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

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

On Wed, Oct 25, 2023 at 09:55:20AM +0000, Parav Pandit 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/msg00
> > > >> > 24
> > > >> > 0.h
> > > >> > tml [2]
> > > >> > https://lists.oasis-open.org/archives/virtio-comment/202310/msg00
> > > >> > 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. ☹
> > >
> > > That's not a link, but a message id... many mail clients support
> > > searching by it, and you can also get it from lore:
> > >
> > > 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

all status bits are set by driver

> and before the driver setting the


setting -> sets

> > DRIVER_OK status bit.
> > +
> > +When VIRTIO_F_RING_DYNAMIC is negotiated, the driver is not required to

try to avoid "required" outside conformance sections though pls.
And when used, we upper-case it.

> > +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.


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