Re: [Qemu-devel] [Xen-devel] [v5][PATCH 0/5] xen: add Intel IGD passthrough support

[Paolo Bonzini]

Il 30/06/2014 12:20, Chen, Tiejun ha scritto:
> I already post this to mainline to change as follows:
>
> -    while ((pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, pch))) {
> +    pch = pci_get_bus_and_slot(0, PCI_DEVFN(0x1f, 0));
> +    if (pch) {
>
> Please refer to this,
>
> [RFC][PATCH] gpu:drm:i915:intel_detect_pch: back to check devfn instead
> of check class type
>
> Linux Native guys would like to accept this. And actually Windows always
> use devfn to detect this.

Fair enough, but that means that, when using IGD, Q35 will have to move 
the ISA bridge off 1f.0.

To me it seems fairly clear that as things stand IGD is not 
virtualizable without PV support.  We're beating a dead horse.

Paolo