Commit 164afb1d authored by Robin Murphy's avatar Robin Murphy Committed by Joerg Roedel
Browse files

iommu/dma: Use correct offset in map_sg

When mapping a non-page-aligned scatterlist entry, we copy the original
offset to the output DMA address before aligning it to hand off to
iommu_map_sg(), then later adding the IOVA page address portion to get
the final mapped address. However, when the IOVA page size is smaller
than the CPU page size, it is the offset within the IOVA page we want,
not that within the CPU page, which can easily be larger than an IOVA
page and thus result in an incorrect final address.

Fix the bug by taking only the IOVA-aligned part of the offset as the
basis of the DMA address, not the whole thing.
Signed-off-by: default avatarRobin Murphy <>
Signed-off-by: default avatarJoerg Roedel <>
parent f64232ee
......@@ -458,7 +458,7 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
size_t s_offset = iova_offset(iovad, s->offset);
size_t s_length = s->length;
sg_dma_address(s) = s->offset;
sg_dma_address(s) = s_offset;
sg_dma_len(s) = s_length;
s->offset -= s_offset;
s_length = iova_align(iovad, s_length + s_offset);
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