From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NLfuK-0002vM-O4 for qemu-devel@nongnu.org; Fri, 18 Dec 2009 11:42:24 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NLfuG-0002tU-T8 for qemu-devel@nongnu.org; Fri, 18 Dec 2009 11:42:24 -0500 Received: from [199.232.76.173] (port=55511 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NLfuG-0002tL-Lw for qemu-devel@nongnu.org; Fri, 18 Dec 2009 11:42:20 -0500 Received: from mail-yw0-f171.google.com ([209.85.211.171]:43004) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NLfuG-0005Od-CG for qemu-devel@nongnu.org; Fri, 18 Dec 2009 11:42:20 -0500 Received: by ywh1 with SMTP id 1so3072014ywh.18 for ; Fri, 18 Dec 2009 08:42:19 -0800 (PST) Message-ID: <4B2BB0E8.7060907@codemonkey.ws> Date: Fri, 18 Dec 2009 10:42:16 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <1261134074-11795-1-git-send-email-kraxel@redhat.com> <4B2B9340.1020001@codemonkey.ws> <4B2BAF25.2070800@redhat.com> In-Reply-To: <4B2BAF25.2070800@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [SeaBIOS] [PATCH 0/8] option rom loading overhaul. List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: qemu-devel@nongnu.org Gerd Hoffmann wrote: > On 12/18/09 15:35, Anthony Liguori wrote: > >> I know this series carries a good bit of risk but I'd like to bring it >> in 0.12.0. Because this has a guest visible change to the PCI devices, >> we cannot carry it in stable-0.12 post release and I think the >> functionality it brings it's very important. > > The guest visible change automatically raises the question: > Do we need to do something for -M pc-0.11? Like loading the pci roms > via fw_cfg too so the guest doesn't see the new pci rom bar? Yes, we do. We can fix that problem as a stable-0.12 update though. Right now, migration with pc-0.11 is broken in other areas too. > Oh, and while thinking about compatibility issues: What about > migration? I think we have to save rom_offset in case $pcidevice has > a rom bar, otherwise your roms are gone after migration. Which you > wouldn't notice until reboot though. It's really unclear to me the best way to handle live migration. The rom_offset is not enough because unfortunately it's not stable after invocations of qemu. I think we're going to have to actually save the some contents with the PCIDevices. For 0.13, we need to change the way that we migrate memory to fix this problem properly. > Is 0.11 -> 0.12 migration supposed to work? That could become quite > nasty too. But maybe that is impossible anyway due to the switch to > seabios? In theory, it should work. SeaBIOS should not be a guest visible change because the guest should not depend on what BIOS we're using. While it's probably debatable about whether that's true, what's really important is whether it's actually functional. IOW, can we migrate, reboot Windows, and not have Windows freak out about the underlying machine changing. If we can make the migration work, I suspect it won't be until 0.12.3 or 0.12.4. Regards, Anthony Liguori