From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34016) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z5BwY-0001ay-Qv for qemu-devel@nongnu.org; Wed, 17 Jun 2015 07:55:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z5BwU-0005Kg-KV for qemu-devel@nongnu.org; Wed, 17 Jun 2015 07:55:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34213) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z5BwU-0005KZ-FA for qemu-devel@nongnu.org; Wed, 17 Jun 2015 07:55:42 -0400 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 (Postfix) with ESMTPS id 0FFD835C115 for ; Wed, 17 Jun 2015 11:55:42 +0000 (UTC) Message-ID: <55816039.3080103@redhat.com> Date: Wed, 17 Jun 2015 13:55:37 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1434480849-23093-1-git-send-email-dgilbert@redhat.com> <558124BD.8010807@redhat.com> <20150617094829-mutt-send-email-mst@redhat.com> <55812BC4.3000600@redhat.com> <20150617121148-mutt-send-email-mst@redhat.com> <55815B06.5030508@redhat.com> <20150617133816-mutt-send-email-mst@redhat.com> <55815FA7.3070205@redhat.com> <20150617135340-mutt-send-email-mst@redhat.com> In-Reply-To: <20150617135340-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] Migration compatibility for serial List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: amit.shah@redhat.com, qemu-devel@nongnu.org, "Dr. David Alan Gilbert (git)" , quintela@redhat.com On 17/06/2015 13:54, Michael S. Tsirkin wrote: >>> > >> > Where, in the specific case of migration? > > > Just look at hour compat flags. > > > > > > For example (intentionally using serial here): > > > {\ > > > .driver = "pci-serial",\ > > > .property = "prog_if",\ > > > .value = stringify(0),\ > > > },\ > > > {\ > > > .driver = "pci-serial-2x",\ > > > .property = "prog_if",\ > > > .value = stringify(0),\ > > > },\ > > > {\ > > > .driver = "pci-serial-4x",\ > > > .property = "prog_if",\ > > > .value = stringify(0),\ > > > },\ > > > > > > apparently some clients check the specific prog if > > > value, completely breaking if the value was incorrect. > > > So we fixed it for new machine types but not old ones. > > > > That has nothing to do with migration. > > If you change prog_if migration fails. No, it doesn't. The guest misbehaves maybe, but the migration format is not affected. Paolo