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Re: [RFC PATCH v2 0/5] virtio: early detect 'modern' virtio
From: |
Michael S. Tsirkin |
Subject: |
Re: [RFC PATCH v2 0/5] virtio: early detect 'modern' virtio |
Date: |
Wed, 8 Dec 2021 13:56:19 -0500 |
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.
> v1 -> v2:
>
> * add callback
> * tweak feature manipulation
> * add generic handling for vhost that needs to be called by devices
> * add handling for virtio
>
> Halil Pasic (5):
> virtio: introduce virtio_force_modern()
> virtio-ccw: use virtio_force_modern()
> virtio-pci: use virtio_force_modern()
> vhost: push features to backend on force_modern
> virtio-net: handle force_modern for vhost
>
> hw/net/virtio-net.c | 20 ++++++++++++++++++++
> hw/s390x/virtio-ccw.c | 3 +++
> hw/virtio/vhost.c | 17 +++++++++++++++++
> hw/virtio/virtio-pci.c | 1 +
> hw/virtio/virtio.c | 13 +++++++++++++
> include/hw/virtio/vhost.h | 2 ++
> include/hw/virtio/virtio.h | 2 ++
> 7 files changed, 58 insertions(+)
>
>
> base-commit: 2c3e83f92d93fbab071b8a96b8ab769b01902475
> --
> 2.25.1
- Re: [RFC PATCH v2 0/5] virtio: early detect 'modern' virtio,
Michael S. Tsirkin <=