diff options
Diffstat (limited to 'drivers/iommu/dma-iommu.c')
| -rw-r--r-- | drivers/iommu/dma-iommu.c | 34 |
1 files changed, 19 insertions, 15 deletions
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index eca1afa36508..f731e4b2a417 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1152,9 +1152,6 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, */ if (dev_use_swiotlb(dev, size, dir) && iova_offset(iovad, phys | size)) { - void *padding_start; - size_t padding_size, aligned_size; - if (!is_swiotlb_active(dev)) { dev_warn_once(dev, "DMA bounce buffers are inactive, unable to map unaligned transaction.\n"); return DMA_MAPPING_ERROR; @@ -1162,24 +1159,30 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, trace_swiotlb_bounced(dev, phys, size); - aligned_size = iova_align(iovad, size); - phys = swiotlb_tbl_map_single(dev, phys, size, aligned_size, + phys = swiotlb_tbl_map_single(dev, phys, size, iova_mask(iovad), dir, attrs); if (phys == DMA_MAPPING_ERROR) return DMA_MAPPING_ERROR; - /* Cleanup the padding area. */ - padding_start = phys_to_virt(phys); - padding_size = aligned_size; + /* + * Untrusted devices should not see padding areas with random + * leftover kernel data, so zero the pre- and post-padding. + * swiotlb_tbl_map_single() has initialized the bounce buffer + * proper to the contents of the original memory buffer. + */ + if (dev_is_untrusted(dev)) { + size_t start, virt = (size_t)phys_to_virt(phys); - if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && - (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) { - padding_start += size; - padding_size -= size; - } + /* Pre-padding */ + start = iova_align_down(iovad, virt); + memset((void *)start, 0, virt - start); - memset(padding_start, 0, padding_size); + /* Post-padding */ + start = virt + size; + memset((void *)start, 0, + iova_align(iovad, start) - start); + } } if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) @@ -1718,7 +1721,8 @@ static size_t iommu_dma_max_mapping_size(struct device *dev) } static const struct dma_map_ops iommu_dma_ops = { - .flags = DMA_F_PCI_P2PDMA_SUPPORTED, + .flags = DMA_F_PCI_P2PDMA_SUPPORTED | + DMA_F_CAN_SKIP_SYNC, .alloc = iommu_dma_alloc, .free = iommu_dma_free, .alloc_pages_op = dma_common_alloc_pages, |