linux

iv/linux

History

Will Deacon 51b30ecb73 swiotlb: Fix alignment checks when both allocation and DMA masks are present

Nicolin reports that swiotlb buffer allocations fail for an NVME device
behind an IOMMU using 64KiB pages. This is because we end up with a
minimum allocation alignment of 64KiB (for the IOMMU to map the buffer
safely) but a minimum DMA alignment mask corresponding to a 4KiB NVME
page (i.e. preserving the 4KiB page offset from the original allocation).
If the original address is not 4KiB-aligned, the allocation will fail
because swiotlb_search_pool_area() erroneously compares these unmasked
bits with the 64KiB-aligned candidate allocation.

Tweak swiotlb_search_pool_area() so that the DMA alignment mask is
reduced based on the required alignment of the allocation.

Fixes: 82612d66d51d ("iommu: Allow the dma-iommu api to use bounce buffers")
Link: https://lore.kernel.org/r/cover.1707851466.git.nicolinc@nvidia.com
Reported-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

2024-03-13 11:39:27 -07:00

coherent.c

dma-mapping: clear dev->dma_mem to NULL after freeing it

2023-12-15 12:32:45 +01:00

contiguous.c

Revert "dma-contiguous: check for memory region overlap"

2023-09-08 05:58:32 -03:00

debug.c

dma-mapping fixes for Linux 6.8

2024-01-18 16:49:34 -08:00

debug.h

dma-debug: teach add_dma_entry() about DMA_ATTR_SKIP_CPU_SYNC