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[Qemu-devel] Re: Seabios dislikes -M isapc
From: |
Kevin O'Connor |
Subject: |
[Qemu-devel] Re: Seabios dislikes -M isapc |
Date: |
Mon, 8 Feb 2010 19:51:10 -0500 |
User-agent: |
Mutt/1.5.20 (2009-08-17) |
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
- [Qemu-devel] Seabios dislikes -M isapc, Jan Kiszka, 2010/02/08
- Re: [Qemu-devel] Seabios dislikes -M isapc, Andreas Färber, 2010/02/09
- Re: [Qemu-devel] Seabios dislikes -M isapc, Anthony Liguori, 2010/02/09
- Re: [Qemu-devel] Seabios dislikes -M isapc, Natalia Portillo, 2010/02/09
- Re: [Qemu-devel] Seabios dislikes -M isapc, Anthony Liguori, 2010/02/09
- Re: [Qemu-devel] Seabios dislikes -M isapc, Natalia Portillo, 2010/02/09
- Re: [Qemu-devel] Seabios dislikes -M isapc, Anthony Liguori, 2010/02/09
- Re: [Qemu-devel] Seabios dislikes -M isapc, malc, 2010/02/09
- Re: [Qemu-devel] Seabios dislikes -M isapc, Aurelien Jarno, 2010/02/09
- Re: [Qemu-devel] Seabios dislikes -M isapc, malc, 2010/02/09