RE: [virtio-comment] RE: [PATCH v3 2/2] content: Support enabling virtqueue after DRIVER_OK stage

[Parav Pandit <parav@nvidia.com>]

> From: Cornelia Huck <cohuck@redhat.com>
> Sent: Wednesday, October 25, 2023 3:48 PM
> 
> On Wed, Oct 25 2023, Parav Pandit <parav@nvidia.com> wrote:
> 
> > Hi Cornelia,
> >
> >> From: Parav Pandit <parav@nvidia.com>
> >> Sent: Monday, October 23, 2023 8:52 PM
> >> To: Cornelia Huck <cohuck@redhat.com>; Michael S. Tsirkin
> >> <mst@redhat.com>
> >> Cc: virtio-comment@lists.oasis-open.org; hengqi@linux.alibaba.com;
> >> xuanzhuo@linux.alibaba.com; Shahaf Shuler <shahafs@nvidia.com>
> >> Subject: RE: [virtio-comment] RE: [PATCH v3 2/2] content: Support
> >> enabling virtqueue after DRIVER_OK stage
> >>
> >>
> >> > From: virtio-comment@lists.oasis-open.org
> >> > <virtio-comment@lists.oasis- open.org> On Behalf Of Cornelia Huck
> >> > Sent: Monday, October 23, 2023 8:31 PM
> >> >
> >> > On Mon, Oct 23 2023, Parav Pandit <parav@nvidia.com> wrote:
> >> >
> >> > >> From: Cornelia Huck <cohuck@redhat.com>
> >> > >> Sent: Monday, October 23, 2023 7:58 PM
> >> > >
> >> > >> On Mon, Oct 23 2023, Parav Pandit <parav@nvidia.com> wrote:
> >> > >>
> >> > >> >> From: virtio-comment@lists.oasis-open.org
> >> > >> >> <virtio-comment@lists.oasis- open.org> On Behalf Of Cornelia
> >> > >> >> Huck
> >> > >> >> Sent: Monday, October 23, 2023 7:27 PM
> >> > >> >
> >> > >> >> Well, there are  still comments from me here that post-date
> >> > >> >> v4 (please wait for a bit before posting another version!),
> >> > >> >> so I'll continue waiting for them to be addressed first.
> >> > >> > The last one was [1].
> >> > >> > Which I replied few days ago at [2].
> >> > >> >
> >> > >> > [1]
> >> > >> > https://lists.oasis-open.org/archives/virtio-comment/202310/ms
> >> > >> > g00
> >> > >> > 24
> >> > >> > 0.h
> >> > >> > tml [2]
> >> > >> > https://lists.oasis-open.org/archives/virtio-comment/202310/ms
> >> > >> > g00
> >> > >> > 24
> >> > >> > 2.h
> >> > >> > tml
> >> > >>
> >> > >> I still have some open questions from
> >> > >> <87sf68cjn0.fsf@redhat.com> (first and last paragraph.)
> >> > >
> >> > > Above link is not accessible to me. â
> >> >
> >> > That's not a link, but a message id... many mail clients support
> >> > searching by it, and you can also get it from lore:
> >> >
> >> > 87sf68cjn0.fsf@redhat.com/">https://lore.kernel.org/all/87sf68cjn0.fsf@redhat.com/
> >> >
> >> > > I addressed your comments/questions in v4.
> >> > > Can you please check v4 if they are addressed? I rewrote as you
> >> > > suggested in
> >> > v3.
> >> >
> >> > This was for points you did not agree with. (Again, it might be
> >> > helpful to wait with posting a new version until discussion has
> >> > somewhat
> >> > concluded.)
> >> Sure, will wait next time.
> >>
> >> Your comment was,
> >> =====
> >> This is not really clear to me just from this text, especially if you
> >> just wrote above that enabling or re-enabling is something
> >> different... my understanding would be:
> >>
> >> - if neither dynamic vqs nor queue reset are supported or negotiated,
> >>   the only way to enable a vq is before DRIVER_OK, during setup
> >> - both of these features rely on the transport supporting enabling
> >>   individual queues (either a queue that has not been enabled before, or
> >>   a queue that has been reset)
> >> - the transport is supposed to use the same mechanism for either
> >>
> >> Did I get it right? If so, I think we should make it a bit more clear.
> >> =====
> >>
> >> Above is clarified in below wording without complicating the queue_reset
> here.
> >>
> >> Does that look ok to you?
> >>
> >> +When VIRTIO_F_RING_DYNAMIC is not negotiated, the driver enables the
> >> +virtqueues during the device initialization sequence, i.e. after the
> >> +device sets the FEATURES_OK status bit and before the driver setting
> >> +the
> >> DRIVER_OK status bit.
> >> +
> >> +When VIRTIO_F_RING_DYNAMIC is negotiated, the driver is not required
> >> +to enable every virtqueue it wants to use before setting the
> >> +DRIVER_OK status bit; the driver can choose to enable a virtqueue
> >> +even after the driver has set the DRIVER_OK status bit. The
> >> +virtqueue enable mechanism is
> >> transport specific.
> >> +
> >
> > Can you please respond?
> > We must make progress with this and the flow filters which are depending on
> this for a long time now.
> 
> I will not be able to look at this before Friday.
Ok. Thanks for the update.
Will seek for your response on Friday.