On Tue, Jul 19, 2016 at 01:36:49PM -0700, Mitchel Humpherys wrote: > The following patch to the ARM SMMU driver: > > commit d346180e70b91b3d5a1ae7e5603e65593d4622bc > Author: Robin Murphy <robin.mur...@arm.com> > Date: Tue Jan 26 18:06:34 2016 +0000 > > iommu/arm-smmu: Treat all device transactions as unprivileged > > started forcing all SMMU transactions to come through as "unprivileged". > The rationale given was that: > > (1) There is no way in the IOMMU API to even request privileged mappings. > > (2) It's difficult to implement a DMA mapper that correctly models the > ARM VMSAv8 behavior of unprivileged-writeable => > privileged-execute-never. > > This series rectifies (1) by introducing an IOMMU API for privileged > mappings and implements it in io-pgtable-arm. > > This series rectifies (2) by introducing a new dma attribute > (DMA_ATTR_PRIVILEGED) for users of the DMA API that need privileged > mappings which are inaccessible to lesser-privileged execution levels, and > implements it in the arm64 IOMMU DMA mapper. The one known user (pl330.c) > is converted over to the new attribute. > > Jordan and Jeremy can provide more info on the use case if needed, but the > high level is that it's a security feature to prevent attacks such as [1].
This all looks good to me: Acked-by: Will Deacon <will.dea...@arm.com> It looks pretty fiddly to merge, however. How are you planning to get this upstream? Will
