Re: [virtio-comment] [PATCH] virtio-net: Add an optional device control over the receive buffers length

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

On Fri, Jan 03, 2020 at 03:22:44PM +0000, Stefan Hajnoczi wrote:
> On Mon, Dec 30, 2019 at 01:59:17PM +0000, Vitaly Mireyno wrote:
> > @@ -2916,6 +2933,15 @@ \subsection{Device configuration layout}\label{sec:Device Types / Network Device
> >  If the driver negotiates the VIRTIO_NET_F_STANDBY feature, the device MAY act
> >  as a standby device for a primary device with the same MAC address.
> >  
> > +A driver SHOULD accept the VIRTIO_NET_F_RXBUF_MIN_LEN feature if offered.
> > +
> > +If VIRTIO_NET_F_RXBUF_MIN_LEN feature has been negotiated, the driver MUST
> > +set \field{min_rx_buf_len}.
> > +
> > +A driver MUST NOT modify \field{min_rx_buf_len} once it has been set.
> 
> When must the driver set the fields?  I guess it makes no sense to set
> this field after starting rx (i.e. populating the rx virtqueue)...  The
> spec should be explicit about this.

If we are going to keep it static then I think the best time is
before features ok.