On 01/03/18 06:52, Lu Baolu wrote: > Can the pasid management code be moved into a common library? > PASID is not stick to SVA. An IOMMU model device could be designed > to use PASID for second level translation (classical DMA translation) > as well. What do you mean by second level translation? Do you see a use-case with nesting translation within the host? I agree that PASID + classical DMA is desirable. A device driver would allocate PASIDs and perform iommu_sva_map(domain, pasid, iova, pa, size, prot) and iommu_sva_unmap(domain, pasid, iova, size). I'm hoping that we can also augment the DMA API with PASIDs, and that a driver can use both shared and private contexts simultaneously. So that it can use a few PASIDs for management purpose, and assign the rest to userspace. The intent is for iommu-sva.c to be this common library. Work for "private" PASID allocation is underway, see Jordan Crouse's series posted last week https://www.spinics.net/lists/arm-kernel/msg635857.html Thanks, Jean
