From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56956) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8nn4-00048J-RF for qemu-devel@nongnu.org; Mon, 12 Aug 2013 04:47:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V8nmy-0006aO-Ni for qemu-devel@nongnu.org; Mon, 12 Aug 2013 04:47:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59156) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8nmy-0006aE-Gm for qemu-devel@nongnu.org; Mon, 12 Aug 2013 04:47:44 -0400 Date: Mon, 12 Aug 2013 11:49:19 +0300 From: "Michael S. Tsirkin" Message-ID: <1376295742-28528-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [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: qemu-devel@nongnu.org Cc: pbonzini@redhat.com, Anthony Liguori , Laszlo Ersek , Gerd Hoffmann 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. 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