x1000" } } ] } }
<- { "return": {} }
Command migrate-incoming (Since: 2.3)

Start an incoming migration. QEMU must have been started with -incoming defer.

Arguments:

  • uri (string, optional) – The Uniform Resource Identifier identifying the source or address to listen on

  • channels ([MigrationChannel], optional) – list of migration stream channels with each stream in the list connected to a destination interface endpoint.

  • exit-on-error (boolean, optional) – Exit on incoming migration failure. Default true. When set to false, the failure triggers a MIGRATION event, and error details could be retrieved with query-migrate. (since 9.1)

Notes

  1. It’s a bad idea to use a string for the uri, but it needs to stay compatible with -incoming and the format of the uri is already exposed above libvirt.

  2. QEMU must be started with -incoming defer to allow migrate-incoming to be used.

  3. The uri format is the same as for -incoming

  4. For now, number of migration streams is restricted to one, i.e. number of items in ‘channels’ list is just 1.

  5. The ‘uri’ and ‘channels’ arguments are mutually exclusive; exactly one of the two should be present.

Example:

-> { "execute": "migrate-incoming",
     "arguments": { "uri": "tcp:0:4446" } }
<- { "return": {} }

-> { "execute": "migrate-incoming",
     "arguments": {
         "channels": [ { "channel-type": "main",
                         "addr": { "transport": "socket",
                                   "type": "inet",
                                   "host": "10.12.34.9",
                                   "port": "1050" } } ] } }
<- { "return": {} }

-> { "execute": "migrate-incoming",
     "arguments": {
         "channels": [ { "channel-type": "main",
                         "addr": { "transport": "exec",
                                   "args": [ "/bin/nc", "-p", "6000",
                                             "/some/sock" ] } } ] } }
<- { "return": {} }

-> { "execute": "migrate-incoming",
     "arguments": {
         "channels": [ { "channel-type": "main",
                         "addr": { "transport": "rdma",
                                   "host": "10.12.34.9",
                                   "port": "1050" } } ] } }
<- { "return": {} }
Command xen-save-devices-state (Since: 1.1)

Save the state of all devices to file. The RAM and the block devices of the VM are not saved by this command.

Arguments:

  • filename (string) – the file to save the state of the devices to as binary data. See xen-save-devices-state.txt for a description of the binary format.

  • live (boolean, optional) – Optional argument to ask QEMU to treat this command as part of a live migration. Default to true. (since 2.11)

Example:

-> { "execute": "xen-save-devices-state",
     "arguments": { "filename": "/tmp/save" } }
<- { "return": {} }
Command xen-set-global-dirty-log (Since: 1.3)

Enable or disable the global dirty log mode.

Arguments:

  • enable (boolean) – true to enable, false to disable.

Example:

-> { "execute": "xen-set-global-dirty-log",
     "arguments": { "enable": true } }
<- { "return": {} }
Command xen-load-devices-state (Since: 2.7)

Load the state of all devices from file. The RAM and the block devices of the VM are not loaded by this command.

Arguments:

  • filename (string) – the file to load the state of the devices from as binary data. See xen-save-devices-state.txt for a description of the binary format.

Example:

-> { "execute": "xen-load-devices-state",
     "arguments": { "filename": "/tmp/resume" } }
<- { "return": {} }
Command xen-set-replication (Since: 2.9)
Availability: CONFIG_REPLICATION

Enable or disable replication.

Arguments:

  • enable (boolean) – true to enable, false to disable.

  • primary (boolean) – true for primary or false for secondary.

  • failover (boolean, optional) – true to do failover, false to stop. Cannot be specified if ‘enable’ is true. Default value is false.

Example:

-> { "execute": "xen-set-replication",
     "arguments": {"enable": true, "primary": false} }
<- { "return": {} }
Object ReplicationStatus (Since: 2.9)
Availability: CONFIG_REPLICATION

The result format for query-xen-replication-status.

Members:

  • error (boolean) – true if an error happened, false if replication is normal.

  • desc (string, optional) – the human readable error description string, when error is ‘true’.

Command query-xen-replication-status (Since: 2.9)
Availability: CONFIG_REPLICATION

Query replication status while the vm is running.

Return:

ReplicationStatus

Example:

-> { "execute": "query-xen-replication-status" }
<- { "return": { "error": false } }
Command xen-colo-do-checkpoint (Since: 2.9)
Availability: CONFIG_REPLICATION

Xen uses this command to notify replication to trigger a checkpoint.

Example:

-> { "execute": "xen-colo-do-checkpoint" }
<- { "return": {} }
Object COLOStatus (Since: 3.1)
Availability: CONFIG_REPLICATION

The result format for query-colo-status.

Members:

  • mode (COLOMode) – COLO running mode. If COLO is running, this field will return ‘primary’ or ‘secondary’.

  • last-mode (COLOMode) – COLO last running mode. If COLO is running, this field will return same like mode field, after failover we can use this field to get last colo mode. (since 4.0)

  • reason (COLOExitReason) – describes the reason for the COLO exit.

Command query-colo-status (Since: 3.1)
Availability: CONFIG_REPLICATION

Query COLO status while the vm is running.

Return:

COLOStatus

Example:

-> { "execute": "query-colo-status" }
<- { "return": { "mode": "primary", "last-mode": "none", "reason": "request" } }
Command migrate-recover (Since: 3.0)

Provide a recovery migration stream URI.

Arguments:

  • uri (string) – the URI to be used for the recovery of migration stream.

Example:

-> { "execute": "migrate-recover",
     "arguments": { "uri": "tcp:192.168.1.200:12345" } }
<- { "return": {} }
Command migrate-pause (Since: 3.0)

Pause a migration. Currently it only supports postcopy.

Example:

-> { "execute": "migrate-pause" }
<- { "return": {} }
Event UNPLUG_PRIMARY (Since: 4.2)

Emitted from source side of a migration when migration state is WAIT_UNPLUG. Device was unplugged by guest operating system. Device resources in QEMU are kept on standby to be able to re-plug it in case of migration failure.

Members:

  • device-id (string) – QEMU device id of the unplugged device

Example:

<- { "event": "UNPLUG_PRIMARY",
     "data": { "device-id": "hostdev0" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
Object DirtyRateVcpu (Since: 6.2)

Dirty rate of vcpu.

Members:

  • id (int) – vcpu index.

  • dirty-rate (int) – dirty rate.

Enum DirtyRateStatus (Since: 5.2)

Dirty page rate measurement status.

Values:

  • unstarted – measuring thread has not been started yet

  • measuring – measuring thread is running

  • measured – dirty page rate is measured and the results are available

Enum DirtyRateMeasureMode (Since: 6.2)

Method used to measure dirty page rate. Differences between available methods are explained in calc-dirty-rate.

Values:

  • page-sampling – use page sampling

  • dirty-ring – use dirty ring

  • dirty-bitmap – use dirty bitmap

Enum TimeUnit (Since: 8.2)

Specifies unit in which time-related value is specified.

Values:

  • second – value is in seconds

  • millisecond – value is in milliseconds

Object DirtyRateInfo (Since: 5.2)

Information about measured dirty page rate.

Members:

  • dirty-rate (int, optional) – an estimate of the dirty page rate of the VM in units of MiB/s. Value is present only when status is ‘measured’.

  • status (DirtyRateStatus) – current status of dirty page rate measurements

  • start-time (int) – start time in units of second for calculation

  • calc-time (int) – time period for which dirty page rate was measured, expressed and rounded down to calc-time-unit.

  • calc-time-unit (TimeUnit) – time unit of calc-time (Since 8.2)

  • sample-pages (int) – number of sampled pages per GiB of guest memory. Valid only in page-sampling mode (Since 6.1)

  • mode (DirtyRateMeasureMode) – mode that was used to measure dirty page rate (Since 6.2)

  • vcpu-dirty-rate ([DirtyRateVcpu], optional) – dirty rate for each vCPU if dirty-ring mode was specified (Since 6.2)

Command calc-dirty-rate (Since: 5.2)

Start measuring dirty page rate of the VM. Results can be retrieved with query-dirty-rate after measurements are completed.

Dirty page rate is the number of pages changed in a given time period expressed in MiB/s. The following methods of calculation are available:

  1. In page sampling mode, a random subset of pages are selected and hashed twice: once at the beginning of measurement time period, and once again at the end. If two hashes for some page are different, the page is counted as changed. Since this method relies on sampling and hashing, calculated dirty page rate is only an estimate of its true value. Increasing sample-pages improves estimation quality at the cost of higher computational overhead.

  2. Dirty bitmap mode captures writes to memory (for example by temporarily revoking write access to all pages) and counting page faults. Information about modified pages is collected into a bitmap, where each bit corresponds to one guest page. This mode requires that KVM accelerator property “dirty-ring-size” is not set.

  3. Dirty ring mode is similar to dirty bitmap mode, but the information about modified pages is collected into ring buffer. This mode tracks page modification per each vCPU separately. It requires that KVM accelerator property “dirty-ring-size” is set.

Arguments:

  • calc-time (int) – time period for which dirty page rate is calculated. By default it is specified in seconds, but the unit can be set explicitly with calc-time-unit. Note that larger calc-time values will typically result in smaller dirty page rates because page dirtying is a one-time event. Once some page is counted as dirty during calc-time period, further writes to this page will not increase dirty page rate anymore.

  • calc-time-unit (TimeUnit, optional) – time unit in which calc-time is specified. By default it is seconds. (Since 8.2)

  • sample-pages (int, optional) – number of sampled pages per each GiB of guest memory. Default value is 512. For 4KiB guest pages this corresponds to sampling ratio of 0.2%. This argument is used only in page sampling mode. (Since 6.1)

  • mode (DirtyRateMeasureMode, optional) – mechanism for tracking dirty pages. Default value is ‘page-sampling’. Others are ‘dirty-bitmap’ and ‘dirty-ring’. (Since 6.1)

Example:

-> {"execute": "calc-dirty-rate", "arguments": {"calc-time": 1,
                                                "sample-pages": 512} }
<- { "return": {} }

Example:

Measure dirty rate using dirty bitmap for 500 milliseconds:

-> {"execute": "calc-dirty-rate", "arguments": {"calc-time": 500,
    "calc-time-unit": "millisecond", "mode": "dirty-bitmap"} }

<- { "return": {} }
Command query-dirty-rate (Since: 5.2)

Query results of the most recent invocation of calc-dirty-rate.

Arguments:

  • calc-time-unit (TimeUnit, optional) – time unit in which to report calculation time. By default it is reported in seconds. (Since 8.2)

Return:

DirtyRateInfo

Example: Measurement is in progress

 <- {"status": "measuring", "sample-pages": 512,
     "mode": "page-sampling", "start-time": 1693900454, "calc-time": 10,
     "calc-time-unit": "second"}

Example: Measurement has been completed

 <- {"status": "measured", "sample-pages": 512, "dirty-rate": 108,
     "mode": "page-sampling", "start-time": 1693900454, "calc-time": 10,
     "calc-time-unit": "second"}
Object DirtyLimitInfo (Since: 7.1)

Dirty page rate limit information of a virtual CPU.

Members:

  • cpu-index (int) – index of a virtual CPU.

  • limit-rate (int) – upper limit of dirty page rate (MB/s) for a virtual CPU, 0 means unlimited.

  • current-rate (int) – current dirty page rate (MB/s) for a virtual CPU.

Command set-vcpu-dirty-limit (Since: 7.1)

Set the upper limit of dirty page rate for virtual CPUs.

Requires KVM with accelerator property “dirty-ring-size” set. A virtual CPU’s dirty page rate is a measure of its memory load. To observe dirty page rates, use calc-dirty-rate.

Arguments:

  • cpu-index (int, optional) – index of a virtual CPU, default is all.

  • dirty-rate (int) – upper limit of dirty page rate (MB/s) for virtual CPUs.

Example:

-> {"execute": "set-vcpu-dirty-limit"}
    "arguments": { "dirty-rate": 200,
                   "cpu-index": 1 } }
<- { "return": {} }
Command cancel-vcpu-dirty-limit (Since: 7.1)

Cancel the upper limit of dirty page rate for virtual CPUs.

Cancel the dirty page limit for the vCPU which has been set with set-vcpu-dirty-limit command. Note that this command requires support from dirty ring, same as the set-vcpu-dirty-limit.

Arguments:

  • cpu-index (int, optional) – index of a virtual CPU, default is all.

Example:

-> {"execute": "cancel-vcpu-dirty-limit"},
    "arguments": { "cpu-index": 1 } }
<- { "return": {} }
Command query-vcpu-dirty-limit (Since: 7.1)

Return information about virtual CPU dirty page rate limits, if any.

Return:

[DirtyLimitInfo]

Example:

-> {"execute": "query-vcpu-dirty-limit"}
<- {"return": [
       { "limit-rate": 60, "current-rate": 3, "cpu-index": 0},
       { "limit-rate": 60, "current-rate": 3, "cpu-index": 1}]}
Command snapshot-save (Since: 6.0)

Save a VM snapshot

Arguments:

  • job-id (string) – identifier for the newly created job

  • tag (string) – name of the snapshot to create

  • vmstate (string) – block device node name to save vmstate to

  • devices ([string]) – list of block device node names to save a snapshot to

Applications should not assume that the snapshot save is complete when this command returns. The job commands / events must be used to determine completion and to fetch details of any errors that arise.

Note that execution of the guest CPUs may be stopped during the time it takes to save the snapshot. A future version of QEMU may ensure CPUs are executing continuously.

It is strongly recommended that devices contain all writable block device nodes if a consistent snapshot is required.

If tag already exists, an error will be reported

Example:

-> { "execute": "snapshot-save",
     "arguments": {
        "job-id": "snapsave0",
        "tag": "my-snap",
        "vmstate": "disk0",
        "devices": ["disk0", "disk1"]
     }
   }
<- { "return": { } }
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1432121972, "microseconds": 744001},
    "data": {"status": "created", "id": "snapsave0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1432122172, "microseconds": 744001},
    "data": {"status": "running", "id": "snapsave0"}}
<- {"event": "STOP",
    "timestamp": {"seconds": 1432122372, "microseconds": 744001} }
<- {"event": "RESUME",
    "timestamp": {"seconds": 1432122572, "microseconds": 744001} }
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1432122772, "microseconds": 744001},
    "data": {"status": "waiting", "id": "snapsave0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1432122972, "microseconds": 744001},
    "data": {"status": "pending", "id": "snapsave0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1432123172, "microseconds": 744001},
    "data": {"status": "concluded", "id": "snapsave0"}}
-> {"execute": "query-jobs"}
<- {"return": [{"current-progress": 1,
                "status": "concluded",
                "total-progress": 1,
                "type": "snapshot-save",
                "id": "snapsave0"}]}
Command snapshot-load (Since: 6.0)

Load a VM snapshot

Arguments:

  • job-id (string) – identifier for the newly created job

  • tag (string) – name of the snapshot to load.

  • vmstate (string) – block device node name to load vmstate from

  • devices ([string]) – list of block device node names to load a snapshot from

Applications should not assume that the snapshot load is complete when this command returns. The job commands / events must be used to determine completion and to fetch details of any errors that arise.

Note that execution of the guest CPUs will be stopped during the time it takes to load the snapshot.

It is strongly recommended that devices contain all writable block device nodes that can have changed since the original snapshot-save command execution.

Example:

-> { "execute": "snapshot-load",
     "arguments": {
        "job-id": "snapload0",
        "tag": "my-snap",
        "vmstate": "disk0",
        "devices": ["disk0", "disk1"]
     }
   }
<- { "return": { } }
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1472124172, "microseconds": 744001},
    "data": {"status": "created", "id": "snapload0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1472125172, "microseconds": 744001},
    "data": {"status": "running", "id": "snapload0"}}
<- {"event": "STOP",
    "timestamp": {"seconds": 1472125472, "microseconds": 744001} }
<- {"event": "RESUME",
    "timestamp": {"seconds": 1472125872, "microseconds": 744001} }
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1472126172, "microseconds": 744001},
    "data": {"status": "waiting", "id": "snapload0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1472127172, "microseconds": 744001},
    "data": {"status": "pending", "id": "snapload0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1472128172, "microseconds": 744001},
    "data": {"status": "concluded", "id": "snapload0"}}
-> {"execute": "query-jobs"}
<- {"return": [{"current-progress": 1,
                "status": "concluded",
                "total-progress": 1,
                "type": "snapshot-load",
                "id": "snapload0"}]}
Command snapshot-delete (Since: 6.0)

Delete a VM snapshot

Arguments:

  • job-id (string) – identifier for the newly created job

  • tag (string) – name of the snapshot to delete.

  • devices ([string]) – list of block device node names to delete a snapshot from

Applications should not assume that the snapshot delete is complete when this command returns. The job commands / events must be used to determine completion and to fetch details of any errors that arise.

Example:

-> { "execute": "snapshot-delete",
     "arguments": {
        "job-id": "snapdelete0",
        "tag": "my-snap",
        "devices": ["disk0", "disk1"]
     }
   }
<- { "return": { } }
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1442124172, "microseconds": 744001},
    "data": {"status": "created", "id": "snapdelete0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1442125172, "microseconds": 744001},
    "data": {"status": "running", "id": "snapdelete0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1442126172, "microseconds": 744001},
    "data": {"status": "waiting", "id": "snapdelete0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1442127172, "microseconds": 744001},
    "data": {"status": "pending", "id": "snapdelete0"}}
<- {"event": "JOB_STATUS_CHANGE",
    "timestamp": {"seconds": 1442128172, "microseconds": 744001},
    "data": {"status": "concluded", "id": "snapdelete0"}}
-> {"execute": "query-jobs"}
<- {"return": [{"current-progress": 1,
                "status": "concluded",
                "total-progress": 1,
                "type": "snapshot-delete",
                "id": "snapdelete0"}]}

Transactions

Object Abort (Since: 1.6)

This action can be used to test transaction failure.

Enum ActionCompletionMode (Since: 2.5)

An enumeration of transactional completion modes.

Values:

  • individual – Do not attempt to cancel any other Actions if any Actions fail after the Transaction request succeeds. All Actions that can complete successfully will do so without waiting on others. This is the default.

  • grouped – If any Action fails after the Transaction succeeds, cancel all Actions. Actions do not complete until all Actions are ready to complete. May be rejected by Actions that do not support this completion mode.

Enum TransactionActionKind (Since: 1.1)
Values:

  • abort – Since 1.6

  • block-dirty-bitmap-add – Since 2.5

  • block-dirty-bitmap-remove – Since 4.2

  • block-dirty-bitmap-clear – Since 2.5

  • block-dirty-bitmap-enable – Since 4.0

  • block-dirty-bitmap-disable – Since 4.0

  • block-dirty-bitmap-merge – Since 4.0

  • blockdev-backup – Since 2.3

  • blockdev-snapshot – Since 2.5

  • blockdev-snapshot-internal-sync – Since 1.7

  • blockdev-snapshot-sync – since 1.1

  • drive-backup – Since 1.6

Features:
Object AbortWrapper (Since: 1.6)
Members:

  • data (Abort) – Not documented

Object BlockDirtyBitmapAddWrapper (Since: 2.5)
Members:
Object BlockDirtyBitmapWrapper (Since: 2.5)
Members:
Object BlockDirtyBitmapMergeWrapper (Since: 4.0)
Members:
Object BlockdevBackupWrapper (Since: 2.3)
Members:
Object BlockdevSnapshotWrapper (Since: 2.5)
Members:
Object BlockdevSnapshotInternalWrapper (Since: 1.7)
Members:
Object BlockdevSnapshotSyncWrapper (Since: 1.1)
Members:
Object DriveBackupWrapper (Since: 1.6)
Members:
Object TransactionAction (Since: 1.1)

A discriminated record of operations that can be performed with transaction.

Members:
Object TransactionProperties (Since: 2.5)

Optional arguments to modify the behavior of a Transaction.

Members:
Command transaction (Since: 1.1)

Executes a number of transactionable QMP commands atomically. If any operation fails, then the entire set of actions will be abandoned and the appropriate error returned.

For external snapshots, the dictionary contains the device, the file to use for the new snapshot, and the format. The default format, if not specified, is qcow2.

Each new snapshot defaults to being created by QEMU (wiping any contents if the file already exists), but it is also possible to reuse an externally-created file. In the latter case, you should ensure that the new image file has the same contents as the current one; QEMU cannot perform any meaningful check. Typically this is achieved by using the current image file as the backing file for the new image.

On failure, the original disks pre-snapshot attempt will be used.

For internal snapshots, the dictionary contains the device and the snapshot’s name. If an internal snapshot matching name already exists, the request will be rejected. Only some image formats support it, for example, qcow2, and rbd,

On failure, QEMU will try delete the newly created internal snapshot in the transaction. When an I/O error occurs during deletion, the user needs to fix it later with qemu-img or other command.

Arguments:
Errors:

  • Any errors from commands in the transaction

Note

The transaction aborts on the first failure. Therefore, there will be information on only one failed operation returned in an error condition, and subsequent actions will not have been attempted.

Example:

-> { "execute": "transaction",
     "arguments": { "actions": [
         { "type": "blockdev-snapshot-sync", "data" : { "device": "ide-hd0",
                                     "snapshot-file": "/some/place/my-image",
                                     "format": "qcow2" } },
         { "type": "blockdev-snapshot-sync", "data" : { "node-name": "myfile",
                                     "snapshot-file": "/some/place/my-image2",
                                     "snapshot-node-name": "node3432",
                                     "mode": "existing",
                                     "format": "qcow2" } },
         { "type": "blockdev-snapshot-sync", "data" : { "device": "ide-hd1",
                                     "snapshot-file": "/some/place/my-image2",
                                     "mode": "existing",
                                     "format": "qcow2" } },
         { "type": "blockdev-snapshot-internal-sync", "data" : {
                                     "device": "ide-hd2",
                                     "name": "snapshot0" } } ] } }
<- { "return": {} }

Tracing

Enum TraceEventState (Since: 2.2)

State of a tracing event.

Values:

  • unavailable – The event is statically disabled.

  • disabled – The event is dynamically disabled.

  • enabled – The event is dynamically enabled.

Object TraceEventInfo (Since: 2.2)

Information of a tracing event.

Members:
Command trace-event-get-state (Since: 2.2)

Query the state of events.

Arguments:

  • name (string) – Event name pattern (case-sensitive glob).

Return:

[TraceEventInfo] – a list of info for the matching events

Example:

-> { "execute": "trace-event-get-state",
     "arguments": { "name": "qemu_memalign" } }
<- { "return": [ { "name": "qemu_memalign", "state": "disabled", "vcpu": false } ] }
Command trace-event-set-state (Since: 2.2)

Set the dynamic tracing state of events.

Arguments:

  • name (string) – Event name pattern (case-sensitive glob).

  • enable (boolean) – Whether to enable tracing.

  • ignore-unavailable (boolean, optional) – Do not match unavailable events with name.

Example:

-> { "execute": "trace-event-set-state",
     "arguments": { "name": "qemu_memalign", "enable": true } }
<- { "return": {} }

Compatibility policy

Enum CompatPolicyInput (Since: 6.0)

Policy for handling “funny” input.

Values:

  • accept – Accept silently

  • reject – Reject with an error

  • crash – abort() the process

Enum CompatPolicyOutput (Since: 6.0)

Policy for handling “funny” output.

Values:

  • accept – Pass on unchanged

  • hide – Filter out

Object CompatPolicy (Since: 6.0)

Policy for handling deprecated management interfaces.

This is intended for testing users of the management interfaces.

Limitation: covers only syntactic aspects of QMP, i.e. stuff tagged with feature ‘deprecated’ or ‘unstable’. We may want to extend it to cover semantic aspects and CLI.

Limitation: deprecated-output policy hide is not implemented for enumeration values. They behave the same as with policy accept.

Members:

  • deprecated-input (CompatPolicyInput, optional) – how to handle deprecated input (default ‘accept’)

  • deprecated-output (CompatPolicyOutput, optional) – how to handle deprecated output (default ‘accept’)

  • unstable-input (CompatPolicyInput, optional) – how to handle unstable input (default ‘accept’) (since 6.2)

  • unstable-output (CompatPolicyOutput, optional) – how to handle unstable output (default ‘accept’) (since 6.2)

QMP monitor control

Command qmp_capabilities (Since: 0.13)

Enable QMP capabilities.

Arguments:

  • enable ([QMPCapability], optional) – An optional list of QMPCapability values to enable. The client must not enable any capability that is not mentioned in the QMP greeting message. If the field is not provided, it means no QMP capabilities will be enabled. (since 2.12)

Example:

-> { "execute": "qmp_capabilities",
     "arguments": { "enable": [ "oob" ] } }
<- { "return": {} }

Note

This command is valid exactly when first connecting: it must be issued before any other command will be accepted, and will fail once the monitor is accepting other commands. (see QEMU Machine Protocol Specification)

Note

The QMP client needs to explicitly enable QMP capabilities, otherwise all the QMP capabilities will be turned off by default.

Enum QMPCapability (Since: 2.12)

Enumeration of capabilities to be advertised during initial client connection, used for agreeing on particular QMP extension behaviors.

Values:

  • oob – QMP ability to support out-of-band requests. (Please refer to qmp-spec.rst for more information on OOB)

Object VersionTriple (Since: 2.4)

A three-part version number.

Members:

  • major (int) – The major version number.

  • minor (int) – The minor version number.

  • micro (int) – The micro version number.

Object VersionInfo (Since: 0.14)

A description of QEMU’s version.

Members:

  • qemu (VersionTriple) – The version of QEMU. By current convention, a micro version of 50 signifies a development branch. A micro version greater than or equal to 90 signifies a release candidate for the next minor version. A micro version of less than 50 signifies a stable release.

  • package (string) – QEMU will always set this field to an empty string. Downstream versions of QEMU should set this to a non-empty string. The exact format depends on the downstream however it highly recommended that a unique name is used.

Command query-version (Since: 0.14)

Return the current version of QEMU.

Return:

VersionInfo – An object describing the current version of QEMU.

Example:

-> { "execute": "query-version" }
<- {
      "return":{
         "qemu":{
            "major":0,
            "minor":11,
            "micro":5
         },
         "package":""
      }
   }
Object CommandInfo (Since: 0.14)

Information about a QMP command

Members:

  • name (string) – The command name

Command query-commands (Since: 0.14)

Return a list of supported QMP commands by this server

Return:

[CommandInfo] – A list of all supported commands

Example:

-> { "execute": "query-commands" }
<- {
     "return":[
        {
           "name":"query-balloon"
        },
        {
           "name":"system_powerdown"
        },
        ...
     ]
   }

This example has been shortened as the real response is too long.

Command quit (Since: 0.14)

Request graceful QEMU process termination.

While every attempt is made to send the QMP response before terminating, this is not guaranteed. When using this interface, a premature EOF would not be unexpected.

Example:

-> { "execute": "quit" }
<- { "return": {} }
Enum MonitorMode (Since: 5.0)

An enumeration of monitor modes.

Values:

  • readline – HMP monitor (human-oriented command line interface)

  • control – QMP monitor (JSON-based machine interface)

Object MonitorOptions (Since: 5.0)

Options to be used for adding a new monitor.

Members:

  • id (string, optional) – Name of the monitor

  • mode (MonitorMode, optional) – Selects the monitor mode (default: readline in the system emulator, control in qemu-storage-daemon)

  • pretty (boolean, optional) – Enables pretty printing (QMP only)

  • chardev (string) – Name of a character device to expose the monitor on

QMP introspection

Command query-qmp-schema (Since: 2.5)

Command query-qmp-schema exposes the QMP wire ABI as an array of SchemaInfo. This lets QMP clients figure out what commands and events are available in this QEMU, and their parameters and results.

However, the SchemaInfo can’t reflect all the rules and restrictions that apply to QMP. It’s interface introspection (figuring out what’s there), not interface specification. The specification is in the QAPI schema.

Furthermore, while we strive to keep the QMP wire format backwards-compatible across QEMU versions, the introspection output is not guaranteed to have the same stability. For example, one version of QEMU may list an object member as an optional non-variant, while another lists the same member only through the object’s variants; or the type of a member may change from a generic string into a specific enum or from one specific type into an alternate that includes the original type alongside something else.

Return:

[SchemaInfo] –

an array where each element describes an entity in the ABI: command, event, type, …

The order of the various elements is unspecified; however, all names are guaranteed to be unique (no name will be duplicated with different meta-types).

Note

The QAPI schema is also used to help define internal interfaces, by defining QAPI types. These are not part of the QMP wire ABI, and therefore not returned by this command.

Enum SchemaMetaType (Since: 2.5)

This is a SchemaInfo’s meta type, i.e. the kind of entity it describes.

Values:

  • builtin – a predefined type such as ‘int’ or ‘bool’.

  • enum – an enumeration type

  • array – an array type

  • object – an object type (struct or union)

  • alternate – an alternate type

  • command – a QMP command

  • event – a QMP event

Object SchemaInfo (Since: 2.5)
Members:

  • name (string) – the entity’s name, inherited from base. The SchemaInfo is always referenced by this name. Commands and events have the name defined in the QAPI schema. Unlike command and event names, type names are not part of the wire ABI. Consequently, type names are meaningless strings here, although they are still guaranteed unique regardless of meta-type.

  • meta-type (SchemaMetaType) – the entity’s meta type, inherited from base.

  • features ([string], optional) – names of features associated with the entity, in no particular order. (since 4.1 for object types, 4.2 for commands, 5.0 for the rest)

  • When meta-type is builtin: The members of SchemaInfoBuiltin.

  • When meta-type is enum: The members of SchemaInfoEnum.

  • When meta-type is array: The members of SchemaInfoArray.

  • When meta-type is object: The members of SchemaInfoObject.

  • When meta-type is alternate: The members of SchemaInfoAlternate.

  • When meta-type is command: The members of SchemaInfoCommand.

  • When meta-type is event: The members of SchemaInfoEvent.

Object SchemaInfoBuiltin (Since: 2.5)

Additional SchemaInfo members for meta-type ‘builtin’.

Members:

  • json-type (JSONType) – the JSON type used for this type on the wire.

Enum JSONType (Since: 2.5)

The four primitive and two structured types according to RFC 8259 section 1, plus ‘int’ (split off ‘number’), plus the obvious top type ‘value’.

Values:

  • string – JSON string

  • number – JSON number

  • int – JSON number that is an integer

  • boolean – literal false or true

  • null – literal null

  • object – JSON object

  • array – JSON array

  • value – any JSON value

Object SchemaInfoEnum (Since: 2.5)

Additional SchemaInfo members for meta-type ‘enum’.

Members:

  • members ([SchemaInfoEnumMember]) – the enum type’s members, in no particular order. (since 6.2)

  • values ([string]) – the enumeration type’s member names, in no particular order. Redundant with members. Just for backward compatibility.

Features:

  • deprecated – Member values is deprecated. Use members instead.

Values of this type are JSON string on the wire.

Object SchemaInfoEnumMember (Since: 6.2)

An object member.

Members:

  • name (string) – the member’s name, as defined in the QAPI schema.

  • features ([string], optional) – names of features associated with the member, in no particular order.

Object SchemaInfoArray (Since: 2.5)

Additional SchemaInfo members for meta-type ‘array’.

Members:

  • element-type (string) – the array type’s element type.

Values of this type are JSON array on the wire.

Object SchemaInfoObject (Since: 2.5)

Additional SchemaInfo members for meta-type ‘object’.

Members:

  • members ([SchemaInfoObjectMember]) – the object type’s (non-variant) members, in no particular order.

  • tag (string, optional) – the name of the member serving as type tag. An element of members with this name must exist.

  • variants ([SchemaInfoObjectVariant], optional) – variant members, i.e. additional members that depend on the type tag’s value. Present exactly when tag is present. The variants are in no particular order, and may even differ from the order of the values of the enum type of the tag.

Values of this type are JSON object on the wire.

Object SchemaInfoObjectMember (Since: 2.5)

An object member.

Members:

  • name (string) – the member’s name, as defined in the QAPI schema.

  • type (string) – the name of the member’s type.

  • default (value, optional) – default when used as command parameter. If absent, the parameter is mandatory. If present, the value must be null. The parameter is optional, and behavior when it’s missing is not specified here. Future extension: if present and non-null, the parameter is optional, and defaults to this value.

  • features ([string], optional) – names of features associated with the member, in no particular order. (since 5.0)

Object SchemaInfoObjectVariant (Since: 2.5)

The variant members for a value of the type tag.

Members:

  • case (string) – a value of the type tag.

  • type (string) – the name of the object type that provides the variant members when the type tag has value case.

Object SchemaInfoAlternate (Since: 2.5)

Additional SchemaInfo members for meta-type ‘alternate’.

Members:

On the wire, this can be any of the members.

Object SchemaInfoAlternateMember (Since: 2.5)

An alternate member.

Members:

  • type (string) – the name of the member’s type.

Object SchemaInfoCommand (Since: 2.5)

Additional SchemaInfo members for meta-type ‘command’.

Members:

  • arg-type (string) – the name of the object type that provides the command’s parameters.

  • ret-type (string) – the name of the command’s result type.

  • allow-oob (boolean, optional) – whether the command allows out-of-band execution, defaults to false (Since: 2.12)

Object SchemaInfoEvent (Since: 2.5)

Additional SchemaInfo members for meta-type ‘event’.

Members:

  • arg-type (string) – the name of the object type that provides the event’s parameters.

QEMU Object Model (QOM)

Object ObjectPropertyInfo (Since: 1.2)
Members:

  • name (string) – the name of the property

  • type (string) –

    the type of the property. This will typically come in one of four forms:

    1. A primitive type such as ‘u8’, ‘u16’, ‘bool’, ‘str’, or ‘double’. These types are mapped to the appropriate JSON type.

    2. A child type in the form ‘child<subtype>’ where subtype is a qdev device type name. Child properties create the composition tree.

    3. A link type in the form ‘link<subtype>’ where subtype is a qdev device type name. Link properties form the device model graph.

  • description (string, optional) – if specified, the description of the property.

  • default-value (value, optional) – the default value, if any (since 5.0)

Object ObjectPropertyValue
Members:

  • name (string) – the name of the property.

  • type (string) – the type of the property, as described in ObjectPropertyInfo.

  • value (value, optional) – the value of the property. Absent when the property cannot be read.

Since 10.1

Object ObjectPropertiesValues
Members:

Since 10.1

Command qom-list (Since: 1.2)

List properties of a object given a path in the object model.

Arguments:

  • path (string) – the path within the object model. See qom-get for a description of this parameter.

Return:

[ObjectPropertyInfo] – a list that describe the properties of the object.

Example:

-> { "execute": "qom-list",
     "arguments": { "path": "/chardevs" } }
<- { "return": [ { "name": "type", "type": "string" },
                 { "name": "parallel0", "type": "child<chardev-vc>" },
                 { "name": "serial0", "type": "child<chardev-vc>" },
                 { "name": "mon0", "type": "child<chardev-stdio>" } ] }
Command qom-get (Since: 1.2)

Get a property value.

Arguments:

  • path (string) –

    The path within the object model. There are two forms of supported paths–absolute and partial paths.

    Absolute paths are derived from the root object and can follow child<> or link<> properties. Since they can follow link<> properties, they can be arbitrarily long. Absolute paths look like absolute filenames and are prefixed with a leading slash.

    Partial paths look like relative filenames. They do not begin with a prefix. The matching rules for partial paths are subtle but designed to make specifying objects easy. At each level of the composition tree, the partial path is matched as an absolute path. The first match is not returned. At least two matches are searched for. A successful result is only returned if only one match is found. If more than one match is found, a flag is return to indicate that the match was ambiguous.

  • property (string) – The property name to read

Return:

value – The property value. The type depends on the property type. child<> and link<> properties are returned as #str pathnames. All integer property types (u8, u16, etc) are returned as #int.

Example: Use absolute path

 -> { "execute": "qom-get",
      "arguments": { "path": "/machine/unattached/device[0]",
                     "property": "hotplugged" } }
 <- { "return": false }

Example: Use partial path

 -> { "execute": "qom-get",
      "arguments": { "path": "unattached/sysbus",
                     "property": "type" } }
 <- { "return": "System" }
Command qom-list-get

List properties and their values for each object path in the input list.

Arguments:

  • paths ([string]) – The absolute or partial path for each object, as described in qom-get.

Errors:

  • If any path is not valid or is ambiguous

Return:

[ObjectPropertiesValues] – A list where each element is the result for the corresponding element of paths.

Since 10.1

Command qom-set (Since: 1.2)

Set a property value.

Arguments:

  • path (string) – see qom-get for a description of this parameter

  • property (string) – the property name to set

  • value (value) – a value who’s type is appropriate for the property type. See qom-get for a description of type mapping.

Example:

-> { "execute": "qom-set",
     "arguments": { "path": "/machine",
                    "property": "graphics",
                    "value": false } }
<- { "return": {} }
Object ObjectTypeInfo (Since: 1.1)

This structure describes a search result from qom-list-types

Members:

  • name (string) – the type name found in the search

  • abstract (boolean, optional) – the type is abstract and can’t be directly instantiated. Omitted if false. (since 2.10)

  • parent (string, optional) – Name of parent type, if any (since 2.10)

Command qom-list-types (Since: 1.1)

Return a list of types given search parameters.

Arguments:

  • implements (string, optional) – if specified, only return types that implement this type name

  • abstract (boolean, optional) – if true, include abstract types in the results

Return:

[ObjectTypeInfo] – a list of types, or an empty list if no results are found

Command qom-list-properties (Since: 2.12)

List properties associated with a QOM object.

Arguments:

  • typename (string) – the type name of an object

Note

Objects can create properties at runtime, for example to describe links between different devices and/or objects. These properties are not included in the output of this command.

Return:

[ObjectPropertyInfo] – a list describing object properties

Object CanHostSocketcanProperties (Since: 2.12)
Availability: CONFIG_LINUX

Properties for can-host-socketcan objects.

Members:

  • if (string) – interface name of the host system CAN bus to connect to

  • canbus (string) – object ID of the can-bus object to connect to the host interface

Object ColoCompareProperties (Since: 2.8)

Properties for colo-compare objects.

Members:

  • primary_in (string) – name of the character device backend to use for the primary input (incoming packets are redirected to outdev)

  • secondary_in (string) – name of the character device backend to use for secondary input (incoming packets are only compared to the input on primary_in and then dropped)

  • outdev (string) – name of the character device backend to use for output

  • iothread (string) – name of the iothread to run in

  • notify_dev (string, optional) – name of the character device backend to be used to communicate with the remote colo-frame (only for Xen COLO)

  • compare_timeout (int, optional) – the maximum time to hold a packet from primary_in for comparison with an incoming packet on secondary_in in milliseconds (default: 3000)

  • expired_scan_cycle (int, optional) – the interval at which colo-compare checks whether packets from primary have timed out, in milliseconds (default: 3000)

  • max_queue_size (int, optional) – the maximum number of packets to keep in the queue for comparing with incoming packets from secondary_in. If the queue is full and additional packets are received, the additional packets are dropped. (default: 1024)

  • vnet_hdr_support (boolean, optional) – if true, vnet header support is enabled (default: false)

Object CryptodevBackendProperties (Since: 2.8)

Properties for cryptodev-backend and cryptodev-backend-builtin objects.

Members:

  • queues (int, optional) – the number of queues for the cryptodev backend. Ignored for cryptodev-backend and must be 1 for cryptodev-backend-builtin. (default: 1)

  • throttle-bps (int, optional) – limit total bytes per second (Since 8.0)

  • throttle-ops (int, optional) – limit total operations per second (Since 8.0)

Object CryptodevVhostUserProperties (Since: 2.12)
Availability: CONFIG_VHOST_CRYPTO

Properties for cryptodev-vhost-user objects.

Members:

  • chardev (string) – the name of a Unix domain socket character device that connects to the vhost-user server

  • The members of CryptodevBackendProperties.

Object DBusVMStateProperties (Since: 5.0)

Properties for dbus-vmstate objects.

Members:

  • addr (string) – the name of the DBus bus to connect to

  • id-list (string, optional) – a comma separated list of DBus IDs of helpers whose data should be included in the VM state on migration

Enum NetfilterInsert (Since: 5.0)

Indicates where to insert a netfilter relative to a given other filter.

Values:

  • before – insert before the specified filter

  • behind – insert behind the specified filter

Object NetfilterProperties (Since: 2.5)

Properties for objects of classes derived from netfilter.

Members:

  • netdev (string) – id of the network device backend to filter

  • queue (NetFilterDirection, optional) – indicates which queue(s) to filter (default: all)

  • status (string, optional) – indicates whether the filter is enabled (“on”) or disabled (“off”) (default: “on”)

  • position (string, optional) – specifies where the filter should be inserted in the filter list. “head” means the filter is inserted at the head of the filter list, before any existing filters. “tail” means the filter is inserted at the tail of the filter list, behind any existing filters (default). “id=<id>” means the filter is inserted before or behind the filter specified by <id>, depending on the insert property. (default: “tail”)

  • insert (NetfilterInsert, optional) – where to insert the filter relative to the filter given in position. Ignored if position is “head” or “tail”. (default: behind)

Object FilterBufferProperties (Since: 2.5)

Properties for filter-buffer objects.

Members:

  • interval (int) – a non-zero interval in microseconds. All packets arriving in the given interval are delayed until the end of the interval.

  • The members of NetfilterProperties.

Object FilterDumpProperties (Since: 2.5)

Properties for filter-dump objects.

Members:

  • file (string) – the filename where the dumped packets should be stored

  • maxlen (int, optional) – maximum number of bytes in a packet that are stored (default: 65536)

  • The members of NetfilterProperties.

Object FilterMirrorProperties (Since: 2.6)

Properties for filter-mirror objects.

Members:

  • outdev (string) – the name of a character device backend to which all incoming packets are mirrored

  • vnet_hdr_support (boolean, optional) – if true, vnet header support is enabled (default: false)

  • The members of NetfilterProperties.

Object FilterRedirectorProperties (Since: 2.6)

Properties for filter-redirector objects.

At least one of indev or outdev must be present. If both are present, they must not refer to the same character device backend.

Members:

  • indev (string, optional) – the name of a character device backend from which packets are received and redirected to the filtered network device

  • outdev (string, optional) – the name of a character device backend to which all incoming packets are redirected

  • vnet_hdr_support (boolean, optional) – if true, vnet header support is enabled (default: false)

  • The members of NetfilterProperties.

Object FilterRewriterProperties (Since: 2.8)

Properties for filter-rewriter objects.

Members:

  • vnet_hdr_support (boolean, optional) – if true, vnet header support is enabled (default: false)

  • The members of NetfilterProperties.

Object InputBarrierProperties (Since: 4.2)

Properties for input-barrier objects.

Members:

  • name (string) – the screen name as declared in the screens section of barrier.conf

  • server (string, optional) – hostname of the Barrier server (default: “localhost”)

  • port (string, optional) – TCP port of the Barrier server (default: “24800”)

  • x-origin (string, optional) – x coordinate of the leftmost pixel on the guest screen (default: “0”)

  • y-origin (string, optional) – y coordinate of the topmost pixel on the guest screen (default: “0”)

  • width (string, optional) – the width of secondary screen in pixels (default: “1920”)

  • height (string, optional) – the height of secondary screen in pixels (default: “1080”)

Object InputLinuxProperties (Since: 2.6)
Availability: CONFIG_LINUX

Properties for input-linux objects.

Members:

  • evdev (string) – the path of the host evdev device to use

  • grab_all (boolean, optional) – if true, grab is toggled for all devices (e.g. both keyboard and mouse) instead of just one device (default: false)

  • repeat (boolean, optional) – enables auto-repeat events (default: false)

  • grab-toggle (GrabToggleKeys, optional) – the key or key combination that toggles device grab (default: ctrl-ctrl)

Object EventLoopBaseProperties (Since: 7.1)

Common properties for event loops

Members:

  • aio-max-batch (int, optional) – maximum number of requests in a batch for the AIO engine, 0 means that the engine will use its default. (default: 0)

  • thread-pool-min (int, optional) – minimum number of threads reserved in the thread pool (default:0)

  • thread-pool-max (int, optional) – maximum number of threads the thread pool can contain (default:64)

Object IothreadProperties (Since: 2.0)

Properties for iothread objects.

Members:

  • poll-max-ns (int, optional) – the maximum number of nanoseconds to busy wait for events. 0 means polling is disabled (default: 32768 on POSIX hosts, 0 otherwise)

  • poll-grow (int, optional) – the multiplier used to increase the polling time when the algorithm detects it is missing events due to not polling long enough. 0 selects a default behaviour (default: 0)

  • poll-shrink (int, optional) – the divisor used to decrease the polling time when the algorithm detects it is spending too long polling without encountering events. 0 selects a default behaviour (default: 0)

  • The members of EventLoopBaseProperties.

The aio-max-batch option is available since 6.1.

Object MainLoopProperties (Since: 7.1)

Properties for the main-loop object.

Members:
Object MemoryBackendProperties (Since: 2.1)

Properties for objects of classes derived from memory-backend.

Members:

  • merge (boolean, optional) – if true, mark the memory as mergeable (default depends on the machine type)

  • dump (boolean, optional) – if true, include the memory in core dumps (default depends on the machine type)

  • host-nodes ([int], optional) – the list of NUMA host nodes to bind the memory to

  • policy (HostMemPolicy, optional) – the NUMA policy (default: ‘default’)

  • prealloc (boolean, optional) – if true, preallocate memory (default: false)

  • prealloc-threads (int, optional) – number of CPU threads to use for prealloc (default: 1)

  • prealloc-context (string, optional) – thread context to use for creation of preallocation threads (default: none) (since 7.2)

  • share (boolean, optional) – if false, the memory is private to QEMU; if true, it is shared (default false for backends memory-backend-file and memory-backend-ram, true for backends memory-backend-epc, memory-backend-memfd, and memory-backend-shm)

  • reserve (boolean, optional) – if true, reserve swap space (or huge pages) if applicable (default: true) (since 6.1)

  • size (int) – size of the memory region in bytes

  • x-use-canonical-path-for-ramblock-id (boolean, optional) – if true, the canonical path is used for ramblock-id. Disable this for 4.0 machine types or older to allow migration with newer QEMU versions. (default: false generally, but true for machine types <= 4.0)

Note

prealloc=true and reserve=false cannot be set at the same time. With reserve=true, the behavior depends on the operating system: for example, Linux will not reserve swap space for shared file mappings – “not applicable”. In contrast, reserve=false will bail out if it cannot be configured accordingly.

Object MemoryBackendFileProperties (Since: 2.1)

Properties for memory-backend-file objects.

Members:

  • align (int, optional) – the base address alignment when QEMU mmap(2)s mem-path. Some backend stores specified by mem-path require an alignment different than the default one used by QEMU, e.g. the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In such cases, users can specify the required alignment via this option. 0 selects a default alignment (currently the page size). (default: 0)

  • offset (int, optional) – the offset into the target file that the region starts at. You can use this option to back multiple regions with a single file. Must be a multiple of the page size. (default: 0) (since 8.1)

  • discard-data (boolean, optional) – if true, the file contents can be destroyed when QEMU exits, to avoid unnecessarily flushing data to the backing file. Note that discard-data is only an optimization, and QEMU might not discard file contents if it aborts unexpectedly or is terminated using SIGKILL. (default: false)

  • mem-path (string) – the path to either a shared memory or huge page filesystem mount

  • pmem (boolean, optional) – specifies whether the backing file specified by mem-path is in host persistent memory that can be accessed using the SNIA NVM programming model (e.g. Intel NVDIMM).

  • readonly (boolean, optional) – if true, the backing file is opened read-only; if false, it is opened read-write. (default: false)

  • rom (OnOffAuto, optional) – whether to create Read Only Memory (ROM) that cannot be modified by the VM. Any write attempts to such ROM will be denied. Most use cases want writable RAM instead of ROM. However, selected use cases, like R/O NVDIMMs, can benefit from ROM. If set to ‘on’, create ROM; if set to ‘off’, create writable RAM; if set to ‘auto’, the value of the readonly property is used. This property is primarily helpful when we want to have proper RAM in configurations that would traditionally create ROM before this property was introduced: VM templating, where we want to open a file readonly (readonly set to true) and mark the memory to be private for QEMU (share set to false). For this use case, we need writable RAM instead of ROM, and want to set this property to ‘off’. (default: auto, since 8.2)

  • The members of MemoryBackendProperties.

Object MemoryBackendMemfdProperties (Since: 2.12)
Availability: CONFIG_LINUX

Properties for memory-backend-memfd objects.

Members:

  • hugetlb (boolean, optional) – if true, the file to be created resides in the hugetlbfs filesystem (default: false)

  • hugetlbsize (int, optional) – the hugetlb page size on systems that support multiple hugetlb page sizes (it must be a power of 2 value supported by the system). 0 selects a default page size. This option is ignored if hugetlb is false. (default: 0)

  • seal (boolean, optional) – if true, create a sealed-file, which will block further resizing of the memory (default: true)

  • The members of MemoryBackendProperties.

Object MemoryBackendShmProperties (Since: 9.1)
Availability: CONFIG_POSIX

Properties for memory-backend-shm objects.

This memory backend supports only shared memory, which is the default.

Members:
Object MemoryBackendEpcProperties (Since: 6.2)
Availability: CONFIG_LINUX

Properties for memory-backend-epc objects.

The merge boolean option is false by default with epc

The dump boolean option is false by default with epc

Members:
Object PrManagerHelperProperties (Since: 2.11)
Availability: CONFIG_LINUX

Properties for pr-manager-helper objects.

Members:

  • path (string) – the path to a Unix domain socket for connecting to the external helper

Object QtestProperties (Since: 6.0)

Properties for qtest objects.

Members:

  • chardev (string) – the chardev to be used to receive qtest commands on.

  • log (string, optional) – the path to a log file

Object RemoteObjectProperties (Since: 6.0)

Properties for x-remote-object objects.

Members:

  • fd (string) – file descriptor name previously passed via getfd command

  • devid (string) – the id of the device to be associated with the file descriptor

Object VfioUserServerProperties (Since: 7.1)

Properties for x-vfio-user-server objects.

Members:

  • socket (SocketAddress) – socket to be used by the libvfio-user library

  • device (string) – the ID of the device to be emulated at the server

Object IOMMUFDProperties (Since: 9.0)

Properties for iommufd objects.

Members:

  • fd (string, optional) – file descriptor name previously passed via getfd command, which represents a pre-opened /dev/iommu. This allows the iommufd object to be shared across several subsystems (VFIO, VDPA, …), and the file descriptor to be shared with other process, e.g. DPDK. (default: QEMU opens /dev/iommu by itself)

Object AcpiGenericInitiatorProperties (Since: 9.0)

Properties for acpi-generic-initiator objects.

Members:

  • pci-dev (string) – PCI device ID to be associated with the node

  • node (int) – NUMA node associated with the PCI device

Object AcpiGenericPortProperties (Since: 9.2)

Properties for acpi-generic-port objects.

Members:

  • pci-bus (string) – QOM path of the PCI bus of the hostbridge associated with this SRAT Generic Port Affinity Structure. This is the same as the bus parameter for the root ports attached to this host bridge. The resulting SRAT Generic Port Affinity Structure will refer to the ACPI object in DSDT that represents the host bridge (e.g. ACPI0016 for CXL host bridges). See ACPI 6.5 Section 5.2.16.7 for more information.

  • node (int) – Similar to a NUMA node ID, but instead of providing a reference point used for defining NUMA distances and access characteristics to memory or from an initiator (e.g. CPU), this node defines the boundary point between non-discoverable system buses which must be described by firmware, and a discoverable bus. NUMA distances and access characteristics are defined to and from that point. For system software to establish full initiator to target characteristics this information must be combined with information retrieved from the discoverable part of the path. An example would use CDAT (see UEFI.org) information read from devices and switches in conjunction with link characteristics read from PCIe Configuration space. To get the full path latency from CPU to CXL attached DRAM CXL device: Add the latency from CPU to Generic Port (from HMAT indexed via the node ID in this SRAT structure) to that for CXL bus links, the latency across intermediate switches and from the EP port to the actual memory. Bandwidth is more complex as there may be interleaving across multiple devices and shared links in the path.

Object RngProperties (Since: 1.3)

Properties for objects of classes derived from rng.

Members:

  • opened (boolean, optional) – if true, the device is opened immediately when applying this option and will probably fail when processing the next option. Don’t use; only provided for compatibility. (default: false)

Features:

  • deprecated – Member opened is deprecated. Setting true doesn’t make sense, and false is already the default.

Object RngEgdProperties (Since: 1.3)

Properties for rng-egd objects.

Members:

  • chardev (string) – the name of a character device backend that provides the connection to the RNG daemon

  • The members of RngProperties.

Object RngRandomProperties (Since: 1.3)
Availability: CONFIG_POSIX

Properties for rng-random objects.

Members:

  • filename (string, optional) – the filename of the device on the host to obtain entropy from (default: “/dev/urandom”)

  • The members of RngProperties.

Object IgvmCfgProperties (Since: 10.1)
Availability: CONFIG_IGVM

Properties common to objects that handle IGVM files.

Members:

  • file (string) – IGVM file to use to configure guest

Object SevCommonProperties (Since: 9.1)

Properties common to objects that are derivatives of sev-common.

Members:

  • sev-device (string, optional) – SEV device to use (default: “/dev/sev”)

  • cbitpos (int, optional) – C-bit location in page table entry (default: 0)

  • reduced-phys-bits (int) – number of bits in physical addresses that become unavailable when SEV is enabled

  • kernel-hashes (boolean, optional) – if true, add hashes of kernel/initrd/cmdline to a designated guest firmware page for measured boot with -kernel (default: false) (since 6.2)

Features:

  • confidential-guest-reset – If present, the hypervisor supports confidential guest resets (since 11.0).

Object SevGuestProperties (Since: 2.12)

Properties for sev-guest objects.

Members:

  • dh-cert-file (string, optional) – guest owners DH certificate (encoded with base64)

  • session-file (string, optional) – guest owners session parameters (encoded with base64)

  • policy (int, optional) – SEV policy value (default: 0x1)

  • handle (int, optional) – SEV firmware handle (default: 0)

  • legacy-vm-type (OnOffAuto, optional) – Use legacy KVM_SEV_INIT KVM interface for creating the VM. The newer KVM_SEV_INIT2 interface, from Linux >= 6.10, syncs additional vCPU state when initializing the VMSA structures, which will result in a different guest measurement. Set this to ‘on’ to force compatibility with older QEMU or kernel versions that rely on legacy KVM_SEV_INIT behavior. ‘auto’ will behave identically to ‘on’, but will automatically switch to using KVM_SEV_INIT2 if the user specifies any additional options that require it. If set to ‘off’, QEMU will require KVM_SEV_INIT2 unconditionally. (default: off) (since 9.1)

  • The members of SevCommonProperties.

Object SevSnpGuestProperties (Since: 9.1)

Properties for sev-snp-guest objects. Most of these are direct arguments for the KVM_SNP_* interfaces documented in the Linux kernel source under Documentation/arch/x86/amd-memory-encryption.rst, which are in turn closely coupled with the SNP_INIT/SNP_LAUNCH_* firmware commands documented in the SEV-SNP Firmware ABI Specification (Rev 0.9).

More usage information is also available in the QEMU source tree under docs/amd-memory-encryption.

Members:

  • policy (int, optional) – the ‘POLICY’ parameter to the SNP_LAUNCH_START command, as defined in the SEV-SNP firmware ABI (default: 0x30000)

  • guest-visible-workarounds (string, optional) – 16-byte, base64-encoded blob to report hypervisor-defined workarounds, corresponding to the ‘GOSVW’ parameter of the SNP_LAUNCH_START command defined in the SEV-SNP firmware ABI (default: all-zero)

  • id-block (string, optional) – 96-byte, base64-encoded blob to provide the ‘ID Block’ structure for the SNP_LAUNCH_FINISH command defined in the SEV-SNP firmware ABI (default: all-zero)

  • id-auth (string, optional) – 4096-byte, base64-encoded blob to provide the ‘ID Authentication Information Structure’ for the SNP_LAUNCH_FINISH command defined in the SEV-SNP firmware ABI (default: all-zero)

  • author-key-enabled (boolean, optional) – true if ‘id-auth’ blob contains the ‘AUTHOR_KEY’ field defined SEV-SNP firmware ABI (default: false)

  • host-data (string, optional) – 32-byte, base64-encoded, user-defined blob to provide to the guest, as documented for the ‘HOST_DATA’ parameter of the SNP_LAUNCH_FINISH command in the SEV-SNP firmware ABI (default: all-zero)

  • vcek-disabled (boolean, optional) – Guests are by default allowed to choose between VLEK (Versioned Loaded Endorsement Key) or VCEK (Versioned Chip Endorsement Key) when requesting attestation reports from firmware. Set this to true to disable the use of VCEK. (default: false) (since: 9.1)

  • The members of SevCommonProperties.

Object TdxGuestProperties (Since: 10.1)

Properties for tdx-guest objects.

Members:

  • attributes (int, optional) – The ‘attributes’ of a TD guest that is passed to KVM_TDX_INIT_VM

  • sept-ve-disable (boolean, optional) – toggle bit 28 of TD attributes to control disabling of EPT violation conversion to #VE on guest TD access of PENDING pages. Some guest OS (e.g., Linux TD guest) may require this to be set, otherwise they refuse to boot.

  • mrconfigid (string, optional) – ID for non-owner-defined configuration of the guest TD, e.g., run-time or OS configuration (base64 encoded SHA384 digest). Defaults to all zeros.

  • mrowner (string, optional) – ID for the guest TD’s owner (base64 encoded SHA384 digest). Defaults to all zeros.

  • mrownerconfig (string, optional) – ID for owner-defined configuration of the guest TD, e.g., specific to the workload rather than the run-time or OS (base64 encoded SHA384 digest). Defaults to all zeros.

  • quote-generation-socket (SocketAddress, optional) – socket address for Quote Generation Service (QGS). QGS is a daemon running on the host. Without it, the guest will not be able to get a TD quote for attestation.

Features:

  • confidential-guest-reset – If present, the hypervisor supports confidential guest resets (since 11.0).

Object ThreadContextProperties (Since: 7.2)

Properties for thread context objects.

Members:

  • cpu-affinity ([int], optional) – the list of host CPU numbers used as CPU affinity for all threads created in the thread context (default: QEMU main thread CPU affinity)

  • node-affinity ([int], optional) – the list of host node numbers that will be resolved to a list of host CPU numbers used as CPU affinity. This is a shortcut for specifying the list of host CPU numbers belonging to the host nodes manually by setting cpu-affinity. (default: QEMU main thread affinity)

Enum ObjectType (Since: 6.0)
Values:

  • acpi-generic-initiator – Not documented

  • acpi-generic-port – Not documented

  • authz-list – Not documented

  • authz-listfile – Not documented

  • authz-pam – Not documented

  • authz-simple – Not documented

  • can-bus – Not documented

  • can-host-socketcan – Not documented

  • colo-compare – Not documented

  • cryptodev-backend – Not documented

  • cryptodev-backend-builtin – Not documented

  • cryptodev-backend-lkcf – Not documented

  • cryptodev-vhost-user – Not documented

  • dbus-vmstate – Not documented

  • filter-buffer – Not documented

  • filter-dump – Not documented

  • filter-mirror – Not documented

  • filter-redirector – Not documented

  • filter-replay – Not documented

  • filter-rewriter – Not documented

  • igvm-cfg – Not documented

  • input-barrier – Not documented

  • input-linux – Not documented

  • iommufd – Not documented

  • iothread – Not documented

  • main-loop – Not documented

  • memory-backend-epc – Not documented

  • memory-backend-file – Not documented

  • memory-backend-memfd – Not documented

  • memory-backend-ram – Not documented

  • memory-backend-shm – Not documented

  • pef-guest – Not documented

  • pr-manager-helper – Not documented

  • qtest – Not documented

  • rng-builtin – Not documented

  • rng-egd – Not documented

  • rng-random – Not documented

  • secret – Not documented

  • secret_keyring – Not documented

  • sev-guest – Not documented

  • sev-snp-guest – Not documented

  • thread-context – Not documented

  • s390-pv-guest – Not documented

  • tdx-guest – Not documented

  • throttle-group – Not documented

  • tls-creds-anon – Not documented

  • tls-creds-psk – Not documented

  • tls-creds-x509 – Not documented

  • tls-cipher-suites – Not documented

  • x-remote-object – Not documented

  • x-vfio-user-server – Not documented

Features:

  • unstable – Members x-remote-object and x-vfio-user-server are experimental.

Object ObjectOptions (Since: 6.0)

Describes the options of a user creatable QOM object.

Members:
Command object-add (Since: 2.0)

Create a QOM object.

Arguments:
Errors:

  • If qom-type is not a valid class name

Example:

-> { "execute": "object-add",
     "arguments": { "qom-type": "rng-random", "id": "rng1",
                    "filename": "/dev/hwrng" } }
<- { "return": {} }
Command object-del (Since: 2.0)

Remove a QOM object.

Arguments:

  • id (string) – the name of the QOM object to remove

Errors:

  • If id is not a valid id for a QOM object

Example:

-> { "execute": "object-del", "arguments": { "id": "rng1" } }
<- { "return": {} }

Device infrastructure (qdev)

Command device-list-properties (Since: 1.2)

List properties associated with a device.

Arguments:

  • typename (string) – the type name of a device

Return:

[ObjectPropertyInfo] – a list describing a devices properties

Note

Objects can create properties at runtime, for example to describe links between different devices and/or objects. These properties are not included in the output of this command.

Command device_add (Since: 0.13)

Add a device.

Arguments:

  • driver (string) – the name of the new device’s driver

  • bus (string, optional) – the device’s parent bus (device tree path)

  • id (string, optional) – the device’s ID, must be unique

Features:

  • json-cli – If present, the “-device” command line option supports JSON syntax with a structure identical to the arguments of this command.

  • json-cli-hotplug – If present, the “-device” command line option supports JSON syntax without the reference counting leak that broke hot-unplug

Notes

  1. Additional arguments depend on the type.

  2. For detailed information about this command, please refer to the ‘docs/qdev-device-use.txt’ file.

  3. It’s possible to list device properties by running QEMU with the -device DEVICE,help command-line argument, where DEVICE is the device’s name.

Example:

-> { "execute": "device_add",
     "arguments": { "driver": "e1000", "id": "net1",
                    "bus": "pci.0",
                    "mac": "52:54:00:12:34:56" } }
<- { "return": {} }
Command device_del (Since: 0.14)

Remove a device from a guest

Arguments:

  • id (string) – the device’s ID or QOM path

Errors:

  • If id is not a valid device, DeviceNotFound

Note

When this command completes, the device may not be removed from the guest. Hot removal is an operation that requires guest cooperation. This command merely requests that the guest begin the hot removal process. Completion of the device removal process is signaled with a DEVICE_DELETED event. Guest reset will automatically complete removal for all devices. If a guest-side error in the hot removal process is detected, the device will not be removed and a DEVICE_UNPLUG_GUEST_ERROR event is sent. Some errors cannot be detected.

Example:

-> { "execute": "device_del",
     "arguments": { "id": "net1" } }
<- { "return": {} }

Example:

-> { "execute": "device_del",
     "arguments": { "id": "/machine/peripheral-anon/device[0]" } }
<- { "return": {} }
Event DEVICE_DELETED (Since: 1.5)

Emitted whenever the device removal completion is acknowledged by the guest. At this point, it’s safe to reuse the specified device ID. Device removal can be initiated by the guest or by HMP/QMP commands.

Members:

  • device (string, optional) – the device’s ID if it has one

  • path (string) – the device’s QOM path

Example:

<- { "event": "DEVICE_DELETED",
     "data": { "device": "virtio-net-pci-0",
               "path": "/machine/peripheral/virtio-net-pci-0" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
Event DEVICE_UNPLUG_GUEST_ERROR (Since: 6.2)

Emitted when a device hot unplug fails due to a guest reported error.

Members:

  • device (string, optional) – the device’s ID if it has one

  • path (string) – the device’s QOM path

Example:

<- { "event": "DEVICE_UNPLUG_GUEST_ERROR",
     "data": { "device": "core1",
               "path": "/machine/peripheral/core1" },
     "timestamp": { "seconds": 1615570772, "microseconds": 202844 } }
Command device-sync-config (Since: 9.2)
This command is unstable/experimental.

Synchronize device configuration from host to guest part. First, copy the configuration from the host part (backend) to the guest part (frontend). Then notify guest software that device configuration changed.

The command may be used to notify the guest about block device capacity change. Currently only vhost-user-blk device supports this.

Arguments:

  • id (string) – the device’s ID or QOM path

Features:

  • unstable – The command is experimental.

Common machine types

Enum S390CpuEntitlement (Since: 8.2)

An enumeration of CPU entitlements that can be assumed by a virtual S390 CPU

Values:

  • auto – Not documented

  • low – Not documented

  • medium – Not documented

  • high – Not documented

Enum CpuTopologyLevel (Since: 9.2)

An enumeration of CPU topology levels.

Values:

  • thread – thread level, which would also be called SMT level or logical processor level. The threads option in SMPConfiguration is used to configure the topology of this level.

  • core – core level. The cores option in SMPConfiguration is used to configure the topology of this level.

  • module – module level. The modules option in SMPConfiguration is used to configure the topology of this level.

  • cluster – cluster level. The clusters option in SMPConfiguration is used to configure the topology of this level.

  • die – die level. The dies option in SMPConfiguration is used to configure the topology of this level.

  • socket – socket level, which would also be called package level. The sockets option in SMPConfiguration is used to configure the topology of this level.

  • book – book level. The books option in SMPConfiguration is used to configure the topology of this level.

  • drawer – drawer level. The drawers option in SMPConfiguration is used to configure the topology of this level.

  • default – default level. Some architectures will have default topology settings (e.g., cache topology), and this special level means following the architecture-specific settings.

Enum CacheLevelAndType (Since: 9.2)

Caches a system may have. The enumeration value here is the combination of cache level and cache type.

Values:

  • l1d – L1 data cache.

  • l1i – L1 instruction cache.

  • l2 – L2 (unified) cache.

  • l3 – L3 (unified) cache

Object SmpCacheProperties (Since: 9.2)

Cache information for SMP system.

Members:

  • cache (CacheLevelAndType) – Cache name, which is the combination of cache level and cache type.

  • topology (CpuTopologyLevel) – Cache topology level. It accepts the CPU topology enumeration as the parameter, i.e., CPUs in the same topology container share the same cache.

Object SmpCachePropertiesWrapper

List wrapper of SmpCacheProperties.

Members:

Since 9.2

Machines

Enum SysEmuTarget (Since: 3.0)

The comprehensive enumeration of QEMU system emulation (“softmmu”) targets. Run “./configure –help” in the project root directory, and look for the *-softmmu targets near the “–target-list” option. The individual target constants are not documented here, for the time being.

Values:

  • rx – since 5.0

  • avr – since 5.1

  • loongarch64 – since 7.1

  • hexagon – since 11.0

  • aarch64 – Not documented

  • alpha – Not documented

  • arm – Not documented

  • hppa – Not documented

  • i386 – Not documented

  • m68k – Not documented

  • microblaze – Not documented

  • mips – Not documented

  • mips64 – Not documented

  • mips64el – Not documented

  • mipsel – Not documented

  • or1k – Not documented

  • ppc – Not documented

  • ppc64 – Not documented

  • riscv32 – Not documented

  • riscv64 – Not documented

  • s390x – Not documented

  • sh4 – Not documented

  • sh4eb – Not documented

  • sparc – Not documented

  • sparc64 – Not documented

  • tricore – Not documented

  • x86_64 – Not documented

  • xtensa – Not documented

  • xtensaeb – Not documented

Note

The resulting QMP strings can be appended to the “qemu-system-” prefix to produce the corresponding QEMU executable name. This is true even for “qemu-system-x86_64”.

Enum S390CpuState (Since: 2.12)

An enumeration of cpu states that can be assumed by a virtual S390 CPU

Values:

  • uninitialized – Not documented

  • stopped – Not documented

  • check-stop – Not documented

  • operating – Not documented

  • load – Not documented

Object CpuInfoS390 (Since: 2.12)

Additional information about a virtual S390 CPU

Members:

  • cpu-state (S390CpuState) – the virtual CPU’s state

  • dedicated (boolean, optional) – the virtual CPU’s dedication (since 8.2)

  • entitlement (S390CpuEntitlement, optional) – the virtual CPU’s entitlement (since 8.2)

Object CpuInfoFast (Since: 2.12)

Information about a virtual CPU

Members:

  • cpu-index (int) – index of the virtual CPU

  • qom-type (string) – QOM type name of the CPU (since 10.1)

  • qom-path (string) – path to the CPU object in the QOM tree

  • thread-id (int) – ID of the underlying host thread

  • props (CpuInstanceProperties, optional) – properties associated with a virtual CPU, e.g. the socket id

  • target (SysEmuTarget) – the QEMU system emulation target, which determines which additional fields will be listed (since 3.0)

  • When target is s390x: The members of CpuInfoS390.

Command query-cpus-fast (Since: 2.12)

Return information about all virtual CPUs.

Return:

[CpuInfoFast]

Example:

-> { "execute": "query-cpus-fast" }
<- { "return": [
        {
            "thread-id": 25627,
            "props": {
                "core-id": 0,
                "thread-id": 0,
                "socket-id": 0
            },
            "qom-path": "/machine/unattached/device[0]",
            "target":"x86_64",
            "cpu-index": 0
        },
        {
            "thread-id": 25628,
            "props": {
                "core-id": 0,
                "thread-id": 0,
                "socket-id": 1
            },
            "qom-path": "/machine/unattached/device[2]",
            "target":"x86_64",
            "cpu-index": 1
        }
    ]
}
Object CompatProperty (Since: 9.1)

Property default values specific to a machine type, for use by scripts/compare-machine-types.

Members:

  • qom-type (string) – name of the QOM type to which the default applies

  • property (string) – name of its property to which the default applies

  • value (string) – the default value (machine-specific default can overwrite the “default” default, to avoid this use -machine none)

Object MachineInfo (Since: 1.2)

Information describing a machine.

Members:

  • name (string) – the name of the machine

  • alias (string, optional) – an alias for the machine name

  • is-default (boolean, optional) – whether the machine is default

  • cpu-max (int) – maximum number of CPUs supported by the machine type (since 1.5)

  • hotpluggable-cpus (boolean) – cpu hotplug via -device is supported (since 2.7)

  • numa-mem-supported (boolean) – true if ‘-numa node,mem’ option is supported by the machine type and false otherwise (since 4.1)

  • deprecated (boolean) – if true, the machine type is deprecated and may be removed in future versions of QEMU according to the QEMU deprecation policy (since 4.1)

  • default-cpu-type (string, optional) – default CPU model typename if none is requested via the -cpu argument. (since 4.2)

  • default-ram-id (string, optional) – the default ID of initial RAM memory backend (since 5.2)

  • acpi (boolean) – machine type supports ACPI (since 8.0)

  • compat-props ([CompatProperty], optional) – The machine type’s compatibility properties. Only present when query-machines argument compat-props is true. (since 9.1)

Features:

  • unstable – Member compat-props is experimental.

Command query-machines (Since: 1.2)

Return a list of supported machines

Arguments:

  • compat-props (boolean, optional) – if true, also return compatibility properties. (default: false) (since 9.1)

Return:

[MachineInfo]

Features:

  • unstable – Argument compat-props is experimental.

Example:

-> { "execute": "query-machines", "arguments": { "compat-props": true } }
<- { "return": [
          {
             "hotpluggable-cpus": true,
             "name": "pc-q35-6.2",
             "compat-props": [
                  {
                     "qom-type": "virtio-mem",
                     "property": "unplugged-inaccessible",
                     "value": "off"
                  }
              ],
              "numa-mem-supported": false,
              "default-cpu-type": "qemu64-x86_64-cpu",
              "cpu-max": 288,
              "deprecated": false,
              "default-ram-id": "pc.ram"
          },
          ...
   }
Object CurrentMachineParams (Since: 4.0)

Information describing the running machine parameters.

Members:

  • wakeup-suspend-support (boolean) – true if the machine supports wake up from suspend

Command query-current-machine (Since: 4.0)

Return information on the current virtual machine.

Return:

CurrentMachineParams

Object QemuTargetInfo (Since: 1.2)

Information on the target configuration built into the QEMU binary.

Members:
Command query-target (Since: 1.2)

Return information about the target for this QEMU

Return:

QemuTargetInfo

Object UuidInfo (Since: 0.14)

Guest UUID information (Universally Unique Identifier).

Members:

  • UUID (string) – the UUID of the guest

Note

If no UUID was specified for the guest, the nil UUID (all zeroes) is returned.

Command query-uuid (Since: 0.14)

Query the guest UUID information.

Return:

UuidInfo

Example:

-> { "execute": "query-uuid" }
<- { "return": { "UUID": "550e8400-e29b-41d4-a716-446655440000" } }
Object GuidInfo (Since: 2.9)

GUID information.

Members:

  • guid (string) – the globally unique identifier

Command query-vm-generation-id (Since: 2.9)

Show Virtual Machine Generation ID

Return:

GuidInfo

Command system_reset (Since: 0.14)

Performs a hard reset of a guest.

Example:

-> { "execute": "system_reset" }
<- { "return": {} }
Command system_powerdown (Since: 0.14)

Requests that a guest perform a powerdown operation.

Note

A guest may or may not respond to this command. This command returning does not indicate that a guest has accepted the request or that it has shut down. Many guests will respond to this command by prompting the user in some way.

Example:

-> { "execute": "system_powerdown" }
<- { "return": {} }
Command system_wakeup (Since: 1.1)

Wake up guest from suspend. If the guest has wake-up from suspend support enabled (wakeup-suspend-support flag from query-current-machine), wake-up guest from suspend if the guest is in SUSPENDED state. Return an error otherwise.

Note

Prior to 4.0, this command does nothing in case the guest isn’t suspended.

Example:

-> { "execute": "system_wakeup" }
<- { "return": {} }
Enum LostTickPolicy (Since: 2.0)

Policy for handling lost ticks in timer devices. Ticks end up getting lost when, for example, the guest is paused.

Values:

  • discard – throw away the missed ticks and continue with future injection normally. The guest OS will see the timer jump ahead by a potentially quite significant amount all at once, as if the intervening chunk of time had simply not existed; needless to say, such a sudden jump can easily confuse a guest OS which is not specifically prepared to deal with it. Assuming the guest OS can deal correctly with the time jump, the time in the guest and in the host should now match.

  • delay – continue to deliver ticks at the normal rate. The guest OS will not notice anything is amiss, as from its point of view time will have continued to flow normally. The time in the guest should now be behind the time in the host by exactly the amount of time during which ticks have been missed.

  • slew – deliver ticks at a higher rate to catch up with the missed ticks. The guest OS will not notice anything is amiss, as from its point of view time will have continued to flow normally. Once the timer has managed to catch up with all the missing ticks, the time in the guest and in the host should match.

Command inject-nmi (Since: 0.14)

Injects a Non-Maskable Interrupt into the default CPU (x86/s390) or all CPUs (ppc64). The command fails when the guest doesn’t support injecting.

Note

Prior to 2.1, this command was only supported for x86 and s390 VMs.

Example:

-> { "execute": "inject-nmi" }
<- { "return": {} }
Enum NumaOptionsType (Since: 2.1)
Values:

  • node – NUMA nodes configuration

  • dist – NUMA distance configuration (since 2.10)

  • cpu – property based CPU(s) to node mapping (Since: 2.10)

  • hmat-lb – memory latency and bandwidth information (Since: 5.0)

  • hmat-cache – memory side cache information (Since: 5.0)

Object NumaOptions (Since: 2.1)

A discriminated record of NUMA options. (for OptsVisitor)

Members:
Object NumaNodeOptions (Since: 2.1)

Create a guest NUMA node. (for OptsVisitor)

Members:

  • nodeid (int, optional) – NUMA node ID (increase by 1 from 0 if omitted)

  • cpus ([int], optional) – VCPUs belonging to this node (assign VCPUS round-robin if omitted)

  • mem (int, optional) – memory size of this node; mutually exclusive with memdev. Equally divide total memory among nodes if both mem and memdev are omitted.

  • memdev (string, optional) – memory backend object. If specified for one node, it must be specified for all nodes.

  • initiator (int, optional) – defined in ACPI 6.3 Chapter 5.2.27.3 Table 5-145, points to the nodeid which has the memory controller responsible for this NUMA node. This field provides additional information as to the initiator node that is closest (as in directly attached) to this node, and therefore has the best performance (since 5.0)

Object NumaDistOptions (Since: 2.10)

Set the distance between 2 NUMA nodes.

Members:

  • src (int) – source NUMA node.

  • dst (int) – destination NUMA node.

  • val (int) – NUMA distance from source node to destination node. When a node is unreachable from another node, set the distance between them to 255.

Object CXLFixedMemoryWindowOptions (Since: 7.1)

Create a CXL Fixed Memory Window

Members:

  • size (int) – Size of the Fixed Memory Window in bytes. Must be a multiple of 256MiB.

  • interleave-granularity (int, optional) – Number of contiguous bytes for which accesses will go to a given interleave target. Accepted values [256, 512, 1k, 2k, 4k, 8k, 16k]

  • targets ([string]) – Target root bridge IDs from -device …,id=<ID> for each root bridge.

Object CXLFMWProperties (Since: 7.1)

List of CXL Fixed Memory Windows.

Members:
Enum X86CPURegister32 (Since: 1.5)

A X86 32-bit register

Values:

  • EAX – Not documented

  • EBX – Not documented

  • ECX – Not documented

  • EDX – Not documented

  • ESP – Not documented

  • EBP – Not documented

  • ESI – Not documented

  • EDI – Not documented

Object X86CPUFeatureWordInfo (Since: 1.5)

Information about a X86 CPU feature word

Members:

  • cpuid-input-eax (int) – Input EAX value for CPUID instruction for that feature word

  • cpuid-input-ecx (int, optional) – Input ECX value for CPUID instruction for that feature word

  • cpuid-register (X86CPURegister32) – Output register containing the feature bits

  • features (int) – value of output register, containing the feature bits

Object DummyForceArrays (Since: 2.5)

Not used by QMP; hack to let us use X86CPUFeatureWordInfoList internally

Members:
Object NumaCpuOptions (Since: 2.10)

Option “-numa cpu” overrides default cpu to node mapping. It accepts the same set of cpu properties as returned by query-hotpluggable-cpus[].props, where node-id could be used to override default node mapping.

Members:
Enum HmatLBMemoryHierarchy (Since: 5.0)

The memory hierarchy in the System Locality Latency and Bandwidth Information Structure of HMAT (Heterogeneous Memory Attribute Table)

For more information about HmatLBMemoryHierarchy, see chapter 5.2.27.4: Table 5-146: Field “Flags” of ACPI 6.3 spec.

Values:

  • memory – the structure represents the memory performance

  • first-level – first level of memory side cache

  • second-level – second level of memory side cache

  • third-level – third level of memory side cache

Enum HmatLBDataType (Since: 5.0)

Data type in the System Locality Latency and Bandwidth Information Structure of HMAT (Heterogeneous Memory Attribute Table)

For more information about HmatLBDataType, see chapter 5.2.27.4: Table 5-146: Field “Data Type” of ACPI 6.3 spec.

Values:

  • access-latency – access latency (nanoseconds)

  • read-latency – read latency (nanoseconds)

  • write-latency – write latency (nanoseconds)

  • access-bandwidth – access bandwidth (Bytes per second)

  • read-bandwidth – read bandwidth (Bytes per second)

  • write-bandwidth – write bandwidth (Bytes per second)

Object NumaHmatLBOptions (Since: 5.0)

Set the system locality latency and bandwidth information between Initiator and Target proximity Domains.

For more information about NumaHmatLBOptions, see chapter 5.2.27.4: Table 5-146 of ACPI 6.3 spec.

Members:

  • initiator (int) – the Initiator Proximity Domain.

  • target (int) – the Target Proximity Domain.

  • hierarchy (HmatLBMemoryHierarchy) – the Memory Hierarchy. Indicates the performance of memory or side cache.

  • data-type (HmatLBDataType) – presents the type of data, access/read/write latency or hit latency.

  • latency (int, optional) – the value of latency from initiator to target proximity domain, the latency unit is “ns(nanosecond)”.

  • bandwidth (int, optional) – the value of bandwidth between initiator and target proximity domain, the bandwidth unit is “Bytes per second”.

Enum HmatCacheAssociativity (Since: 5.0)

Cache associativity in the Memory Side Cache Information Structure of HMAT

For more information of HmatCacheAssociativity, see chapter 5.2.27.5: Table 5-147 of ACPI 6.3 spec.

Values:

  • none – None (no memory side cache in this proximity domain, or cache associativity unknown)

  • direct – Direct Mapped

  • complex – Complex Cache Indexing (implementation specific)

Enum HmatCacheWritePolicy (Since: 5.0)

Cache write policy in the Memory Side Cache Information Structure of HMAT

For more information of HmatCacheWritePolicy, see chapter 5.2.27.5: Table 5-147: Field “Cache Attributes” of ACPI 6.3 spec.

Values:

  • none – None (no memory side cache in this proximity domain, or cache write policy unknown)

  • write-back – Write Back (WB)

  • write-through – Write Through (WT)

Object NumaHmatCacheOptions (Since: 5.0)

Set the memory side cache information for a given memory domain.

For more information of NumaHmatCacheOptions, see chapter 5.2.27.5: Table 5-147: Field “Cache Attributes” of ACPI 6.3 spec.

Members:

  • node-id (int) – the memory proximity domain to which the memory belongs.

  • size (int) – the size of memory side cache in bytes.

  • level (int) – the cache level described in this structure.

  • associativity (HmatCacheAssociativity) – the cache associativity, none/direct-mapped/complex(complex cache indexing).

  • policy (HmatCacheWritePolicy) – the write policy, none/write-back/write-through.

  • line (int) – the cache line size in bytes.

Command memsave (Since: 0.14)

Save a portion of guest memory to a file.

Arguments:

  • val (int) – the virtual address of the guest to start from

  • size (int) – the size of memory region to save

  • filename (string) – the file to save the memory to as binary data

  • cpu-index (int, optional) – the index of the virtual CPU to use for translating the virtual address (defaults to CPU 0)

Caution

Errors were not reliably returned until 1.1.

Example:

-> { "execute": "memsave",
     "arguments": { "val": 10,
                    "size": 100,
                    "filename": "/tmp/virtual-mem-dump" } }
<- { "return": {} }
Command pmemsave (Since: 0.14)

Save a portion of guest physical memory to a file.

Arguments:

  • val (int) – the physical address of the guest to start from

  • size (int) – the size of memory region to save

  • filename (string) – the file to save the memory to as binary data

Caution

Errors were not reliably returned until 1.1.

Example:

-> { "execute": "pmemsave",
     "arguments": { "val": 10,
                    "size": 100,
                    "filename": "/tmp/physical-mem-dump" } }
<- { "return": {} }
Object Memdev (Since: 2.1)

Information about memory backend

Members:

  • id (string, optional) – backend’s ID if backend has ‘id’ property (since 2.9)

  • size (int) – memory backend size

  • merge (boolean) – whether memory merge support is enabled

  • dump (boolean) – whether memory backend’s memory is included in a core dump

  • prealloc (boolean) – whether memory was preallocated

  • share (boolean) – whether memory is private to QEMU or shared (since 6.1)

  • reserve (boolean, optional) – whether swap space (or huge pages) was reserved if applicable. This corresponds to the user configuration and not the actual behavior implemented in the OS to perform the reservation. For example, Linux will never reserve swap space for shared file mappings. (since 6.1)

  • host-nodes ([int]) – host nodes for its memory policy

  • policy (HostMemPolicy) – memory policy of memory backend

Command query-memdev (Since: 2.1)

Return information for all memory backends.

Return:

[Memdev]

Example:

-> { "execute": "query-memdev" }
<- { "return": [
       {
         "id": "mem1",
         "size": 536870912,
         "merge": false,
         "dump": true,
         "prealloc": false,
         "share": false,
         "host-nodes": [0, 1],
         "policy": "bind"
       },
       {
         "size": 536870912,
         "merge": false,
         "dump": true,
         "prealloc": true,
         "share": false,
         "host-nodes": [2, 3],
         "policy": "preferred"
       }
     ]
   }
Object CpuInstanceProperties (Since: 2.7)