From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39114) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8scq-0003NU-IH for qemu-devel@nongnu.org; Mon, 12 Aug 2013 09:57:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V8sch-0003Rt-H0 for qemu-devel@nongnu.org; Mon, 12 Aug 2013 09:57:36 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:42865) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8sch-0003Rg-B1 for qemu-devel@nongnu.org; Mon, 12 Aug 2013 09:57:27 -0400 Received: from /spool/local by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 12 Aug 2013 07:57:26 -0600 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id E45A71FF0051 for ; Mon, 12 Aug 2013 07:51:57 -0600 (MDT) Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r7CDvJdb193588 for ; Mon, 12 Aug 2013 07:57:21 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r7CDvJWa029930 for ; Mon, 12 Aug 2013 07:57:19 -0600 From: Anthony Liguori In-Reply-To: <1376295742-28528-1-git-send-email-mst@redhat.com> References: <1376295742-28528-1-git-send-email-mst@redhat.com> Date: Mon, 12 Aug 2013 08:57:11 -0500 Message-ID: <874navhv0o.fsf@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: Re: [Qemu-devel] [PATCH for-1.6 0/2] future proof rom loading for cross versiom migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" , qemu-devel@nongnu.org Cc: pbonzini@redhat.com, Laszlo Ersek , Gerd Hoffmann "Michael S. Tsirkin" writes: > ROM files that are put in FW CFG are copied to guest ram, by BIOS, but > they are not backed by RAM so they don't get migrated. > > Each time we'll change at least two bytes in such a ROM this will break > cross-version migration: since we can migrate after BIOS has read the first > byte but before it has read the second one, getting an inconsistent state. > > This patchset makes QEMU future-proof against such changes. > > Naturally, this only helps for -M 1.6 and up, older machine types > will still have the cross-version migration bug. > > I think this should be applied for 1.6, this way we won't > have this problem from 1.7 and on. This is not for 1.6. It's far too late to make a change like this. Regards, Anthony Liguori > > Michael S. Tsirkin (2): > memory: export target page size > loader: put FW CFG ROM files into RAM > > exec.c | 2 ++ > hw/core/loader.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++--- > hw/i386/pc_piix.c | 2 ++ > hw/i386/pc_q35.c | 2 ++ > include/exec/memory.h | 2 ++ > include/hw/loader.h | 1 + > 6 files changed, 60 insertions(+), 3 deletions(-) > > -- > MST