On Tue, Oct 12, 2010 at 09:33:16AM -0700, H. Peter Anvin wrote: > On 10/12/2010 01:01 AM, Gleb Natapov wrote: > > On Mon, Oct 11, 2010 at 02:15:26PM -0700, H. Peter Anvin wrote: > >>> I don't disagree. > >>> > >>> I think the best thing to do is to let SeaBIOS create a boot order table > >>> that contains descriptive information and then advertise that to QEMU. > >>> > >>> QEMU can then try to associate the list of bootable devices with it's > >>> own set of devices and select a preferred order that it can then give > >>> back to SeaBIOS. SeaBIOS can then present that list to the user for > >>> additional refinement. > >> > >> Really, this kind of comes down to having a data structure that anything > >> (Qemu, SeaBIOS and if needed the guest OS) can read and modify as needed. > >> > > But then QEMU and seabios will have to have shared storage they can > > both write too. And this shared storage is part of VM now so you need > > to carry it around when you move your VM elsewhere. > > > > Yes, and it's part of real hardware, too. It's usually called "the > CMOS", short for CMOS RAM. > On real hardware it is not shared between HW and bios. It is written/read only by BIOS. In qemu it is not persistent and generated for each qemu invocation. Previously it was used to pass config params from qemu to a bios (and some legacy params are still passed that way), but we moved to better interface for that (firmware config).
-- Gleb.