KVM - User contributions [en]

MonitorProtocol

2010-03-15T16:48:21Z

Dorileo: removed libvirt todo since it`s described on last editing

= QEMU Monitor Protocol =

The QEMU Monitor Protocol (QMP) allows applications to communicate with QEMU's Monitor.

QMP is [http://www.json.org/ JSON]-based, its main features are:

* Lightweight, text-based, easy to parse data format
* Asynchronous events support

The [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP/README README] file explains how to use it and its full specification can be found [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP/qmp-spec.txt here].

== General Status ==

A '''preview''' version of QMP is available in QEMU version 0.12.

However, QMP is still under development being considered unstable and incomplete. For more information about converted handlers, please check [[#Conversion Status]].

== Examples ==

In the following examples, 'C' stands for 'Client' and 'S' stands for 'Server'.

=== Server Greeting ===

S: {"QMP": {"capabilities": []}}

=== Query version ===

C: { "execute": "query-version" }
S: {"return": {"qemu": "0.11.50", "package": ""}}

=== Eject a device ===

C: { "execute": "eject", "arguments": { "device": "ide1-cd0" } }
S: {"return": {}}

== Development ==

Primary contact is [mailto:lcapitulino@redhat.com Luiz Capitulino], but all QMP-related discussions happen on the [http://lists.nongnu.org/mailman/listinfo/qemu-devel qemu-devel] mailing list.

Next features, hot fixes and other patches are stored in the QMP unstable repository:

http://repo.or.cz/w/qemu/qmp-unstable.git

'''NOTE''': all branches in this repository are constantly ''rebased'' (master inclusive).

== TODO ==

* Convert all remaining commands
* High-level protocol documentation
* High-level internal documentation
* Improve internal API, currently it's too [http://lists.gnu.org/archive/html/qemu-devel/2009-12/msg02537.html low-level]
* Better QObjects and QMP debug support
* Array-based Monitor's command table
* Libqmp

== Conversion Status ==

'''UPDATED''': 2009-12-16

{| border="1"
|
|Command
|Info
|-
|Handlers
|62
|36
|-
|Converted
|19
|15
|-
|Percentage
|30%
|41%
|-
|}

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: merged, but error handling is incomplete

'''NOTE:''' Handlers used by [http://libvirt.org Libvirt] are marked with yellow.

==== Command handlers ====

{| border="1"
|'''Handler name'''
|'''Status'''
|'''Version'''
|'''Comments'''
|-
|do_acl_add()
|
|
|
|-
|do_acl_policy()
|
|
|
|-
|do_acl_remove()
|
|
|
|-
|do_acl_reset()
|
|
|
|-
|do_acl_show()
|
|
|
|- style="background-color:yellow;"
|do_balloon()
|merged
|0.12
|
|-
|do_block_set_passwd()
|merged
|0.12
|
|-
|do_boot_set()
|
|
|
|- style="background-color:yellow;"
|do_change()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_closefd()
|merged
|0.12
|
|-
|do_commit()
|
|
|
|- style="background-color:yellow;"
|do_cont()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_cpu_set()
|merged
|0.12.50
|
|-
|do_delvm()
|
|
|
|- style="background-color:yellow;"
|do_device_add()
|
|
|
|- style="background-color:yellow;"
|do_device_del()
|
|
|
|- style="background-color:yellow;"
|do_eject()
|merged
|0.12
|
|-
|do_gdbserver()
|
|
|
|- style="background-color:yellow;"
|do_getfd()
|merged
|0.12
|
|-
|do_help_cmd()
|
|
|
|-
|do_info()
|merged
|0.12
|as 'query-' commands
|-
|do_inject_mce()
|
|
|
|-
|do_inject_nmi()
|
|
|
|-
|do_ioport_read()
|
|
|
|-
|do_ioport_write()
|
|
|
|-
|do_loadvm()
|
|
|
|-
|do_log()
|
|
|
|-
|do_logfile()
|
|
|
|-
|do_memory_dump()
|
|
|
|- style="background-color:yellow;"
|do_memory_save()
|merged
|0.12.50
|
|- style="background-color:yellow;"
|do_migrate()
|partial
|0.12
|
|- style="background-color:yellow;"
|do_migrate_cancel()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_migrate_set_downtime()
|merged
|0.12.50
|
|- style="background-color:yellow;"
|do_migrate_set_speed()
|merged
|0.12.50
|
|-
|do_mouse_button()
|
|
|
|-
|do_mouse_move()
|
|
|
|-
|do_mouse_set()
|
|
|
|- style="background-color:yellow;"
|do_pci_device_hot_remove()
|partial
|0.12
|legacy, use device_del instead
|-
|do_physical_memory_dump()
|
|
|
|- style="background-color:yellow;"
|do_physical_memory_save()
|merged
|0.12.50
|
|-
|do_print()
|
|
|
|-
|do_quit()
|merged
|0.12
|
|-
|do_savevm()
|
|
|
|-
|do_screen_dump()
|
|
|
|-
|do_sendkey()
|
|
|
|- style="background-color:yellow;"
|do_set_link()
|
|
|
|-
|do_singlestep()
|
|
|
|- style="background-color:yellow;"
|do_stop()
|merged
|0.12
|
|-
|do_stop_capture()
|
|
|
|-
|do_sum()
|
|
|
|- style="background-color:yellow;"
|do_system_powerdown()
|merged
|0.12
|
|-
|do_system_reset()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_usb_add()
|
|
|legacy, use device_add instead
|- style="background-color:yellow;"
|do_usb_del()
|
|
|legacy, use device_del instead
|-
|do_watchdog_action()
|
|
|
|-
|do_wav_capture()
|
|
|
|- style="background-color:yellow;"
|drive_hot_add()
|
|
|
|- style="background-color:yellow;"
|net_host_device_add()
|
|
|consider do_netdev_add() instead
|- style="background-color:yellow;"
|net_host_device_remove()
|
|
|consider do_netdev_del() instead
|-
|net_slirp_hostfwd_add()
|
|
|
|-
|net_slirp_hostfwd_remove()
|
|
|
|- style="background-color:yellow;"
|pci_device_hot_add()
|partial
|0.12
|legacy, use device_add instead
|-
|do_chardev_add()
|
|
|to be created
|-
|do_chardev_del()
|
|
|to be created
|-
|do_blockdev_add()
|
|
|to be created
|-
|do_blockdev_del()
|
|
|to be created
|-
|do_netdev_add()
|
|
|to be created
|-
|do_netdev_del()
|
|
|to be created
|-
|}

==== Info handlers ====

{| border="1"
|'''Handler name'''
|'''Status'''
|'''Version'''
|'''Comments'''
|- style="background-color:yellow;"
|bdrv_info()
|merged
|0.12
|
|- style="background-color:yellow;"
|bdrv_info_stats()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_info_balloon()
|merged
|0.12
|
|-
|do_info_capture()
|
|
|
|- style="background-color:yellow;"
|do_info_cpus()
|merged
|0.12
|
|-
|do_info_cpu_stats()
|
|
|
|-
|do_info_history()
|
|
|
|-
|do_info_hpet()
|merged
|0.12
|
|-
|do_info_jit()
|
|
|
|-
|do_info_kvm()
|merged
|0.12
|
|-
|do_info_mice()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_info_migrate()
|merged
|0.12
|
|-
|do_info_name()
|merged
|0.12
|
|-
|do_info_network()
|
|
|
|-
|do_info_numa()
|
|
|
|-
|do_info_profile()
|
|
|
|-
|do_info_qdm()
|
|
|
|-
|do_info_qtree()
|
|
|
|-
|do_info_registers()
|
|
|
|-
|do_info_roms()
|
|
|
|-
|do_info_snapshots()
|
|
|
|-
|do_info_status()
|merged
|0.12
|
|-
|do_info_usernet()
|
|
|
|-
|do_info_uuid()
|merged
|0.12
|
|-
|do_info_version()
|merged
|0.12
|
|-
|do_info_vnc()
|merged
|0.12
|
|-
|irq_info()
|
|
|
|-
|mem_info()
|
|
|
|- style="background-color:yellow;"
|pci_info()
|
|
|
|-
|pcmcia_info()
|
|
|
|-
|pic_info()
|
|
|
|-
|qemu_chr_info()
|merged
|0.12
|
|-
|tlb_info()
|
|
|
|-
|usb_host_info()
|
|
|
|- style="background-color:yellow;"
|usb_info()
|
|
|
|-
|}

== Testing ==

Unfortunately, there is no automated tool to test QMP correctness yet. Probably, the right thing to do is to integrate with [http://www.linux-kvm.org/page/KVM-Autotest kvm-autotest] but we still have to think how this should be done.

Meanwhile, QMP testing is a low-level procedure which requires knowledge about the protocol and its implementation, so the first thing to do is to read the [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP/README README] and [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP/qmp-spec.txt spec] files.

This section describes two ways of testing QMP:

* By hand (difficult, only worth it if you're chasing a specific bug)
* Using qmp-shell script (automates part of the job)

=== Libvirt ===

1. Install [http://lloyd.github.com/yajl yajl-devel] before running 'autogen.sh'. Make sure the final summary of autogen.sh tells you that it found the yajl library. If you`re running Fedora 12(or above) just yum install yajl-devel.

2. From a fresh checkout of [http://libvirt.org/git/?p=libvirt.git;a=summary GIT master] run the following:

./autogen.sh --system --enable-compile-warnings=error

'''NOTE:''' The '--system' flag is a shortcut for compiling with the --prefix and other directories matching a system RPM build.

3. Run 'make' to build. There is no need to 'make install' anything
especially since that would overwrite your RPM based install

4. As root simply stop the current daemon & start the one you built

/etc/init.d/libvirtd stop
$HOME/your/git/checkout/of/libvirt/daemon/libvirtd

5. As root you can use the newly built virsh too

cd $HOME/your/git/checkout/of/libvirt/src
./virsh <BLAH>

6. To enable QMP support, before you build edit '''src/qemu/qemu_conf.c''' and find:

#if 0
if (version >= 13000)
flags |= QEMUD_CMD_FLAG_MONITOR_JSON;
#endif

'''NOTE:''' If enabled libvirt will use QMP as default monitor.

7. Change that to an '#if 1', and change the version to 12000 so it detects your GIT build of QEMU

=== By hand ===

1. Start QMP on a TCP socket, so that telnet can be used

qemu [...] -qmp tcp:localhost:4444,server

2. Now, run telnet

telnet localhost 4444

3. You should see the following prompt

{"QMP": {"capabilities": []}}

4. Now you can issue commands. To get a list of QMP supported commands, run ''query-commands''

{ "execute": "query-commands" }

'''NOTE:''' all "info" commands are available under QMP as "query-", for example "info vnc" is "query-vnc".

The output of ''query-commands'' is a JSON array of objects, each with a 'name' key, which has the name of the supported command. QMP doesn't have user documentation yet, this means that, to find out which arguments a command accepts or what's its output, you will have to either check the [http://git.savannah.gnu.org/cgit/qemu.git/tree/qemu-monitor.hx qemu-monitor.hx] file and/or the function which implements the command.

Yes, it's that low-level.

=== qmp-shell script ===

This script is available under the [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP QMP] directory in QEMU's source-tree. It automates a bit the testing work, as it can construct commands.

1. Start QMP on a unix socket, like:

qemu [...] -qmp unix:./qmp-sock,server

2. Run the script

qmp-shell ./qmp-sock

3. You should get the following prompt

(QEMU)

4. Now you can run commands. For example, let's change the VNC password:

(QEMU) change device=vnc target=password arg='1234'

So, it's needed to name the arguments and the script is not very smart. Again, to find out what arguments a command accepts, you have to either check the [http://git.savannah.gnu.org/cgit/qemu.git/tree/qemu-monitor.hx qemu-monitor.hx] file and/or the function which implements the command.

Have fun!

== History ==

This was the fourth proposal for a Monitor 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

MonitorProtocol

2010-03-15T16:34:31Z

Dorileo:

= QEMU Monitor Protocol =

The QEMU Monitor Protocol (QMP) allows applications to communicate with QEMU's Monitor.

QMP is [http://www.json.org/ JSON]-based, its main features are:

* Lightweight, text-based, easy to parse data format
* Asynchronous events support

The [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP/README README] file explains how to use it and its full specification can be found [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP/qmp-spec.txt here].

== General Status ==

A '''preview''' version of QMP is available in QEMU version 0.12.

However, QMP is still under development being considered unstable and incomplete. For more information about converted handlers, please check [[#Conversion Status]].

== Examples ==

In the following examples, 'C' stands for 'Client' and 'S' stands for 'Server'.

=== Server Greeting ===

S: {"QMP": {"capabilities": []}}

=== Query version ===

C: { "execute": "query-version" }
S: {"return": {"qemu": "0.11.50", "package": ""}}

=== Eject a device ===

C: { "execute": "eject", "arguments": { "device": "ide1-cd0" } }
S: {"return": {}}

== Development ==

Primary contact is [mailto:lcapitulino@redhat.com Luiz Capitulino], but all QMP-related discussions happen on the [http://lists.nongnu.org/mailman/listinfo/qemu-devel qemu-devel] mailing list.

Next features, hot fixes and other patches are stored in the QMP unstable repository:

http://repo.or.cz/w/qemu/qmp-unstable.git

'''NOTE''': all branches in this repository are constantly ''rebased'' (master inclusive).

== TODO ==

* Convert all remaining commands
* High-level protocol documentation
* High-level internal documentation
* Improve internal API, currently it's too [http://lists.gnu.org/archive/html/qemu-devel/2009-12/msg02537.html low-level]
* Better QObjects and QMP debug support
* Array-based Monitor's command table
* Libqmp

== Conversion Status ==

'''UPDATED''': 2009-12-16

{| border="1"
|
|Command
|Info
|-
|Handlers
|62
|36
|-
|Converted
|19
|15
|-
|Percentage
|30%
|41%
|-
|}

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: merged, but error handling is incomplete

'''NOTE:''' Handlers used by [http://libvirt.org Libvirt] are marked with yellow.

==== Command handlers ====

{| border="1"
|'''Handler name'''
|'''Status'''
|'''Version'''
|'''Comments'''
|-
|do_acl_add()
|
|
|
|-
|do_acl_policy()
|
|
|
|-
|do_acl_remove()
|
|
|
|-
|do_acl_reset()
|
|
|
|-
|do_acl_show()
|
|
|
|- style="background-color:yellow;"
|do_balloon()
|merged
|0.12
|
|-
|do_block_set_passwd()
|merged
|0.12
|
|-
|do_boot_set()
|
|
|
|- style="background-color:yellow;"
|do_change()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_closefd()
|merged
|0.12
|
|-
|do_commit()
|
|
|
|- style="background-color:yellow;"
|do_cont()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_cpu_set()
|merged
|0.12.50
|
|-
|do_delvm()
|
|
|
|- style="background-color:yellow;"
|do_device_add()
|
|
|
|- style="background-color:yellow;"
|do_device_del()
|
|
|
|- style="background-color:yellow;"
|do_eject()
|merged
|0.12
|
|-
|do_gdbserver()
|
|
|
|- style="background-color:yellow;"
|do_getfd()
|merged
|0.12
|
|-
|do_help_cmd()
|
|
|
|-
|do_info()
|merged
|0.12
|as 'query-' commands
|-
|do_inject_mce()
|
|
|
|-
|do_inject_nmi()
|
|
|
|-
|do_ioport_read()
|
|
|
|-
|do_ioport_write()
|
|
|
|-
|do_loadvm()
|
|
|
|-
|do_log()
|
|
|
|-
|do_logfile()
|
|
|
|-
|do_memory_dump()
|
|
|
|- style="background-color:yellow;"
|do_memory_save()
|merged
|0.12.50
|
|- style="background-color:yellow;"
|do_migrate()
|partial
|0.12
|
|- style="background-color:yellow;"
|do_migrate_cancel()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_migrate_set_downtime()
|merged
|0.12.50
|
|- style="background-color:yellow;"
|do_migrate_set_speed()
|merged
|0.12.50
|
|-
|do_mouse_button()
|
|
|
|-
|do_mouse_move()
|
|
|
|-
|do_mouse_set()
|
|
|
|- style="background-color:yellow;"
|do_pci_device_hot_remove()
|partial
|0.12
|legacy, use device_del instead
|-
|do_physical_memory_dump()
|
|
|
|- style="background-color:yellow;"
|do_physical_memory_save()
|merged
|0.12.50
|
|-
|do_print()
|
|
|
|-
|do_quit()
|merged
|0.12
|
|-
|do_savevm()
|
|
|
|-
|do_screen_dump()
|
|
|
|-
|do_sendkey()
|
|
|
|- style="background-color:yellow;"
|do_set_link()
|
|
|
|-
|do_singlestep()
|
|
|
|- style="background-color:yellow;"
|do_stop()
|merged
|0.12
|
|-
|do_stop_capture()
|
|
|
|-
|do_sum()
|
|
|
|- style="background-color:yellow;"
|do_system_powerdown()
|merged
|0.12
|
|-
|do_system_reset()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_usb_add()
|
|
|legacy, use device_add instead
|- style="background-color:yellow;"
|do_usb_del()
|
|
|legacy, use device_del instead
|-
|do_watchdog_action()
|
|
|
|-
|do_wav_capture()
|
|
|
|- style="background-color:yellow;"
|drive_hot_add()
|
|
|
|- style="background-color:yellow;"
|net_host_device_add()
|
|
|consider do_netdev_add() instead
|- style="background-color:yellow;"
|net_host_device_remove()
|
|
|consider do_netdev_del() instead
|-
|net_slirp_hostfwd_add()
|
|
|
|-
|net_slirp_hostfwd_remove()
|
|
|
|- style="background-color:yellow;"
|pci_device_hot_add()
|partial
|0.12
|legacy, use device_add instead
|-
|do_chardev_add()
|
|
|to be created
|-
|do_chardev_del()
|
|
|to be created
|-
|do_blockdev_add()
|
|
|to be created
|-
|do_blockdev_del()
|
|
|to be created
|-
|do_netdev_add()
|
|
|to be created
|-
|do_netdev_del()
|
|
|to be created
|-
|}

==== Info handlers ====

{| border="1"
|'''Handler name'''
|'''Status'''
|'''Version'''
|'''Comments'''
|- style="background-color:yellow;"
|bdrv_info()
|merged
|0.12
|
|- style="background-color:yellow;"
|bdrv_info_stats()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_info_balloon()
|merged
|0.12
|
|-
|do_info_capture()
|
|
|
|- style="background-color:yellow;"
|do_info_cpus()
|merged
|0.12
|
|-
|do_info_cpu_stats()
|
|
|
|-
|do_info_history()
|
|
|
|-
|do_info_hpet()
|merged
|0.12
|
|-
|do_info_jit()
|
|
|
|-
|do_info_kvm()
|merged
|0.12
|
|-
|do_info_mice()
|merged
|0.12
|
|- style="background-color:yellow;"
|do_info_migrate()
|merged
|0.12
|
|-
|do_info_name()
|merged
|0.12
|
|-
|do_info_network()
|
|
|
|-
|do_info_numa()
|
|
|
|-
|do_info_profile()
|
|
|
|-
|do_info_qdm()
|
|
|
|-
|do_info_qtree()
|
|
|
|-
|do_info_registers()
|
|
|
|-
|do_info_roms()
|
|
|
|-
|do_info_snapshots()
|
|
|
|-
|do_info_status()
|merged
|0.12
|
|-
|do_info_usernet()
|
|
|
|-
|do_info_uuid()
|merged
|0.12
|
|-
|do_info_version()
|merged
|0.12
|
|-
|do_info_vnc()
|merged
|0.12
|
|-
|irq_info()
|
|
|
|-
|mem_info()
|
|
|
|- style="background-color:yellow;"
|pci_info()
|
|
|
|-
|pcmcia_info()
|
|
|
|-
|pic_info()
|
|
|
|-
|qemu_chr_info()
|merged
|0.12
|
|-
|tlb_info()
|
|
|
|-
|usb_host_info()
|
|
|
|- style="background-color:yellow;"
|usb_info()
|
|
|
|-
|}

== Testing ==

Unfortunately, there is no automated tool to test QMP correctness yet. Probably, the right thing to do is to integrate with [http://www.linux-kvm.org/page/KVM-Autotest kvm-autotest] but we still have to think how this should be done.

Meanwhile, QMP testing is a low-level procedure which requires knowledge about the protocol and its implementation, so the first thing to do is to read the [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP/README README] and [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP/qmp-spec.txt spec] files.

This section describes two ways of testing QMP:

* By hand (difficult, only worth it if you're chasing a specific bug)
* Using qmp-shell script (automates part of the job)

'''TODO''': libvirt should be far easier, describe it!

=== Libvirt ===

1. Install [http://lloyd.github.com/yajl yajl-devel] before running 'autogen.sh'. Make sure the final summary of autogen.sh tells you that it found the yajl library. If you`re running Fedora 12(or above) just yum install yajl-devel.

2. From a fresh checkout of [http://libvirt.org/git/?p=libvirt.git;a=summary GIT master] run the following:

./autogen.sh --system --enable-compile-warnings=error

'''NOTE:''' The '--system' flag is a shortcut for compiling with the --prefix and other directories matching a system RPM build.

3. Run 'make' to build. There is no need to 'make install' anything
especially since that would overwrite your RPM based install

4. As root simply stop the current daemon & start the one you built

/etc/init.d/libvirtd stop
$HOME/your/git/checkout/of/libvirt/daemon/libvirtd

5. As root you can use the newly built virsh too

cd $HOME/your/git/checkout/of/libvirt/src
./virsh <BLAH>

6. To enable QMP support, before you build edit '''src/qemu/qemu_conf.c''' and find:

#if 0
if (version >= 13000)
flags |= QEMUD_CMD_FLAG_MONITOR_JSON;
#endif

'''NOTE:''' If enabled libvirt will use QMP as default monitor.

7. Change that to an '#if 1', and change the version to 12000 so it detects your GIT build of QEMU

=== By hand ===

1. Start QMP on a TCP socket, so that telnet can be used

qemu [...] -qmp tcp:localhost:4444,server

2. Now, run telnet

telnet localhost 4444

3. You should see the following prompt

{"QMP": {"capabilities": []}}

4. Now you can issue commands. To get a list of QMP supported commands, run ''query-commands''

{ "execute": "query-commands" }

'''NOTE:''' all "info" commands are available under QMP as "query-", for example "info vnc" is "query-vnc".

The output of ''query-commands'' is a JSON array of objects, each with a 'name' key, which has the name of the supported command. QMP doesn't have user documentation yet, this means that, to find out which arguments a command accepts or what's its output, you will have to either check the [http://git.savannah.gnu.org/cgit/qemu.git/tree/qemu-monitor.hx qemu-monitor.hx] file and/or the function which implements the command.

Yes, it's that low-level.

=== qmp-shell script ===

This script is available under the [http://git.savannah.gnu.org/cgit/qemu.git/tree/QMP QMP] directory in QEMU's source-tree. It automates a bit the testing work, as it can construct commands.

1. Start QMP on a unix socket, like:

qemu [...] -qmp unix:./qmp-sock,server

2. Run the script

qmp-shell ./qmp-sock

3. You should get the following prompt

(QEMU)

4. Now you can run commands. For example, let's change the VNC password:

(QEMU) change device=vnc target=password arg='1234'

So, it's needed to name the arguments and the script is not very smart. Again, to find out what arguments a command accepts, you have to either check the [http://git.savannah.gnu.org/cgit/qemu.git/tree/qemu-monitor.hx qemu-monitor.hx] file and/or the function which implements the command.

Have fun!

== History ==

This was the fourth proposal for a Monitor 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