Re: [virtio-comment] Re: [RFC PATCH v2 2/2] virtio-blk: add support for VIRTIO_F_ADMIN_VQ

[Max Gurtovoy <mgurtovoy@nvidia.com>]

On 7/27/2021 3:24 PM, Stefan Hajnoczi wrote:
> On Mon, Jul 26, 2021 at 07:52:54PM +0300, Max Gurtovoy wrote:
> > Set the relevant index in case of VIRTIO_F_ADMIN_VQ negotiation. Also
> > restrict the negotiation of VIRTIO_F_ADMIN_VQ to be possible only if
> > VIRTIO_BLK_F_MQ is negotiated.
> >
> > Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
> > ---
> >   content.tex | 16 ++++++++++++++++
> >   1 file changed, 16 insertions(+)
> >
> > diff --git a/content.tex b/content.tex
> > index d350175..03e25da 100644
> > --- a/content.tex
> > +++ b/content.tex
> > @@ -4406,6 +4406,16 @@ \subsection{Virtqueues}\label{sec:Device Types / Block Device / Virtqueues}
> >    N=1 if VIRTIO_BLK_F_MQ is not negotiated, otherwise N is set by
> >    \field{num_queues}.
> >   
> > + If VIRTIO_F_ADMIN_VQ is negotiated, queue0 is an admin virtqueue and the
> > + request queues are shifted as the following:
> "as follows:"
>
> > +\begin{description}
> > +\item[1] requestq1
> > +\item[\ldots]
> > +\item[N] requestqN
> > +\end{description}
> > +
> > + if VIRTIO_BLK_F_MQ is not negotiated, VIRTIO_F_ADMIN_VQ MUST NOT be
> > + negotiated.
> Why?

To distinguish between adminq and requestq.