arm-smmu-v3 sharing SID

[Jason Gunthorpe]

On Thu, May 18, 2023 at 12:33:25PM +0100, Robin Murphy wrote:

> I'm fairly confident in reasoning about this for basic .attach_dev purposes,
> since I did implement the equivalent for SMMUv2, but I'm not sure I even
> want to think about what it would mean for SVA, PASIDs and nesting...

IIRC we've already taken the approach elsewhere to block PASID if the
group is not singleton.

Jason