Re: [RFC PATCH v2 0/5] virtio: early detect 'modern' virtio

[Halil Pasic]

On Wed, 8 Dec 2021 13:56:19 -0500
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Fri, Nov 12, 2021 at 03:57:44PM +0100, Halil Pasic wrote:
> > This is an early RFC for a transport specific early detecton of
> > modern virtio, which is most relevant for transitional devices on big
> > endian platforms, when drivers access the config space before
> > FEATURES_OK is set.
> > 
> > The most important part that is missing here is fixing all the problems
> > that arise in the situation described in the previous paragraph, when
> > the config is managed by a vhost device (and thus outside QEMU. This
> > series tackles this problem only for virtio_net+vhost as an example. If
> > this approach is deemed good, we need to do something very similar for
> > every single affected device.
> > 
> > This series was only lightly tested. The vhost stuff is entirely
> > untested, unfortunately I don't have a working setup where this
> > handling would be needed (because the config space is handled in the
> > device). DPDK is not supported on s390x so at the moment I can't test
> > DPDK based setups.   
> 
> So this looks sane to me. Cornelia requested some name tweaks and we
> need to add vhost-user things and more devices, but otherwise we are
> good.

Thanks for your feedback! There were several points where I could
not reach agreement with Cornelia. From your response I recon that:

1) I should rename virtio_force_modern() to virtio_indicate_modern()
(per maintainer request).
2) Keep the call to virtio_set_features()?

Is that right?

Regards,
Halil