Re: [PATCH v4 3/6] iommu/sva: Stop using ioasid_set for SVA

[Jason Gunthorpe]

On Fri, Mar 03, 2023 at 05:57:41PM +0800, Baolu Lu wrote:
> On 2023/3/3 17:32, Jean-Philippe Brucker wrote:
> > > I suppose the common thing is reserving some kind of special PASIDs.
> > Are you planning to use RID_PASID != 0 in VT-d?  Otherwise we could just
> > communicate min_pasid from the IOMMU driver the same way we do max_pasid.
> > 
> > Otherwise I guess re-introduce a lighter ioasid_alloc() that the IOMMU
> > driver calls to reserve PASID0/RID_PASID.
> 
> Yes. We probably will use a non-zero RID_PASID in the future. An
> interface to reserve (or allocate) a PASID from iommu_global_pasid_ida
> should work then.

Just allowing the driver to store XA_ZERO_ENTRY would be fine

Jason