[SeaBIOS] Proper support for PCI-based option rom loading (was Re: [Qemu-devel] Re: qdev property bug?)

Anthony Liguori anthony at codemonkey.ws
Wed Dec 16 01:41:33 CET 2009

Kevin OConnor wrote:
> On Tue, Dec 15, 2009 at 12:35 PM, Anthony Liguori 
> <anthony at codemonkey.ws <mailto:anthony at codemonkey.ws>> wrote:
>     Avi Kivity wrote:
>         bochs bios required all 128kB, so this is probably a leftover.
>     This is apparently well defined in the PIIX spec.  There is a bit
>     of a difference between the lower half and upper half of the BIOS
>     region though and I expect this is part of what the problem is.
>      FYI, the following patch works.  Surprisingly, we only need to
>     restore the 0xe8000..0xe8fff region.  Still trying to understand
>     what's happening.
> SeaBIOS is currently using over 64K of space.  So, it is extending 
> into the e-segment
> and thus needs to have the e-segment copied properly (I missed that in my
> earlier email).

Okay.  So I assume this is something that SeaBIOS needs to do?  I've 
been trying to understand the origin of:

// Need to copy optionroms to work around qemu implementation

What is it that we're doing wrong in the qemu implementation?  If it's 
the lack of PCI option loading, then I guess we're okay post my changes 
provided that SeaBIOS can take care of what it needs in the e-segment.


Anthony Liguori

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