Re: [RFC PATCH v1 0/3] virtio: early detect 'modern' virtio

[Michael S. Tsirkin]

On Fri, Oct 29, 2021 at 12:00:14AM +0200, 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 the problems that
> arrise in the situation described in the previous paragraph, when the
> config is managed by a vhost device (and thus outside QEMU).
> 
> This series was only lightly tested. 

I think it's a good enough approach, and we are getting close
to release. For vhost - a new callback just for that? Would be ok.
Or just invoke set features - if this works.


> Halil Pasic (3):
>   virtio: introduce virtio_force_modern()
>   virtio-ccw: use virtio_force_modern
>   virtio-pci: use virtio_force_modern()
> 
>  hw/s390x/virtio-ccw.c      |  3 +++
>  hw/virtio/virtio-pci.c     |  1 +
>  hw/virtio/virtio.c         | 12 ++++++++++++
>  include/hw/virtio/virtio.h |  1 +
>  4 files changed, 17 insertions(+)
> 
> 
> base-commit: 2c3e83f92d93fbab071b8a96b8ab769b01902475
> -- 
> 2.25.1