From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48614) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cHCOx-0003kW-Ow for qemu-devel@nongnu.org; Wed, 14 Dec 2016 11:27:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cHCOs-0001lP-70 for qemu-devel@nongnu.org; Wed, 14 Dec 2016 11:27:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49998) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cHCOs-0001lB-0a for qemu-devel@nongnu.org; Wed, 14 Dec 2016 11:27:26 -0500 References: <20161214161958.2958-1-maxime.coquelin@redhat.com> <20161214172448.7619816e.cornelia.huck@de.ibm.com> From: Maxime Coquelin Message-ID: Date: Wed, 14 Dec 2016 17:27:21 +0100 MIME-Version: 1.0 In-Reply-To: <20161214172448.7619816e.cornelia.huck@de.ibm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] virtio-pci: Fix cross-version migration with older machines List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: mdroth@linux.vnet.ibm.com, stefanha@redhat.com, qemu-devel@nongnu.org, mst@redhat.com, marcel@redhat.com, "Dr . David Alan Gilbert" On 12/14/2016 05:24 PM, Cornelia Huck wrote: > On Wed, 14 Dec 2016 17:19:58 +0100 > Maxime Coquelin wrote: > >> > This patch fixes a cross-version migration regression introduced >> > by commit d1b4259f ("virtio-bus: Plug devices after features are >> > negotiated"). >> > >> > The problem is encountered when host's vhost backend does not support >> > VIRTIO_F_VERSION_1, and migration is initiated from a v2.7 or prior >> > QEMU version with virtio-pci modern capabilities enabled to a v2.8 >> > QEMU version. >> > >> > In this case, modern capabilities get exposed to the guest by the source, >> > whereas the target will detect version 1 is not supported so will only >> > expose legacy capabilities. >> > >> > The problem is fixed by introducing a new "x-modern-broken" property, > wrong property name... > Whoops... v3 on its way. Thanks, Maxime