On Wed, Apr 01, 2015 at 03:28:10PM +0100, David Woodhouse wrote: > On Wed, 2015-04-01 at 15:05 +0100, Will Deacon wrote: > > That just leaves the case where the caller tries to map something > > smaller than a page. Do we want to return the amount mapped in > > iommu_map? > > Perhaps we should just expose the *minimum* page size? Although for the > IOMMU API I thought that was always assumed to be the same as PAGE_SIZE, > and for the DMA API it doesn't matter much because you're *given* the > IOVA, and you just know that it's mapped *enough*.
We can certainly run with a 64k CPU page size and a 4k IOMMU page size on arm64 systems. The other way around is much more problematic, so I think you're right to suggest the minimum page size. However, once we have that, we run into the same problem that we've got with the current pgsize_bitmap. Namely, that it needs to be a per-domain property to avoid it changing dynamically following an initial map request or a probe of a new IOMMU device. Will _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
