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 6f5dc76
("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: cf5bb83 ("crypto: qat - fix DMA transfer direction")
Reviewed-by: Ahsan Atta <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

Author: gcabiddu

drivers/crypto/intel/qat/qat_common/qat_bl.c

@@ -38,7 +38,7 @@ void qat_bl_free_bufl(struct adf_accel_dev *accel_dev,
 		for (i = 0; i < blout->num_mapped_bufs; i++) {
 			dma_unmap_single(dev, blout->buffers[i].addr,
 					 blout->buffers[i].len,
-					 DMA_FROM_DEVICE);
+					 DMA_BIDIRECTIONAL);
 		}
 		dma_unmap_single(dev, blpout, sz_out, DMA_TO_DEVICE);
 
@@ -162,7 +162,7 @@ static int __qat_bl_sgl_to_bufl(struct adf_accel_dev *accel_dev,
 			}
 			buffers[y].addr = dma_map_single(dev, sg_virt(sg) + left,
 							 sg->length - left,
-							 DMA_FROM_DEVICE);
+							 DMA_BIDIRECTIONAL);
 			if (unlikely(dma_mapping_error(dev, buffers[y].addr)))
 				goto err_out;
 			buffers[y].len = sg->length;
@@ -204,7 +204,7 @@ static int __qat_bl_sgl_to_bufl(struct adf_accel_dev *accel_dev,
 		if (!dma_mapping_error(dev, buflout->buffers[i].addr))
 			dma_unmap_single(dev, buflout->buffers[i].addr,
 					 buflout->buffers[i].len,
-					 DMA_FROM_DEVICE);
+					 DMA_BIDIRECTIONAL);
 	}
 
 	if (!buf->sgl_dst_valid)

drivers/crypto/intel/qat/qat_common/qat_compression.c

@@ -204,7 +204,7 @@ static int qat_compression_alloc_dc_data(struct adf_accel_dev *accel_dev)
 	if (!obuff)
 		goto err;
 
-	obuff_p = dma_map_single(dev, obuff, ovf_buff_sz, DMA_FROM_DEVICE);
+	obuff_p = dma_map_single(dev, obuff, ovf_buff_sz, DMA_BIDIRECTIONAL);
 	if (unlikely(dma_mapping_error(dev, obuff_p)))
 		goto err;
 
@@ -232,7 +232,7 @@ static void qat_free_dc_data(struct adf_accel_dev *accel_dev)
 		return;
 
 	dma_unmap_single(dev, dc_data->ovf_buff_p, dc_data->ovf_buff_sz,
-			 DMA_FROM_DEVICE);
+			 DMA_BIDIRECTIONAL);
 	kfree_sensitive(dc_data->ovf_buff);
 	kfree(dc_data);
 	accel_dev->dc_data = NULL;