Re: [Qemu-devel] vfio IGD assignment (was Re: [PATCH v6 0/8] Series short description)

Alex Williamson
2016-05-20T15:09:00Z

On Fri, 20 May 2016 14:19:19 +0200
Gerd Hoffmann <kraxel@redhat.com> wrote:

> On Mi, 2016-05-18 at 12:45 -0600, Alex Williamson wrote:
> > On Wed, 18 May 2016 16:24:49 +0200
> > Gerd Hoffmann <kraxel@redhat.com> wrote:
> >
> > > Hi,
> > >
> > > > I believe we're no longer blocked by SeaBIOS being willing to
> > > > consume the new fw_cfg entries, so barring feedback otherwise, my
> > > > plan will be to send a pull request including these changes (after
> > > > an appropriate review period), ask Kevin to apply the matching
> > > > SeaBIOS change, then see if Gerd will help me pull that support
> > > > into the default QEMU SeaBIOS image.
> > >
> > > Sounds good. Patches look sane to me too.
> > >
> > > Will try to set aside some time to test them later this week (and also
> > > push a branch with updated seabios etc for others to try).
> >
> > Thanks Gerd!
>
> Works flawlessly.
>
> Linux works fine with the igd assigned as primary (pc machine type and
> igd using slot 2).
>
> Linux doesn't work in UPT mode for me. That is more a guest driver
> issue though. The i915 driver of older kernels Oopses. The i915 driver
> of recent kernels (4.4.5+) loads fine on q35, but fails to drive my
> monitor, no matter whenever I enable the opregion or not. For pc an
> additional kernel patch is needed (which hopefully lands upstream soon)
> to reach feature parity (as-in: no Oops on load) with q35.

Yes, I've never had success with UPT for Linux guests either.

> For windows UPT mode is the only thing supported by the drivers. Needs
> the opregion enabled to show something on the connected display. Works
> fine on both pc and q35, in parallel with a emulated display, and you
> can configure things as you want (mirror, expand desktop, use only one
> of the displays).

UPT is probably the only thing Intel cares to support on Windows, yes,
but did you have any issues or try legacy mode on Windows? I find that
Windows 7/8/10 all work well with legacy mode, including the basic
drivers in the shrink-wrap images. Please let me know if you find
otherwise.

>
> Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
> Tested-by: Gerd Hoffmann <kraxel@redhat.com>

Awesome, thanks!

Alex