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

[Chen, Tiejun]

On 2014/6/26 18:03, Paolo Bonzini wrote:
> Il 26/06/2014 11:18, Chen, Tiejun ha scritto:
> > > - offsets 0x0000..0x0fff map to configuration space of the host MCH
> >
> > Are you saying the config space in the video device?
>
> No, I am saying in a new BAR, or at some magic offset of an existing
> MMIO BAR.

As I mentioned previously, the IGD guy told me we have no any unused a 
offset or BAR in the config space.

And guy who are responsible for the native driver seems not be accept to 
extend some magic offset of an existing MMIO BAR.

In addition I think in a short time its not possible to migrate i440fx 
to q35 as a PCIe machine of xen. So could we do this step by step:

#1 phase: We just cover current qemu-xen implementation based on i44fx, 
so still provide that pseudo ISA bridge at 00:1f.0 as we already did.

#2 phase: Now, we will choose a capability ID that won't be conflicting 
with others. To do this properly, we need to get one from PCI SIG group. 
To have this workable and consistently validated, this method shouldn't 
be virt specific. Then native driver should use the same method. So when 
xen work on q35 PCIe machine, we can walk this way.

Anthony,

Any comments to address this in xen case?

Thanks
Tiejun