Messages in this thread Patch in this message | | | From | David Stevens <> | Subject | [PATCH v4 5/6] swiotlb: support aligned swiotlb buffers | Date | Fri, 13 Aug 2021 16:38:38 +0900 |
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From: David Stevens <stevensd@chromium.org>
Add an argument to swiotlb_tbl_map_single that specifies the desired alignment of the allocated buffer. This is used by dma-iommu to ensure the buffer is aligned to the iova granule size when using swiotlb with untrusted sub-granule mappings. This addresses an issue where adjacent slots could be exposed to the untrusted device if IO_TLB_SIZE < iova granule < PAGE_SIZE.
Signed-off-by: David Stevens <stevensd@chromium.org> --- drivers/iommu/dma-iommu.c | 4 ++-- include/linux/swiotlb.h | 3 ++- kernel/dma/swiotlb.c | 11 +++++++---- 3 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index bad813d63ea6..b1b0327cc2f6 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -801,8 +801,8 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, size_t padding_size; aligned_size = iova_align(iovad, size); - phys = swiotlb_tbl_map_single(dev, phys, size, - aligned_size, dir, attrs); + phys = swiotlb_tbl_map_single(dev, phys, size, aligned_size, + iova_mask(iovad), dir, attrs); if (phys == DMA_MAPPING_ERROR) return DMA_MAPPING_ERROR; diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 216854a5e513..93d82e43eb3a 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -44,7 +44,8 @@ extern void __init swiotlb_update_mem_attributes(void); phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys, size_t mapping_size, size_t alloc_size, - enum dma_data_direction dir, unsigned long attrs); + unsigned int alloc_aligned_mask, enum dma_data_direction dir, + unsigned long attrs); extern void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index e50df8d8f87e..d4c45d8cd1fa 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -427,7 +427,7 @@ static unsigned int wrap_index(struct io_tlb_mem *mem, unsigned int index) * allocate a buffer from that IO TLB pool. */ static int find_slots(struct device *dev, phys_addr_t orig_addr, - size_t alloc_size) + size_t alloc_size, unsigned int alloc_align_mask) { struct io_tlb_mem *mem = io_tlb_default_mem; unsigned long boundary_mask = dma_get_seg_boundary(dev); @@ -450,6 +450,7 @@ static int find_slots(struct device *dev, phys_addr_t orig_addr, stride = (iotlb_align_mask >> IO_TLB_SHIFT) + 1; if (alloc_size >= PAGE_SIZE) stride = max(stride, stride << (PAGE_SHIFT - IO_TLB_SHIFT)); + stride = max(stride, (alloc_align_mask >> IO_TLB_SHIFT) + 1); spin_lock_irqsave(&mem->lock, flags); if (unlikely(nslots > mem->nslabs - mem->used)) @@ -504,7 +505,8 @@ static int find_slots(struct device *dev, phys_addr_t orig_addr, phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, size_t mapping_size, size_t alloc_size, - enum dma_data_direction dir, unsigned long attrs) + unsigned int alloc_align_mask, enum dma_data_direction dir, + unsigned long attrs) { struct io_tlb_mem *mem = io_tlb_default_mem; unsigned int offset = swiotlb_align_offset(dev, orig_addr); @@ -524,7 +526,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, return (phys_addr_t)DMA_MAPPING_ERROR; } - index = find_slots(dev, orig_addr, alloc_size + offset); + index = find_slots(dev, orig_addr, + alloc_size + offset, alloc_align_mask); if (index == -1) { if (!(attrs & DMA_ATTR_NO_WARN)) dev_warn_ratelimited(dev, @@ -636,7 +639,7 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size, trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size, swiotlb_force); - swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, dir, + swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, 0, dir, attrs); if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR) return DMA_MAPPING_ERROR; -- 2.33.0.rc1.237.g0d66db33f3-goog
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