[PATCH v5 0/7] Fixes for dma-iommu swiotlb bounce buffers

[David Stevens]

From: David Stevens <stevensd@xxxxxxxxxxxx>

This patch set includes various fixes for dma-iommu's swiotlb bounce
buffers for untrusted devices. There are four fixes for correctness
issues, one for a performance issue, and one for general cleanup.

The min_align_mask issue was found when running fio on an untrusted nvme
device with bs=512. The other issues were found via code inspection, so
I don't have any specific use cases where things were not working, nor
any concrete performance numbers.

v4 -> v5:
 - Fix xen build error
 - Move _swiotlb refactor into its own patch

v3 -> v4:
 - Fold _swiotlb functions into _page functions
 - Add patch to align swiotlb buffer to iovad granule
 - Combine if checks in iommu_dma_sync_sg_* functions

v2 -> v3:
 - Add new patch to address min_align_mask bug
 - Set SKIP_CPU_SYNC flag after syncing in map/unmap
 - Properly call arch_sync_dma_for_cpu in iommu_dma_sync_sg_for_cpu

v1 -> v2:
 - Split fixes into dedicated patches
 - Less invasive changes to fix arch_sync when mapping
 - Leave dev_is_untrusted check for strict iommu

David Stevens (7):
  dma-iommu: fix sync_sg with swiotlb
  dma-iommu: fix arch_sync_dma for map
  dma-iommu: skip extra sync during unmap w/swiotlb
  dma-iommu: fold _swiotlb helpers into callers
  dma-iommu: Check CONFIG_SWIOTLB more broadly
  swiotlb: support aligned swiotlb buffers
  dma-iommu: account for min_align_mask

 drivers/iommu/dma-iommu.c | 193 +++++++++++++++++---------------------
 drivers/xen/swiotlb-xen.c |   2 +-
 include/linux/swiotlb.h   |   3 +-
 kernel/dma/swiotlb.c      |  11 ++-
 4 files changed, 98 insertions(+), 111 deletions(-)

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2.33.0.rc1.237.g0d66db33f3-goog