Re: [Qemu-devel] [SeaBIOS] [RFC PATCH v2] fw/pci: Add support for mapping Intel IGD OpRegion via QEMU

[Alex Williamson <alex.williamson@redhat.com>]

On Wed, 2016-02-03 at 12:43 -0700, Alex Williamson wrote:
> On Wed, 2016-02-03 at 10:04 +0100, Gerd Hoffmann wrote:
> >   Hi,
> >  
> > > +static void intel_igd_opregion_setup(struct pci_device *dev, void *arg)
> > > +{
> > > +    struct romfile_s *file = romfile_find("etc/igd-opregion");
> >  
> > Is it possible to have multiple igd devices in a single machine?
> > So, should we include the pci address in the file name?
> >  
> > Guess not needed, it's chipset graphics after all ...
> 
> Hmm, I think that's probably a pretty good observation, we don't want to
> revisit this if vGPUs need/want an OpRegion or if Intel decides to start
> allowing more than one per system.  Either could pretty easily introduce
> multiple into a VM.

Naming is always more complicated than it seems.  For anything other
than a root bus devices, the PCI address doesn't exist until SeaBIOS
enumerates devices and assigns bus numbers for bridges.  So unless we
want to provide a path to the device like ACPI defines, maybe we should
just stick with "etc/igd-opregion".  It seems easily extensible to add
more specific files later and default to this one if those aren't found.
Thanks,

Alex