QEMU monitorThe QEMU monitor is used to give complex commands to the QEMU emulator. You can use it to: − Remove or insert removable media images (such as CD-ROM or floppies). − Freeze/unfreeze the Virtual Machine (VM) and save or restore its state from a disk file. − Inspect the VM state without an external debugger. The following commands are available: help or ? [cmd] helpShow the help for all commands or just for command cmd. commit commitCommit changes to the disk images (if -snapshot is used) or backing files. If the backing file is smaller than the snapshot, then the backing file will be resized to be the same size as the snapshot. If the snapshot is smaller than the backing file, the backing file will not be truncated. If you want the backing file to match the size of the smaller snapshot, you can safely truncate it yourself once the commit operation successfully completes. q or quit quitQuit the emulator. block_resize block_resizeResize a block image while a guest is running. Usually requires guest action to see the updated size. Resize to a lower size is supported, but should be used with extreme caution. Note that this command only resizes image files, it can not resize block devices like LVM volumes. block_stream block_streamCopy data from a backing file into a block device. block_job_set_speed block_job_set_speedSet maximum speed for a background block operation. block_job_cancel block_job_cancelStop an active background block operation (streaming, mirroring). block_job_complete block_job_completeManually trigger completion of an active background block operation. For mirroring, this will switch the device to the destination path. block_job_pause block_job_pausePause an active block streaming operation. block_job_resume block_job_resumeResume a paused block streaming operation. eject [-f] device ejectEject a removable medium (use -f to force it). drive_del device drive_delRemove host block device. The result is that guest generated IO is no longer submitted against the host device underlying the disk. Once a drive has been deleted, the QEMU Block layer returns -EIO which results in IO errors in the guest for applications that are reading/writing to the device. These errors are always reported to the guest, regardless of the drive’s error actions (drive options rerror, werror). change device setting changeChange the configuration of a device. change diskdevice filename [format [read-only-mode]] Change the medium for a removable disk device to point to filename. eg (qemu) change ide1-cd0 /path/to/some.iso format is optional. read-only-mode may be used to change the read-only status of the device. It accepts the following values: retain Retains the current status; this is the default. read-only Makes the device read-only. read-write Makes the device writable. change vnc display,options Change the configuration of the VNC server. The valid syntax for display and options are described at sec_invocation. eg (qemu) change vnc localhost:1 change vnc password [password] Change the password associated with the VNC server. If the new password is not supplied, the monitor will prompt for it to be entered. VNC passwords are only significant up to 8 letters. eg (qemu) change vnc password Password: ******** screendump filename screendumpSave screen into PPM image filename. logfile filename logfileOutput logs to filename. trace-event trace-eventchanges status of a trace event trace-file on|off|flush trace-fileOpen, close, or flush the trace file. If no argument is given, the status of the trace file is displayed. log item1[,...] logActivate logging of the specified items. savevm [tag|id] savevmCreate a snapshot of the whole virtual machine. If tag is provided, it is used as human readable identifier. If there is already a snapshot with the same tag or ID, it is replaced. More info at vm_snapshots. loadvm tag|id loadvmSet the whole virtual machine to the snapshot identified by the tag tag or the unique snapshot ID id. delvm tag|id delvmDelete the snapshot identified by tag or id. singlestep [off] singlestepRun the emulation in single step mode. If called with option off, the emulation returns to normal mode. stop stopStop emulation. c or cont contResume emulation. system_wakeup system_wakeupWakeup guest from suspend. gdbserver [port] gdbserverStart gdbserver session (default port=1234) x/fmt addr xVirtual memory dump starting at addr. xp /fmt addr xpPhysical memory dump starting at addr. fmt is a format which tells the command how to format the data. Its syntax is: /{count}{format}{size} count is the number of items to be dumped. format can be x (hex), d (signed decimal), u (unsigned decimal), o (octal), c (char) or i (asm instruction). size can be b (8 bits), h (16 bits), w (32 bits) or g (64 bits). On x86, h or w can be specified with the i format to respectively select 16 or 32 bit code instruction size. Examples: Dump 10 instructions at the current instruction pointer: (qemu) x/10i $eip 0x90107063: ret 0x90107064: sti 0x90107065: lea 0x0(%esi,1),%esi 0x90107069: lea 0x0(%edi,1),%edi 0x90107070: ret 0x90107071: jmp 0x90107080 0x90107073: nop 0x90107074: nop 0x90107075: nop 0x90107076: nop Dump 80 16 bit values at the start of the video memory. (qemu) xp/80hx 0xb8000 0x000b8000: 0x0b50 0x0b6c 0x0b65 0x0b78 0x0b38 0x0b36 0x0b2f 0x0b42 0x000b8010: 0x0b6f 0x0b63 0x0b68 0x0b73 0x0b20 0x0b56 0x0b47 0x0b41 0x000b8020: 0x0b42 0x0b69 0x0b6f 0x0b73 0x0b20 0x0b63 0x0b75 0x0b72 0x000b8030: 0x0b72 0x0b65 0x0b6e 0x0b74 0x0b2d 0x0b63 0x0b76 0x0b73 0x000b8040: 0x0b20 0x0b30 0x0b35 0x0b20 0x0b4e 0x0b6f 0x0b76 0x0b20 0x000b8050: 0x0b32 0x0b30 0x0b30 0x0b33 0x0720 0x0720 0x0720 0x0720 0x000b8060: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x000b8070: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x000b8080: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x000b8090: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 p or print/fmt expr printPrint expression value. Only the format part of fmt is used. i/fmt addr [.index] iRead I/O port. o/fmt addr val oWrite to I/O port. sendkey keys sendkeySend keys to the guest. keys could be the name of the key or the raw value in hexadecimal format. Use - to press several keys simultaneously. Example: sendkey ctrl-alt-f1 This command is useful to send keys that your graphical user interface intercepts at low level, such as ctrl-alt-f1 in X Window. system_reset system_resetReset the system. system_powerdown system_powerdownPower down the system (if supported). sum addr size sumCompute the checksum of a memory region. usb_add devname usb_addAdd the USB device devname. For details of available devices see usb_devices usb_del devname usb_delRemove the USB device devname from the QEMU virtual USB hub. devname has the syntax bus.addr. Use the monitor command info usb to see the devices you can remove. device_add config device_addAdd device. device_del id device_delRemove device id. id may be a short ID or a QOM object path. cpu index cpuSet the default CPU. mouse_move dx dy [dz] mouse_moveMove the active mouse to the specified coordinates dx dy with optional scroll axis dz. mouse_button val mouse_buttonChange the active mouse button state val (1=L, 2=M, 4=R). mouse_set index mouse_setSet which mouse device receives events at given index, index can be obtained with info mice wavcapture filename [frequency [bits [channels]]] wavcaptureCapture audio into filename. Using sample rate frequency bits per sample bits and number of channels channels. Defaults: − Sample rate = 44100 Hz - CD quality − Bits = 16 − Number of channels = 2 - Stereo stopcapture index stopcaptureStop capture with a given index, index can be obtained with info capture memsave addr size file memsavesave to disk virtual memory dump starting at addr of size size. pmemsave addr size file pmemsavesave to disk physical memory dump starting at addr of size size. boot_set bootdevicelist boot_setDefine new values for the boot device list. Those values will override the values specified on the command line through the -boot option. The values that can be specified here depend on the machine type, but are the same that can be specified in the -boot command line option. nmi cpu nmiInject an NMI on the default CPU (x86/s390) or all CPUs (ppc64). ringbuf_write device data ringbuf_writeWrite data to ring buffer character device device. data must be a UTF-8 string. ringbuf_read device ringbuf_readRead and print up to size bytes from ring buffer character device device. Certain non-printable characters are printed \uXXXX, where XXXX is the character code in hexadecimal. Character \ is printed \\. 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. migrate [-d] [-b] [-i] uri migrateMigrate to uri (using -d to not wait for completion). -b for migration with full copy of disk -i for migration with incremental copy of disk (base image is shared) migrate_cancel migrate_cancelCancel the current VM migration. migrate_incoming uri migrate_incomingContinue an incoming migration using the uri (that has the same syntax as the -incoming option). migrate_set_cache_size value migrate_set_cache_sizeSet cache size to value (in bytes) for xbzrle migrations. migrate_set_speed value migrate_set_speedSet maximum speed to value (in bytes) for migrations. migrate_set_downtime second migrate_set_downtimeSet maximum tolerated downtime (in seconds) for migration. migrate_set_capability capability state migrate_set_capabilityEnable/Disable the usage of a capability capability for migration. migrate_set_parameter parameter value migrate_set_parameterSet the parameter parameter for migration. migrate_start_postcopy migrate_start_postcopySwitch in-progress migration to postcopy mode. Ignored after the end of migration (or once already in postcopy). x_colo_lost_heartbeat x_colo_lost_heartbeatTell COLO that heartbeat is lost, a failover or takeover is needed. client_migrate_info protocol hostname port tls-port cert-subject client_migrate_infoSet 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. dump-guest-memory [-p] filename begin length dump-guest-memory [-z|-l|-s] filename dump-guest-memoryDump guest memory to protocol. The file can be processed with crash or gdb. Without -z|-l|-s, the dump format is ELF. -p: do paging to get guest’s memory mapping. -z: dump in kdump-compressed format, with zlib compression. -l: dump in kdump-compressed format, with lzo compression. -s: dump in kdump-compressed format, with snappy compression. filename: dump file name. begin: the starting physical address. It’s optional, and should be specified together with length. length: the memory size, in bytes. It’s optional, and should be specified together with begin. dump-skeys filename dump-skeysSave guest storage keys to a file. snapshot_blkdev snapshot_blkdevSnapshot device, using snapshot file as target if provided snapshot_blkdev_internal snapshot_blkdev_internalTake an internal snapshot on device if it support snapshot_delete_blkdev_internal snapshot_delete_blkdev_internalDelete an internal snapshot on device if it support drive_mirror drive_mirrorStart mirroring a block device’s writes to a new destination, using the specified target. drive_backup drive_backupStart a point-in-time copy of a block device to a specificed target. drive_add drive_addAdd drive to PCI storage controller. pcie_aer_inject_error pcie_aer_inject_errorInject PCIe AER error host_net_add host_net_addAdd host VLAN client. host_net_remove host_net_removeRemove host VLAN client. netdev_add netdev_addAdd host network device. netdev_del netdev_delRemove host network device. object_add object_addCreate QOM object. object_del object_delDestroy QOM object. hostfwd_add hostfwd_addRedirect TCP or UDP connections from host to guest (requires -net user). hostfwd_remove hostfwd_removeRemove host-to-guest TCP or UDP redirection. balloon value balloonRequest VM to change its memory allocation to value (in MB). set_link name [on|off] set_linkSwitch link name on (i.e. up) or off (i.e. down). watchdog_action watchdog_actionChange watchdog action. acl_show aclname acl_showList all the matching rules in the access control list, and the default policy. There are currently two named access control lists, vnc.x509dname and vnc.username matching on the x509 client certificate distinguished name, and SASL username respectively. acl_policy aclname allow|deny acl_policySet the default access control list policy, used in the event that none of the explicit rules match. The default policy at startup is always deny. acl_add aclname match allow|deny [index] acl_addAdd a match rule to the access control list, allowing or denying access. The match will normally be an exact username or x509 distinguished name, but can optionally include wildcard globs. eg *@EXAMPLE.COM to allow all users in the EXAMPLE.COM kerberos realm. The match will normally be appended to the end of the ACL, but can be inserted earlier in the list if the optional index parameter is supplied. acl_remove aclname match acl_removeRemove the specified match rule from the access control list. acl_reset aclname acl_resetRemove all matches from the access control list, and set the default policy back to deny. nbd_server_start host:port nbd_server_startStart an NBD server on the given host and/or port. If the -a option is included, all of the virtual machine’s block devices that have an inserted media on them are automatically exported; in this case, the -w option makes the devices writable too. nbd_server_add device nbd_server_addExport a block device through QEMU’s NBD server, which must be started beforehand with nbd_server_start. The -w option makes the exported device writable too. nbd_server_stop nbd_server_stopStop the QEMU embedded NBD server. mce cpu bank status mcgstatus addr misc mce (x86)Inject an MCE on the given CPU (x86 only). getfd fdname getfdIf a file descriptor is passed alongside this command using the SCM_RIGHTS mechanism on unix sockets, it is stored using the name fdname for later use by other monitor commands. closefd fdname closefdClose the file descriptor previously assigned to fdname using the getfd command. This is only needed if the file descriptor was never used by another monitor command. block_passwd device password block_passwdSet the encrypted device device password to password block_set_io_throttle device bps bps_rd bps_wr iops iops_rd iops_wr block_set_io_throttleChange I/O throttle limits for a block drive to bps bps_rd bps_wr iops iops_rd iops_wr set_password [ vnc | spice ] password [ action-if-connected ] set_passwordChange spice/vnc password. Use zero to make the password stay valid forever. action-if-connected specifies what should happen in case a connection is established: fail makes the password change fail. disconnect changes the password and disconnects the client. keep changes the password and keeps the connection up. keep is the default. expire_password [ vnc | spice ] expire-time expire_passwordSpecify when a password for spice/vnc becomes invalid. expire-time accepts: now Invalidate password instantly. never Password stays valid forever. +nsec Password stays valid for nsec seconds starting now. nsec Password is invalidated at the given time. nsec are the seconds passed since 1970, i.e. unix epoch. chardev-add args chardev-addchardev_add accepts the same parameters as the -chardev command line switch. chardev-remove id chardev-removeRemoves the chardev id. qemu-io device command qemu-ioExecutes a qemu-io command on the given block device. cpu-add id cpu-addAdd CPU with id id qom-list [path] Print QOM properties of object at location path qom-set path property value Set QOM property property of object at location path to value value info subcommand infoShow various information about the system state. info version versionShow the version of QEMU. info network networkShow the network state. info chardev chardevShow the character devices. info block blockShow info of one block device or all block devices. info blockstats blockstatsShow block device statistics. info block-jobs block-jobsShow progress of ongoing block device operations. info registers registersShow the cpu registers. info lapic lapicShow local APIC state info ioapic ioapicShow io APIC state info cpus cpusShow infos for each CPU. info history historyShow the command line history. info irq irqShow the interrupts statistics (if available). info pic picShow i8259 (PIC) state. info pci pciShow PCI information. info tlb tlbShow virtual to physical memory mappings. info mem memShow the active virtual memory mappings. info mtree mtreeShow memory tree. info jit jitShow dynamic compiler info. info opcount opcountShow dynamic compiler opcode counters info kvm kvmShow KVM information. info numa numaShow NUMA information. info usb usbShow guest USB devices. info usbhost usbhostShow host USB devices. info profile profileShow profiling information. info capture captureShow capture information. info snapshots snapshotsShow the currently saved VM snapshots. info status statusShow the current VM status (running|paused). info mice miceShow which guest mouse is receiving events. info vnc vncShow the vnc server status. info spice spiceShow the spice server status. info name nameShow the current VM name. info uuid uuidShow the current VM UUID. info cpustats cpustatsShow CPU statistics. info usernet usernetShow user network stack connection states. info migrate migrateShow migration status. info migrate_capabilities migrate_capabilitiesShow current migration capabilities. info migrate_parameters migrate_parametersShow current migration parameters. info migrate_cache_size migrate_cache_sizeShow current migration xbzrle cache size. info balloon balloonShow balloon information. info qtree qtreeShow device tree. info qdm qdmShow qdev device model list. info qom-tree qom-treeShow QOM composition tree. info roms romsShow roms. info trace-events trace-eventsShow available trace-events & their state. info tpm tpmShow the TPM device. info memdev memdevShow memory backends info memory-devices memory-devicesShow memory devices. info iothreads iothreadsShow iothread’s identifiers. info rocker name rockerShow rocker switch. info rocker_ports name-ports ocker-portsShow rocker ports. info rocker_of_dpa_flows name [tbl_id] rocker-of-dpa-flowsShow rocker OF-DPA flow tables. info rocker-of-dpa-groups name [type] rocker-of-dpa-groupsShow rocker OF-DPA groups. info skeys address skeysDisplay the value of a storage key (s390 only) info dump dumpDisplay the latest dump status. info hotpluggable-cpus hotpluggable-cpusShow information about hotpluggable CPUs The monitor understands integers expressions for every integer argument. You can use register names to get the value of specifics CPU registers by prefixing them with $.