| Message ID | 8317d001da4f48831fa23d8d7729a4659ac72b49.1451924092.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jan 04, 2016 at 04:19:42PM +0000, Robin Murphy wrote: > 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: Robin Murphy <robin.murphy@arm.com> Applied, thanks.
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 2e7417f..72d6182 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -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);
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: Robin Murphy <robin.murphy@arm.com> --- Rebased onto iommu/fixes. drivers/iommu/dma-iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)