From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34762) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y8tRu-0005Q7-92 for qemu-devel@nongnu.org; Wed, 07 Jan 2015 11:27:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y8tRn-0004vj-FB for qemu-devel@nongnu.org; Wed, 07 Jan 2015 11:27:10 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48432) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y8tRn-0004uv-7j for qemu-devel@nongnu.org; Wed, 07 Jan 2015 11:27:03 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t07GR1oX027102 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Wed, 7 Jan 2015 11:27:02 -0500 Date: Wed, 7 Jan 2015 16:26:57 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20150107162657.GB8871@work-vm> References: <1418148909-19870-1-git-send-email-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1418148909-19870-1-git-send-email-dgilbert@redhat.com> Subject: Re: [Qemu-devel] [PATCH 0/2] ATAPI migration fix/hack List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: kwolf@redhat.com, stefanha@redhat.com Cc: pbonzini@redhat.com, jsnow@redhat.com, qemu-devel@nongnu.org Oops, forgot to include Kevin and Stefan on cc for this. Dave * Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: > From: "Dr. David Alan Gilbert" > > This pair of patches fixes a problem where IDE/ATAPI cdrom > reads get lost/corrupted over migration. > > The first of the patches (restore atapi_dma flag) is > a simple fix that I think is safe; it no longer causes > corruption in the case we saw, but does still trigger > a long timeout. > > The second is a hack; it throws a medium error causing > the guest to retry the command in the case where migration > happens just between the IDE/ATAPI command being submitted > and the bmdma being finished. This recovers a lot > faster than the timeout. > > Only tried on Linux guests so far; I think it might be possible > to replace both of these by reparsing the command buffer for > ATAPI; I'm just not confident I know when that's safe to do, > and I wanted to see how disgusted people were by the 2nd hack. > > Dave > > Dr. David Alan Gilbert (2): > Restore atapi_dma flag across migration > atapi migration: Throw recoverable error to avoid recovery > > hw/ide/atapi.c | 17 +++++++++++++++++ > hw/ide/core.c | 1 + > hw/ide/internal.h | 2 ++ > hw/ide/pci.c | 11 +++++++++++ > 4 files changed, 31 insertions(+) > > -- > 2.1.0 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK