Re: [PATCH V1 vfio 0/9] Introduce a vfio driver over virtio devices

Alex Williamson
2023-10-23T16:10:31Z

On Mon, 23 Oct 2023 12:42:57 -0300
Jason Gunthorpe <jgg@nvidia.com> wrote:

> On Mon, Oct 23, 2023 at 09:33:23AM -0600, Alex Williamson wrote:
>
> > > Alex,
> > > Are you fine to leave the provisioning of the VF including the control
> > > of its transitional capability in the device hands as was suggested by
> > > Jason ?
> >
> > If this is the standard we're going to follow, ie. profiling of a
> > device is expected to occur prior to the probe of the vfio-pci variant
> > driver, then we should get the out-of-tree NVIDIA vGPU driver on board
> > with this too.
>
> Those GPU drivers are using mdev not vfio-pci..

The SR-IOV mdev vGPUs rely on the IOMMU backing device support which
was removed from upstream. They only exist in the mdev form on
downstreams which have retained this interface for compatibility and
continuity. I'm not aware of any other means by which the SR-IOV RID
can be used in the mdev model, therefore only the pre-SR-IOV GPUs
should continue to use the mdev interface.

> mdev doesn't have a way in its uapi to configure the mdev before it is
> created.

Of course. Thanks,

Alex