"Aneesh Kumar K.V (Arm)" <[email protected]> writes: > This series tracks confidential-computing shared DMA state through the > dma-direct, dma-pool, and swiotlb paths so that encrypted and decrypted > DMA buffers are handled consistently. > > Today, the direct DMA path mostly relies on force_dma_unencrypted() for > shared/decrypted buffer handling. This series consolidates the > force_dma_unencrypted() checks in the top-level functions and ensures > that the remaining DMA interfaces use DMA attributes to make the correct > decisions. > > The series separates mapping and allocation state: > - DMA_ATTR_CC_SHARED describes the DMA address attribute requested for a > mapping. It tells the DMA mapping path that the DMA address must target > shared/decrypted memory. > - __DMA_ATTR_ALLOC_CC_SHARED is an internal DMA-mapping attribute used only > by allocation paths after the DMA core decides that the backing pages > must be allocated as shared/decrypted memory. > > The series: > - moves swiotlb-backed allocations out of __dma_direct_alloc_pages(), > - uses __DMA_ATTR_ALLOC_CC_SHARED through the dma-direct alloc/free paths > - teaches the atomic DMA pools to track encrypted versus decrypted > state > - tracks swiotlb pool encryption state and enforces strict pool > selection > - centralizes encrypted/decrypted pgprot handling in dma_pgprot() using > DMA attributes > - passes DMA attributes down to dma_capable() so capability checks can > validate whether the selected DMA address encoding matches > DMA_ATTR_CC_SHARED > - makes dma_direct_map_phys() choose the DMA address encoding from > DMA_ATTR_CC_SHARED and fall back to swiotlb when a shared DMA request > cannot use the direct mapping, which lets arm64 and x86 CCA guests stop > relying on SWIOTLB_FORCE for DMA mappings > - use the selected swiotlb pool state to derive the returned DMA > address > - reports CC_ATTR_GUEST_MEM_ENCRYPT for arm64 Realms, powerpc secure > guests, and s390 protected virtualization guests. > > Dependency: > This series depends on the pKVM changes posted at: > https://lore.kernel.org/all/[email protected] > > Please merge this series only after the pKVM changes above are merged. > Otherwise pKVM will be broken. >
A rebased tree on top of the dependent pKVM changes can be found at: https://gitlab.arm.com/linux-arm/linux-cca/-/tree/scratch/pkvm/testing?ref_type=heads The patches had minor conflicts. I am not sure how we want to get this merged. Should we ask the pKVM maintainers for a topic branch, and then I can repost the updated series on top of that? -aneesh
