On Mon, Feb 08, 2010 at 08:09:17PM +0100, Jan Kiszka wrote: > Sebastian Herbszt wrote: > > Jan Kiszka wrote: > >> Hi, > >> > >> Seabios seems to have some assumptions built in that break when -M isapc > >> is selected. Is this supposed to work or is isapc about to die? > > > > SeaBIOS doesn't POST if the F-segment is not writeable [1]. A possible, but > > IMO > > wrong fix was posted on the list [2]. > > > > [1] http://lists.gnu.org/archive/html/qemu-devel/2009-11/msg01188.html > > [2] http://lists.gnu.org/archive/html/qemu-devel/2009-12/msg00445.html > > > > Indeed, [2] makes it work again. > > But taking away IO_MEM_ROM really looks like a lazy workaround. I don't > know how much Seabios needs to write - can't it use normal RAM for this?
Handling a read-only f-segment in SeaBIOS would result in significant code complexity, and some features (like smbios) couldn't be made to work at all. I believe it would be far simpler to add a mechanism for locking/unlocking the f-segment in non-pci mode than it would be to make seabios work with a read-only f-segment. Finally, in the normal pci enabled case, both SeaBIOS and bochs bios will lock the f-segment regardless of how it starts. So, the patch at [1] is pretty harmless and it leads to an overall simplification. -Kevin
