[vfio-users] What's the difference between physical and passed through IGD?

[Alex Williamson]

On Sun, 26 Aug 2018 23:15:02 +0800
Acewind <acewind at gmail.com> wrote:

> I pass through Intel Corporation HD Graphics 530, an IGD card to windows 7
> vm by legacy mode, in fedora 25(kernel=4.8.6, qemu=2.7).
> I can see windows output on the screen successfully, but always confused
> graphic during booting and low resolution (640*480) when running.
> After installation of driver downloaded from Intel official website,
> nothing improved, and the driver show error code 43.
> 
> >From the view of driver, what’s the difference between an original,  
> physical IGD and a passed through IGD? Any functions disappeared? What
> should I do to correct the error？ Or there’s another version of driver？

I think you've already resolved with by adding stolen memory to the
configuration, it's nice to follow-up to the mailing list thread so the
next person to hit this issue can find the resolution.  This can be
done in libvirt by adding:

  <qemu:commandline>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.x-igd-gms=1'/>
  </qemu:commandline>

Within the <domain> section and specifying the opening of the <domain>
section as:

<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>

These sorts of x- options are really the only time we should be using
<qemu:arg> entries for vfio devices.

Of course on the QEMU commandline, it's simply a matter of adding
x-igd-gms=1 to the vfio-pci -device option list.  Thanks,

Alex