MonitorProtocol
QEMU Monitor Protocol
The QEMU Monitor Protocol (QMP) is a JSON-based protocol, which allows applications to communicate with QEMU's Monitor.
QMP is available in QEMU since version 0.13, although it is still under development and not complete.
Features
- Lightweight, text-based, easy to parse data format
- Asynchronous events support
Libqmp
Although this is still under discussion, we are also going to provide a C library with a stable ABI.
The short-term plan is to have a simple API to send commands and receive responses, this way C clients do not need to have their own JSON implementation.
The long-term plan is to provide a full management API for QEMU.
Development
The development takes place in the QMP unstable tree:
http://repo.or.cz/w/qemu/qmp-unstable.git
NOTE: all branches in this repository are constantly rebased.
Important branches:
- master: contains a functional QMP implementation, its draft specification can be found here.
- conversions-qobject: output in QObject conversions
- conversions-qerror: error handling conversions
Project status (2009-12-07)
All the infrastructure has been merged and the protocol is already functional, but only a few commands will work.
Main building blocks
- QObject Layer (merged)
- QObject Monitor infrastructure (merged)
- JSON encoder/decoder (merged)
- Error framework (merged)
Conversion work
- Input through QDict (merged)
- Output in QObject style (in progress)
- Error handling (in progress)
Conversion work detailed status
Command | Info | |
Handlers | 61 | 35 |
Fully Converted | 7 | 14 |
Percentage | 11% | 40% |
The following tables have a per-function status. There is one table for command handlers and another one for info handlers.
Status can be:
- merged: already merged upstream
- converted: converted but not merged yet
- partial: not fully converted
- never fails: does not need error handling
NOTE: Handlers used by Libvirt are marked with yellow.
Command handlers
Handler name | Output in QObject | Error handling | Comments |
do_acl_add() | |||
do_acl_policy() | |||
do_acl_remove() | |||
do_acl_reset() | |||
do_acl_show() | |||
do_balloon() | merged | never fails | |
do_boot_set() | |||
do_change() | |||
do_closefd() | merged | ||
do_commit() | |||
do_cont() | merged | never fails | TODO: encrypted images |
do_cpu_set() | |||
do_delvm() | |||
do_device_add() | |||
do_device_del() | |||
do_eject() | merged | ||
do_gdbserver() | |||
do_getfd() | merged | ||
do_help_cmd() | |||
do_info() | merged | ||
do_inject_mce() | |||
do_inject_nmi() | |||
do_ioport_read() | |||
do_ioport_write() | |||
do_loadvm() | |||
do_log() | |||
do_logfile() | |||
do_memory_dump() | |||
do_memory_save() | merged | ||
do_migrate() | merged | ||
do_migrate_cancel() | merged | never fails | |
do_migrate_set_downtime() | |||
do_migrate_set_speed() | merged | never fails | |
do_mouse_button() | |||
do_mouse_move() | |||
do_mouse_set() | |||
do_pci_device_hot_remove() | merged | ||
do_physical_memory_dump() | |||
do_physical_memory_save() | merged | ||
do_print() | |||
do_quit() | merged | ||
do_savevm() | |||
do_screen_dump() | |||
do_sendkey() | |||
do_set_link() | |||
do_singlestep() | |||
do_stop() | merged | never fails | |
do_stop_capture() | |||
do_sum() | |||
do_system_powerdown() | merged | nerver fails | |
do_system_reset() | merged | never fails | |
do_usb_add() | |||
do_usb_del() | |||
do_watchdog_action() | |||
do_wav_capture() | |||
drive_hot_add() | |||
net_host_device_add() | |||
net_host_device_remove() | |||
net_slirp_hostfwd_add() | |||
net_slirp_hostfwd_remove() | |||
pci_device_hot_add() | converted |
Info handlers
Handler name | Status | Comments |
bdrv_info() | converted | |
bdrv_info_stats() | converted | |
do_info_balloon() | merged | |
do_info_capture() | ||
do_info_cpus() | merged | |
do_info_cpu_stats() | ||
do_info_history() | ||
do_info_hpet() | converted | |
do_info_jit() | ||
do_info_kvm() | converted | |
do_info_mice() | converted | |
do_info_migrate() | converted | |
do_info_name() | converted | |
do_info_network() | partial | |
do_info_numa() | ||
do_info_profile() | ||
do_info_qdm() | ||
do_info_qtree() | ||
do_info_registers() | ||
do_info_roms() | ||
do_info_snapshots() | ||
do_info_status() | converted | |
do_info_usernet() | partial | |
do_info_uuid() | converted | |
do_info_version() | merged | |
do_info_vnc() | converted | |
irq_info() | ||
mem_info() | ||
pci_info() | ||
pcmcia_info() | ||
pic_info() | ||
qemu_chr_info() | converted | |
tlb_info() | ||
usb_host_info() | ||
usb_info() |
History
This is the fourth proposal for a machine protocol, past discussions can be found in the following links:
- http://www.mail-archive.com/qemu-devel@nongnu.org/msg14593.html
- http://lists.gnu.org/archive/html/qemu-devel/2009-01/msg00655.html
- http://lists.gnu.org/archive/html/qemu-devel/2009-06/msg01584.html
Contact
Primary contact is Luiz Capitulino <lcapitulino at redhat dot com> but most project discussions happen on the QEMU-devel mailing list: