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Subject[PATCH v2] vfio/type1: fix dirty bitmap calculation in vfio_dma_rw
Date
the count of dirtied pages is not only determined by count of copied
pages, but also by the start offset.

e.g. if offset = PAGE_SIZE - 1, and *copied=2, the dirty pages count is
2, instead of 1 or 0.

Fixes: d6a4c185660c ("vfio iommu: Implementation of ioctl for dirty pages tracking")

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>

---
v2: updated the format of the Fixes: line.
---
drivers/vfio/vfio_iommu_type1.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 5fbf0c1f7433..d0438388feeb 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2933,7 +2933,8 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu,
* size
*/
bitmap_set(dma->bitmap, offset >> pgshift,
- *copied >> pgshift);
+ ((offset + *copied - 1) >> pgshift) -
+ (offset >> pgshift) + 1);
}
} else
*copied = copy_from_user(data, (void __user *)vaddr,
--
2.17.1
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