From patchwork Thu Jul 22 14:47:00 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luiz Capitulino X-Patchwork-Id: 59581 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 1FD62B70B9 for ; Fri, 23 Jul 2010 00:50:32 +1000 (EST) Received: from localhost ([127.0.0.1]:51539 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Obx65-0005D3-Kb for incoming@patchwork.ozlabs.org; Thu, 22 Jul 2010 10:50:05 -0400 Received: from [140.186.70.92] (port=55386 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Obx3P-0003xL-ME for qemu-devel@nongnu.org; Thu, 22 Jul 2010 10:47:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Obx3O-0005KH-AI for qemu-devel@nongnu.org; Thu, 22 Jul 2010 10:47:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43343) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Obx3O-0005K6-1M for qemu-devel@nongnu.org; Thu, 22 Jul 2010 10:47:18 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o6MElHtS014326 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 22 Jul 2010 10:47:17 -0400 Received: from localhost (ovpn-113-87.phx2.redhat.com [10.3.113.87]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o6MElG3P011444; Thu, 22 Jul 2010 10:47:16 -0400 From: Luiz Capitulino To: qemu-devel@nongnu.org Date: Thu, 22 Jul 2010 11:47:00 -0300 Message-Id: <1279810021-11875-2-git-send-email-lcapitulino@redhat.com> In-Reply-To: <1279810021-11875-1-git-send-email-lcapitulino@redhat.com> References: <1279810021-11875-1-git-send-email-lcapitulino@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. Cc: armbru@redhat.com Subject: [Qemu-devel] [PATCH 1/2] QMP: Update README file X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org A number of changes I prefer to do in one shot: - Add a note about instability - Add multiple monitors example - Add 'Development Process' section - Small clarifications Signed-off-by: Luiz Capitulino --- QMP/README | 67 +++++++++++++++++++++++++++++++++++++++++------------------ 1 files changed, 46 insertions(+), 21 deletions(-) diff --git a/QMP/README b/QMP/README index 35a80c7..8618c6f 100644 --- a/QMP/README +++ b/QMP/README @@ -5,44 +5,52 @@ Introduction ------------- The QEMU Monitor Protocol (QMP) allows applications to communicate with -QEMU's Monitor. +QEMU's Monitor the right way. -QMP is JSON[1] based and has the following features: +QMP is JSON[1] based and currently has the following features: - Lightweight, text-based, easy to parse data format -- Asynchronous events support -- Stability +- Asynchronous messages support (ie. events) +- Capabilities Negotiation -For more information, please, refer to the following files: +However, QMP is still under heavy development and is considered an unstable +protocol. This means that its interface is going to have incompatible changes +between QEMU releases. We plan to make QMP stable as soon as possible. + +For detailed information on QMP's usage, please, refer to the following files: o qmp-spec.txt QEMU Monitor Protocol current specification -o qmp-commands.txt QMP supported commands +o qmp-commands.txt QMP supported commands (auto-generated at build-time) o qmp-events.txt List of available asynchronous events There are also two simple Python scripts available: -o qmp-shell A shell -o vm-info Show some information about the Virtual Machine +o qmp-shell A shell +o vm-info Show some information about the Virtual Machine [1] http://www.json.org Usage ----- -To enable QMP, QEMU has to be started in "control mode". There are -two ways of doing this, the simplest one is using the the '-qmp' -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 [...] -qmp tcp:localhost:4444,server +However, in order to have more complex combinations, like multiple monitors, +the '-mon' command-line option should be used 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 -It is also possible to use the '-mon' command-line option to have -more complex combinations. Please, refer to the QEMU's manpage for -more information. +Please, refer to QEMU's manpage for more information. Simple Testing -------------- @@ -59,8 +67,25 @@ Escape character is '^]'. { "execute": "query-version" } {"return": {"qemu": "0.12.50", "package": ""}} -Contact -------- +Development Process +------------------- + +When changing QMP's interface (by adding new commands, events or modifying +existing ones) it's mandatory to update the relevant documention, 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. It's very likely that the interface will change during review, updating + the code at the same time might be a big waste of time + +* The qmp-commands.txt file is generated from the qemu-monitor.hx one, which + is the file that should be edited. + +Homepage +-------- http://www.linux-kvm.org/page/MonitorProtocol -Luiz Fernando N. Capitulino