Re: graphics card pci passthrough success report

[Lennert Buytenhek <buytenh@wantstofly.org>]

On Thu, Sep 13, 2012 at 11:05:07AM -0600, Alex Williamson wrote:

> > > > - Apply the hacky patch at the end of this mail to SeaBIOS to
> > > >   always skip initialising the Radeon's option ROMs, or the VM
> > > >   would hang inside the Radeon option ROM if you boot the VM
> > > >   without the default cirrus video.
> > > 
> > > A better way to handle that would probably be to add an pci passthrough
> > > config option to not expose the rom to the guest.
> > > 
> > > Any clue *why* the rom doesn't run?
> > 
> > No idea, we didn't look into that -- this was just a one afternoon
> > hacking session.
> 
> Thanks for the report.  Spawned by your success, I tested a Radeon HD
> 5450 using VFIO based device assignment.  I can get it to work on
> Windows XP, with no changes (from the version I'll post soon),

Yay!


> but Win7 dies (still need to play around more with your suggestions
> of cpu type).

ACK.  That's a nasty one, don't ask how we found that out...

Note that the bluescreen I described when the cpu type is wrong only
actually happened for us if the AMD drivers were installed in the
VM -- maybe you can try without AMD drivers to see if that makes it
go away.  If you still have a bluescreen without the AMD drivers
installed, it's probably a different issue.


> For skipping the option rom, is it sufficient to not expose it
> (rombar=0) or does the guest OS driver need it as well?

I don't actually know.  Something to try out when we get round to
testing this again, I suppose..


cheers,
Lennert