Re: [virtio-dev] [PATCH] virtio-net: use mtu size as buffer length for big packets

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

On Wed, Aug 10, 2022 at 04:00:08PM +0000, Parav Pandit wrote:
> 
> > From: Michael S. Tsirkin <mst@redhat.com>
> > Sent: Wednesday, August 10, 2022 5:03 AM
> > > >
> > > > Should we make this depend on the vq reset ability maybe?
> > >
> > > The advantage of this is to keep TX working. Or we can use device
> > > reset as a fallback if there's no vq reset.
> > >
> > > Thanks
> > 
> > Device reset is really annoying in that it loses all the state:
> > rx filters etc etc.
> 
> The elegant solution is let driver tell the new mtu to the device.
> One way to do so is by using existing ctrl vq.

That will need a new feature bit.

> If merged buffer is done, and new mtu is > minimum posting size, no need to undergo vq reset.
> If merged buffer is not done, and buffer posted are smaller than new mtu, undergo vq reset optionally.

This can be done with or without sending mtu to device.

-- 
MST