RE: [virtio-dev] Re: [PATCH 2/5] Introduce VIRTIO_F_ADMIN_VQ_INDIRECT_DESC/VIRTIO_F_ADMIN_VQ_IN_ORDER

[Parav Pandit <parav@nvidia.com>]

> From: Michael S. Tsirkin <mst@redhat.com>
> Sent: Wednesday, January 19, 2022 10:10 PM
> 
> On Wed, Jan 19, 2022 at 10:10:38AM +0000, Parav Pandit wrote:
> > Virtio spec should define a minimum expectations from the system such
> > as flushing the cache or no cache
> 
> well one of the things virtio is trying to do is being compatible with a wide
> range of hypervisors/OSes. 
We are not breaking any compatibility with this optional enhancement.

> it might be tricky to change how they work
> internally. if we are relying on tricks like this it might be necessary to poke at
> some popular systems to see what they do.
Sure it should work on wide range of hypervisors/OSes. It's a new feature so those will implement when scale is critical for them.

If we consider Linux as popular system than Linux pci subsystem and mlx5 driver already implements it in upstream kernel 5.13.
(It doesn't cache it).

Similar implementation for non virtio also exists in _other_ popular OS, which I should avoid annotating here.