crypto: qat - fix DMA direction for compression on GEN2 devices

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 commit 6f5dc7658094
("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 <[email protected]>
Fixes: cf5bb835b7c8 ("crypto: qat - fix DMA transfer direction")
Reviewed-by: Ahsan Atta <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

0 files changed, 0 insertions, 0 deletions