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crypto: convert xts_tweak_encdec to use xts_uint128 type

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Using 64-bit arithmetic increases the performance for xts-aes-128
when built with gcrypt:

  Encrypt: 272 MB/s -> 355 MB/s
  Decrypt: 275 MB/s -> 362 MB/s

Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrangé 2018-10-09 10:50:43 +01:00
parent cc36930e40
commit db217c69f0
1 changed files with 57 additions and 25 deletions
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82
crypto/xts.c
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@ -31,6 +31,13 @@ typedef union {
uint64_t u[2];
} xts_uint128;
static inline void xts_uint128_xor(xts_uint128 *D,
const xts_uint128 *S1,
const xts_uint128 *S2)
{
D->u[0] = S1->u[0] ^ S2->u[0];
D->u[1] = S1->u[1] ^ S2->u[1];
}
static void xts_mult_x(uint8_t *I)
{
@ -60,25 +67,19 @@ static void xts_mult_x(uint8_t *I)
*/
static void xts_tweak_encdec(const void *ctx,
xts_cipher_func *func,
const uint8_t *src,
uint8_t *dst,
uint8_t *iv)
const xts_uint128 *src,
xts_uint128 *dst,
xts_uint128 *iv)
{
unsigned long x;
/* tweak encrypt block i */
for (x = 0; x < XTS_BLOCK_SIZE; x++) {
dst[x] = src[x] ^ iv[x];
}
xts_uint128_xor(dst, src, iv);
func(ctx, XTS_BLOCK_SIZE, dst, dst);
func(ctx, XTS_BLOCK_SIZE, dst->b, dst->b);
for (x = 0; x < XTS_BLOCK_SIZE; x++) {
dst[x] = dst[x] ^ iv[x];
}
xts_uint128_xor(dst, dst, iv);
/* LFSR the tweak */
xts_mult_x(iv);
xts_mult_x(iv->b);
}
@ -110,20 +111,34 @@ void xts_decrypt(const void *datactx,
/* encrypt the iv */
encfunc(tweakctx, XTS_BLOCK_SIZE, T.b, iv);
for (i = 0; i < lim; i++) {
xts_tweak_encdec(datactx, decfunc, src, dst, T.b);
if (QEMU_PTR_IS_ALIGNED(src, sizeof(uint64_t)) &&
QEMU_PTR_IS_ALIGNED(dst, sizeof(uint64_t))) {
xts_uint128 *S = (xts_uint128 *)src;
xts_uint128 *D = (xts_uint128 *)dst;
for (i = 0; i < lim; i++, S++, D++) {
xts_tweak_encdec(datactx, decfunc, S, D, &T);
}
} else {
xts_uint128 D;
src += XTS_BLOCK_SIZE;
dst += XTS_BLOCK_SIZE;
for (i = 0; i < lim; i++) {
memcpy(&D, src, XTS_BLOCK_SIZE);
xts_tweak_encdec(datactx, decfunc, &D, &D, &T);
memcpy(dst, &D, XTS_BLOCK_SIZE);
src += XTS_BLOCK_SIZE;
dst += XTS_BLOCK_SIZE;
}
}
/* if length is not a multiple of XTS_BLOCK_SIZE then */
if (mo > 0) {
xts_uint128 S, D;
memcpy(&CC, &T, XTS_BLOCK_SIZE);
xts_mult_x(CC.b);
/* PP = tweak decrypt block m-1 */
xts_tweak_encdec(datactx, decfunc, src, PP.b, CC.b);
memcpy(&S, src, XTS_BLOCK_SIZE);
xts_tweak_encdec(datactx, decfunc, &S, &PP, &CC);
/* Pm = first length % XTS_BLOCK_SIZE bytes of PP */
for (i = 0; i < mo; i++) {
@ -135,7 +150,8 @@ void xts_decrypt(const void *datactx,
}
/* Pm-1 = Tweak uncrypt CC */
xts_tweak_encdec(datactx, decfunc, CC.b, dst, T.b);
xts_tweak_encdec(datactx, decfunc, &CC, &D, &T);
memcpy(dst, &D, XTS_BLOCK_SIZE);
}
/* Decrypt the iv back */
@ -171,17 +187,32 @@ void xts_encrypt(const void *datactx,
/* encrypt the iv */
encfunc(tweakctx, XTS_BLOCK_SIZE, T.b, iv);
for (i = 0; i < lim; i++) {
xts_tweak_encdec(datactx, encfunc, src, dst, T.b);
if (QEMU_PTR_IS_ALIGNED(src, sizeof(uint64_t)) &&
QEMU_PTR_IS_ALIGNED(dst, sizeof(uint64_t))) {
xts_uint128 *S = (xts_uint128 *)src;
xts_uint128 *D = (xts_uint128 *)dst;
for (i = 0; i < lim; i++, S++, D++) {
xts_tweak_encdec(datactx, encfunc, S, D, &T);
}
} else {
xts_uint128 D;
dst += XTS_BLOCK_SIZE;
src += XTS_BLOCK_SIZE;
for (i = 0; i < lim; i++) {
memcpy(&D, src, XTS_BLOCK_SIZE);
xts_tweak_encdec(datactx, encfunc, &D, &D, &T);
memcpy(dst, &D, XTS_BLOCK_SIZE);
dst += XTS_BLOCK_SIZE;
src += XTS_BLOCK_SIZE;
}
}
/* if length is not a multiple of XTS_BLOCK_SIZE then */
if (mo > 0) {
xts_uint128 S, D;
/* CC = tweak encrypt block m-1 */
xts_tweak_encdec(datactx, encfunc, src, CC.b, T.b);
memcpy(&S, src, XTS_BLOCK_SIZE);
xts_tweak_encdec(datactx, encfunc, &S, &CC, &T);
/* Cm = first length % XTS_BLOCK_SIZE bytes of CC */
for (i = 0; i < mo; i++) {
@ -194,7 +225,8 @@ void xts_encrypt(const void *datactx,
}
/* Cm-1 = Tweak encrypt PP */
xts_tweak_encdec(datactx, encfunc, PP.b, dst, T.b);
xts_tweak_encdec(datactx, encfunc, &PP, &D, &T);
memcpy(dst, &D, XTS_BLOCK_SIZE);
}
/* Decrypt the iv back */