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Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios
From: |
Kevin O'Connor |
Subject: |
Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios |
Date: |
Fri, 27 Nov 2009 00:39:54 -0500 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Thu, Nov 26, 2009 at 11:35:52PM +0100, Sebastian Herbszt wrote:
> Maybe the expansion rom bar can be used for pci devices like on real
> hardware. The bios will check it and load the rom itself instead of
> relying on qemu to do the job.
SeaBIOS can pull roms from pci space today. Long term, I would prefer
to see qemu use this.
> If a soft reset is requested with the goal of a transition from
> protected to real mode and the bios is reloaded, it should not do
> any harm because the internal device states are kept and the cmos
> still has the correct shutdown status code for the transition.
SeaBIOS stores internal state in the f-segment - it wont function
properly if that state is cleared. (For example, disk read requests
will fail, e820 requests will fail, etc.)
>Bochs
> bios doesn't rely on shadowing so none of its internal state is lost
> either, but the created tables (smbios, mp table, etc.) will be
> gone.
Clearing the tables is also broken (though less likely to be noticed).
In a nutshell, qemu can't reset the f-segment and expect a resume
operation to work. As Gleb pointed out though, it seems this use case
is more theoretical than practical, so worrying about this may not be
productive.
-Kevin
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, (continued)
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Kevin O'Connor, 2009/11/25
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Gleb Natapov, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Kevin O'Connor, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Gleb Natapov, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Kevin O'Connor, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Gleb Natapov, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Kevin O'Connor, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Gleb Natapov, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Kevin O'Connor, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Sebastian Herbszt, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios,
Kevin O'Connor <=
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Gleb Natapov, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Sebastian Herbszt, 2009/11/26
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Gleb Natapov, 2009/11/27
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Sebastian Herbszt, 2009/11/27
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Gleb Natapov, 2009/11/29
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Natalia Portillo, 2009/11/29
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Gleb Natapov, 2009/11/30
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Jamie Lokier, 2009/11/30
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Natalia Portillo, 2009/11/30
- Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios, Kevin O'Connor, 2009/11/30