Re: [virtio-comment] Re: [PATCH V2 2/5] Introduce feature bit VIRTIO_F_TRANSPT_VQ_MDEV

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

On Tue, Aug 02, 2022 at 11:17:51AM +0800, Zhu, Lingshan wrote:
> 
> 
> On 8/2/2022 4:27 AM, Michael S. Tsirkin wrote:
> > On Mon, Aug 01, 2022 at 05:32:13PM +0800, Zhu Lingshan wrote:
> > > This commit introduces feature bit VIRTIO_F_TRANSPT_VQ_MDEV,
> > > which depends on VIRTIO_F_TRANSPT_VQ.
> > > 
> > > Feature bit VIRTIO_F_TRANSPT_VQ_MDEV indicates that the managed
> > > devices are created, configured and destroyed through the
> > > transport virtqueue, the transport virtqueue is the
> > > transport layer for the managed devices.
> > I'd avoid the term MDEV if possible, it's already used in virt contexts.
> yes, let me work out a better name, it was vdev (virtual device) before, and
> maybe
> sdev(sub device) or a better one.

Besides mdev can thinkably stand for both managed and management.
Nvidia patches have the concept of a device group and
group member but do not have a name for the device that controls
the group. Admin device? Control device?

Also, creating/destroying is one thing that seems to only apply to
SIOV. configuring seems to apply to SRIOV as well?



> > 
> > 
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
> > > ---
> > >   content.tex | 12 ++++++++++++
> > >   1 file changed, 12 insertions(+)
> > > 
> > > diff --git a/content.tex b/content.tex
> > > index 969ca46..143949e 100644
> > > --- a/content.tex
> > > +++ b/content.tex
> > > @@ -2968,6 +2968,18 @@ \subsection{Managed Devices Dscovery}\label{sec:Virtio Transport Options /Virtio
> > >   Managed devices are created and discovered through a transport virtqueue.
> > > +\subsection{Transport Virtqueue Features}\label{sec:Virtio Transport Options /Virtio Over Transport Virtqueue / Transport Virtqueue Features}
> > > +
> > > +Feature bit VIRTIO_F_TRANSPT_VQ_MDEV indicates that the managed devices are created, configured
> > > +and destroyed through the transport virtqueue.
> > Feature bit being present where? On the management device?
> Yes, the management device, I will add this.
> > 
> > > +This means the transport virtqueue is the transport layer for the managed devices.
> > confused. how does this differ from VIRTIO_F_TRANSPT_VQ?
> VIRTIO_F_TRANSPT_VQ means the management device offers a transport vq.
> VIRTIO_F_TRANSPT_VQ_MDEV is a feature of the transport vq, means the
> management device create / destroy and configure the managed device via the
> transport vq.
> 
> This reminds me that maybe I should use the term vdev(virtual device), so
> that other kinds of devices can add their own feature bits under
> VIRTIO_F_TRANSPT_VQ
> 
> Thanks,
> Zhu Lingshan
> > 
> > > +
> > > +Feature bit VIRTIO_F_TRANSPT_VQ_MDEV depends on VIRTIO_F_TRANSPT_VQ
> > > +
> > > +\devicenormative{\subsubsection}{Transport Virtqueue Features}{Virtio Transport Options / Virtio Over Transport Virtqueue / Transport Virtqueue Features}
> > > +
> > > +The management device MUST not accept VIRTIO_F_TRANSPT_VQ_MDEV if VIRTIO_F_TRANSPT_VQ is not negotiated.
> > > +
> > >   \chapter{Device Types}\label{sec:Device Types}
> > >   On top of the queues, config space and feature negotiation facilities
> > > -- 
> > > 2.35.3
> > 
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