[Qemu-devel] xen-pci-passthrough PCI Express support? (Re: [Xen-devel] [PATCH v2 4/5] pci: Add INTERFACE_CONVENTIONAL_PCI_DEVICE to Conventional PCI devices)

[Eduardo Habkost <ehabkost@redhat.com>]

On Thu, Sep 28, 2017 at 10:12:34AM -0300, Eduardo Habkost wrote:
> On Thu, Sep 28, 2017 at 02:33:57AM -0600, Jan Beulich wrote:
> > >>> On 27.09.17 at 21:56, <ehabkost@redhat.com> wrote:
> > > --- a/hw/xen/xen_pt.c
> > > +++ b/hw/xen/xen_pt.c
> > > @@ -964,6 +964,10 @@ static const TypeInfo xen_pci_passthrough_info = {
> > >      .instance_size = sizeof(XenPCIPassthroughState),
> > >      .instance_finalize = xen_pci_passthrough_finalize,
> > >      .class_init = xen_pci_passthrough_class_init,
> > > +    .interfaces = (InterfaceInfo[]) {
> > > +        { INTERFACE_CONVENTIONAL_PCI_DEVICE },
> > > +        { },
> > > +    },
> > >  };
> > 
> > Passed through devices can be both PCI and PCIe, so following
> > the description of the patch I don't think these can be statically
> > given either property. Granted quite a bit of PCIe specific
> > functionality may be missing in the Xen code ...
> 
> This is just static data about what the device type supports, not
> about what a given device instance really is.  Deciding if the
> device is PCIe or Conventional at runtime is out of the scope of
> this series.
> 
> That said, if passed through PCI Express devices are really
> supported, it looks like this should be marked as hybrid.

Can anybody confirm if PCI Express devices are really supported
by xen-pci-passthrough?

I suggest we add only INTERFACE_CONVENTIONAL_PCI_DEVICE to the
class info until we confirm that.

(In other words, apply this patch as-is, and add
INTERFACE_PCIE_DEVICE later as a follow-up patch if appropriate.)

-- 
Eduardo