From 5249fe526e66a92e293bc638ab53eb3d8cd68881 Mon Sep 17 00:00:00 2001

From: "Daniel P. Berrange" <berrange@redhat.com>

Date: Wed, 24 Apr 2019 09:56:40 +0100

Subject: [PATCH 6/9] crypto: convert xts_mult_x to use xts_uint128 type

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RH-Author: Daniel P. Berrange <berrange@redhat.com>

Message-id: <20190424095643.796-7-berrange@redhat.com>

Patchwork-id: 85879

O-Subject: [RHEL-8.1.0 qemu-kvm PATCH 6/9] crypto: convert xts_mult_x to use xts_uint128 type

Bugzilla: 1680231

RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>

RH-Acked-by: John Snow <jsnow@redhat.com>

RH-Acked-by: Eric Blake <eblake@redhat.com>

Using 64-bit arithmetic increases the performance for xts-aes-128

when built with gcrypt:

  Encrypt: 355 MB/s -> 545 MB/s

  Decrypt: 362 MB/s -> 568 MB/s

Reviewed-by: Alberto Garcia <berto@igalia.com>

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

(cherry picked from commit 7dac0dd67426753646df0c23c819609b9e704f59)

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 crypto/xts.c | 40 ++++++++++++++++++++++++++++------------

 1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/crypto/xts.c b/crypto/xts.c

index 0ad231f..10ec83f 100644

--- a/crypto/xts.c

+++ b/crypto/xts.c

@@ -24,6 +24,7 @@

  */

 #include "qemu/osdep.h"

+#include "qemu/bswap.h"

 #include "crypto/xts.h"

 typedef union {

@@ -39,19 +40,34 @@ static inline void xts_uint128_xor(xts_uint128 *D,

     D->u[1] = S1->u[1] ^ S2->u[1];

 }

-static void xts_mult_x(uint8_t *I)

+static inline void xts_uint128_cpu_to_les(xts_uint128 *v)

 {

-    int x;

-    uint8_t t, tt;

+    cpu_to_le64s(&v->u[0]);

+    cpu_to_le64s(&v->u[1]);

+}

-    for (x = t = 0; x < 16; x++) {

-        tt = I[x] >> 7;

-        I[x] = ((I[x] << 1) | t) & 0xFF;

-        t = tt;

-    }

-    if (tt) {

-        I[0] ^= 0x87;

+static inline void xts_uint128_le_to_cpus(xts_uint128 *v)

+{

+    le64_to_cpus(&v->u[0]);

+    le64_to_cpus(&v->u[1]);

+}

+

+static void xts_mult_x(xts_uint128 *I)

+{

+    uint64_t tt;

+

+    xts_uint128_le_to_cpus(I);

+

+    tt = I->u[0] >> 63;

+    I->u[0] <<= 1;

+

+    if (I->u[1] >> 63) {

+        I->u[0] ^= 0x87;

     }

+    I->u[1] <<= 1;

+    I->u[1] |= tt;

+

+    xts_uint128_cpu_to_les(I);

 }

@@ -79,7 +95,7 @@ static void xts_tweak_encdec(const void *ctx,

     xts_uint128_xor(dst, dst, iv);

     /* LFSR the tweak */

-    xts_mult_x(iv->b);

+    xts_mult_x(iv);

 }

@@ -134,7 +150,7 @@ void xts_decrypt(const void *datactx,

     if (mo > 0) {

         xts_uint128 S, D;

         memcpy(&CC, &T, XTS_BLOCK_SIZE);

-        xts_mult_x(CC.b);

+        xts_mult_x(&CC;;

         /* PP = tweak decrypt block m-1 */

         memcpy(&S, src, XTS_BLOCK_SIZE);

-- 

1.8.3.1