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Date: Wed, 25 Jun 2014 15:53:30 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [v5][PATCH 0/5] xen: add Intel IGD passthrough
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: peter.maydell@linaro.org, xen-devel@lists.xensource.com, stefano.stabellini@eu.citrix.com, allen.m.kay@intel.com, Kelly.Zytaruk@amd.com, qemu-devel@nongnu.org, anthony.perard@citrix.com, anthony@codemonkey.ws, yang.z.zhang@intel.com, "Chen, Tiejun" <tiejun.chen@intel.com>

Il 25/06/2014 15:47, Michael S. Tsirkin ha scritto:
> OK, so how about doing this: either for the ISA
> bridge, or for the VGA card itself:
>
>     set subsystem vendor id to PCI_VENDOR_ID_XEN,
>     set subsystem device id to PCH device id

That would work, but the same problem would then arise for the MCH.  The 
driver there is banging at random places in the configuration space.

This is why I asked for a solution that is future-proof, and since you 
can make one that works for both MCH and PCH it is nice to do the work 
just once.

Paolo