diff --git a/arch/riscv/crypto/Kconfig b/arch/riscv/crypto/Kconfig
index 2ad44e1d464a..ad58dad9a580 100644
--- a/arch/riscv/crypto/Kconfig
+++ b/arch/riscv/crypto/Kconfig
@@ -1,23 +1,23 @@
 # SPDX-License-Identifier: GPL-2.0
 
 menu "Accelerated Cryptographic Algorithms for CPU (riscv)"
 
 config CRYPTO_AES_RISCV64
-	tristate "Ciphers: AES, modes: ECB, CBC, CTR, XTS"
+	tristate "Ciphers: AES, modes: ECB, CBC, CTS, CTR, XTS"
 	depends on 64BIT && RISCV_ISA_V && TOOLCHAIN_HAS_VECTOR_CRYPTO
 	select CRYPTO_ALGAPI
 	select CRYPTO_LIB_AES
 	select CRYPTO_SKCIPHER
 	help
 	  Block cipher: AES cipher algorithms
-	  Length-preserving ciphers: AES with ECB, CBC, CTR, XTS
+	  Length-preserving ciphers: AES with ECB, CBC, CTS, CTR, XTS
 
 	  Architecture: riscv64 using:
 	  - Zvkned vector crypto extension
 	  - Zvbb vector extension (XTS)
 	  - Zvkb vector crypto extension (CTR)
 	  - Zvkg vector crypto extension (XTS)
 
 config CRYPTO_CHACHA_RISCV64
 	tristate "Ciphers: ChaCha"
 	depends on 64BIT && RISCV_ISA_V && TOOLCHAIN_HAS_VECTOR_CRYPTO
diff --git a/arch/riscv/crypto/aes-riscv64-glue.c b/arch/riscv/crypto/aes-riscv64-glue.c
index 37bc6ef0be40..f814ee048555 100644
--- a/arch/riscv/crypto/aes-riscv64-glue.c
+++ b/arch/riscv/crypto/aes-riscv64-glue.c
@@ -1,20 +1,22 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * AES using the RISC-V vector crypto extensions.  Includes the bare block
- * cipher and the ECB, CBC, CTR, and XTS modes.
+ * cipher and the ECB, CBC, CBC-CTS, CTR, and XTS modes.
  *
  * Copyright (C) 2023 VRULL GmbH
  * Author: Heiko Stuebner <heiko.stuebner@vrull.eu>
  *
  * Copyright (C) 2023 SiFive, Inc.
  * Author: Jerry Shih <jerry.shih@sifive.com>
+ *
+ * Copyright 2024 Google LLC
  */
 
 #include <asm/simd.h>
 #include <asm/vector.h>
 #include <crypto/aes.h>
 #include <crypto/internal/cipher.h>
 #include <crypto/internal/simd.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/scatterwalk.h>
 #include <crypto/xts.h>
@@ -33,20 +35,24 @@ asmlinkage void aes_ecb_encrypt_zvkned(const struct crypto_aes_ctx *key,
 asmlinkage void aes_ecb_decrypt_zvkned(const struct crypto_aes_ctx *key,
 				       const u8 *in, u8 *out, size_t len);
 
 asmlinkage void aes_cbc_encrypt_zvkned(const struct crypto_aes_ctx *key,
 				       const u8 *in, u8 *out, size_t len,
 				       u8 iv[AES_BLOCK_SIZE]);
 asmlinkage void aes_cbc_decrypt_zvkned(const struct crypto_aes_ctx *key,
 				       const u8 *in, u8 *out, size_t len,
 				       u8 iv[AES_BLOCK_SIZE]);
 
+asmlinkage void aes_cbc_cts_crypt_zvkned(const struct crypto_aes_ctx *key,
+					 const u8 *in, u8 *out, size_t len,
+					 const u8 iv[AES_BLOCK_SIZE], bool enc);
+
 asmlinkage void aes_ctr32_crypt_zvkned_zvkb(const struct crypto_aes_ctx *key,
 					    const u8 *in, u8 *out, size_t len,
 					    u8 iv[AES_BLOCK_SIZE]);
 
 asmlinkage void aes_xts_encrypt_zvkned_zvbb_zvkg(
 			const struct crypto_aes_ctx *key,
 			const u8 *in, u8 *out, size_t len,
 			u8 tweak[AES_BLOCK_SIZE]);
 
 asmlinkage void aes_xts_decrypt_zvkned_zvbb_zvkg(
@@ -157,21 +163,21 @@ static int riscv64_aes_ecb_encrypt(struct skcipher_request *req)
 	return riscv64_aes_ecb_crypt(req, true);
 }
 
 static int riscv64_aes_ecb_decrypt(struct skcipher_request *req)
 {
 	return riscv64_aes_ecb_crypt(req, false);
 }
 
 /* AES-CBC */
 
-static inline int riscv64_aes_cbc_crypt(struct skcipher_request *req, bool enc)
+static int riscv64_aes_cbc_crypt(struct skcipher_request *req, bool enc)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	const struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_walk walk;
 	unsigned int nbytes;
 	int err;
 
 	err = skcipher_walk_virt(&walk, req, false);
 	while ((nbytes = walk.nbytes) != 0) {
 		kernel_vector_begin();
@@ -195,20 +201,84 @@ static inline int riscv64_aes_cbc_crypt(struct skcipher_request *req, bool enc)
 static int riscv64_aes_cbc_encrypt(struct skcipher_request *req)
 {
 	return riscv64_aes_cbc_crypt(req, true);
 }
 
 static int riscv64_aes_cbc_decrypt(struct skcipher_request *req)
 {
 	return riscv64_aes_cbc_crypt(req, false);
 }
 
+/* AES-CBC-CTS */
+
+static int riscv64_aes_cbc_cts_crypt(struct skcipher_request *req, bool enc)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	const struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct scatterlist sg_src[2], sg_dst[2];
+	struct skcipher_request subreq;
+	struct scatterlist *src, *dst;
+	struct skcipher_walk walk;
+	unsigned int cbc_len;
+	int err;
+
+	if (req->cryptlen < AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	err = skcipher_walk_virt(&walk, req, false);
+	if (err)
+		return err;
+	/*
+	 * If the full message is available in one step, decrypt it in one call
+	 * to the CBC-CTS assembly function.  This reduces overhead, especially
+	 * on short messages.  Otherwise, fall back to doing CBC up to the last
+	 * two blocks, then invoke CTS just for the ciphertext stealing.
+	 */
+	if (unlikely(walk.nbytes != req->cryptlen)) {
+		cbc_len = round_down(req->cryptlen - AES_BLOCK_SIZE - 1,
+				     AES_BLOCK_SIZE);
+		skcipher_walk_abort(&walk);
+		skcipher_request_set_tfm(&subreq, tfm);
+		skcipher_request_set_callback(&subreq,
+					      skcipher_request_flags(req),
+					      NULL, NULL);
+		skcipher_request_set_crypt(&subreq, req->src, req->dst,
+					   cbc_len, req->iv);
+		err = riscv64_aes_cbc_crypt(&subreq, enc);
+		if (err)
+			return err;
+		dst = src = scatterwalk_ffwd(sg_src, req->src, cbc_len);
+		if (req->dst != req->src)
+			dst = scatterwalk_ffwd(sg_dst, req->dst, cbc_len);
+		skcipher_request_set_crypt(&subreq, src, dst,
+					   req->cryptlen - cbc_len, req->iv);
+		err = skcipher_walk_virt(&walk, &subreq, false);
+		if (err)
+			return err;
+	}
+	kernel_vector_begin();
+	aes_cbc_cts_crypt_zvkned(ctx, walk.src.virt.addr, walk.dst.virt.addr,
+				 walk.nbytes, req->iv, enc);
+	kernel_vector_end();
+	return skcipher_walk_done(&walk, 0);
+}
+
+static int riscv64_aes_cbc_cts_encrypt(struct skcipher_request *req)
+{
+	return riscv64_aes_cbc_cts_crypt(req, true);
+}
+
+static int riscv64_aes_cbc_cts_decrypt(struct skcipher_request *req)
+{
+	return riscv64_aes_cbc_cts_crypt(req, false);
+}
+
 /* AES-CTR */
 
 static int riscv64_aes_ctr_crypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	const struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 	unsigned int nbytes, p1_nbytes;
 	struct skcipher_walk walk;
 	u32 ctr32, nblocks;
 	int err;
@@ -427,20 +497,36 @@ static struct skcipher_alg riscv64_zvkned_aes_skcipher_algs[] = {
 		.max_keysize = AES_MAX_KEY_SIZE,
 		.ivsize = AES_BLOCK_SIZE,
 		.base = {
 			.cra_blocksize = AES_BLOCK_SIZE,
 			.cra_ctxsize = sizeof(struct crypto_aes_ctx),
 			.cra_priority = 300,
 			.cra_name = "cbc(aes)",
 			.cra_driver_name = "cbc-aes-riscv64-zvkned",
 			.cra_module = THIS_MODULE,
 		},
+	}, {
+		.setkey = riscv64_aes_setkey_skcipher,
+		.encrypt = riscv64_aes_cbc_cts_encrypt,
+		.decrypt = riscv64_aes_cbc_cts_decrypt,
+		.min_keysize = AES_MIN_KEY_SIZE,
+		.max_keysize = AES_MAX_KEY_SIZE,
+		.ivsize = AES_BLOCK_SIZE,
+		.walksize = 4 * AES_BLOCK_SIZE, /* matches LMUL=4 */
+		.base = {
+			.cra_blocksize = AES_BLOCK_SIZE,
+			.cra_ctxsize = sizeof(struct crypto_aes_ctx),
+			.cra_priority = 300,
+			.cra_name = "cts(cbc(aes))",
+			.cra_driver_name = "cts-cbc-aes-riscv64-zvkned",
+			.cra_module = THIS_MODULE,
+		},
 	}
 };
 
 static struct skcipher_alg riscv64_zvkned_zvkb_aes_skcipher_alg = {
 	.setkey = riscv64_aes_setkey_skcipher,
 	.encrypt = riscv64_aes_ctr_crypt,
 	.decrypt = riscv64_aes_ctr_crypt,
 	.min_keysize = AES_MIN_KEY_SIZE,
 	.max_keysize = AES_MAX_KEY_SIZE,
 	.ivsize = AES_BLOCK_SIZE,
@@ -533,18 +619,19 @@ static void __exit riscv64_aes_mod_exit(void)
 	if (riscv_isa_extension_available(NULL, ZVKB))
 		crypto_unregister_skcipher(&riscv64_zvkned_zvkb_aes_skcipher_alg);
 	crypto_unregister_skciphers(riscv64_zvkned_aes_skcipher_algs,
 				    ARRAY_SIZE(riscv64_zvkned_aes_skcipher_algs));
 	crypto_unregister_alg(&riscv64_zvkned_aes_cipher_alg);
 }
 
 module_init(riscv64_aes_mod_init);
 module_exit(riscv64_aes_mod_exit);
 
-MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS (RISC-V accelerated)");
+MODULE_DESCRIPTION("AES-ECB/CBC/CTS/CTR/XTS (RISC-V accelerated)");
 MODULE_AUTHOR("Jerry Shih <jerry.shih@sifive.com>");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_CRYPTO("aes");
 MODULE_ALIAS_CRYPTO("ecb(aes)");
 MODULE_ALIAS_CRYPTO("cbc(aes)");
+MODULE_ALIAS_CRYPTO("cts(cbc(aes))");
 MODULE_ALIAS_CRYPTO("ctr(aes)");
 MODULE_ALIAS_CRYPTO("xts(aes)");
diff --git a/arch/riscv/crypto/aes-riscv64-zvkned.S b/arch/riscv/crypto/aes-riscv64-zvkned.S
index 43541aad6386..23d063f94ce6 100644
--- a/arch/riscv/crypto/aes-riscv64-zvkned.S
+++ b/arch/riscv/crypto/aes-riscv64-zvkned.S
@@ -177,10 +177,163 @@ SYM_FUNC_END(aes_cbc_encrypt_zvkned)
 
 // Same prototype and calling convention as the encryption function
 SYM_FUNC_START(aes_cbc_decrypt_zvkned)
 	aes_begin	KEYP, 128f, 192f
 	aes_cbc_decrypt	256
 128:
 	aes_cbc_decrypt	128
 192:
 	aes_cbc_decrypt	192
 SYM_FUNC_END(aes_cbc_decrypt_zvkned)
+
+.macro	aes_cbc_cts_encrypt	keylen
+
+	// CBC-encrypt all blocks except the last.  But don't store the
+	// second-to-last block to the output buffer yet, since it will be
+	// handled specially in the ciphertext stealing step.  Exception: if the
+	// message is single-block, still encrypt the last (and only) block.
+	li		t0, 16
+	j		2f
+1:
+	vse32.v		v16, (OUTP)	// Store ciphertext block
+	addi		OUTP, OUTP, 16
+2:
+	vle32.v		v17, (INP)	// Load plaintext block
+	vxor.vv		v16, v16, v17	// XOR with IV or prev ciphertext block
+	aes_encrypt	v16, \keylen	// Encrypt
+	addi		INP, INP, 16
+	addi		LEN, LEN, -16
+	bgt		LEN, t0, 1b	// Repeat if more than one block remains
+
+	// Special case: if the message is a single block, just do CBC.
+	beqz		LEN, .Lcts_encrypt_done\@
+
+	// Encrypt the last two blocks using ciphertext stealing as follows:
+	//	C[n-1] = Encrypt(Encrypt(P[n-1] ^ C[n-2]) ^ P[n])
+	//	C[n] = Encrypt(P[n-1] ^ C[n-2])[0..LEN]
+	//
+	// C[i] denotes the i'th ciphertext block, and likewise P[i] the i'th
+	// plaintext block.  Block n, the last block, may be partial; its length
+	// is 1 <= LEN <= 16.  If there are only 2 blocks, C[n-2] means the IV.
+	//
+	// v16 already contains Encrypt(P[n-1] ^ C[n-2]).
+	// INP points to P[n].  OUTP points to where C[n-1] should go.
+	// To support in-place encryption, load P[n] before storing C[n].
+	addi		t0, OUTP, 16	// Get pointer to where C[n] should go
+	vsetvli		zero, LEN, e8, m1, tu, ma
+	vle8.v		v17, (INP)	// Load P[n]
+	vse8.v		v16, (t0)	// Store C[n]
+	vxor.vv		v16, v16, v17	// v16 = Encrypt(P[n-1] ^ C[n-2]) ^ P[n]
+	vsetivli	zero, 4, e32, m1, ta, ma
+	aes_encrypt	v16, \keylen
+.Lcts_encrypt_done\@:
+	vse32.v		v16, (OUTP)	// Store C[n-1] (or C[n] in single-block case)
+	ret
+.endm
+
+#define LEN32		t4 // Length of remaining full blocks in 32-bit words
+#define LEN_MOD16	t5 // Length of message in bytes mod 16
+
+.macro	aes_cbc_cts_decrypt	keylen
+	andi		LEN32, LEN, ~15
+	srli		LEN32, LEN32, 2
+	andi		LEN_MOD16, LEN, 15
+
+	// Save C[n-2] in v28 so that it's available later during the ciphertext
+	// stealing step.  If there are fewer than three blocks, C[n-2] means
+	// the IV, otherwise it means the third-to-last ciphertext block.
+	vmv.v.v		v28, v16	// IV
+	add		t0, LEN, -33
+	bltz		t0, .Lcts_decrypt_loop\@
+	andi		t0, t0, ~15
+	add		t0, t0, INP
+	vle32.v		v28, (t0)
+
+	// CBC-decrypt all full blocks.  For the last full block, or the last 2
+	// full blocks if the message is block-aligned, this doesn't write the
+	// correct output blocks (unless the message is only a single block),
+	// because it XORs the wrong values with the raw AES plaintexts.  But we
+	// fix this after this loop without redoing the AES decryptions.  This
+	// approach allows more of the AES decryptions to be parallelized.
+.Lcts_decrypt_loop\@:
+	vsetvli		t0, LEN32, e32, m4, ta, ma
+	addi		t1, t0, -4
+	vle32.v		v20, (INP)	// Load next set of ciphertext blocks
+	vmv.v.v		v24, v16	// Get IV or last ciphertext block of prev set
+	vslideup.vi	v24, v20, 4	// Setup prev ciphertext blocks
+	vslidedown.vx	v16, v20, t1	// Save last ciphertext block of this set
+	aes_decrypt	v20, \keylen	// Decrypt this set of blocks
+	vxor.vv		v24, v24, v20	// XOR prev ciphertext blocks with decrypted blocks
+	vse32.v		v24, (OUTP)	// Store this set of plaintext blocks
+	sub		LEN32, LEN32, t0
+	slli		t0, t0, 2	// Words to bytes
+	add		INP, INP, t0
+	add		OUTP, OUTP, t0
+	bnez		LEN32, .Lcts_decrypt_loop\@
+
+	vsetivli	zero, 4, e32, m4, ta, ma
+	vslidedown.vx	v20, v20, t1	// Extract raw plaintext of last full block
+	addi		t0, OUTP, -16	// Get pointer to last full plaintext block
+	bnez		LEN_MOD16, .Lcts_decrypt_non_block_aligned\@
+
+	// Special case: if the message is a single block, just do CBC.
+	li		t1, 16
+	beq		LEN, t1, .Lcts_decrypt_done\@
+
+	// Block-aligned message.  Just fix up the last 2 blocks.  We need:
+	//
+	//	P[n-1] = Decrypt(C[n]) ^ C[n-2]
+	//	P[n] = Decrypt(C[n-1]) ^ C[n]
+	//
+	// We have C[n] in v16, Decrypt(C[n]) in v20, and C[n-2] in v28.
+	// Together with Decrypt(C[n-1]) ^ C[n-2] from the output buffer, this
+	// is everything needed to fix the output without re-decrypting blocks.
+	addi		t1, OUTP, -32	// Get pointer to where P[n-1] should go
+	vxor.vv		v20, v20, v28	// Decrypt(C[n]) ^ C[n-2] == P[n-1]
+	vle32.v		v24, (t1)	// Decrypt(C[n-1]) ^ C[n-2]
+	vse32.v		v20, (t1)	// Store P[n-1]
+	vxor.vv		v20, v24, v16	// Decrypt(C[n-1]) ^ C[n-2] ^ C[n] == P[n] ^ C[n-2]
+	j		.Lcts_decrypt_finish\@
+
+.Lcts_decrypt_non_block_aligned\@:
+	// Decrypt the last two blocks using ciphertext stealing as follows:
+	//
+	//	P[n-1] = Decrypt(C[n] || Decrypt(C[n-1])[LEN_MOD16..16]) ^ C[n-2]
+	//	P[n] = (Decrypt(C[n-1]) ^ C[n])[0..LEN_MOD16]
+	//
+	// We already have Decrypt(C[n-1]) in v20 and C[n-2] in v28.
+	vmv.v.v		v16, v20	// v16 = Decrypt(C[n-1])
+	vsetvli		zero, LEN_MOD16, e8, m1, tu, ma
+	vle8.v		v20, (INP)	// v20 = C[n] || Decrypt(C[n-1])[LEN_MOD16..16]
+	vxor.vv		v16, v16, v20	// v16 = Decrypt(C[n-1]) ^ C[n]
+	vse8.v		v16, (OUTP)	// Store P[n]
+	vsetivli	zero, 4, e32, m1, ta, ma
+	aes_decrypt	v20, \keylen	// v20 = Decrypt(C[n] || Decrypt(C[n-1])[LEN_MOD16..16])
+.Lcts_decrypt_finish\@:
+	vxor.vv		v20, v20, v28	// XOR with C[n-2]
+	vse32.v		v20, (t0)	// Store last full plaintext block
+.Lcts_decrypt_done\@:
+	ret
+.endm
+
+.macro	aes_cbc_cts_crypt	keylen
+	vle32.v		v16, (IVP)	// Load IV
+	beqz		a5, .Lcts_decrypt\@
+	aes_cbc_cts_encrypt \keylen
+.Lcts_decrypt\@:
+	aes_cbc_cts_decrypt \keylen
+.endm
+
+// void aes_cbc_cts_crypt_zvkned(const struct crypto_aes_ctx *key,
+//			         const u8 *in, u8 *out, size_t len,
+//				 const u8 iv[16], bool enc);
+//
+// Encrypts or decrypts a message with the CS3 variant of AES-CBC-CTS.
+// This is the variant that unconditionally swaps the last two blocks.
+SYM_FUNC_START(aes_cbc_cts_crypt_zvkned)
+	aes_begin	KEYP, 128f, 192f
+	aes_cbc_cts_crypt 256
+128:
+	aes_cbc_cts_crypt 128
+192:
+	aes_cbc_cts_crypt 192
+SYM_FUNC_END(aes_cbc_cts_crypt_zvkned)
