target-arm/cpu.h: Make cpu_init("nonexistent cpu") return NULL

[qemu.git] / QMP / README

diff --git a/QMP/README b/QMP/README
index 50c31f20c91bf9c2b9cdb036e8a5e9f64158d689..c95a08c23416d3459b765ea477a3767087dc3ce9 100644 (file)
--- a/QMP/README
+++ b/QMP/README
@@ -4,48 +4,85 @@
 Introduction
 -------------
 
-The QEMU Monitor Protocol (QMP) is a JSON[1] based protocol for QEMU.
+The QEMU Monitor Protocol (QMP) allows applications to communicate with
+QEMU's Monitor.
 
-By using it applications can control QEMU in reliable and "parseable" way,
-QMP also provides asynchronous events support.
+QMP is JSON[1] based and currently has the following features:
 
-For more information, please, refer to the following files:
+- Lightweight, text-based, easy to parse data format
+- Asynchronous messages support (ie. events)
+- Capabilities Negotiation
 
-o qmp-spec.txt    QEMU Monitor Protocol current draft specification
-o qmp-events.txt  List of available asynchronous events
+For detailed information on QMP's usage, please, refer to the following files:
 
-There are also two simple Python scripts available:
+o qmp-spec.txt      QEMU Monitor 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.
 
-o qmp-shell       A shell
-o vm-info         Show some informations about the Virtal Machine
 
 [1] http://www.json.org
 
 Usage
 -----
 
-To enable QMP, QEMU has to be started in "control mode". This is done
-by passing the flag "control" to the "-monitor" command-line option.
+To enable QMP, you need a QEMU monitor instance in "control mode". There are
+two ways of doing this.
+
+The simplest one is using the '-qmp' command-line option. The following
+example makes QMP available on localhost port 4444:
 
-For example:
+  $ qemu [...] -qmp tcp:localhost:4444,server
 
-$ qemu [...] -monitor control,tcp:localhost:4444,server
+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.
 
-Will start QEMU in control mode, waiting for a client TCP connection
-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
 
-To manually test it you can connect with telnet and issue commands:
+Please, refer to QEMU's manpage for more information.
+
+Simple Testing
+--------------
+
+To manually test QMP one can connect with telnet and issue commands by hand:
 
 $ telnet localhost 4444
-Trying ::1...
+Trying 127.0.0.1...
 Connected to localhost.
 Escape character is '^]'.
-{"QMP": {"capabilities": []}}
+{"QMP": {"version": {"qemu": {"micro": 50, "minor": 13, "major": 0}, "package": ""}, "capabilities": []}}
+{ "execute": "qmp_capabilities" }
+{"return": {}}
 { "execute": "query-version" }
-{"return": "0.11.50"}
+{"return": {"qemu": {"micro": 50, "minor": 13, "major": 0}, "package": ""}}
+
+Development Process
+-------------------
+
+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*.
+
+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.
 
-Contact
--------
+Homepage
+--------
 
-http://www.linux-kvm.org/page/MonitorProtocol
-Luiz Fernando N. Capitulino <[email protected]>
+http://wiki.qemu.org/QMP