Re: [PATCH v2 3/3] tun: Set num_buffers for virtio 1.0

[Akihiko Odaki]

On 2025/01/10 19:23, Michael S. Tsirkin wrote:
> On Fri, Jan 10, 2025 at 11:27:13AM +0800, Jason Wang wrote:
> > On Thu, Jan 9, 2025 at 2:59 PM Akihiko Odaki <akihiko.odaki@xxxxxxxxxx> wrote:
> > > The specification says the device MUST set num_buffers to 1 if
> > > VIRTIO_NET_F_MRG_RXBUF has not been negotiated.
> >
> > Have we agreed on how to fix the spec or not?
> >
> > As I replied in the spec patch, if we just remove this "MUST", it
> > looks like we are all fine?
> >
> > Thanks
>
> We should replace MUST with SHOULD but it is not all fine,
> ignoring SHOULD is a quality of implementation issue.

Should we really replace it? It would mean that a driver conformant with 
the current specification may not be compatible with a device conformant 
with the future specification.

We are going to fix all implementations known to buggy (QEMU and Linux) 
anyway so I think it's just fine to leave that part of specification as is.