Re: [PATCH 2/2] crypto: vmx - Adding support for XTS

From: "Leonidas S. Barbosa" <redacted>

This patch add XTS support using VMX-crypto driver.

Signed-off-by: Leonidas S. Barbosa <redacted>
Signed-off-by: Paulo Flabiano Smorigo <redacted>
---
 drivers/crypto/vmx/Makefile  |   2 +-
 drivers/crypto/vmx/aes_xts.c | 187
+++++++++++++++++++++++++++++++++++++++++++ drivers/crypto/vmx/vmx.c     | 
 2 +
 3 files changed, 190 insertions(+), 1 deletion(-)
 create mode 100644 drivers/crypto/vmx/aes_xts.c

diff --git a/drivers/crypto/vmx/Makefile b/drivers/crypto/vmx/Makefile
index d28ab96..de6e241 100644
--- a/drivers/crypto/vmx/Makefile
+++ b/drivers/crypto/vmx/Makefile

@@ -1,5 +1,5 @@
 obj-$(CONFIG_CRYPTO_DEV_VMX_ENCRYPT) += vmx-crypto.o
-vmx-crypto-objs := vmx.o aesp8-ppc.o ghashp8-ppc.o aes.o aes_cbc.o

aes_ctr.o ghash.o +vmx-crypto-objs := vmx.o aesp8-ppc.o ghashp8-ppc.o aes.o
aes_cbc.o aes_ctr.o aes_xts.o ghash.o

 ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)
 TARGET := linux-ppc64le

diff --git a/drivers/crypto/vmx/aes_xts.c b/drivers/crypto/vmx/aes_xts.c
new file mode 100644
index 0000000..62e698c
--- /dev/null
+++ b/drivers/crypto/vmx/aes_xts.c

@@ -0,0 +1,187 @@
+/**
+ * AES XTS routines supporting VMX In-core instructions on Power 8
+ *
+ * Copyright (C) 2015 International Business Machines Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundations; version 2 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY of FITNESS FOR A PARTICUPAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Author: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
+ */
+
+#include <linux/types.h>
+#include <linux/err.h>
+#include <linux/crypto.h>
+#include <linux/delay.h>
+#include <linux/hardirq.h>
+#include <asm/switch_to.h>
+#include <crypto/aes.h>
+#include <crypto/scatterwalk.h>
+
+#include "aesp8-ppc.h"
+
+struct p8_aes_xts_ctx {
+	struct crypto_blkcipher *fallback;
+	struct aes_key enc_key;
+	struct aes_key dec_key;
+	struct aes_key tweak_key;
+};
+
+static int p8_aes_xts_init(struct crypto_tfm *tfm)
+{
+	const char *alg;
+	struct crypto_blkcipher *fallback;
+	struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	if (!(alg = crypto_tfm_alg_name(tfm))) {
+		printk(KERN_ERR "Failed to get algorithm name.\n");
+		return -ENOENT;
+	}
+
+	fallback =
+		crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
+	if (IS_ERR(fallback)) {
+		printk(KERN_ERR
+			"Failed to allocate transformation for '%s': %ld\n",
+			alg, PTR_ERR(fallback));
+		return PTR_ERR(fallback);
+	}
+	printk(KERN_INFO "Using '%s' as fallback implementation.\n",
+		crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
+
+	crypto_blkcipher_set_flags(
+		fallback,
+		crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
+	ctx->fallback = fallback;
+
+	return 0;
+}
+
+static void p8_aes_xts_exit(struct crypto_tfm *tfm)
+{
+	struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	if (ctx->fallback) {
+		crypto_free_blkcipher(ctx->fallback);
+		ctx->fallback = NULL;
+	}
+}
+
+static int p8_aes_xts_setkey(struct crypto_tfm *tfm, const u8 *key,
+			     unsigned int keylen)
+{
+	int ret;
+	struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	if (keylen % 2)
+		return -EINVAL;

+	}
+	return ret;
+}
+
+static int p8_aes_xts_encrypt(struct blkcipher_desc *desc,
+			      struct scatterlist *dst,
+			      struct scatterlist *src, unsigned int nbytes)
+{
+	return p8_aes_xts_crypt(desc, dst, src, nbytes, 1);
+}
+
+static int p8_aes_xts_decrypt(struct blkcipher_desc *desc,
+			      struct scatterlist *dst,
+			      struct scatterlist *src, unsigned int nbytes)
+{
+	return p8_aes_xts_crypt(desc, dst, src, nbytes, 0);
+}
+
+struct crypto_alg p8_aes_xts_alg = {
+	.cra_name = "xts(aes)",
+	.cra_driver_name = "p8_aes_xts",
+	.cra_module = THIS_MODULE,
+	.cra_priority = 2000,
+	.cra_type = &crypto_blkcipher_type,
+	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
+	.cra_alignmask = 0,
+	.cra_blocksize = AES_BLOCK_SIZE,
+	.cra_ctxsize = sizeof(struct p8_aes_xts_ctx),
+	.cra_init = p8_aes_xts_init,
+	.cra_exit = p8_aes_xts_exit,
+	.cra_blkcipher = {
+			.ivsize = AES_BLOCK_SIZE,
+			.min_keysize = 2 * AES_MIN_KEY_SIZE,
+			.max_keysize = 2 * AES_MAX_KEY_SIZE,
+			.setkey	 = p8_aes_xts_setkey,
+			.encrypt = p8_aes_xts_encrypt,
+			.decrypt = p8_aes_xts_decrypt,
+	}
+};

diff --git a/drivers/crypto/vmx/vmx.c b/drivers/crypto/vmx/vmx.c
index e163d57..f688c32 100644
--- a/drivers/crypto/vmx/vmx.c
+++ b/drivers/crypto/vmx/vmx.c

@@ -31,10 +31,12 @@ extern struct shash_alg p8_ghash_alg;
 extern struct crypto_alg p8_aes_alg;
 extern struct crypto_alg p8_aes_cbc_alg;
 extern struct crypto_alg p8_aes_ctr_alg;
+extern struct crypto_alg p8_aes_xts_alg;
 static struct crypto_alg *algs[] = {
 	&p8_aes_alg,
 	&p8_aes_cbc_alg,
 	&p8_aes_ctr_alg,
+	&p8_aes_xts_alg,
 	NULL,
 };