From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41736) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XgFW6-00030i-Jw for qemu-devel@nongnu.org; Mon, 20 Oct 2014 12:09:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XgFVx-0007nV-SR for qemu-devel@nongnu.org; Mon, 20 Oct 2014 12:09:06 -0400 Message-ID: <54453398.2060102@suse.de> Date: Mon, 20 Oct 2014 18:08:56 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1413788223-16235-1-git-send-email-mst@redhat.com> In-Reply-To: <1413788223-16235-1-git-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3] virtio-pci: fix migration for pci bus master List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" , qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org, Anthony Liguori On 20.10.14 08:58, Michael S. Tsirkin wrote: > Current support for bus master (clearing OK bit) together with the need to > support guests which do not enable PCI bus mastering, leads to extra state in > VIRTIO_PCI_FLAG_BUS_MASTER_BUG bit, which isn't robust in case of cross-version > migration for the case when guests use the device before setting DRIVER_OK. > > Rip out this code, and replace it: > - Modern QEMU doesn't need VIRTIO_PCI_FLAG_BUS_MASTER_BUG > so just drop it for latest machine type. > - For compat machine types, set PCI_COMMAND if DRIVER_OK > is set. > > As this is needed for 2.1 for both pc and ppc, move PC_COMPAT macros from pc.h > to a new common header. > > Reviewed-by: Greg Kurz > Tested-by: Greg Kurz > Signed-off-by: Michael S. Tsirkin > --- > > Alexander, could you pls ack me merging this? > Thanks! Have you tried whether this works with old kernel versions? We introduced the broken flag for very specific old kernel versions that got their flags wrong IIRC. Alex