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| author | David Stevens <stevensd@chromium.org> | 2021-09-29 05:33:00 +0300 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2021-09-29 13:50:42 +0300 |
| commit | 2cbc61a1b1665c84282dbf2b1747ffa0b6248639 (patch) | |
| tree | ed387add6bbcd2a61edef807e0e7e2daeb63c476 | |
| parent | e81e99bacc9f9347bda7808a949c1ce9fcc2bbf4 (diff) | |
| download | linux-2cbc61a1b1665c84282dbf2b1747ffa0b6248639.tar.xz | |
iommu/dma: Account for min_align_mask w/swiotlb
Pass the non-aligned size to __iommu_dma_map when using swiotlb bounce
buffers in iommu_dma_map_page, to account for min_align_mask.
To deal with granule alignment, __iommu_dma_map maps iova_align(size +
iova_off) bytes starting at phys - iova_off. If iommu_dma_map_page
passes aligned size when using swiotlb, then this becomes
iova_align(iova_align(orig_size) + iova_off). Normally iova_off will be
zero when using swiotlb. However, this is not the case for devices that
set min_align_mask. When iova_off is non-zero, __iommu_dma_map ends up
mapping an extra page at the end of the buffer. Beyond just being a
security issue, the extra page is not cleaned up by __iommu_dma_unmap.
This causes problems when the IOVA is reused, due to collisions in the
iommu driver. Just passing the original size is sufficient, since
__iommu_dma_map will take care of granule alignment.
Fixes: 1f221a0d0dbf ("swiotlb: respect min_align_mask")
Signed-off-by: David Stevens <stevensd@chromium.org>
Link: https://lore.kernel.org/r/20210929023300.335969-8-stevensd@google.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
| -rw-r--r-- | drivers/iommu/dma-iommu.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 289c49ead01a..342359727a59 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -806,7 +806,6 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, struct iommu_domain *domain = iommu_get_dma_domain(dev); struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; - size_t aligned_size = size; dma_addr_t iova, dma_mask = dma_get_mask(dev); /* @@ -815,7 +814,7 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, */ if (dev_use_swiotlb(dev) && iova_offset(iovad, phys | size)) { void *padding_start; - size_t padding_size; + size_t padding_size, aligned_size; aligned_size = iova_align(iovad, size); phys = swiotlb_tbl_map_single(dev, phys, size, aligned_size, @@ -840,7 +839,7 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) arch_sync_dma_for_device(phys, size, dir); - iova = __iommu_dma_map(dev, phys, aligned_size, prot, dma_mask); + iova = __iommu_dma_map(dev, phys, size, prot, dma_mask); if (iova == DMA_MAPPING_ERROR && is_swiotlb_buffer(dev, phys)) swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs); return iova; |