RE: [PATCH v3] virtio-network: Clarify VLAN filter table configuration

[Parav Pandit <parav@nvidia.com>]

> From: Si-Wei Liu <si-wei.liu@oracle.com>
> Sent: Tuesday, January 3, 2023 8:49 PM
> 
> Hi Parav,
> 
> Great write-up! Just a couple minor suggestions, please see below in line.
> 
> On 1/3/2023 2:07 PM, Parav Pandit wrote:
> > The filtering behavior of the VLAN filter commands is not very clear
> > as discussed in thread [1].
> >
> > Hence, add the command description and device requirements for it.
> >
> > [1] https://www.mail-archive.com/qemu-
> devel@nongnu.org/msg912392.html
> > Fixes: https://github.com/oasis-tcs/virtio-spec/issues/147
> > Suggested-by: Si-Wei Liu <si-wei.liu@oracle.com>
> > Signed-off-by: Parav Pandit <parav@nvidia.com>
> > ---
> > changelog:
> > v2->v3:
> > - corrected grammar
> > - simplified description for untagged packets
> > v1->v2:
> > - adapt to new file path
> > v0->v1:
> > - added missing conformance section link
> > ---
> >   .../virtio-network/device-conformance.tex      |  1 +
> >   device-types/virtio-network/device.tex         | 18 ++++++++++++++++++
> >   2 files changed, 19 insertions(+)
> >
> > diff --git a/device-types/virtio-network/device-conformance.tex
> > b/device-types/virtio-network/device-conformance.tex
> > index c686377..54f6783 100644
> > --- a/device-types/virtio-network/device-conformance.tex
> > +++ b/device-types/virtio-network/device-conformance.tex
> > @@ -9,6 +9,7 @@
> >   \item \ref{devicenormative:Device Types / Network Device / Device
> Operation / Processing of Incoming Packets}
> >   \item \ref{devicenormative:Device Types / Network Device / Device
> Operation / Control Virtqueue / Packet Receive Filtering}
> >   \item \ref{devicenormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Setting MAC Address Filtering}
> > +\item \ref{devicenormative:Device Types / Network Device / Device
> > +Operation / Control Virtqueue / VLAN Filtering}
> >   \item \ref{devicenormative:Device Types / Network Device / Device
> Operation / Control Virtqueue / Gratuitous Packet Sending}
> >   \item \ref{devicenormative:Device Types / Network Device / Device
> Operation / Control Virtqueue / Automatic receive steering in multiqueue
> mode}
> >   \item \ref{devicenormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Receive-side scaling (RSS) / RSS
> > processing} diff --git a/device-types/virtio-network/device.tex
> > b/device-types/virtio-network/device.tex
> > index e7cdd6f..ea4b524 100644
> > --- a/device-types/virtio-network/device.tex
> > +++ b/device-types/virtio-network/device.tex
> > @@ -1210,6 +1210,24 @@ \subsubsection{Control
> Virtqueue}\label{sec:Device Types / Network Device / Devi
> >   Both the VIRTIO_NET_CTRL_VLAN_ADD and VIRTIO_NET_CTRL_VLAN_DEL
> >   command take a little-endian 16-bit VLAN id as the command-specific-data.
> >
> > +VIRTIO_NET_CTRL_VLAN_ADD command adds the specified VLAN to the
> VLAN
> > +filtering table.
> > +
> > +VIRTIO_NET_CTRL_VLAN_DEL command removes specified VLAN from the
> VLAN
> > +filtering table which was previously added using
> > +VIRTIO_NET_CTRL_VLAN_ADD command.
> > +
> > +\devicenormative{\subparagraph}{VLAN Filtering}{Device Types /
> > +Network Device / Device Operation / Control Virtqueue / VLAN
> > +Filtering}
> > +
> > +When VIRTIO_NET_F_CTRL_VLAN is negotiated, the device starts with an
> > +empty VLAN filtering table.
> Should we mention this VLAN filtering table gets emptied on device reset?
> 
Good point. When a device is reset all the configuration of the driver gets cleared.
So instead of explicitly mentioning in each ctrl field, lets do this in generic place in the "Device Cleanup" section.

Currently device cleanup section only explicitly talks about virtio operation.
Will do in follow up patch in common section.

> ...; if VIRTIO_NET_F_CTRL_VLAN is not negotiated, device does not have a VLAN
> filter table thus MUST NOT specifically drop VLAN tagged packets.

Ah yes, from v0 to v3, this part of the text got lost. I will add it back.
Thanks.