[dpdk-dev] [PATCH] cryptodev: support multiple cipher block sizes

Matan Azrad matan at nvidia.com
Thu Feb 4 15:34:12 CET 2021

In cryptography, a block cipher is a deterministic algorithm operating
on fixed-length groups of bits, called blocks.

A block cipher consists of two paired algorithms, one for encryption
and the other for decryption. Both algorithms accept two inputs:
an input block of size n bits and a key of size k bits; and both yield
an n-bit output block. The decryption algorithm is defined to be the
inverse function of the encryption.

Some cipher algorithms support multiple block sizes, e.g. AES-XTS
supports any block size in range [16B, 2^24B], in this case,
A plain-text data, divided into N amount of n-bits blocks, which is
encrypted to the same data size, cipher-text, must be decrypted in the
same division of N amount of n-bits blocks in order to get the same
plain-text data.

The current cryptodev API doesn't allow the user to select a specific
block size supported by the devices
In addition, there is no definition how the IV is detected per block
when single operation includes more than one block.

That causes applications to use single operation per block even though
all the data is continuous in memory what reduces datapath performance.

Add a new feature flag to support multiple block sizes, called
Add a new field in cipher capability, called bsf - block size flags,
where the devices can report the range of the supported block sizes.
Add a new cipher transformation field, called block_size, where the user
can select one block size from the supported range.

All the new fields do not change the size of their structures.

Using flags to report the supported block sizes capability allows the
devices to report a range simply as same as the user to read it simply.
Also, thus sizes are usually common and probably will be shared between
the devices.

Signed-off-by: Matan Azrad <matan at nvidia.com>
 lib/librte_cryptodev/rte_crypto_sym.h | 12 ++++++++++++
 lib/librte_cryptodev/rte_cryptodev.h  | 23 ++++++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/lib/librte_cryptodev/rte_crypto_sym.h b/lib/librte_cryptodev/rte_crypto_sym.h
index 9d572ec..9a1215d 100644
--- a/lib/librte_cryptodev/rte_crypto_sym.h
+++ b/lib/librte_cryptodev/rte_crypto_sym.h
@@ -265,6 +265,18 @@ struct rte_crypto_cipher_xform {
 		 * which can be in the range 7 to 13 inclusive.
 	} iv;	/**< Initialisation vector parameters */
+	uint32_t block_size;
+	/**< When RTE_CRYPTODEV_FF_CIPHER_MULITPLE_BLOCKS is reported, this is
+	 * the block size of the algorithm, otherwise or when the value is 0,
+	 * use the default block size provided in the capability.
+	 * The value should be in the range defined by the bsf field in the
+	 * cipher capability.
+	 *
+	 * - For AES-XTS it is the size of data-unit, from IEEE Std 1619-2007.
+	 * For-each data-unit in the operation, the tweak(IV) value is
+	 * assigned consecutively starting from the operation assigned tweak.
+	 */
 /** Symmetric Authentication / Hash Algorithms
diff --git a/lib/librte_cryptodev/rte_cryptodev.h b/lib/librte_cryptodev/rte_cryptodev.h
index ae34f33..60ba839 100644
--- a/lib/librte_cryptodev/rte_cryptodev.h
+++ b/lib/librte_cryptodev/rte_cryptodev.h
@@ -96,6 +96,19 @@ struct rte_crypto_param_range {
+ * Crypto device supported block size flags for cipher algorithms
+ * Each flag represents single or range of supported block sizes
+ */
+/* All the sizes from the algorithm standard */
+#define RTE_CRYPTO_CIPHER_BSF_4096_BYTES 0x10
+#define RTE_CRYPTO_CIPHER_BSF_4160_BYTES 0x20
  * Symmetric Crypto Capability
 struct rte_cryptodev_symmetric_capability {
@@ -122,11 +135,19 @@ struct rte_cryptodev_symmetric_capability {
 			enum rte_crypto_cipher_algorithm algo;
 			/**< cipher algorithm */
 			uint16_t block_size;
-			/**< algorithm block size */
+			/**<
+			 * algorithm block size
+			 * For algorithms support more than single block size,
+			 * this is the default block size supported by the
+			 * driver, all the supported sizes are reflected in the
+			 * bsf field.
+			 */
 			struct rte_crypto_param_range key_size;
 			/**< cipher key size range */
 			struct rte_crypto_param_range iv_size;
 			/**< Initialisation vector data size range */
+			uint32_t bsf;
+			/**< Block size flags */
 		} cipher;
 		/**< Symmetric Cipher transform capabilities */
 		struct {

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