diff options
Diffstat (limited to 'target/linux/ipq40xx/patches-5.10/0015-v5.7-crypto-qce-use-AES-fallback-for-small-requests.patch')
| -rw-r--r-- | target/linux/ipq40xx/patches-5.10/0015-v5.7-crypto-qce-use-AES-fallback-for-small-requests.patch | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/target/linux/ipq40xx/patches-5.10/0015-v5.7-crypto-qce-use-AES-fallback-for-small-requests.patch b/target/linux/ipq40xx/patches-5.10/0015-v5.7-crypto-qce-use-AES-fallback-for-small-requests.patch new file mode 100644 index 0000000000..0b5c8c6d66 --- /dev/null +++ b/target/linux/ipq40xx/patches-5.10/0015-v5.7-crypto-qce-use-AES-fallback-for-small-requests.patch @@ -0,0 +1,113 @@ +From ce163ba0bf298f1707321ac025ef639f88e62801 Mon Sep 17 00:00:00 2001 +From: Eneas U de Queiroz <cotequeiroz@gmail.com> +Date: Fri, 7 Feb 2020 12:02:26 -0300 +Subject: [PATCH 10/11] crypto: qce - use AES fallback for small requests + +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> +Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> +--- + +--- a/drivers/crypto/Kconfig ++++ b/drivers/crypto/Kconfig +@@ -684,6 +684,29 @@ 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 +--- 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 cr + 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 skc + 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); |