crypto: Add generic 64-bit carry-less multiply routine

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

host/include/generic/host/crypto/clmul.h

@@ -0,0 +1,15 @@
+/*
+ * No host specific carry-less multiply acceleration.
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef GENERIC_HOST_CRYPTO_CLMUL_H
+#define GENERIC_HOST_CRYPTO_CLMUL_H
+
+#define HAVE_CLMUL_ACCEL  false
+#define ATTR_CLMUL_ACCEL
+
+Int128 clmul_64_accel(uint64_t, uint64_t)
+    QEMU_ERROR("unsupported accel");
+
+#endif /* GENERIC_HOST_CRYPTO_CLMUL_H */