Re: [Qemu-devel] [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

[Chen, Tiejun]

> > > > > > +     */
> > > > > > +    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
> > > > > > +                            "xen-igd-passthrough-isa-bridge");
> > > > > > +    if (dev) {
> > > > > > +        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f,
> > > > > > 0), 0);
> > > > > > +        if (!r) {
> > > > > > +            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
> > > > > > +            pci_config_set_device_id(dev->config, hdev.device_id);
> > >
> > > Can you, instead, implement the reverse logic, probing
> > > the card and supplying the correct device id for PCH?
> >
> > Here what is your so-called reverse logic as I already asked you
> > previously? Do you mean I should list all PCHs with a combo illustrated
> > with the vendor/device id in advance? Then look up if we can find a
>
> Michael,

Ping.

Thanks
Tiejun

> Could you explain this exactly? Then I can try follow-up your idea ASAP
> if this is necessary and possible.
>
> Thanks
> Tiejun
>
> > matched PCH? If yes, what is that benefit you expect in passthrough
> > case? Shouldn't we pass these info to VM directly in passthrough case?
> >
> > Thanks
> > Tiejun