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

[Michael S. Tsirkin]

On Tue, Dec 15, 2009 at 01:21:38PM -0600, Anthony Liguori wrote:
> Gerd Hoffmann wrote:
>> On 12/15/09 03:37, Anthony Liguori wrote:
>>> 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?
>>
>> Is this needed in the first place?
>
> Only if we care about 'info roms' working.  Problem is roms is very  
> centric now to roms at a static guest physical location.  In this case,  
> the rom lives in hardware and is mapped into physical memory based on  
> what the guest does.
>
> Regards,
>
> Anthony Liguori


I also think it is very important to have roms sent during
migration, otherwise things break if we migrate in the middle
of accessing roms.

-- 
MST