This is a note to let you know that I've just added the patch titled
iommu/dma: Fix sync_sg with swiotlb
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-dma-fix-sync_sg-with-swiotlb.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 29e89631ce7e9b7df7a93881a0f90fbc82c8196a
Author: David Stevens <stevensd@xxxxxxxxxxxx>
Date: Wed Sep 29 11:32:54 2021 +0900
iommu/dma: Fix sync_sg with swiotlb
[ Upstream commit 08ae5d4a1ae96b72222e7b02d072bb997ff29dac ]
The is_swiotlb_buffer function takes the physical address of the swiotlb
buffer, not the physical address of the original buffer. The sglist
contains the physical addresses of the original buffer, so for the
sync_sg functions to work properly when a bounce buffer might have been
used, we need to use iommu_iova_to_phys to look up the physical address.
This is what sync_single does, so call that function on each sglist
segment.
The previous code mostly worked because swiotlb does the transfer on map
and unmap. However, any callers which use DMA_ATTR_SKIP_CPU_SYNC with
sglists or which call sync_sg would not have had anything copied to the
bounce buffer.
Fixes: 82612d66d51d ("iommu: Allow the iommu/dma api to use bounce buffers")
Signed-off-by: David Stevens <stevensd@xxxxxxxxxxxx>
Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Link: https://lore.kernel.org/r/20210929023300.335969-2-stevensd@xxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 896bea04c347e..c4d205b63c582 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -828,17 +828,13 @@ static void iommu_dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sg;
int i;
- if (dev_is_dma_coherent(dev) && !dev_is_untrusted(dev))
- return;
-
- for_each_sg(sgl, sg, nelems, i) {
- if (!dev_is_dma_coherent(dev))
+ if (dev_is_untrusted(dev))
+ for_each_sg(sgl, sg, nelems, i)
+ iommu_dma_sync_single_for_cpu(dev, sg_dma_address(sg),
+ sg->length, dir);
+ else if (!dev_is_dma_coherent(dev))
+ for_each_sg(sgl, sg, nelems, i)
arch_sync_dma_for_cpu(sg_phys(sg), sg->length, dir);
-
- if (is_swiotlb_buffer(dev, sg_phys(sg)))
- swiotlb_sync_single_for_cpu(dev, sg_phys(sg),
- sg->length, dir);
- }
}
static void iommu_dma_sync_sg_for_device(struct device *dev,
@@ -848,17 +844,14 @@ static void iommu_dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sg;
int i;
- if (dev_is_dma_coherent(dev) && !dev_is_untrusted(dev))
- return;
-
- for_each_sg(sgl, sg, nelems, i) {
- if (is_swiotlb_buffer(dev, sg_phys(sg)))
- swiotlb_sync_single_for_device(dev, sg_phys(sg),
- sg->length, dir);
-
- if (!dev_is_dma_coherent(dev))
+ if (dev_is_untrusted(dev))
+ for_each_sg(sgl, sg, nelems, i)
+ iommu_dma_sync_single_for_device(dev,
+ sg_dma_address(sg),
+ sg->length, dir);
+ else if (!dev_is_dma_coherent(dev))
+ for_each_sg(sgl, sg, nelems, i)
arch_sync_dma_for_device(sg_phys(sg), sg->length, dir);
- }
}
static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
