QMP: Update README file

Drop unneeded info, fix some of the examples and rename QEMU Monitor
Protocol to QEMU Machine Protocol.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Luiz Capitulino 2013-09-10 17:15:49 -04:00
parent 7537fe0487
commit 52bbff77c4

View File

@ -1,13 +1,13 @@
QEMU Monitor Protocol
QEMU Machine Protocol
=====================
Introduction
-------------
------------
The QEMU Monitor Protocol (QMP) allows applications to communicate with
QEMU's Monitor.
The QEMU Machine Protocol (QMP) allows applications to operate a
QEMU instance.
QMP is JSON[1] based and currently has the following features:
QMP is JSON[1] based and features the following:
- Lightweight, text-based, easy to parse data format
- Asynchronous messages support (ie. events)
@ -15,37 +15,28 @@ QMP is JSON[1] based and currently has the following features:
For detailed information on QMP's usage, please, refer to the following files:
o qmp-spec.txt QEMU Monitor Protocol current specification
o qmp-spec.txt QEMU Machine Protocol current specification
o qmp-commands.txt QMP supported commands (auto-generated at build-time)
o qmp-events.txt List of available asynchronous events
There is also a simple Python script called 'qmp-shell' available.
IMPORTANT: It's strongly recommended to read the 'Stability Considerations'
section in the qmp-commands.txt file before making any serious use of QMP.
[1] http://www.json.org
Usage
-----
To enable QMP, you need a QEMU monitor instance in "control mode". There are
two ways of doing this.
You can use the -qmp option to enable QMP. For example, the following
makes QMP available on localhost port 4444:
The simplest one is using the '-qmp' command-line option. The following
example makes QMP available on localhost port 4444:
$ qemu [...] -qmp tcp:localhost:4444,server,nowait
$ qemu [...] -qmp tcp:localhost:4444,server
However, for more flexibility and to make use of more options, the -mon
command-line option should be used. For instance, the following example
creates one HMP instance (human monitor) on stdio and one QMP instance
on localhost port 4444:
However, in order to have more complex combinations, like multiple monitors,
the '-mon' command-line option should be used along with the '-chardev' one.
For instance, the following example creates one user monitor on stdio and one
QMP monitor on localhost port 4444.
$ qemu [...] -chardev stdio,id=mon0 -mon chardev=mon0,mode=readline \
-chardev socket,id=mon1,host=localhost,port=4444,server \
-mon chardev=mon1,mode=control
$ qemu [...] -chardev stdio,id=mon0 -mon chardev=mon0,mode=readline \
-chardev socket,id=mon1,host=localhost,port=4444,server,nowait \
-mon chardev=mon1,mode=control,pretty=on
Please, refer to QEMU's manpage for more information.
@ -58,31 +49,39 @@ $ telnet localhost 4444
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
{"QMP": {"version": {"qemu": {"micro": 50, "minor": 13, "major": 0}, "package": ""}, "capabilities": []}}
{
"QMP": {
"version": {
"qemu": {
"micro": 50,
"minor": 6,
"major": 1
},
"package": ""
},
"capabilities": [
]
}
}
{ "execute": "qmp_capabilities" }
{"return": {}}
{ "execute": "query-version" }
{"return": {"qemu": {"micro": 50, "minor": 13, "major": 0}, "package": ""}}
{
"return": {
}
}
Development Process
-------------------
{ "execute": "query-status" }
{
"return": {
"status": "prelaunch",
"singlestep": false,
"running": false
}
}
When changing QMP's interface (by adding new commands, events or modifying
existing ones) it's mandatory to update the relevant documentation, which is
one (or more) of the files listed in the 'Introduction' section*.
Please, refer to the qapi-schema.json file for a complete command reference.
Also, it's strongly recommended to send the documentation patch first, before
doing any code change. This is so because:
1. Avoids the code dictating the interface
2. Review can improve your interface. Letting that happen before
you implement it can save you work.
* The qmp-commands.txt file is generated from the qmp-commands.hx one, which
is the file that should be edited.
Homepage
--------
QMP wiki page
-------------
http://wiki.qemu.org/QMP