[PATCH 12/12] RISC-V: crypto: add Zvkb accelerated ChaCha20 implementation

[Jerry Shih]

On Nov 2, 2023, at 13:43, Eric Biggers <ebiggers at kernel.org> wrote:
> On Thu, Oct 26, 2023 at 02:36:44AM +0800, Jerry Shih wrote:
>> +static struct skcipher_alg riscv64_chacha_alg_zvkb[] = { {
>> +	.base = {
>> +		.cra_name = "chacha20",
>> +		.cra_driver_name = "chacha20-riscv64-zvkb",
>> +		.cra_priority = 300,
>> +		.cra_blocksize = 1,
>> +		.cra_ctxsize = sizeof(struct chacha_ctx),
>> +		.cra_module = THIS_MODULE,
>> +	},
>> +	.min_keysize = CHACHA_KEY_SIZE,
>> +	.max_keysize = CHACHA_KEY_SIZE,
>> +	.ivsize = CHACHA_IV_SIZE,
>> +	.chunksize = CHACHA_BLOCK_SIZE,
>> +	.walksize = CHACHA_BLOCK_SIZE * 4,
>> +	.setkey = chacha20_setkey,
>> +	.encrypt = chacha20_encrypt,
>> +	.decrypt = chacha20_encrypt,
>> +} };
>> +
>> +static inline bool check_chacha20_ext(void)
>> +{
>> +	return riscv_isa_extension_available(NULL, ZVKB) &&
>> +	       riscv_vector_vlen() >= 128;
>> +}
>> +
>> +static int __init riscv64_chacha_mod_init(void)
>> +{
>> +	if (check_chacha20_ext())
>> +		return crypto_register_skciphers(
>> +			riscv64_chacha_alg_zvkb,
>> +			ARRAY_SIZE(riscv64_chacha_alg_zvkb));
>> +
>> +	return -ENODEV;
>> +}
>> +
>> +static void __exit riscv64_chacha_mod_fini(void)
>> +{
>> +	if (check_chacha20_ext())
>> +		crypto_unregister_skciphers(
>> +			riscv64_chacha_alg_zvkb,
>> +			ARRAY_SIZE(riscv64_chacha_alg_zvkb));
>> +}
> 
> When there's just one algorithm being registered/unregistered,
> crypto_register_skcipher() and crypto_unregister_skcipher() can be used.

Fixed.

>> +# - RV64I
>> +# - RISC-V Vector ('V') with VLEN >= 128
>> +# - RISC-V Vector Cryptography Bit-manipulation extension ('Zvkb')
>> +# - RISC-V Zicclsm(Main memory supports misaligned loads/stores)
> 
> How is the presence of the Zicclsm extension guaranteed?
> 
> - Eric

I have the addition extension parser for `Zicclsm` in the v2 patch set.


-Jerry