[PATCH v4 1/3] crypto: qce - use cryptlen when adding extra sgl

[PATCH v4 1/3] crypto: qce - use cryptlen when adding extra sgl

[Eneas U de Queiroz]

The qce crypto driver appends an extra entry to the dst sgl, to maintain
private state information.

When the gcm driver sends requests to the ctr skcipher, it passes the
authentication tag after the actual crypto payload, but it must not be
touched.

Commit 1336c2221bee ("crypto: qce - save a sg table slot for result
buf") limited the destination sgl to avoid overwriting the
authentication tag but it assumed the tag would be in a separate sgl
entry.

This is not always the case, so it is better to limit the length of the
destination buffer to req->cryptlen before appending the result buf.

Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>
--
v1 -> v4: no change

diff --git a/drivers/crypto/qce/dma.c b/drivers/crypto/qce/dma.c
index 7da893dc00e7..46db5bf366b4 100644
--- a/drivers/crypto/qce/dma.c
+++ b/drivers/crypto/qce/dma.c
@@ -48,9 +48,10 @@ void qce_dma_release(struct qce_dma_data *dma)
 
 struct scatterlist *
 qce_sgtable_add(struct sg_table *sgt, struct scatterlist *new_sgl,
-		int max_ents)
+		unsigned int max_len)
 {
 	struct scatterlist *sg = sgt->sgl, *sg_last = NULL;
+	unsigned int new_len;
 
 	while (sg) {
 		if (!sg_page(sg))
@@ -61,13 +62,13 @@ qce_sgtable_add(struct sg_table *sgt, struct scatterlist *new_sgl,
 	if (!sg)
 		return ERR_PTR(-EINVAL);
 
-	while (new_sgl && sg && max_ents) {
-		sg_set_page(sg, sg_page(new_sgl), new_sgl->length,
-			    new_sgl->offset);
+	while (new_sgl && sg && max_len) {
+		new_len = new_sgl->length > max_len ? max_len : new_sgl->length;
+		sg_set_page(sg, sg_page(new_sgl), new_len, new_sgl->offset);
 		sg_last = sg;
 		sg = sg_next(sg);
 		new_sgl = sg_next(new_sgl);
-		max_ents--;
+		max_len -= new_len;
 	}
 
 	return sg_last;
diff --git a/drivers/crypto/qce/dma.h b/drivers/crypto/qce/dma.h
index ed25a0d9829e..786402169360 100644
--- a/drivers/crypto/qce/dma.h
+++ b/drivers/crypto/qce/dma.h
@@ -43,6 +43,6 @@ void qce_dma_issue_pending(struct qce_dma_data *dma);
 int qce_dma_terminate_all(struct qce_dma_data *dma);
 struct scatterlist *
 qce_sgtable_add(struct sg_table *sgt, struct scatterlist *sg_add,
-		int max_ents);
+		unsigned int max_len);
 
 #endif /* _DMA_H_ */
diff --git a/drivers/crypto/qce/skcipher.c b/drivers/crypto/qce/skcipher.c
index 4217b745f124..63ae75809cb7 100644
--- a/drivers/crypto/qce/skcipher.c
+++ b/drivers/crypto/qce/skcipher.c
@@ -97,13 +97,14 @@ qce_skcipher_async_req_handle(struct crypto_async_request *async_req)
 
 	sg_init_one(&rctx->result_sg, qce->dma.result_buf, QCE_RESULT_BUF_SZ);
 
-	sg = qce_sgtable_add(&rctx->dst_tbl, req->dst, rctx->dst_nents - 1);
+	sg = qce_sgtable_add(&rctx->dst_tbl, req->dst, req->cryptlen);
 	if (IS_ERR(sg)) {
 		ret = PTR_ERR(sg);
 		goto error_free;
 	}
 
-	sg = qce_sgtable_add(&rctx->dst_tbl, &rctx->result_sg, 1);
+	sg = qce_sgtable_add(&rctx->dst_tbl, &rctx->result_sg,
+			     QCE_RESULT_BUF_SZ);
 	if (IS_ERR(sg)) {
 		ret = PTR_ERR(sg);
 		goto error_free;

[PATCH v4 2/3] crypto: qce - use AES fallback for small requests

[Eneas U de Queiroz]

Process small blocks using the fallback cipher, as a workaround for an
observed failure (DMA-related, apparently) when computing the GCM ghash
key.  This brings a speed gain as well, since it avoids the latency of
using the hardware engine to process small blocks.

Using software for all 16-byte requests would be enough to make GCM
work, but to increase performance, a larger threshold would be better.
Measuring the performance of supported ciphers with openssl speed,
software matches hardware at around 768-1024 bytes.

Considering the 256-bit ciphers, software is 2-3 times faster than qce
at 256-bytes, 30% faster at 512, and about even at 768-bytes.  With
128-bit keys, the break-even point would be around 1024-bytes.

This adds the 'aes_sw_max_len' parameter, to set the largest request
length processed by the software fallback.  Its default is being set to
512 bytes, a little lower than the break-even point, to balance the cost
in CPU usage.

Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>
--

v3 -> v4:
Corrected a missing 'static' declaration of aes_sw_max_len

v2 -> v3:
Corrected style issues pointed out by checkpatch.pl

v1 -> v2:
Changed the threshold from a fixed number to a module parameter

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index c2767ed54dfe..052d3ff7fb20 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -685,6 +685,29 @@ choice
 
 endchoice
 
+config CRYPTO_DEV_QCE_SW_MAX_LEN
+	int "Default maximum request size to use software for AES"
+	depends on CRYPTO_DEV_QCE && CRYPTO_DEV_QCE_SKCIPHER
+	default 512
+	help
+	  This sets the default maximum request size to perform AES requests
+	  using software instead of the crypto engine.  It can be changed by
+	  setting the aes_sw_max_len parameter.
+
+	  Small blocks are processed faster in software than hardware.
+	  Considering the 256-bit ciphers, software is 2-3 times faster than
+	  qce at 256-bytes, 30% faster at 512, and about even at 768-bytes.
+	  With 128-bit keys, the break-even point would be around 1024-bytes.
+
+	  The default is set a little lower, to 512 bytes, to balance the
+	  cost in CPU usage.  The minimum recommended setting is 16-bytes
+	  (1 AES block), since AES-GCM will fail if you set it lower.
+	  Setting this to zero will send all requests to the hardware.
+
+	  Note that 192-bit keys are not supported by the hardware and are
+	  always processed by the software fallback, and all DES requests
+	  are done by the hardware.
+
 config CRYPTO_DEV_QCOM_RNG
 	tristate "Qualcomm Random Number Generator Driver"
 	depends on ARCH_QCOM || COMPILE_TEST
diff --git a/drivers/crypto/qce/skcipher.c b/drivers/crypto/qce/skcipher.c
index 63ae75809cb7..e55348bba36f 100644
--- a/drivers/crypto/qce/skcipher.c
+++ b/drivers/crypto/qce/skcipher.c
@@ -5,6 +5,7 @@
 
 #include <linux/device.h>
 #include <linux/interrupt.h>
+#include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <crypto/aes.h>
 #include <crypto/internal/des.h>
@@ -12,6 +13,13 @@
 
 #include "cipher.h"
 
+static unsigned int aes_sw_max_len = CONFIG_CRYPTO_DEV_QCE_SW_MAX_LEN;
+module_param(aes_sw_max_len, uint, 0644);
+MODULE_PARM_DESC(aes_sw_max_len,
+		 "Only use hardware for AES requests larger than this "
+		 "[0=always use hardware; anything <16 breaks AES-GCM; default="
+		 __stringify(CONFIG_CRYPTO_DEV_QCE_SOFT_THRESHOLD)"]");
+
 static LIST_HEAD(skcipher_algs);
 
 static void qce_skcipher_done(void *data)
@@ -166,15 +174,10 @@ static int qce_skcipher_setkey(struct crypto_skcipher *ablk, const u8 *key,
 	switch (IS_XTS(flags) ? keylen >> 1 : keylen) {
 	case AES_KEYSIZE_128:
 	case AES_KEYSIZE_256:
+		memcpy(ctx->enc_key, key, keylen);
 		break;
-	default:
-		goto fallback;
 	}
 
-	ctx->enc_keylen = keylen;
-	memcpy(ctx->enc_key, key, keylen);
-	return 0;
-fallback:
 	ret = crypto_sync_skcipher_setkey(ctx->fallback, key, keylen);
 	if (!ret)
 		ctx->enc_keylen = keylen;
@@ -224,8 +227,9 @@ static int qce_skcipher_crypt(struct skcipher_request *req, int encrypt)
 	rctx->flags |= encrypt ? QCE_ENCRYPT : QCE_DECRYPT;
 	keylen = IS_XTS(rctx->flags) ? ctx->enc_keylen >> 1 : ctx->enc_keylen;
 
-	if (IS_AES(rctx->flags) && keylen != AES_KEYSIZE_128 &&
-	    keylen != AES_KEYSIZE_256) {
+	if (IS_AES(rctx->flags) &&
+	    ((keylen != AES_KEYSIZE_128 && keylen != AES_KEYSIZE_256)
+	     || req->cryptlen <= aes_sw_max_len)) {
 		SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, ctx->fallback);
 
 		skcipher_request_set_sync_tfm(subreq, ctx->fallback);

[PATCH v4 3/3] crypto: qce - handle AES-XTS cases that qce fails

[Eneas U de Queiroz]

QCE hangs when presented with an AES-XTS request whose length is larger
than QCE_SECTOR_SIZE (512-bytes), and is not a multiple of it.  Let the
fallback cipher handle them.

Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>
--
v3 -> v4
no change

v2 -> v3
Corrected style issues pointed out by checkpatch.pl

v1 -> v2
Patch was first added to the series

diff --git a/drivers/crypto/qce/common.c b/drivers/crypto/qce/common.c
index 629e7f34dc09..5006e74c40cd 100644
--- a/drivers/crypto/qce/common.c
+++ b/drivers/crypto/qce/common.c
@@ -15,8 +15,6 @@
 #include "regs-v5.h"
 #include "sha.h"
 
-#define QCE_SECTOR_SIZE		512
-
 static inline u32 qce_read(struct qce_device *qce, u32 offset)
 {
 	return readl(qce->base + offset);
diff --git a/drivers/crypto/qce/common.h b/drivers/crypto/qce/common.h
index 282d4317470d..9f989cba0f1b 100644
--- a/drivers/crypto/qce/common.h
+++ b/drivers/crypto/qce/common.h
@@ -12,6 +12,9 @@
 #include <crypto/hash.h>
 #include <crypto/internal/skcipher.h>
 
+/* xts du size */
+#define QCE_SECTOR_SIZE			512
+
 /* key size in bytes */
 #define QCE_SHA_HMAC_KEY_SIZE		64
 #define QCE_MAX_CIPHER_KEY_SIZE		AES_KEYSIZE_256
diff --git a/drivers/crypto/qce/skcipher.c b/drivers/crypto/qce/skcipher.c
index e55348bba36f..9458db683679 100644
--- a/drivers/crypto/qce/skcipher.c
+++ b/drivers/crypto/qce/skcipher.c
@@ -227,9 +227,14 @@ static int qce_skcipher_crypt(struct skcipher_request *req, int encrypt)
 	rctx->flags |= encrypt ? QCE_ENCRYPT : QCE_DECRYPT;
 	keylen = IS_XTS(rctx->flags) ? ctx->enc_keylen >> 1 : ctx->enc_keylen;
 
+	/* qce is hanging when AES-XTS request len > QCE_SECTOR_SIZE and
+	 * is not a multiple of it; pass such requests to the fallback
+	 */
 	if (IS_AES(rctx->flags) &&
 	    ((keylen != AES_KEYSIZE_128 && keylen != AES_KEYSIZE_256)
-	     || req->cryptlen <= aes_sw_max_len)) {
+	     || req->cryptlen <= aes_sw_max_len)
+	     || (IS_XTS(rctx->flags) && req->cryptlen > QCE_SECTOR_SIZE &&
+		 req->cryptlen % QCE_SECTOR_SIZE)) {
 		SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, ctx->fallback);
 
 		skcipher_request_set_sync_tfm(subreq, ctx->fallback);