1 files changed, 85 insertions, 0 deletions
diff --git a/lib/crypto/x86/aes.h b/lib/crypto/x86/aes.h
new file mode 100644
index 000000000..b047dee94
--- /dev/null
+++ b/lib/crypto/x86/aes.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * AES block cipher using AES-NI instructions
+ *
+ * Copyright 2026 Google LLC
+ */
+
+#include <asm/fpu/api.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_aes);
+
+void aes128_expandkey_aesni(u32 rndkeys[], u32 *inv_rndkeys,
+			    const u8 in_key[AES_KEYSIZE_128]);
+void aes256_expandkey_aesni(u32 rndkeys[], u32 *inv_rndkeys,
+			    const u8 in_key[AES_KEYSIZE_256]);
+void aes_encrypt_aesni(const u32 rndkeys[], int nrounds,
+		       u8 out[AES_BLOCK_SIZE], const u8 in[AES_BLOCK_SIZE]);
+void aes_decrypt_aesni(const u32 inv_rndkeys[], int nrounds,
+		       u8 out[AES_BLOCK_SIZE], const u8 in[AES_BLOCK_SIZE]);
+
+/*
+ * Expand an AES key using AES-NI if supported and usable or generic code
+ * otherwise.  The expanded key format is compatible between the two cases.  The
+ * outputs are @k->rndkeys (required) and @inv_k->inv_rndkeys (optional).
+ *
+ * We could just always use the generic key expansion code.  AES key expansion
+ * is usually less performance-critical than AES en/decryption.  However,
+ * there's still *some* value in speed here, as well as in non-key-dependent
+ * execution time which AES-NI provides.  So, do use AES-NI to expand AES-128
+ * and AES-256 keys.  (Don't bother with AES-192, as it's almost never used.)
+ */
+static void aes_preparekey_arch(union aes_enckey_arch *k,
+				union aes_invkey_arch *inv_k,
+				const u8 *in_key, int key_len, int nrounds)
+{
+	u32 *rndkeys = k->rndkeys;
+	u32 *inv_rndkeys = inv_k ? inv_k->inv_rndkeys : NULL;
+
+	if (static_branch_likely(&have_aes) && key_len != AES_KEYSIZE_192 &&
+	    irq_fpu_usable()) {
+		kernel_fpu_begin();
+		if (key_len == AES_KEYSIZE_128)
+			aes128_expandkey_aesni(rndkeys, inv_rndkeys, in_key);
+		else
+			aes256_expandkey_aesni(rndkeys, inv_rndkeys, in_key);
+		kernel_fpu_end();
+	} else {
+		aes_expandkey_generic(rndkeys, inv_rndkeys, in_key, key_len);
+	}
+}
+
+static void aes_encrypt_arch(const struct aes_enckey *key,
+			     u8 out[AES_BLOCK_SIZE],
+			     const u8 in[AES_BLOCK_SIZE])
+{
+	if (static_branch_likely(&have_aes) && irq_fpu_usable()) {
+		kernel_fpu_begin();
+		aes_encrypt_aesni(key->k.rndkeys, key->nrounds, out, in);
+		kernel_fpu_end();
+	} else {
+		aes_encrypt_generic(key->k.rndkeys, key->nrounds, out, in);
+	}
+}
+
+static void aes_decrypt_arch(const struct aes_key *key,
+			     u8 out[AES_BLOCK_SIZE],
+			     const u8 in[AES_BLOCK_SIZE])
+{
+	if (static_branch_likely(&have_aes) && irq_fpu_usable()) {
+		kernel_fpu_begin();
+		aes_decrypt_aesni(key->inv_k.inv_rndkeys, key->nrounds,
+				  out, in);
+		kernel_fpu_end();
+	} else {
+		aes_decrypt_generic(key->inv_k.inv_rndkeys, key->nrounds,
+				    out, in);
+	}
+}
+
+#define aes_mod_init_arch aes_mod_init_arch
+static void aes_mod_init_arch(void)
+{
+	if (boot_cpu_has(X86_FEATURE_AES))
+		static_branch_enable(&have_aes);
+}