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commit2cbc61a1b1upstream. 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:1f221a0d0d("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.