Re: [PATCH v7] VT-d: use correct BDF for VF to search VT-d unit

[Chao Gao <chao.gao@intel.com>]

On Wed, Aug 23, 2017 at 02:04:24AM -0600, Jan Beulich wrote:
>>>> On 23.08.17 at 03:05, <chao.gao@intel.com> wrote:
>> Strictly speaking, the VF can be an extended function. The definition is
>> within ARI device (in this kind of device, device field is treated as an
>> extension of function number) and function number is greater than 7. But
>> this field isn't used as we don't care about whether a VF is or not an
>> extended function (at least at present).
>
>Hmm, that's not in line with what Linux'es xen_add_device() does:
>
>#ifdef CONFIG_PCI_IOV
>		if (pci_dev->is_virtfn) {
>			add->flags = XEN_PCI_DEV_VIRTFN;
>			add->physfn.bus = physfn->bus->number;
>			add->physfn.devfn = physfn->devfn;
>		} else
>#endif
>		if (pci_ari_enabled(pci_dev->bus) && PCI_SLOT(pci_dev->devfn))
>			add->flags = XEN_PCI_DEV_EXTFN;
>
>Note the "else" in there. Are you saying this is actually wrong? (I
>indeed do see ARI capability structures in the VFs of the one
>SR-IOV capable system I have direct access to.)

Yes. I think it is wrong. Considering no one in Xen needs this
information, don't set XEN_PCI_DEV_EXTFN for VF is acceptable.

Thanks
Chao

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