Re: [RFC v2] /dev/iommu uAPI proposal

From: Jason Gunthorpe
Date: Wed Aug 04 2021 - 10:04:53 EST


On Mon, Aug 02, 2021 at 02:49:44AM +0000, Tian, Kevin wrote:

> Can you elaborate? IMO the user only cares about the label (device cookie
> plus optional vPASID) which is generated by itself when doing the attaching
> call, and expects this virtual label being used in various spots (invalidation,
> page fault, etc.). How the system labels the traffic (the physical RID or RID+
> PASID) should be completely invisible to userspace.

I don't think that is true if the vIOMMU driver is also emulating
PASID. Presumably the same is true for other PASID-like schemes.

Jason