crypto: Add aesdec_ISB_ISR_AK

Add a primitive for InvSubBytes + InvShiftRows + AddRoundKey. Reviewed-by: Daniel P. Berrangé <[email protected]> Signed-off-by: Richard Henderson <[email protected]>
huazq · Jul 8, 2023 · 192fa84 · 192fa84
1 parent 6b0a96c
commit 192fa84
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diff --git a/crypto/aes.c b/crypto/aes.c
@@ -1261,6 +1261,51 @@ void aesenc_SB_SR_AK_genrev(AESState *r, const AESState *s, const AESState *k)
     aesenc_SB_SR_AK_swap(r, s, k, true);
 }
 
+/*
+ * Perform InvSubBytes + InvShiftRows + AddRoundKey.
+ */
+static inline void
+aesdec_ISB_ISR_AK_swap(AESState *ret, const AESState *st,
+                       const AESState *rk, bool swap)
+{
+    const int swap_b = swap ? 15 : 0;
+    AESState t;
+
+    t.b[swap_b ^ 0x0] = AES_isbox[st->b[swap_b ^ AES_ISH(0x0)]];
+    t.b[swap_b ^ 0x1] = AES_isbox[st->b[swap_b ^ AES_ISH(0x1)]];
+    t.b[swap_b ^ 0x2] = AES_isbox[st->b[swap_b ^ AES_ISH(0x2)]];
+    t.b[swap_b ^ 0x3] = AES_isbox[st->b[swap_b ^ AES_ISH(0x3)]];
+    t.b[swap_b ^ 0x4] = AES_isbox[st->b[swap_b ^ AES_ISH(0x4)]];
+    t.b[swap_b ^ 0x5] = AES_isbox[st->b[swap_b ^ AES_ISH(0x5)]];
+    t.b[swap_b ^ 0x6] = AES_isbox[st->b[swap_b ^ AES_ISH(0x6)]];
+    t.b[swap_b ^ 0x7] = AES_isbox[st->b[swap_b ^ AES_ISH(0x7)]];
+    t.b[swap_b ^ 0x8] = AES_isbox[st->b[swap_b ^ AES_ISH(0x8)]];
+    t.b[swap_b ^ 0x9] = AES_isbox[st->b[swap_b ^ AES_ISH(0x9)]];
+    t.b[swap_b ^ 0xa] = AES_isbox[st->b[swap_b ^ AES_ISH(0xA)]];
+    t.b[swap_b ^ 0xb] = AES_isbox[st->b[swap_b ^ AES_ISH(0xB)]];
+    t.b[swap_b ^ 0xc] = AES_isbox[st->b[swap_b ^ AES_ISH(0xC)]];
+    t.b[swap_b ^ 0xd] = AES_isbox[st->b[swap_b ^ AES_ISH(0xD)]];
+    t.b[swap_b ^ 0xe] = AES_isbox[st->b[swap_b ^ AES_ISH(0xE)]];
+    t.b[swap_b ^ 0xf] = AES_isbox[st->b[swap_b ^ AES_ISH(0xF)]];
+
+    /*
+     * Perform the AddRoundKey with generic vectors.
+     * This may be expanded to either host integer or host vector code.
+     * The key and output endianness match, so no bswap required.
+     */
+    ret->v = t.v ^ rk->v;
+}
+
+void aesdec_ISB_ISR_AK_gen(AESState *r, const AESState *s, const AESState *k)
+{
+    aesdec_ISB_ISR_AK_swap(r, s, k, false);
+}
+
+void aesdec_ISB_ISR_AK_genrev(AESState *r, const AESState *s, const AESState *k)
+{
+    aesdec_ISB_ISR_AK_swap(r, s, k, true);
+}
+
 /**
  * Expand the cipher key into the encryption key schedule.
  */

diff --git a/host/include/generic/host/crypto/aes-round.h b/host/include/generic/host/crypto/aes-round.h
@@ -13,4 +13,8 @@ void aesenc_SB_SR_AK_accel(AESState *, const AESState *,
                            const AESState *, bool)
     QEMU_ERROR("unsupported accel");
 
+void aesdec_ISB_ISR_AK_accel(AESState *, const AESState *,
+                             const AESState *, bool)
+    QEMU_ERROR("unsupported accel");
+
 #endif /* GENERIC_HOST_CRYPTO_AES_ROUND_H */
diff --git a/include/crypto/aes-round.h b/include/crypto/aes-round.h
@@ -41,4 +41,25 @@ static inline void aesenc_SB_SR_AK(AESState *r, const AESState *st,
     }
 }
 
+/*
+ * Perform InvSubBytes + InvShiftRows + AddRoundKey.
+ */
+
+void aesdec_ISB_ISR_AK_gen(AESState *ret, const AESState *st,
+                           const AESState *rk);
+void aesdec_ISB_ISR_AK_genrev(AESState *ret, const AESState *st,
+                              const AESState *rk);
+
+static inline void aesdec_ISB_ISR_AK(AESState *r, const AESState *st,
+                                     const AESState *rk, bool be)
+{
+    if (HAVE_AES_ACCEL) {
+        aesdec_ISB_ISR_AK_accel(r, st, rk, be);
+    } else if (HOST_BIG_ENDIAN == be) {
+        aesdec_ISB_ISR_AK_gen(r, st, rk);
+    } else {
+        aesdec_ISB_ISR_AK_genrev(r, st, rk);
+    }
+}
+
 #endif /* CRYPTO_AES_ROUND_H */