From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35250) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z5BzI-0004NG-8N for qemu-devel@nongnu.org; Wed, 17 Jun 2015 07:58:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z5BzH-0006hv-51 for qemu-devel@nongnu.org; Wed, 17 Jun 2015 07:58:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42742) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z5BzH-0006hZ-0H for qemu-devel@nongnu.org; Wed, 17 Jun 2015 07:58:35 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 7E64236B38C for ; Wed, 17 Jun 2015 11:58:34 +0000 (UTC) Date: Wed, 17 Jun 2015 13:58:31 +0200 From: "Michael S. Tsirkin" Message-ID: <20150617135716-mutt-send-email-mst@redhat.com> 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> <55816039.3080103@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55816039.3080103@redhat.com> Subject: Re: [Qemu-devel] [PATCH] Migration compatibility for serial List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: amit.shah@redhat.com, qemu-devel@nongnu.org, "Dr. David Alan Gilbert (git)" , quintela@redhat.com On Wed, Jun 17, 2015 at 01:55:37PM +0200, Paolo Bonzini wrote: > > > 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 I just tried, set prog_if to different values, sure it failed. Here's another one, at random: Author: Michael S. Tsirkin Date: Thu Feb 14 19:11:27 2013 +0200 e1000: unbreak the guest network migration to 1.3 QEMU 1.3 does not emulate the link auto negotiation, so if migrate to a 1.3 machine during link auto negotiation, the guest link will be set to down. Fix this by just disabling auto negotiation for 1.3 and older. Signed-off-by: Michael S. Tsirkin -- MST