crypto: Add aesdec_ISB_ISR_IMC_AK

Add a primitive for InvSubBytes + InvShiftRows +
InvMixColumns + AddRoundKey.

Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

crypto/aes.c

@@ -1484,6 +1484,64 @@ void aesdec_ISB_ISR_AK_genrev(AESState *r, const AESState *s, const AESState *k)
     aesdec_ISB_ISR_AK_swap(r, s, k, true);
 }
 
+/*
+ * Perform InvSubBytes + InvShiftRows + InvMixColumns + AddRoundKey.
+ */
+static inline void
+aesdec_ISB_ISR_IMC_AK_swap(AESState *r, const AESState *st,
+                           const AESState *rk, bool swap)
+{
+    int swap_b = swap * 0xf;
+    int swap_w = swap * 0x3;
+    bool be = HOST_BIG_ENDIAN ^ swap;
+    uint32_t w0, w1, w2, w3;
+
+    w0 = (AES_Td0[st->b[swap_b ^ AES_ISH(0x0)]] ^
+          AES_Td1[st->b[swap_b ^ AES_ISH(0x1)]] ^
+          AES_Td2[st->b[swap_b ^ AES_ISH(0x2)]] ^
+          AES_Td3[st->b[swap_b ^ AES_ISH(0x3)]]);
+
+    w1 = (AES_Td0[st->b[swap_b ^ AES_ISH(0x4)]] ^
+          AES_Td1[st->b[swap_b ^ AES_ISH(0x5)]] ^
+          AES_Td2[st->b[swap_b ^ AES_ISH(0x6)]] ^
+          AES_Td3[st->b[swap_b ^ AES_ISH(0x7)]]);
+
+    w2 = (AES_Td0[st->b[swap_b ^ AES_ISH(0x8)]] ^
+          AES_Td1[st->b[swap_b ^ AES_ISH(0x9)]] ^
+          AES_Td2[st->b[swap_b ^ AES_ISH(0xA)]] ^
+          AES_Td3[st->b[swap_b ^ AES_ISH(0xB)]]);
+
+    w3 = (AES_Td0[st->b[swap_b ^ AES_ISH(0xC)]] ^
+          AES_Td1[st->b[swap_b ^ AES_ISH(0xD)]] ^
+          AES_Td2[st->b[swap_b ^ AES_ISH(0xE)]] ^
+          AES_Td3[st->b[swap_b ^ AES_ISH(0xF)]]);
+
+    /* Note that AES_TdX is encoded for big-endian. */
+    if (!be) {
+        w0 = bswap32(w0);
+        w1 = bswap32(w1);
+        w2 = bswap32(w2);
+        w3 = bswap32(w3);
+    }
+
+    r->w[swap_w ^ 0] = rk->w[swap_w ^ 0] ^ w0;
+    r->w[swap_w ^ 1] = rk->w[swap_w ^ 1] ^ w1;
+    r->w[swap_w ^ 2] = rk->w[swap_w ^ 2] ^ w2;
+    r->w[swap_w ^ 3] = rk->w[swap_w ^ 3] ^ w3;
+}
+
+void aesdec_ISB_ISR_IMC_AK_gen(AESState *r, const AESState *st,
+                               const AESState *rk)
+{
+    aesdec_ISB_ISR_IMC_AK_swap(r, st, rk, false);
+}
+
+void aesdec_ISB_ISR_IMC_AK_genrev(AESState *r, const AESState *st,
+                                  const AESState *rk)
+{
+    aesdec_ISB_ISR_IMC_AK_swap(r, st, rk, true);
+}
+
 /**
  * Expand the cipher key into the encryption key schedule.
  */

host/include/generic/host/crypto/aes-round.h

@@ -23,5 +23,8 @@ void aesdec_IMC_accel(AESState *, const AESState *, bool)
 void aesdec_ISB_ISR_AK_accel(AESState *, const AESState *,
                              const AESState *, bool)
     QEMU_ERROR("unsupported accel");
+void aesdec_ISB_ISR_IMC_AK_accel(AESState *, const AESState *,
+                                 const AESState *, bool)
+    QEMU_ERROR("unsupported accel");
 
 #endif /* GENERIC_HOST_CRYPTO_AES_ROUND_H */

include/crypto/aes-round.h

@@ -119,4 +119,25 @@ static inline void aesdec_ISB_ISR_AK(AESState *r, const AESState *st,
     }
 }
 
+/*
+ * Perform InvSubBytes + InvShiftRows + InvMixColumns + AddRoundKey.
+ */
+
+void aesdec_ISB_ISR_IMC_AK_gen(AESState *ret, const AESState *st,
+                               const AESState *rk);
+void aesdec_ISB_ISR_IMC_AK_genrev(AESState *ret, const AESState *st,
+                                  const AESState *rk);
+
+static inline void aesdec_ISB_ISR_IMC_AK(AESState *r, const AESState *st,
+                                         const AESState *rk, bool be)
+{
+    if (HAVE_AES_ACCEL) {
+        aesdec_ISB_ISR_IMC_AK_accel(r, st, rk, be);
+    } else if (HOST_BIG_ENDIAN == be) {
+        aesdec_ISB_ISR_IMC_AK_gen(r, st, rk);
+    } else {
+        aesdec_ISB_ISR_IMC_AK_genrev(r, st, rk);
+    }
+}
+
 #endif /* CRYPTO_AES_ROUND_H */