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QAT devices perform an additional integrity check during compression by decompressing the output. Starting from QAT GEN4, this verification is done in-line by the hardware. However, on GEN2 devices, the hardware reads back the compressed output from the destination buffer and performs a decompression operation using it as the source. In the current QAT driver, destination buffers are always marked as write-only. This is incorrect for QAT GEN2 compression, where the buffer is also read during verification. Since commit6f5dc76580("iommu/vt-d: Restore WO permissions on second-level paging entries"), merged in v6.16-rc1, write-only permissions are strictly enforced, leading to DMAR errors when using QAT GEN2 devices for compression, if VT-d is enabled. Mark the destination buffers as DMA_BIDIRECTIONAL. This ensures compatibility with GEN2 devices, even though it is not required for QAT GEN4 and later. Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com> Fixes:cf5bb835b7("crypto: qat - fix DMA transfer direction") Reviewed-by: Ahsan Atta <ahsan.atta@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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 reStructuredText 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.