Re: [PATCH] kvm tools: virtio-net mergable rx buffers

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

On Wed, Apr 24, 2013 at 09:51:57AM +0300, Pekka Enberg wrote:
> Hi,
> 
> On 04/23/2013 12:35 PM, Eric Northup wrote:
> >> Do you care about guests with drivers that don't negotiate
> >> VIRTIO_NET_F_MRG_RXBUF?
> 
> On Wed, Apr 24, 2013 at 5:51 AM, Sasha Levin <sasha.levin@oracle.com> wrote:
> > We usually try to keep backward compatibility, but in this case
> > mergable RX buffers are about 5 years old now, so it's safe to
> > assume they'll be running in any guest.
> >
> > Unless there is a specific reason to allow working without them
> > I'd rather keep the code simple in this case.
> 
> Are there such guests around? What's the failure scenario for them
> after this patch?
> 
>                         Pekka

Warning: have not looked at the patch, just a general comment.

I think it's reasonable to assume embedded guests such as PXE won't
negotiate any features.  And, running old guests is one of the reasons
people use virtualization at all. So 5 years is not a lot.

In any case, stick to the device spec please, if you want it changed
please send a spec patch, don't deviate from it randomly.

-- 
MST