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Note preservation here > means preservation of physical memory using KHO only. IOVAs and IOMMU > mappings are out of scope. > > The complexity and need of this was discussed in the thread mentioned > below. It was proposed to allow preservation of only a subset of > allocations with minimum support. Offline discussion with Will Deacon > concluded that this series is still needed, because we still want to use > coherent allocations for Arm sMMUv3 ste/cds, so sending this v2. Was this before or after concluding that ARM was OK with using cachable memory? > include/linux/dma-direct.h | 29 +++++ > include/linux/dma-map-ops.h | 10 ++ > include/linux/dma-mapping.h | 100 ++++++++++++++ > include/linux/kho/abi/dma_alloc.h | 32 +++++ > kernel/dma/Kconfig | 12 ++ > kernel/dma/Makefile | 1 + > kernel/dma/coherent.c | 11 ++ > kernel/dma/contiguous.c | 27 ++++ > kernel/dma/direct.c | 189 +++++++++++++++++++++++++++ > kernel/dma/direct_test.c | 208 ++++++++++++++++++++++++++++++ > kernel/dma/mapping.c | 132 +++++++++++++++++++ > kernel/dma/pool.c | 17 +++ > 12 files changed, 768 insertions(+) Because this seems like quite a big change to swallow compared to just using iommu pages.h Jason