Re: [PATCH 4/5] virtio-net: add support for VIRTIO_F_ADMIN_VQ

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jan 19, 2022 at 12:16:47PM +0800, Jason Wang wrote:
> > We also need
> > - something like injecting cvq commands to control rx mode from the admin device
> > - page fault / dirty page handling
> >
> > these two seem to call for a vq.
> 
> Right, but vq is not necessarily for PF if we had PASID. And with
> PASID we don't even need a dedicated new cvq.

I don't think it's a good idea to mix transactions from
multiple PASIDs on the same vq.

Attaching a PASID to a queue seems more reasonable.
cvq is under guest control, so yes I think a separate
vq is preferable.

What is true is that with subfunctions you would have
PASID per subfunction and then one subfunction for control.

I think a sketch of how things will work with scalable iov can't hurt as
part of this proposal.  And, I'm not sure we should have so much
flexibility: if there's an interface that works for SRIOV and SIOV then
that seems preferable than having distinct transports for SRIOV and
SIOV.


-- 
MST