From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NCwWq-0004JK-Lb for qemu-devel@nongnu.org; Tue, 24 Nov 2009 09:38:04 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NCwWm-0004Gg-OC for qemu-devel@nongnu.org; Tue, 24 Nov 2009 09:38:04 -0500 Received: from [199.232.76.173] (port=55773 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NCwWm-0004GY-IS for qemu-devel@nongnu.org; Tue, 24 Nov 2009 09:38:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43527) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NCwWm-0005Gx-4v for qemu-devel@nongnu.org; Tue, 24 Nov 2009 09:38:00 -0500 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 nAOEbxI4001230 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 24 Nov 2009 09:37:59 -0500 Date: Tue, 24 Nov 2009 16:35:23 +0200 From: "Michael S. Tsirkin" Message-ID: <20091124143523.GQ2405@redhat.com> References: <4B0952C9.9010803@redhat.com> <4B0A899F.2090805@codemonkey.ws> <20091124140517.GL2405@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juan Quintela Cc: dlaor@redhat.com, qemu-devel On Tue, Nov 24, 2009 at 03:20:47PM +0100, Juan Quintela wrote: > "Michael S. Tsirkin" wrote: > > >> But to really make it work, we need to take a list of each savevm format > >> change and put it here. Notice that several changes are needed: > >> - savevm infrastructure save functions don't know about version id > >> - devices don't know to "behave" as other version > >> - other things that I have probably missed > >> > >> Later, Juan. > > > > Why do you think this the right place for it, I wonder? > > This describes the machine, it does not seem to have > > anything to do with how we migrate it. > > Becase here is where we know that _this_ machine had _this_ versions of > each device. So? migration format is not related to what devices you have at all. It's how you save them. > And this is also the trivial part to describe: I want a > machine like the one in qemu-0.11. Yes, but there might be a ton of reasons to want a machine like the one in qemu 0.11. The need to migrate to old qemu is very rare, it is a completely separate decision one might take long after starting qemu, > What is more, it makes trivial for downstream to do things like: > - I define my machine, called foo-7.0, and the changes that it has over > any other machine. > > Later, Juan. Yes, machine desacription is a good thing. No, using it for things that have nothing to do with describing the machine is not a good thing. -- MST