Messages in this thread | | | Date | Fri, 10 Dec 2021 14:53:40 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 3/4] iommu/vt-d: Support PASID DMA for in-kernel usage |
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On Fri, Dec 10, 2021 at 10:18:20AM -0800, Jacob Pan wrote:
> > If one device has 10 PASID's pointing to this domain you must flush > > them all if that is what the HW requires. > > > Yes. My point is that other than PASID 0 is a given, we must track the 10 > PASIDs to avoid wasted flush. It also depend on how TLBs are tagged and > flush granularity available. But at the API level, should we support all the > cases?
Yes, iommufd will expose all the cases to userspace and anything is possible.
A scheme that can only attach a domain to one PASID is functionally useless except for this IDXD problem, so don't make something so broken.
Jason
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