From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:46110) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RbBVR-0003Oi-C2 for qemu-devel@nongnu.org; Thu, 15 Dec 2011 08:37:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RbBVI-00064T-84 for qemu-devel@nongnu.org; Thu, 15 Dec 2011 08:37:53 -0500 Received: from goliath.siemens.de ([192.35.17.28]:16829) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RbBVH-00063p-MC for qemu-devel@nongnu.org; Thu, 15 Dec 2011 08:37:44 -0500 Message-ID: <4EE9F822.4060601@siemens.com> Date: Thu, 15 Dec 2011 14:37:38 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <4EE9F3B8.6000407@siemens.com> <4EE9F734.7050305@redhat.com> In-Reply-To: <4EE9F734.7050305@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Transitioning from HMP to QMP for QEMU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Anthony Liguori , "libvir-list@redhat.com" , Stefan Hajnoczi , qemu-devel , Luiz Capitulino , Adam Litke On 2011-12-15 14:33, Kevin Wolf wrote: > Am 15.12.2011 14:18, schrieb Jan Kiszka: >> On 2011-12-15 14:02, Stefan Hajnoczi wrote: >>> What is the status of QEMU's transition from HMP to the QMP interface? >>> >>> My current understanding is that QEMU provides new HMP commands for >>> humans, but HMP is being phased out as an API. Management tools >>> should rely only on QMP for new commands. That would mean new HMP >>> commands are not guaranteed to produce backwards-compatible output >>> because tools are not supposed to parse the output. >>> >>> On the libvirt side, new QEMU features should only be supported via >>> the json monitor in the future (i.e. human monitor patches should not >>> be sent/merged)? Existing HMP commands will still need the human >>> monitor support in order to handle old QEMU versions gracefully, but >>> I'm thinking about new commands only. >>> >>> Does everyone agree on this? I think this is an important discussion >>> if we want our management interface to get better and more consistent >>> in the future. >> >> To phase out the classic HMP implementation, we need an internal >> HMP-over-JSON wrapper (with tab expansion etc.) so that virtual console >> and gdbstub monitors continue to benefit from new commands. Those >> interfaces will stay for a long time, I'm sure. > > I think we're not talking about dropping HMP here, only about how long > to support it as a stable API for management tools. I believe that we > have been in a transitional phase for long enough now that we can start > changing the output format of HMP commands without considering it an API > breakage. We are also talking about introducing new commands twice, which is a PITA. Also, peoples interest in HMP vs. QMP varies. Some focus on management usability, others on human-machine interaction. So you get suggestions for new command typical either for one, not for both. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux