Re: [PATCH] xen: don't require virtio with grants for non-PV guests

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Wed, Jun 15, 2022 at 02:53:54PM +0200, Juergen Gross wrote:
> On 15.06.22 13:54, Christoph Hellwig wrote:
> > On Wed, Jun 15, 2022 at 01:39:01PM +0200, Juergen Gross wrote:
> > > No, it doesn't. I'm working on a qemu patch series enabling the qemu
> > > based backends to support grants with virtio. The code is working fine
> > > on x86, too (apart from the fact that the backends aren't ready yet).
> > 
> > The code right now in mainline only ever sets the ops for DMA.  So
> > I can't see how you could make it work.
> 
> Ah, you are right. I was using a guest with an older version of the series.
> Sorry for the noise.

No problem.  But whatever you end up using to enable the grant DMA
ops n x86 should also require the platform access feature.  We already
have that information so we can make use of it.