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

[Anthony Liguori <anthony@codemonkey.ws>]

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Michael S. Tsirkin wrote:
> On Mon, Dec 14, 2009 at 02:44:34PM -0600, Anthony Liguori wrote:
>   
>> Michael S. Tsirkin wrote:
>>     
>>> Or, we could have a very small ROM, that loads
>>> more actual code from card or from qemu directly
>>> when it is run.
>>>   
>>>       
>> It's not as simple as it sounds but it's possible, in theory at least.
>>
>> But I think the question really is, what problem are we trying to solve?
>>     
>
> Support 256 devices on PCI bus seamlessly

Okay, I think I've figured out how this is supposed to work.  With these 
two patches to SeaBIOS and the patch to qemu, I can run:

qemu -net nic,model=rtl8139 -net nic,model=virtio -net nic,model=e1000 
-boot menu=on

And all three option roms load.  I can also select which NIC I want to 
boot from using the F12 menu.  This works by not actually loading the 
option roms in the 1M space, but instead making them mappable through 
the PCI devices.  With PMM and DDIM, the result is that we only have to 
copy in 2K for each option rom which means we can support up to 48 
unique option roms.  That should be plenty for now.

These patches are very rough but I'll clean them up tomorrow.  I'm not 
sure the best way to integrate with the rom infrastructure since we no 
longer have a physical address to map to.  Any suggestions Gerd?

Regards,

Anthony Liguori

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