From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MOXRg-0002UJ-Lj for qemu-devel@nongnu.org; Wed, 08 Jul 2009 09:44:24 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MOXRb-0002P8-VU for qemu-devel@nongnu.org; Wed, 08 Jul 2009 09:44:24 -0400 Received: from [199.232.76.173] (port=42147 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MOXRb-0002Ou-N7 for qemu-devel@nongnu.org; Wed, 08 Jul 2009 09:44:19 -0400 Received: from qw-out-1920.google.com ([74.125.92.150]:25789) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MOXRb-0003DL-D4 for qemu-devel@nongnu.org; Wed, 08 Jul 2009 09:44:19 -0400 Received: by qw-out-1920.google.com with SMTP id 5so1920332qwc.4 for ; Wed, 08 Jul 2009 06:44:18 -0700 (PDT) Message-ID: <4A54A2B0.6050605@codemonkey.ws> Date: Wed, 08 Jul 2009 08:44:16 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 3/3 v2] Add a pc-0-10 machine type for compatibility with 0.10.x References: <1244821292.30522.56.camel@blaa> <4A327E4A.7010300@codemonkey.ws> <1244825303.26769.19.camel@blaa> <20090614095016.GA7560@redhat.com> <1245056916.6891.31.camel@blaa> <4A3613EC.6030608@redhat.com> <20090615103249.GB6351@redhat.com> <4A363012.8050409@redhat.com> <20090615114858.GG6351@redhat.com> <4A3636FA.1040609@redhat.com> <20090615124101.GH6351@redhat.com> <4A364381.401@redhat.com> <4A364401.6010500@codemonkey.ws> <4A3647FB.9010808@redhat.com> <4A364B53.9080007@codemonkey.ws> <4A364FE0.40204@redhat.com> <4A3651EB.3070204@codemonkey.ws> <4A36555A.4090303@redhat.com> <4A3659A0.3050108@codemonkey.ws> <4A366348.1030202@redhat.com> <1245083229.3222.103.camel@blaa> <4A368F12.2090504@codemonkey.ws> <1246964898.2836.38.camel@blaa> <1246964950.2836.39.camel@blaa> <1246964998.2836.40.camel@blaa> <1246965054.2836.41.camel@blaa> <4A5338FC.9030301@redhat.com> <1247049984.3270.52.camel@blaa> <1247050083.3270.54.camel@blaa> <4A54986D.301@redhat.com> In-Reply-To: <4A54986D.301@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: Mark McLoughlin , Avi Kivity , qemu-devel@nongnu.org Gerd Hoffmann wrote: > On 07/08/09 12:48, Mark McLoughlin wrote: >> Add a pc-0-10 machine type to allow a pc machine to be created with >> virtio block and console devices compatibility with qemu-0.10.x. > >> +enum { >> + COMPAT_DEFAULT = 0, >> + COMPAT_0_10, /* compatible with qemu 0.10.x */ >> +}; > > Hmm. Just digged in the virtio blk code. Noticed some ppc machines > have virtio block devices too. So linking it to a machine type looks > wrong to me. No, it's right. A machine type is nothing more than a default device tree. If we want to change what the default device tree is and wish to maintain compatibility, we need to introduce a new device tree so that the old one can be still accessed. So basically, if we had device config files, it would look like: /usr/share/qemu/configs/pc-0-10.dts /usr/share/qemu/configs/pc-0-11.dts /usr/share/qemu/configs/pc -> /usr/share/qemu/configs/pc-0-11.dts For other board types, they would also need to version their device trees too. > Another question: Is migrating from 0.11 in 0.10-compat mode to 0.10 > supposed to work? If so we make virtio-net better turn off msi then. If you mean live migration, no. However, live migration from 0.10 to 0.11 in 0.10-compat mode should work. But from the guest perspective, 0.10-compat mode should look identical to 0.10 which means we do want to turn off msi. Regards, Anthony Liguori > cheers, > Gerd > > >