15. MLX5 Crypto Driver

The MLX5 crypto driver library (librte_crypto_mlx5) provides support for NVIDIA ConnectX-6 family adapters.

15.1. Overview

The device can provide disk encryption services, allowing data encryption and decryption towards a disk. Having all encryption/decryption operations done in a single device can reduce cost and overheads of the related FIPS certification, as ConnectX-6 is FIPS 140-2 level-2 ready. The encryption cipher is AES-XTS of 256/512 bit key size.

MKEY is a memory region object in the hardware, that holds address translation information and attributes per memory area. Its ID must be tied to addresses provided to the hardware. The encryption operations are performed with MKEY read/write transactions, when the MKEY is configured to perform crypto operations.

The encryption does not require text to be aligned to the AES block size (128b).

See MLX5 Common Driver guide for more design details.

15.2. Configuration

See the mlx5 common configuration.

A device comes out of NVIDIA factory with pre-defined import methods. There are two possible import methods: wrapped or plaintext.

In case the device is in wrapped mode, it needs to be moved to crypto operational mode. In order to move the device to crypto operational mode, credential and KEK (Key Encrypting Key) should be set as the first step. The credential will be used by the software in order to perform crypto login, and the KEK is the AES Key Wrap Algorithm (rfc3394) key that will be used for sensitive data wrapping. The credential and the AES-XTS keys should be provided to the hardware, as ciphertext encrypted by the KEK.

A keytag (64 bits) should be appended to the AES-XTS keys (before wrapping), and will be validated when the hardware attempts to access it.

When crypto engines are defined to work in wrapped import method, they come out of the factory in Commissioning mode, and thus, cannot be used for crypto operations yet. A dedicated tool is used for changing the mode from Commissioning to Operational, while setting the first import_KEK and credential in plaintext. The mlxreg dedicated tool should be used as follows:

  • Set CRYPTO_OPERATIONAL register to set the device in crypto operational mode.

    The input to this tool is:

    • The first credential in plaintext, 40B.
    • The first import_KEK in plaintext: kek size 0 for 16B or 1 for 32B, kek data.


    mlxreg -d /dev/mst/mt4123_pciconf0 --reg_name CRYPTO_OPERATIONAL --get

    The “wrapped_crypto_operational” value will be “0x00000000”. The command to set the register should be executed only once, and all the values mentioned above should be specified in the same command.


    mlxreg -d /dev/mst/mt4123_pciconf0 --reg_name CRYPTO_OPERATIONAL \
    --set "credential[0]=0x10000000, credential[1]=0x10000000, kek[0]=0x00000000"

    All values not specified will remain 0. “wrapped_crypto_going_to_commissioning” and “wrapped_crypto_operational” should not be specified.

    All the device ports should set it in order to move to operational mode. For BlueField-2, the internal ports in the ARM system should also be set.

  • Query CRYPTO_OPERATIONAL register to make sure the device is in Operational mode.


    mlxreg -d /dev/mst/mt4123_pciconf0 --reg_name CRYPTO_OPERATIONAL --get

    The “wrapped_crypto_operational” value will be “0x00000001” if the mode was successfully changed to operational mode.

On the other hand, in case of plaintext mode, there is no need for all the above, DEK is passed in plaintext without keytag.

The mlx5 crypto PMD can be verified by running the test application::
Wrapped mode:
dpdk-test -c 1 -n 1 -w <dev>,class=crypto,wcs_file=<file_path> RTE>>cryptodev_mlx5_autotest
Plaintext mode:
dpdk-test -c 1 -n 1 -w <dev>,class=crypto RTE>>cryptodev_mlx5_autotest

15.3. Driver options

Please refer to mlx5 common options for an additional list of options shared with other mlx5 drivers.

  • wcs_file parameter [string] - mandatory in wrapped mode

    File path including only the wrapped credential in string format of hexadecimal numbers, represent 48 bytes (8 bytes IV added by the AES key wrap algorithm).

  • import_kek_id parameter [int]

    The identifier of the KEK, default value is 0 represents the operational register import_kek..

  • credential_id parameter [int]

    The identifier of the credential, default value is 0 represents the operational register credential.

  • keytag parameter [int]

    The plaintext of the keytag appended to the AES-XTS keys, default value is 0.

  • max_segs_num parameter [int]

    Maximum number of mbuf chain segments(src or dest), default value is 8.

15.4. Supported NICs

  • NVIDIA® ConnectX®-6 200G MCX654106A-HCAT (2x200G)
  • NVIDIA® ConnectX®-6 Dx
  • NVIDIA® BlueField-2 SmartNIC

15.5. Limitations

  • AES-XTS keys provided in xform must include keytag and should be wrapped.
  • The supported data-unit lengths are 512B and 4KB and 1MB. In case the dataunit_len is not provided in the cipher xform, the OP length is limited to the above values.

15.6. Prerequisites

15.6.1. FW Prerequisites

  • xx.31.0328 for ConnectX-6.
  • xx.32.0108 for ConnectX-6 Dx and BlueField-2.

15.6.2. Linux Prerequisites

  • Mellanox OFED version: 5.3.

  • Compilation can be done also with rdma-core v15+.

    See mlx5 common prerequisites for more details.

15.6.3. Windows Prerequisites