[v3,2/3] s390/crypto: Rework protected key AES for true asynch support

Commit Message

Harald Freudenberger April 1, 2025, 2:50 p.m. UTC

This is a complete rework of the protected key AES (PAES) implementation.
The goal of this rework is to implement the 4 modes (ecb, cbc, ctr, xts)
in a real asynchronous fashion:
- init(), exit() and setkey() are synchronous and don't allocate any memory.
- the encrypt/decrypt functions first try to do the job in a synchronous
  manner. If this fails, for example the protected key got invalid caused
  by for example a guest suspend/resume or guest migration action, the
  encrypt/decrypt is transfered to an instance of the crypto engine (see
  below) for asynchronous processing.
  These via crypto engine postponed requests are then handled via the
  do_one_request() callback but may of course again run into a still
  not converted key or the key is getting invalid. If the key is
  still not converted, the first thread does the conversion and updates
  the key status in the transformation context. The conversion is
  invoked via pkey API with a new flag PKEY_XFLAG_NOMEMALLOC.

The pkey API used here - the function pkey_key2protkey() - uses
a new version of this in-kernel-API. A new flag PKEY_XFLAG_NOMEMALLOC
tells the PKEY layer (and subsidiary layers) that it must not allocate
any memory causing IO operations. Note that the patches for this
pkey/zcrypt/AP extensions are currently under review and yet not
upstream available. SO THIS PATCH DOES NOT COMPILE YET.

This patch together with the pkey/zcrypt/AP extensions should
toughen the paes crypto algorithms to truly meet the requirements
for in-kernel skcipher implementations and the usage patterns for
the dm-crypt and dm-integrity layers.

Signed-off-by: Harald Freudenberger <[e-mail]>
---
 arch/s390/crypto/paes_s390.c | 1725 +++++++++++++++++++++++-----------
 1 file changed, 1183 insertions(+), 542 deletions(-)

Comments

Herbert Xu April 2, 2025, 4:04 a.m. UTC | #1

On Tue, Apr 01, 2025 at 04:50:47PM +0200, Harald Freudenberger wrote:
>
> +static int ecb_paes_do_crypt(struct s390_paes_ctx *ctx,
> +			     struct s390_pecb_req_ctx *req_ctx,
> +			     bool maysleep)

...

> +	/* always walk on the ... */
> +	while ((nbytes = walk->nbytes) != 0) {
> +		/* only use complete blocks */
> +		n = nbytes & ~(AES_BLOCK_SIZE - 1);
> +		k = cpacf_km(ctx->fc | req_ctx->modifier, param,
> +			     walk->dst.virt.addr, walk->src.virt.addr, n);
> +		if (k)
> +			rc = skcipher_walk_done(walk, nbytes - k);
> +		if (k < n) {
> +			if (!maysleep) {
> +				rc = -EKEYEXPIRED;
> +				goto out;
> +			}

So this leaves the skcipher walk in a mapped state, to be resumed in
a work queue later.  Now I don't believe you guys have the horror of
HIGHMEM so it's not fatal, but it's still a bit of a hack and worthy
of a comment to at least stop people from other architectures copying
this.

> +			rc = paes_convert_key(ctx);

At first I thought this was racy, but then I realised that it is not
because only the crypto_engine thread gets called with maysleep ==
true.  Since there is only one crypto_engine thread this is safe.

I think this is not really obvious though and worthy of a comment to
explain the reliance on the single crypto engine thread.

There is one more subtle issue to do with request ordering.  Because
networking requires packets to not be reordered, we enforce this in
the Crypto API.  An algorithm must not reorder the requests sent to
the same tfm.

To do that here, once a ctx goes into the crypto_engine, all future
requests to the same ctx must also go through the crypto_engine, as
long as at the time of the request being submitted prior work is still
outstanding.

The easiest way would be to have a counter in the ctx that keeps
track of how many requests are currently outstanding in the engine.
Then in paes_do_crypt you'd simply check the counter, and if it is
non-zero you always put the request into the engine.

Cheers,

Patch

diff --git a/arch/s390/crypto/paes_s390.c b/arch/s390/crypto/paes_s390.c
index 646cbbf0678d..1d1f1a98ec4d 100644
--- a/arch/s390/crypto/paes_s390.c
+++ b/arch/s390/crypto/paes_s390.c
@@ -5,7 +5,7 @@ 
  * s390 implementation of the AES Cipher Algorithm with protected keys.
  *
  * s390 Version:
- *   Copyright IBM Corp. 2017, 2023
+ *   Copyright IBM Corp. 2017, 2025
  *   Author(s): Martin Schwidefsky <[e-mail]>
  *		Harald Freudenberger <[e-mail]>
  */
@@ -13,16 +13,17 @@ 
 #define KMSG_COMPONENT "paes_s390"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
-#include <crypto/aes.h>
-#include <crypto/algapi.h>
-#include <linux/bug.h>
-#include <linux/err.h>
-#include <linux/module.h>
 #include <linux/cpufeature.h>
+#include <linux/delay.h>
+#include <linux/err.h>
 #include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/spinlock.h>
-#include <linux/delay.h>
+#include <crypto/aes.h>
+#include <crypto/algapi.h>
+#include <crypto/engine.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/xts.h>
 #include <asm/cpacf.h>
@@ -44,23 +45,55 @@  static DEFINE_MUTEX(ctrblk_lock);
 
 static cpacf_mask_t km_functions, kmc_functions, kmctr_functions;
 
+static struct crypto_engine *paes_crypto_engine;
+#define MAX_QLEN 10
+
+/*
+ * protected key specific stuff
+ */
+
 struct paes_protkey {
 	u32 type;
 	u32 len;
 	u8 protkey[PXTS_256_PROTKEY_SIZE];
 };
 
-struct key_blob {
-	/*
-	 * Small keys will be stored in the keybuf. Larger keys are
-	 * stored in extra allocated memory. In both cases does
-	 * key point to the memory where the key is stored.
-	 * The code distinguishes by checking keylen against
-	 * sizeof(keybuf). See the two following helper functions.
-	 */
-	u8 *key;
-	u8 keybuf[128];
+#define PK_STATE_NO_KEY		     0
+#define PK_STATE_CONVERT_IN_PROGRESS 1
+#define PK_STATE_VALID		     2
+
+struct s390_paes_ctx {
+	/* source key material used to derive a protected key from */
+	u8 keybuf[PAES_MAX_KEYSIZE];
+	unsigned int keylen;
+
+	/* cpacf function code to use with this protected key type */
+	long fc;
+
+	/* spinlock to atomic read/update all the following fields */
+	spinlock_t pk_lock;
+
+	/* see PK_STATE* defines above, < 0 holds convert failure rc  */
+	int pk_state;
+	/* if state is valid, pk holds the protected key */
+	struct paes_protkey pk;
+};
+
+struct s390_pxts_ctx {
+	/* source key material used to derive a protected key from */
+	u8 keybuf[2 * PAES_MAX_KEYSIZE];
 	unsigned int keylen;
+
+	/* cpacf function code to use with this protected key type */
+	long fc;
+
+	/* spinlock to atomic read/update all the following fields */
+	spinlock_t pk_lock;
+
+	/* see PK_STATE* defines above, < 0 holds convert failure rc  */
+	int pk_state;
+	/* if state is valid, pk[] hold(s) the protected key(s) */
+	struct paes_protkey pk[2];
 };
 
 /*
@@ -89,214 +122,344 @@  static inline u32 make_clrkey_token(const u8 *ck, size_t cklen, u8 *dest)
 	return sizeof(*token) + cklen;
 }
 
-static inline int _key_to_kb(struct key_blob *kb,
-			     const u8 *key,
-			     unsigned int keylen)
+/*
+ * key_to_ctx() - Set key value into context, maybe construct
+ * a clear key token digestable by pkey from a clear key value.
+ */
+static inline int key_to_ctx(struct s390_paes_ctx *ctx,
+			     const u8 *key, unsigned int keylen)
 {
+	if (keylen > sizeof(ctx->keybuf))
+		return -EINVAL;
+
 	switch (keylen) {
 	case 16:
 	case 24:
 	case 32:
 		/* clear key value, prepare pkey clear key token in keybuf */
-		memset(kb->keybuf, 0, sizeof(kb->keybuf));
-		kb->keylen = make_clrkey_token(key, keylen, kb->keybuf);
-		kb->key = kb->keybuf;
+		memset(ctx->keybuf, 0, sizeof(ctx->keybuf));
+		ctx->keylen = make_clrkey_token(key, keylen, ctx->keybuf);
 		break;
 	default:
 		/* other key material, let pkey handle this */
-		if (keylen <= sizeof(kb->keybuf))
-			kb->key = kb->keybuf;
-		else {
-			kb->key = kmalloc(keylen, GFP_KERNEL);
-			if (!kb->key)
-				return -ENOMEM;
-		}
-		memcpy(kb->key, key, keylen);
-		kb->keylen = keylen;
+		memcpy(ctx->keybuf, key, keylen);
+		ctx->keylen = keylen;
 		break;
 	}
 
 	return 0;
 }
 
-static inline int _xts_key_to_kb(struct key_blob *kb,
-				 const u8 *key,
-				 unsigned int keylen)
+/*
+ * xts_key_to_ctx() - Set key value into context, maybe construct
+ * a clear key token digestable by pkey from a clear key value.
+ */
+static inline int xts_key_to_ctx(struct s390_pxts_ctx *ctx,
+				 const u8 *key, unsigned int keylen)
 {
 	size_t cklen = keylen / 2;
 
-	memset(kb->keybuf, 0, sizeof(kb->keybuf));
+	if (keylen > sizeof(ctx->keybuf))
+		return -EINVAL;
 
 	switch (keylen) {
 	case 32:
 	case 64:
 		/* clear key value, prepare pkey clear key tokens in keybuf */
-		kb->key = kb->keybuf;
-		kb->keylen  = make_clrkey_token(key, cklen, kb->key);
-		kb->keylen += make_clrkey_token(key + cklen, cklen,
-						kb->key + kb->keylen);
+		memset(ctx->keybuf, 0, sizeof(ctx->keybuf));
+		ctx->keylen = make_clrkey_token(key, cklen, ctx->keybuf);
+		ctx->keylen += make_clrkey_token(key + cklen, cklen,
+						 ctx->keybuf + ctx->keylen);
 		break;
 	default:
 		/* other key material, let pkey handle this */
-		if (keylen <= sizeof(kb->keybuf)) {
-			kb->key = kb->keybuf;
-		} else {
-			kb->key = kmalloc(keylen, GFP_KERNEL);
-			if (!kb->key)
-				return -ENOMEM;
-		}
-		memcpy(kb->key, key, keylen);
-		kb->keylen = keylen;
+		memcpy(ctx->keybuf, key, keylen);
+		ctx->keylen = keylen;
 		break;
 	}
 
 	return 0;
 }
 
-static inline void _free_kb_keybuf(struct key_blob *kb)
+/*
+ * Convert the raw key material into a protected key via PKEY api.
+ * This function may sleep - don't call in non-sleeping context.
+ */
+static inline int convert_key(const u8 *key, unsigned int keylen,
+			      struct paes_protkey *pk)
 {
-	if (kb->key && kb->key != kb->keybuf
-	    && kb->keylen > sizeof(kb->keybuf)) {
-		kfree_sensitive(kb->key);
-		kb->key = NULL;
-	}
-	memzero_explicit(kb->keybuf, sizeof(kb->keybuf));
-}
-
-struct s390_paes_ctx {
-	struct key_blob kb;
-	struct paes_protkey pk;
-	spinlock_t pk_lock;
-	unsigned long fc;
-};
-
-struct s390_pxts_ctx {
-	struct key_blob kb;
-	struct paes_protkey pk[2];
-	spinlock_t pk_lock;
-	unsigned long fc;
-};
+	int rc, i;
 
-static inline int __paes_keyblob2pkey(const u8 *key, unsigned int keylen,
-				      struct paes_protkey *pk)
-{
-	int i, rc = -EIO;
+	pk->len = sizeof(pk->protkey);
 
 	/* try three times in case of busy card */
-	for (i = 0; rc && i < 3; i++) {
-		if (rc == -EBUSY && in_task()) {
-			if (msleep_interruptible(1000))
-				return -EINTR;
+	for (rc = -EIO, i = 0; rc && i < 3; i++) {
+		if (rc == -EBUSY && msleep_interruptible((1 << i) * 100)) {
+			rc = -EINTR;
+			goto out;
 		}
-		rc = pkey_key2protkey(key, keylen, pk->protkey, &pk->len,
-				      &pk->type, PKEY_XFLAG_NOMEMALLOC);
+		rc = pkey_key2protkey(key, keylen,
+				      pk->protkey, &pk->len, &pk->type,
+				      PKEY_XFLAG_NOMEMALLOC);
 	}
 
+out:
+	pr_debug("rc=%d\n", rc);
 	return rc;
 }
 
-static inline int __paes_convert_key(struct s390_paes_ctx *ctx)
+/*
+ * (Re-)Convert the raw key material from the ctx into a
+ * protected key via convert_key() function. Update the
+ * pk_state, pk_type, pk_len and the protected key in
+ * the param block.
+ */
+static int paes_convert_key(struct s390_paes_ctx *ctx)
 {
 	struct paes_protkey pk;
 	int rc;
 
-	pk.len = sizeof(pk.protkey);
-	rc = __paes_keyblob2pkey(ctx->kb.key, ctx->kb.keylen, &pk);
-	if (rc)
-		return rc;
+	spin_lock_bh(&ctx->pk_lock);
+	ctx->pk_state = PK_STATE_CONVERT_IN_PROGRESS;
+	spin_unlock_bh(&ctx->pk_lock);
 
+	rc = convert_key(ctx->keybuf, ctx->keylen, &pk);
+
+	/* update context */
 	spin_lock_bh(&ctx->pk_lock);
-	memcpy(&ctx->pk, &pk, sizeof(pk));
+	if (rc) {
+		ctx->pk_state = rc;
+	} else {
+		ctx->pk_state = PK_STATE_VALID;
+		ctx->pk = pk;
+	}
 	spin_unlock_bh(&ctx->pk_lock);
 
-	return 0;
+	memzero_explicit(&pk, sizeof(pk));
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static int ecb_paes_init(struct crypto_skcipher *tfm)
+/*
+ * (Re-)Convert the raw xts key material from the ctx into
+ * a protected key via convert_key() function. Update the
+ * pk_state, pk_type, pk_len and the protected key in
+ * the param block.
+ */
+static int pxts_convert_key(struct s390_pxts_ctx *ctx)
 {
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct paes_protkey pk0, pk1;
+	size_t split_keylen;
+	int rc;
 
-	ctx->kb.key = NULL;
-	spin_lock_init(&ctx->pk_lock);
+	spin_lock_bh(&ctx->pk_lock);
+	ctx->pk_state = PK_STATE_CONVERT_IN_PROGRESS;
+	spin_unlock_bh(&ctx->pk_lock);
 
-	return 0;
-}
+	rc = convert_key(ctx->keybuf, ctx->keylen, &pk0);
+	if (rc)
+		goto out;
 
-static void ecb_paes_exit(struct crypto_skcipher *tfm)
-{
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	switch (pk0.type) {
+	case PKEY_KEYTYPE_AES_128:
+	case PKEY_KEYTYPE_AES_256:
+		/* second keytoken required */
+		if (ctx->keylen % 2) {
+			rc = -EINVAL;
+			goto out;
+		}
+		split_keylen = ctx->keylen / 2;
+		rc = convert_key(ctx->keybuf + split_keylen,
+				 split_keylen, &pk1);
+		if (rc)
+			goto out;
+		if (pk0.type != pk1.type) {
+			rc = -EINVAL;
+			goto out;
+		}
+		break;
+	case PKEY_KEYTYPE_AES_XTS_128:
+	case PKEY_KEYTYPE_AES_XTS_256:
+		/* single key */
+		pk1.type = 0;
+		break;
+	default:
+		/* unsupported protected keytype */
+		rc = -EINVAL;
+		goto out;
+	}
+
+out:
+	/* update context */
+	spin_lock_bh(&ctx->pk_lock);
+	if (rc) {
+		ctx->pk_state = rc;
+	} else {
+		ctx->pk_state = PK_STATE_VALID;
+		ctx->pk[0] = pk0;
+		ctx->pk[1] = pk1;
+	}
+	spin_unlock_bh(&ctx->pk_lock);
 
-	_free_kb_keybuf(&ctx->kb);
+	memzero_explicit(&pk0, sizeof(pk0));
+	memzero_explicit(&pk1, sizeof(pk1));
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static inline int __ecb_paes_set_key(struct s390_paes_ctx *ctx)
+/*
+ * PAES ECB implementation
+ */
+
+struct ecb_param {
+	u8 key[PAES_256_PROTKEY_SIZE];
+} __packed;
+
+struct s390_pecb_req_ctx {
+	unsigned long modifier;
+	struct skcipher_walk walk;
+	bool param_init_done;
+	struct ecb_param param;
+};
+
+static int ecb_paes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			   unsigned int key_len)
 {
-	unsigned long fc;
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	long fc;
 	int rc;
 
-	rc = __paes_convert_key(ctx);
+	/* set raw key into context */
+	rc = key_to_ctx(ctx, in_key, key_len);
 	if (rc)
-		return rc;
+		goto out;
 
-	/* Pick the correct function code based on the protected key type */
-	fc = (ctx->pk.type == PKEY_KEYTYPE_AES_128) ? CPACF_KM_PAES_128 :
-		(ctx->pk.type == PKEY_KEYTYPE_AES_192) ? CPACF_KM_PAES_192 :
-		(ctx->pk.type == PKEY_KEYTYPE_AES_256) ? CPACF_KM_PAES_256 : 0;
+	/* convert key into protected key */
+	rc = paes_convert_key(ctx);
+	if (rc)
+		goto out;
 
-	/* Check if the function code is available */
+	/* Pick the correct function code based on the protected key type */
+	switch (ctx->pk.type) {
+	case PKEY_KEYTYPE_AES_128:
+		fc = CPACF_KM_PAES_128;
+		break;
+	case PKEY_KEYTYPE_AES_192:
+		fc = CPACF_KM_PAES_192;
+		break;
+	case PKEY_KEYTYPE_AES_256:
+		fc = CPACF_KM_PAES_256;
+		break;
+	default:
+		fc = 0;
+		break;
+	}
 	ctx->fc = (fc && cpacf_test_func(&km_functions, fc)) ? fc : 0;
 
-	return ctx->fc ? 0 : -EINVAL;
+	rc = fc ? 0 : -EINVAL;
+
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static int ecb_paes_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			    unsigned int key_len)
+static int ecb_paes_do_crypt(struct s390_paes_ctx *ctx,
+			     struct s390_pecb_req_ctx *req_ctx,
+			     bool maysleep)
 {
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
-	int rc;
+	struct ecb_param *param = &req_ctx->param;
+	struct skcipher_walk *walk = &req_ctx->walk;
+	unsigned int nbytes, n, k;
+	int pk_state, rc;
+
+	if (!req_ctx->param_init_done) {
+		/* fetch and check protected key state */
+		spin_lock_bh(&ctx->pk_lock);
+		pk_state = ctx->pk_state;
+		memcpy(param->key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
+		spin_unlock_bh(&ctx->pk_lock);
+		switch (pk_state) {
+		case PK_STATE_NO_KEY:
+			rc = -ENOKEY;
+			goto out;
+		case PK_STATE_CONVERT_IN_PROGRESS:
+			rc = -EKEYEXPIRED;
+			goto out;
+		case PK_STATE_VALID:
+			req_ctx->param_init_done = true;
+			break;
+		default:
+			rc = pk_state < 0 ? pk_state : -EIO;
+			goto out;
+		}
+	}
 
-	_free_kb_keybuf(&ctx->kb);
-	rc = _key_to_kb(&ctx->kb, in_key, key_len);
-	if (rc)
-		return rc;
+	rc = 0;
+
+	/* always walk on the ... */
+	while ((nbytes = walk->nbytes) != 0) {
+		/* only use complete blocks */
+		n = nbytes & ~(AES_BLOCK_SIZE - 1);
+		k = cpacf_km(ctx->fc | req_ctx->modifier, param,
+			     walk->dst.virt.addr, walk->src.virt.addr, n);
+		if (k)
+			rc = skcipher_walk_done(walk, nbytes - k);
+		if (k < n) {
+			if (!maysleep) {
+				rc = -EKEYEXPIRED;
+				goto out;
+			}
+			rc = paes_convert_key(ctx);
+			if (rc)
+				goto out;
+			spin_lock_bh(&ctx->pk_lock);
+			memcpy(param->key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
+			spin_unlock_bh(&ctx->pk_lock);
+		}
+	}
 
-	return __ecb_paes_set_key(ctx);
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
 static int ecb_paes_crypt(struct skcipher_request *req, unsigned long modifier)
 {
+	struct s390_pecb_req_ctx *req_ctx = skcipher_request_ctx(req);
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
-	struct {
-		u8 key[PAES_256_PROTKEY_SIZE];
-	} param;
-	struct skcipher_walk walk;
-	unsigned int nbytes, n, k;
+	struct skcipher_walk *walk = &req_ctx->walk;
 	int rc;
 
-	rc = skcipher_walk_virt(&walk, req, false);
+	/*
+	 * First try synchronous. If this fails for any reason
+	 * schedule this request asynchronous via crypto engine.
+	 */
+
+	rc = skcipher_walk_virt(walk, req, false);
 	if (rc)
-		return rc;
+		goto out;
 
-	spin_lock_bh(&ctx->pk_lock);
-	memcpy(param.key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
-	spin_unlock_bh(&ctx->pk_lock);
+	req_ctx->modifier = modifier;
+	req_ctx->param_init_done = false;
 
-	while ((nbytes = walk.nbytes) != 0) {
-		/* only use complete blocks */
-		n = nbytes & ~(AES_BLOCK_SIZE - 1);
-		k = cpacf_km(ctx->fc | modifier, &param,
-			     walk.dst.virt.addr, walk.src.virt.addr, n);
-		if (k)
-			rc = skcipher_walk_done(&walk, nbytes - k);
-		if (k < n) {
-			if (__paes_convert_key(ctx))
-				return skcipher_walk_done(&walk, -EIO);
-			spin_lock_bh(&ctx->pk_lock);
-			memcpy(param.key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
-			spin_unlock_bh(&ctx->pk_lock);
-		}
+	rc = ecb_paes_do_crypt(ctx, req_ctx, false);
+	if (rc != -EKEYEXPIRED) {
+		if (rc)
+			skcipher_walk_done(walk, rc);
+		goto out;
 	}
+
+	rc = crypto_transfer_skcipher_request_to_engine(paes_crypto_engine, req);
+	if (rc)
+		goto out;
+
+	rc = -EINPROGRESS;
+
+out:
+	if (rc != -EINPROGRESS)
+		memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("rc=%d\n", rc);
 	return rc;
 }
 
@@ -310,112 +473,242 @@  static int ecb_paes_decrypt(struct skcipher_request *req)
 	return ecb_paes_crypt(req, CPACF_DECRYPT);
 }
 
-static struct skcipher_alg ecb_paes_alg = {
-	.base.cra_name		=	"ecb(paes)",
-	.base.cra_driver_name	=	"ecb-paes-s390",
-	.base.cra_priority	=	401,	/* combo: aes + ecb + 1 */
-	.base.cra_blocksize	=	AES_BLOCK_SIZE,
-	.base.cra_ctxsize	=	sizeof(struct s390_paes_ctx),
-	.base.cra_module	=	THIS_MODULE,
-	.base.cra_list		=	LIST_HEAD_INIT(ecb_paes_alg.base.cra_list),
-	.init			=	ecb_paes_init,
-	.exit			=	ecb_paes_exit,
-	.min_keysize		=	PAES_MIN_KEYSIZE,
-	.max_keysize		=	PAES_MAX_KEYSIZE,
-	.setkey			=	ecb_paes_set_key,
-	.encrypt		=	ecb_paes_encrypt,
-	.decrypt		=	ecb_paes_decrypt,
-};
-
-static int cbc_paes_init(struct crypto_skcipher *tfm)
+static int ecb_paes_init(struct crypto_skcipher *tfm)
 {
 	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	ctx->kb.key = NULL;
+	memset(ctx, 0, sizeof(*ctx));
 	spin_lock_init(&ctx->pk_lock);
 
+	crypto_skcipher_set_reqsize(tfm, sizeof(struct s390_pecb_req_ctx));
+
 	return 0;
 }
 
-static void cbc_paes_exit(struct crypto_skcipher *tfm)
+static void ecb_paes_exit(struct crypto_skcipher *tfm)
 {
 	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	_free_kb_keybuf(&ctx->kb);
+	memzero_explicit(ctx, sizeof(*ctx));
 }
 
-static inline int __cbc_paes_set_key(struct s390_paes_ctx *ctx)
+static int ecb_paes_do_one_request(struct crypto_engine *engine, void *areq)
 {
-	unsigned long fc;
+	struct skcipher_request *req = skcipher_request_cast(areq);
+	struct s390_pecb_req_ctx *req_ctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk *walk = &req_ctx->walk;
 	int rc;
 
-	rc = __paes_convert_key(ctx);
-	if (rc)
-		return rc;
-
-	/* Pick the correct function code based on the protected key type */
-	fc = (ctx->pk.type == PKEY_KEYTYPE_AES_128) ? CPACF_KMC_PAES_128 :
-		(ctx->pk.type == PKEY_KEYTYPE_AES_192) ? CPACF_KMC_PAES_192 :
-		(ctx->pk.type == PKEY_KEYTYPE_AES_256) ? CPACF_KMC_PAES_256 : 0;
+	/* walk has already been prepared */
 
-	/* Check if the function code is available */
-	ctx->fc = (fc && cpacf_test_func(&kmc_functions, fc)) ? fc : 0;
+	rc = ecb_paes_do_crypt(ctx, req_ctx, true);
+	if (rc != -EKEYEXPIRED) {
+		if (rc)
+			skcipher_walk_done(walk, rc);
+		goto complete;
+	}
 
-	return ctx->fc ? 0 : -EINVAL;
+	/*
+	 * Protected key expired, conversion is in process.
+	 * Trigger a re-schedule of this request by returning
+	 * -ENOSPC ("hardware queue is full") to the crypto engine.
+	 * To avoid immediately re-invocation of this callback,
+	 * tell the scheduler to voluntarily give up the CPU here.
+	 */
+	yield();
+	pr_debug("rescheduling request\n");
+	return -ENOSPC;
+
+complete:
+	memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("request complete with rc=%d\n", rc);
+	local_bh_disable();
+	crypto_finalize_skcipher_request(engine, req, rc);
+	local_bh_enable();
+	return rc;
 }
 
-static int cbc_paes_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			    unsigned int key_len)
+static struct skcipher_engine_alg ecb_paes_alg = {
+	.base = {
+		.base.cra_name	      = "ecb(paes)",
+		.base.cra_driver_name = "ecb-paes-s390",
+		.base.cra_priority    = 401,	/* combo: aes + ecb + 1 */
+		.base.cra_blocksize   = AES_BLOCK_SIZE,
+		.base.cra_ctxsize     = sizeof(struct s390_paes_ctx),
+		.base.cra_module      = THIS_MODULE,
+		.base.cra_list	      = LIST_HEAD_INIT(ecb_paes_alg.base.base.cra_list),
+		.init		      = ecb_paes_init,
+		.exit		      = ecb_paes_exit,
+		.min_keysize	      = PAES_MIN_KEYSIZE,
+		.max_keysize	      = PAES_MAX_KEYSIZE,
+		.setkey		      = ecb_paes_setkey,
+		.encrypt	      = ecb_paes_encrypt,
+		.decrypt	      = ecb_paes_decrypt,
+	},
+	.op = {
+		.do_one_request	      = ecb_paes_do_one_request,
+	},
+};
+
+/*
+ * PAES CBC implementation
+ */
+
+struct cbc_param {
+	u8 iv[AES_BLOCK_SIZE];
+	u8 key[PAES_256_PROTKEY_SIZE];
+} __packed;
+
+struct s390_pcbc_req_ctx {
+	unsigned long modifier;
+	struct skcipher_walk walk;
+	bool param_init_done;
+	struct cbc_param param;
+};
+
+static int cbc_paes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			   unsigned int key_len)
 {
 	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	long fc;
 	int rc;
 
-	_free_kb_keybuf(&ctx->kb);
-	rc = _key_to_kb(&ctx->kb, in_key, key_len);
+	/* set raw key into context */
+	rc = key_to_ctx(ctx, in_key, key_len);
 	if (rc)
-		return rc;
+		goto out;
+
+	/* convert raw key into protected key */
+	rc = paes_convert_key(ctx);
+	if (rc)
+		goto out;
+
+	/* Pick the correct function code based on the protected key type */
+	switch (ctx->pk.type) {
+	case PKEY_KEYTYPE_AES_128:
+		fc = CPACF_KMC_PAES_128;
+		break;
+	case PKEY_KEYTYPE_AES_192:
+		fc = CPACF_KMC_PAES_192;
+		break;
+	case PKEY_KEYTYPE_AES_256:
+		fc = CPACF_KMC_PAES_256;
+		break;
+	default:
+		fc = 0;
+		break;
+	}
+	ctx->fc = (fc && cpacf_test_func(&kmc_functions, fc)) ? fc : 0;
 
-	return __cbc_paes_set_key(ctx);
+	rc = fc ? 0 : -EINVAL;
+
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static int cbc_paes_crypt(struct skcipher_request *req, unsigned long modifier)
+static int cbc_paes_do_crypt(struct s390_paes_ctx *ctx,
+			     struct s390_pcbc_req_ctx *req_ctx,
+			     bool maysleep)
 {
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
-	struct {
-		u8 iv[AES_BLOCK_SIZE];
-		u8 key[PAES_256_PROTKEY_SIZE];
-	} param;
-	struct skcipher_walk walk;
+	struct cbc_param *param = &req_ctx->param;
+	struct skcipher_walk *walk = &req_ctx->walk;
 	unsigned int nbytes, n, k;
-	int rc;
-
-	rc = skcipher_walk_virt(&walk, req, false);
-	if (rc)
-		return rc;
+	int pk_state, rc;
+
+	if (!req_ctx->param_init_done) {
+		/* fetch and check protected key state */
+		spin_lock_bh(&ctx->pk_lock);
+		pk_state = ctx->pk_state;
+		memcpy(param->key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
+		spin_unlock_bh(&ctx->pk_lock);
+		switch (pk_state) {
+		case PK_STATE_NO_KEY:
+			rc = -ENOKEY;
+			goto out;
+		case PK_STATE_CONVERT_IN_PROGRESS:
+			rc = -EKEYEXPIRED;
+			goto out;
+		case PK_STATE_VALID:
+			req_ctx->param_init_done = true;
+			break;
+		default:
+			rc = pk_state < 0 ? pk_state : -EIO;
+			goto out;
+		}
+	}
 
-	memcpy(param.iv, walk.iv, AES_BLOCK_SIZE);
-	spin_lock_bh(&ctx->pk_lock);
-	memcpy(param.key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
-	spin_unlock_bh(&ctx->pk_lock);
+	memcpy(param->iv, walk->iv, AES_BLOCK_SIZE);
+	rc = 0;
 
-	while ((nbytes = walk.nbytes) != 0) {
+	/* always walk on the ... */
+	while ((nbytes = walk->nbytes) != 0) {
 		/* only use complete blocks */
 		n = nbytes & ~(AES_BLOCK_SIZE - 1);
-		k = cpacf_kmc(ctx->fc | modifier, &param,
-			      walk.dst.virt.addr, walk.src.virt.addr, n);
+		k = cpacf_kmc(ctx->fc | req_ctx->modifier, param,
+			      walk->dst.virt.addr, walk->src.virt.addr, n);
 		if (k) {
-			memcpy(walk.iv, param.iv, AES_BLOCK_SIZE);
-			rc = skcipher_walk_done(&walk, nbytes - k);
+			memcpy(walk->iv, param->iv, AES_BLOCK_SIZE);
+			rc = skcipher_walk_done(walk, nbytes - k);
 		}
 		if (k < n) {
-			if (__paes_convert_key(ctx))
-				return skcipher_walk_done(&walk, -EIO);
+			if (!maysleep) {
+				rc = -EKEYEXPIRED;
+				goto out;
+			}
+			rc = paes_convert_key(ctx);
+			if (rc)
+				goto out;
 			spin_lock_bh(&ctx->pk_lock);
-			memcpy(param.key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
+			memcpy(param->key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
 			spin_unlock_bh(&ctx->pk_lock);
 		}
 	}
+
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
+}
+
+static int cbc_paes_crypt(struct skcipher_request *req, unsigned long modifier)
+{
+	struct s390_pcbc_req_ctx *req_ctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk *walk = &req_ctx->walk;
+	int rc;
+
+	/*
+	 * First try synchronous. If this fails for any reason
+	 * schedule this request asynchronous via crypto engine.
+	 */
+
+	rc = skcipher_walk_virt(walk, req, false);
+	if (rc)
+		goto out;
+
+	req_ctx->modifier = modifier;
+	req_ctx->param_init_done = false;
+
+	rc = cbc_paes_do_crypt(ctx, req_ctx, false);
+	if (rc != -EKEYEXPIRED) {
+		if (rc)
+			skcipher_walk_done(walk, rc);
+		goto out;
+	}
+
+	rc = crypto_transfer_skcipher_request_to_engine(paes_crypto_engine, req);
+	if (rc)
+		goto out;
+
+	rc = -EINPROGRESS;
+
+out:
+	if (rc != -EINPROGRESS)
+		memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("rc=%d\n", rc);
 	return rc;
 }
 
@@ -429,496 +722,839 @@  static int cbc_paes_decrypt(struct skcipher_request *req)
 	return cbc_paes_crypt(req, CPACF_DECRYPT);
 }
 
-static struct skcipher_alg cbc_paes_alg = {
-	.base.cra_name		=	"cbc(paes)",
-	.base.cra_driver_name	=	"cbc-paes-s390",
-	.base.cra_priority	=	402,	/* ecb-paes-s390 + 1 */
-	.base.cra_blocksize	=	AES_BLOCK_SIZE,
-	.base.cra_ctxsize	=	sizeof(struct s390_paes_ctx),
-	.base.cra_module	=	THIS_MODULE,
-	.base.cra_list		=	LIST_HEAD_INIT(cbc_paes_alg.base.cra_list),
-	.init			=	cbc_paes_init,
-	.exit			=	cbc_paes_exit,
-	.min_keysize		=	PAES_MIN_KEYSIZE,
-	.max_keysize		=	PAES_MAX_KEYSIZE,
-	.ivsize			=	AES_BLOCK_SIZE,
-	.setkey			=	cbc_paes_set_key,
-	.encrypt		=	cbc_paes_encrypt,
-	.decrypt		=	cbc_paes_decrypt,
-};
-
-static int xts_paes_init(struct crypto_skcipher *tfm)
+static int cbc_paes_init(struct crypto_skcipher *tfm)
 {
-	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	ctx->kb.key = NULL;
+	memset(ctx, 0, sizeof(*ctx));
 	spin_lock_init(&ctx->pk_lock);
 
+	crypto_skcipher_set_reqsize(tfm, sizeof(struct s390_pcbc_req_ctx));
+
 	return 0;
 }
 
-static void xts_paes_exit(struct crypto_skcipher *tfm)
+static void cbc_paes_exit(struct crypto_skcipher *tfm)
 {
-	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	_free_kb_keybuf(&ctx->kb);
+	memzero_explicit(ctx, sizeof(*ctx));
 }
 
-static inline int __xts_paes_convert_key(struct s390_pxts_ctx *ctx)
+static int cbc_paes_do_one_request(struct crypto_engine *engine, void *areq)
 {
-	struct paes_protkey pk0, pk1;
-	size_t split_keylen;
+	struct skcipher_request *req = skcipher_request_cast(areq);
+	struct s390_pcbc_req_ctx *req_ctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk *walk = &req_ctx->walk;
 	int rc;
 
-	pk0.len = sizeof(pk0.protkey);
-	pk1.len = sizeof(pk1.protkey);
+	/* walk has already been prepared */
 
-	rc = __paes_keyblob2pkey(ctx->kb.key, ctx->kb.keylen, &pk0);
-	if (rc)
-		return rc;
+	rc = cbc_paes_do_crypt(ctx, req_ctx, true);
+	if (rc != -EKEYEXPIRED) {
+		if (rc)
+			skcipher_walk_done(walk, rc);
+		goto complete;
+	}
 
-	switch (pk0.type) {
-	case PKEY_KEYTYPE_AES_128:
-	case PKEY_KEYTYPE_AES_256:
-		/* second keytoken required */
-		if (ctx->kb.keylen % 2)
-			return -EINVAL;
-		split_keylen = ctx->kb.keylen / 2;
+	/*
+	 * Protected key expired, conversion is in process.
+	 * Trigger a re-schedule of this request by returning
+	 * -ENOSPC ("hardware queue is full") to the crypto engine.
+	 * To avoid immediately re-invocation of this callback,
+	 * tell the scheduler to voluntarily give up the CPU here.
+	 */
+	yield();
+	pr_debug("rescheduling request\n");
+	return -ENOSPC;
+
+complete:
+	memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("request complete with rc=%d\n", rc);
+	local_bh_disable();
+	crypto_finalize_skcipher_request(engine, req, rc);
+	local_bh_enable();
+	return rc;
+}
 
-		rc = __paes_keyblob2pkey(ctx->kb.key + split_keylen,
-					 split_keylen, &pk1);
-		if (rc)
-			return rc;
+static struct skcipher_engine_alg cbc_paes_alg = {
+	.base = {
+		.base.cra_name	      = "cbc(paes)",
+		.base.cra_driver_name = "cbc-paes-s390",
+		.base.cra_priority    = 402,	/* cbc-paes-s390 + 1 */
+		.base.cra_blocksize   = AES_BLOCK_SIZE,
+		.base.cra_ctxsize     = sizeof(struct s390_paes_ctx),
+		.base.cra_module      = THIS_MODULE,
+		.base.cra_list	      = LIST_HEAD_INIT(cbc_paes_alg.base.base.cra_list),
+		.init		      = cbc_paes_init,
+		.exit		      = cbc_paes_exit,
+		.min_keysize	      = PAES_MIN_KEYSIZE,
+		.max_keysize	      = PAES_MAX_KEYSIZE,
+		.ivsize		      = AES_BLOCK_SIZE,
+		.setkey		      = cbc_paes_setkey,
+		.encrypt	      = cbc_paes_encrypt,
+		.decrypt	      = cbc_paes_decrypt,
+	},
+	.op = {
+		.do_one_request	      = cbc_paes_do_one_request,
+	},
+};
 
-		if (pk0.type != pk1.type)
-			return -EINVAL;
-		break;
-	case PKEY_KEYTYPE_AES_XTS_128:
-	case PKEY_KEYTYPE_AES_XTS_256:
-		/* single key */
-		pk1.type = 0;
-		break;
-	default:
-		/* unsupported protected keytype */
-		return -EINVAL;
-	}
+/*
+ * PAES CTR implementation
+ */
 
-	spin_lock_bh(&ctx->pk_lock);
-	ctx->pk[0] = pk0;
-	ctx->pk[1] = pk1;
-	spin_unlock_bh(&ctx->pk_lock);
+struct ctr_param {
+	u8 key[PAES_256_PROTKEY_SIZE];
+} __packed;
 
-	return 0;
-}
+struct s390_pctr_req_ctx {
+	unsigned long modifier;
+	struct skcipher_walk walk;
+	bool param_init_done;
+	struct ctr_param param;
+};
 
-static inline int __xts_paes_set_key(struct s390_pxts_ctx *ctx)
+static int ctr_paes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			   unsigned int key_len)
 {
-	unsigned long fc;
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	long fc;
 	int rc;
 
-	rc = __xts_paes_convert_key(ctx);
+	/* set raw key into context */
+	rc = key_to_ctx(ctx, in_key, key_len);
 	if (rc)
-		return rc;
+		goto out;
+
+	/* convert raw key into protected key */
+	rc = paes_convert_key(ctx);
+	if (rc)
+		goto out;
 
 	/* Pick the correct function code based on the protected key type */
-	switch (ctx->pk[0].type) {
+	switch (ctx->pk.type) {
 	case PKEY_KEYTYPE_AES_128:
-		fc = CPACF_KM_PXTS_128;
+		fc = CPACF_KMCTR_PAES_128;
 		break;
-	case PKEY_KEYTYPE_AES_256:
-		fc = CPACF_KM_PXTS_256;
+	case PKEY_KEYTYPE_AES_192:
+		fc = CPACF_KMCTR_PAES_192;
 		break;
-	case PKEY_KEYTYPE_AES_XTS_128:
-		fc = CPACF_KM_PXTS_128_FULL;
-		break;
-	case PKEY_KEYTYPE_AES_XTS_256:
-		fc = CPACF_KM_PXTS_256_FULL;
+	case PKEY_KEYTYPE_AES_256:
+		fc = CPACF_KMCTR_PAES_256;
 		break;
 	default:
 		fc = 0;
 		break;
 	}
+	ctx->fc = (fc && cpacf_test_func(&kmctr_functions, fc)) ? fc : 0;
 
-	/* Check if the function code is available */
-	ctx->fc = (fc && cpacf_test_func(&km_functions, fc)) ? fc : 0;
+	rc = fc ? 0 : -EINVAL;
 
-	return ctx->fc ? 0 : -EINVAL;
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static int xts_paes_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			    unsigned int in_keylen)
+static inline unsigned int __ctrblk_init(u8 *ctrptr, u8 *iv, unsigned int nbytes)
+{
+	unsigned int i, n;
+
+	/* only use complete blocks, max. PAGE_SIZE */
+	memcpy(ctrptr, iv, AES_BLOCK_SIZE);
+	n = (nbytes > PAGE_SIZE) ? PAGE_SIZE : nbytes & ~(AES_BLOCK_SIZE - 1);
+	for (i = (n / AES_BLOCK_SIZE) - 1; i > 0; i--) {
+		memcpy(ctrptr + AES_BLOCK_SIZE, ctrptr, AES_BLOCK_SIZE);
+		crypto_inc(ctrptr + AES_BLOCK_SIZE, AES_BLOCK_SIZE);
+		ctrptr += AES_BLOCK_SIZE;
+	}
+	return n;
+}
+
+static int ctr_paes_do_crypt(struct s390_paes_ctx *ctx,
+			     struct s390_pctr_req_ctx *req_ctx,
+			     bool maysleep)
+{
+	struct ctr_param *param = &req_ctx->param;
+	struct skcipher_walk *walk = &req_ctx->walk;
+	u8 buf[AES_BLOCK_SIZE], *ctrptr;
+	unsigned int nbytes, n, k;
+	int pk_state, locked, rc;
+
+	if (!req_ctx->param_init_done) {
+		/* fetch and check protected key state */
+		spin_lock_bh(&ctx->pk_lock);
+		pk_state = ctx->pk_state;
+		memcpy(param->key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
+		spin_unlock_bh(&ctx->pk_lock);
+		switch (pk_state) {
+		case PK_STATE_NO_KEY:
+			rc = -ENOKEY;
+			goto out;
+		case PK_STATE_CONVERT_IN_PROGRESS:
+			rc = -EKEYEXPIRED;
+			goto out;
+		case PK_STATE_VALID:
+			req_ctx->param_init_done = true;
+			break;
+		default:
+			rc = pk_state < 0 ? pk_state : -EIO;
+			goto out;
+		}
+	}
+
+	rc = 0;
+	locked = mutex_trylock(&ctrblk_lock);
+
+	/* always walk on the ... */
+	while ((nbytes = walk->nbytes) >= AES_BLOCK_SIZE) {
+		n = AES_BLOCK_SIZE;
+		if (nbytes >= 2 * AES_BLOCK_SIZE && locked)
+			n = __ctrblk_init(ctrblk, walk->iv, nbytes);
+		ctrptr = (n > AES_BLOCK_SIZE) ? ctrblk : walk->iv;
+		k = cpacf_kmctr(ctx->fc, param, walk->dst.virt.addr,
+				walk->src.virt.addr, n, ctrptr);
+		if (k) {
+			if (ctrptr == ctrblk)
+				memcpy(walk->iv, ctrptr + k - AES_BLOCK_SIZE,
+				       AES_BLOCK_SIZE);
+			crypto_inc(walk->iv, AES_BLOCK_SIZE);
+			rc = skcipher_walk_done(walk, nbytes - k);
+		}
+		if (k < n) {
+			if (!maysleep) {
+				if (locked)
+					mutex_unlock(&ctrblk_lock);
+				rc = -EKEYEXPIRED;
+				goto out;
+			}
+			rc = paes_convert_key(ctx);
+			if (rc) {
+				if (locked)
+					mutex_unlock(&ctrblk_lock);
+				goto out;
+			}
+			spin_lock_bh(&ctx->pk_lock);
+			memcpy(param->key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
+			spin_unlock_bh(&ctx->pk_lock);
+		}
+	}
+	if (locked)
+		mutex_unlock(&ctrblk_lock);
+
+	/* final block may be < AES_BLOCK_SIZE, copy only nbytes */
+	if (nbytes) {
+		memset(buf, 0, AES_BLOCK_SIZE);
+		memcpy(buf, walk->src.virt.addr, nbytes);
+		while (1) {
+			if (cpacf_kmctr(ctx->fc, param, buf,
+					buf, AES_BLOCK_SIZE,
+					walk->iv) == AES_BLOCK_SIZE)
+				break;
+			if (!maysleep) {
+				rc = -EKEYEXPIRED;
+				goto out;
+			}
+			rc = paes_convert_key(ctx);
+			if (rc)
+				goto out;
+			spin_lock_bh(&ctx->pk_lock);
+			memcpy(param->key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
+			spin_unlock_bh(&ctx->pk_lock);
+		}
+		memcpy(walk->dst.virt.addr, buf, nbytes);
+		crypto_inc(walk->iv, AES_BLOCK_SIZE);
+		rc = skcipher_walk_done(walk, 0);
+	}
+
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
+}
+
+static int ctr_paes_crypt(struct skcipher_request *req)
+{
+	struct s390_pctr_req_ctx *req_ctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk *walk = &req_ctx->walk;
+	int rc;
+
+	/*
+	 * First try synchronous. If this fails for any reason
+	 * schedule this request asynchronous via crypto engine.
+	 */
+
+	rc = skcipher_walk_virt(walk, req, false);
+	if (rc)
+		goto out;
+
+	req_ctx->param_init_done = false;
+
+	rc = ctr_paes_do_crypt(ctx, req_ctx, false);
+	if (rc != -EKEYEXPIRED) {
+		if (rc)
+			skcipher_walk_done(walk, rc);
+		goto out;
+	}
+
+	rc = crypto_transfer_skcipher_request_to_engine(paes_crypto_engine, req);
+	if (rc)
+		goto out;
+
+	rc = -EINPROGRESS;
+
+out:
+	if (rc != -EINPROGRESS)
+		memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("rc=%d\n", rc);
+	return rc;
+}
+
+static int ctr_paes_init(struct crypto_skcipher *tfm)
+{
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	memset(ctx, 0, sizeof(*ctx));
+	spin_lock_init(&ctx->pk_lock);
+
+	crypto_skcipher_set_reqsize(tfm, sizeof(struct s390_pctr_req_ctx));
+
+	return 0;
+}
+
+static void ctr_paes_exit(struct crypto_skcipher *tfm)
+{
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	memzero_explicit(ctx, sizeof(*ctx));
+}
+
+static int ctr_paes_do_one_request(struct crypto_engine *engine, void *areq)
+{
+	struct skcipher_request *req = skcipher_request_cast(areq);
+	struct s390_pctr_req_ctx *req_ctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk *walk = &req_ctx->walk;
+	int rc;
+
+	/* walk has already been prepared */
+
+	rc = ctr_paes_do_crypt(ctx, req_ctx, true);
+	if (rc != -EKEYEXPIRED) {
+		if (rc)
+			skcipher_walk_done(walk, rc);
+		goto complete;
+	}
+
+	/*
+	 * Protected key expired, conversion is in process.
+	 * Trigger a re-schedule of this request by returning
+	 * -ENOSPC ("hardware queue is full") to the crypto engine.
+	 * To avoid immediately re-invocation of this callback,
+	 * tell the scheduler to voluntarily give up the CPU here.
+	 */
+	yield();
+	pr_debug("rescheduling request\n");
+	return -ENOSPC;
+
+complete:
+	memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("request complete with rc=%d\n", rc);
+	local_bh_disable();
+	crypto_finalize_skcipher_request(engine, req, rc);
+	local_bh_enable();
+	return rc;
+}
+
+static struct skcipher_engine_alg ctr_paes_alg = {
+	.base = {
+		.base.cra_name	      =	"ctr(paes)",
+		.base.cra_driver_name =	"ctr-paes-s390",
+		.base.cra_priority    =	402,	/* ecb-paes-s390 + 1 */
+		.base.cra_blocksize   =	1,
+		.base.cra_ctxsize     =	sizeof(struct s390_paes_ctx),
+		.base.cra_module      =	THIS_MODULE,
+		.base.cra_list	      =	LIST_HEAD_INIT(ctr_paes_alg.base.base.cra_list),
+		.init		      =	ctr_paes_init,
+		.exit		      =	ctr_paes_exit,
+		.min_keysize	      =	PAES_MIN_KEYSIZE,
+		.max_keysize	      =	PAES_MAX_KEYSIZE,
+		.ivsize		      =	AES_BLOCK_SIZE,
+		.setkey		      =	ctr_paes_setkey,
+		.encrypt	      =	ctr_paes_crypt,
+		.decrypt	      =	ctr_paes_crypt,
+		.chunksize	      =	AES_BLOCK_SIZE,
+	},
+	.op = {
+		.do_one_request	      = ctr_paes_do_one_request,
+	},
+};
+
+/*
+ * PAES XTS implementation
+ */
+
+struct xts_full_km_param {
+	u8 key[64];
+	u8 tweak[16];
+	u8 nap[16];
+	u8 wkvp[32];
+} __packed;
+
+struct xts_km_param {
+	u8 key[PAES_256_PROTKEY_SIZE];
+	u8 init[16];
+} __packed;
+
+struct xts_pcc_param {
+	u8 key[PAES_256_PROTKEY_SIZE];
+	u8 tweak[16];
+	u8 block[16];
+	u8 bit[16];
+	u8 xts[16];
+} __packed;
+
+struct s390_pxts_req_ctx {
+	unsigned long modifier;
+	struct skcipher_walk walk;
+	bool param_init_done;
+	union {
+		struct xts_full_km_param full_km_param;
+		struct xts_km_param km_param;
+	} param;
+};
+
+static int xts_paes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			   unsigned int in_keylen)
 {
 	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
 	u8 ckey[2 * AES_MAX_KEY_SIZE];
 	unsigned int ckey_len;
+	long fc;
 	int rc;
 
 	if ((in_keylen == 32 || in_keylen == 64) &&
 	    xts_verify_key(tfm, in_key, in_keylen))
 		return -EINVAL;
 
-	_free_kb_keybuf(&ctx->kb);
-	rc = _xts_key_to_kb(&ctx->kb, in_key, in_keylen);
+	/* set raw key into context */
+	rc = xts_key_to_ctx(ctx, in_key, in_keylen);
 	if (rc)
-		return rc;
+		goto out;
 
-	rc = __xts_paes_set_key(ctx);
+	/* convert raw key(s) into protected key(s) */
+	rc = pxts_convert_key(ctx);
 	if (rc)
-		return rc;
+		goto out;
 
-	/*
-	 * It is not possible on a single protected key (e.g. full AES-XTS) to
-	 * check, if k1 and k2 are the same.
-	 */
-	if (ctx->pk[0].type == PKEY_KEYTYPE_AES_XTS_128 ||
-	    ctx->pk[0].type == PKEY_KEYTYPE_AES_XTS_256)
-		return 0;
 	/*
 	 * xts_verify_key verifies the key length is not odd and makes
 	 * sure that the two keys are not the same. This can be done
-	 * on the two protected keys as well
+	 * on the two protected keys as well - but not for full xts keys.
 	 */
-	ckey_len = (ctx->pk[0].type == PKEY_KEYTYPE_AES_128) ?
-		AES_KEYSIZE_128 : AES_KEYSIZE_256;
-	memcpy(ckey, ctx->pk[0].protkey, ckey_len);
-	memcpy(ckey + ckey_len, ctx->pk[1].protkey, ckey_len);
-	return xts_verify_key(tfm, ckey, 2*ckey_len);
+	if (ctx->pk[0].type == PKEY_KEYTYPE_AES_128 ||
+	    ctx->pk[0].type == PKEY_KEYTYPE_AES_256) {
+		ckey_len = (ctx->pk[0].type == PKEY_KEYTYPE_AES_128) ?
+			AES_KEYSIZE_128 : AES_KEYSIZE_256;
+		memcpy(ckey, ctx->pk[0].protkey, ckey_len);
+		memcpy(ckey + ckey_len, ctx->pk[1].protkey, ckey_len);
+		rc = xts_verify_key(tfm, ckey, 2 * ckey_len);
+		memzero_explicit(ckey, sizeof(ckey));
+		if (rc)
+			goto out;
+	}
+
+	/* Pick the correct function code based on the protected key type */
+	switch (ctx->pk[0].type) {
+	case PKEY_KEYTYPE_AES_128:
+		fc = CPACF_KM_PXTS_128;
+		break;
+	case PKEY_KEYTYPE_AES_256:
+		fc = CPACF_KM_PXTS_256;
+		break;
+	case PKEY_KEYTYPE_AES_XTS_128:
+		fc = CPACF_KM_PXTS_128_FULL;
+		break;
+	case PKEY_KEYTYPE_AES_XTS_256:
+		fc = CPACF_KM_PXTS_256_FULL;
+		break;
+	default:
+		fc = 0;
+		break;
+	}
+	ctx->fc = (fc && cpacf_test_func(&km_functions, fc)) ? fc : 0;
+
+	rc = fc ? 0 : -EINVAL;
+
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static int paes_xts_crypt_full(struct skcipher_request *req,
-			       unsigned long modifier)
+static int xts_paes_do_crypt_fullkey(struct s390_pxts_ctx *ctx,
+				     struct s390_pxts_req_ctx *req_ctx,
+				     bool maysleep)
 {
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct xts_full_km_param *param = &req_ctx->param.full_km_param;
+	struct skcipher_walk *walk = &req_ctx->walk;
 	unsigned int keylen, offset, nbytes, n, k;
-	struct {
-		u8 key[64];
-		u8 tweak[16];
-		u8 nap[16];
-		u8 wkvp[32];
-	} fxts_param = {
-		.nap = {0},
-	};
-	struct skcipher_walk walk;
-	int rc;
-
-	rc = skcipher_walk_virt(&walk, req, false);
-	if (rc)
-		return rc;
+	int rc = 0;
 
 	keylen = (ctx->pk[0].type == PKEY_KEYTYPE_AES_XTS_128) ? 32 : 64;
 	offset = (ctx->pk[0].type == PKEY_KEYTYPE_AES_XTS_128) ? 32 : 0;
 
-	spin_lock_bh(&ctx->pk_lock);
-	memcpy(fxts_param.key + offset, ctx->pk[0].protkey, keylen);
-	memcpy(fxts_param.wkvp, ctx->pk[0].protkey + keylen,
-	       sizeof(fxts_param.wkvp));
-	spin_unlock_bh(&ctx->pk_lock);
-	memcpy(fxts_param.tweak, walk.iv, sizeof(fxts_param.tweak));
-	fxts_param.nap[0] = 0x01; /* initial alpha power (1, little-endian) */
+	if (!req_ctx->param_init_done) {
+		memset(param, 0, sizeof(*param));
+		spin_lock_bh(&ctx->pk_lock);
+		memcpy(param->key + offset, ctx->pk[0].protkey, keylen);
+		memcpy(param->wkvp, ctx->pk[0].protkey + keylen, sizeof(param->wkvp));
+		spin_unlock_bh(&ctx->pk_lock);
+		memcpy(param->tweak, walk->iv, sizeof(param->tweak));
+		param->nap[0] = 0x01; /* initial alpha power (1, little-endian) */
+		req_ctx->param_init_done = true;
+	}
 
-	while ((nbytes = walk.nbytes) != 0) {
+	/* always walk on the ... */
+	while ((nbytes = walk->nbytes) != 0) {
 		/* only use complete blocks */
 		n = nbytes & ~(AES_BLOCK_SIZE - 1);
-		k = cpacf_km(ctx->fc | modifier, fxts_param.key + offset,
-			     walk.dst.virt.addr, walk.src.virt.addr, n);
+		k = cpacf_km(ctx->fc | req_ctx->modifier, param->key + offset,
+			     walk->dst.virt.addr, walk->src.virt.addr, n);
 		if (k)
-			rc = skcipher_walk_done(&walk, nbytes - k);
+			rc = skcipher_walk_done(walk, nbytes - k);
 		if (k < n) {
-			if (__xts_paes_convert_key(ctx))
-				return skcipher_walk_done(&walk, -EIO);
+			if (!maysleep) {
+				rc = -EKEYEXPIRED;
+				goto out;
+			}
+			rc = pxts_convert_key(ctx);
+			if (rc)
+				goto out;
 			spin_lock_bh(&ctx->pk_lock);
-			memcpy(fxts_param.key + offset, ctx->pk[0].protkey,
-			       keylen);
-			memcpy(fxts_param.wkvp, ctx->pk[0].protkey + keylen,
-			       sizeof(fxts_param.wkvp));
+			memcpy(param->key + offset, ctx->pk[0].protkey, keylen);
+			memcpy(param->wkvp, ctx->pk[0].protkey + keylen, sizeof(param->wkvp));
 			spin_unlock_bh(&ctx->pk_lock);
 		}
 	}
 
+out:
+	pr_debug("rc=%d\n", rc);
 	return rc;
 }
 
-static int paes_xts_crypt(struct skcipher_request *req, unsigned long modifier)
+static inline int __xts_2keys_prep_param(struct s390_pxts_ctx *ctx,
+					 struct xts_km_param *param,
+					 struct skcipher_walk *walk,
+					 unsigned int keylen,
+					 unsigned int offset, bool maysleep)
 {
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
-	unsigned int keylen, offset, nbytes, n, k;
-	struct {
-		u8 key[PAES_256_PROTKEY_SIZE];
-		u8 tweak[16];
-		u8 block[16];
-		u8 bit[16];
-		u8 xts[16];
-	} pcc_param;
-	struct {
-		u8 key[PAES_256_PROTKEY_SIZE];
-		u8 init[16];
-	} xts_param;
-	struct skcipher_walk walk;
-	int rc;
+	struct xts_pcc_param pcc_param;
+	unsigned long cc = 1;
+	int rc = 0;
+
+	while (cc) {
+		memset(&pcc_param, 0, sizeof(pcc_param));
+		memcpy(pcc_param.tweak, walk->iv, sizeof(pcc_param.tweak));
+		spin_lock_bh(&ctx->pk_lock);
+		memcpy(pcc_param.key + offset, ctx->pk[1].protkey, keylen);
+		memcpy(param->key + offset, ctx->pk[0].protkey, keylen);
+		spin_unlock_bh(&ctx->pk_lock);
+		cc = cpacf_pcc(ctx->fc, pcc_param.key + offset);
+		if (cc) {
+			if (!maysleep) {
+				rc = -EKEYEXPIRED;
+				break;
+			}
+			rc = pxts_convert_key(ctx);
+			if (rc)
+				break;
+			continue;
+		}
+		memcpy(param->init, pcc_param.xts, 16);
+	}
 
-	rc = skcipher_walk_virt(&walk, req, false);
-	if (rc)
-		return rc;
+	memzero_explicit(pcc_param.key, sizeof(pcc_param.key));
+	return rc;
+}
+
+static int xts_paes_do_crypt_2keys(struct s390_pxts_ctx *ctx,
+				   struct s390_pxts_req_ctx *req_ctx,
+				   bool maysleep)
+{
+	struct xts_km_param *param = &req_ctx->param.km_param;
+	struct skcipher_walk *walk = &req_ctx->walk;
+	unsigned int keylen, offset, nbytes, n, k;
+	int rc = 0;
 
 	keylen = (ctx->pk[0].type == PKEY_KEYTYPE_AES_128) ? 48 : 64;
 	offset = (ctx->pk[0].type == PKEY_KEYTYPE_AES_128) ? 16 : 0;
 
-	memset(&pcc_param, 0, sizeof(pcc_param));
-	memcpy(pcc_param.tweak, walk.iv, sizeof(pcc_param.tweak));
-	spin_lock_bh(&ctx->pk_lock);
-	memcpy(pcc_param.key + offset, ctx->pk[1].protkey, keylen);
-	memcpy(xts_param.key + offset, ctx->pk[0].protkey, keylen);
-	spin_unlock_bh(&ctx->pk_lock);
-	cpacf_pcc(ctx->fc, pcc_param.key + offset);
-	memcpy(xts_param.init, pcc_param.xts, 16);
+	if (!req_ctx->param_init_done) {
+		rc = __xts_2keys_prep_param(ctx, param, walk,
+					    keylen, offset, maysleep);
+		if (rc)
+			goto out;
+		req_ctx->param_init_done = true;
+	}
 
-	while ((nbytes = walk.nbytes) != 0) {
+	/* always walk on the ... */
+	while ((nbytes = walk->nbytes) != 0) {
 		/* only use complete blocks */
 		n = nbytes & ~(AES_BLOCK_SIZE - 1);
-		k = cpacf_km(ctx->fc | modifier, xts_param.key + offset,
-			     walk.dst.virt.addr, walk.src.virt.addr, n);
+		k = cpacf_km(ctx->fc | req_ctx->modifier, param->key + offset,
+			     walk->dst.virt.addr, walk->src.virt.addr, n);
 		if (k)
-			rc = skcipher_walk_done(&walk, nbytes - k);
+			rc = skcipher_walk_done(walk, nbytes - k);
 		if (k < n) {
-			if (__xts_paes_convert_key(ctx))
-				return skcipher_walk_done(&walk, -EIO);
+			if (!maysleep) {
+				rc = -EKEYEXPIRED;
+				goto out;
+			}
+			rc = pxts_convert_key(ctx);
+			if (rc)
+				goto out;
 			spin_lock_bh(&ctx->pk_lock);
-			memcpy(xts_param.key + offset,
-			       ctx->pk[0].protkey, keylen);
+			memcpy(param->key + offset, ctx->pk[0].protkey, keylen);
 			spin_unlock_bh(&ctx->pk_lock);
 		}
 	}
 
+out:
+	pr_debug("rc=%d\n", rc);
 	return rc;
 }
 
-static inline int xts_paes_crypt(struct skcipher_request *req, unsigned long modifier)
+static int xts_paes_do_crypt(struct s390_pxts_ctx *ctx,
+			     struct s390_pxts_req_ctx *req_ctx,
+			     bool maysleep)
 {
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	int pk_state, rc;
 
+	/* fetch and check protected key state */
+	spin_lock_bh(&ctx->pk_lock);
+	pk_state = ctx->pk_state;
+	spin_unlock_bh(&ctx->pk_lock);
+	switch (pk_state) {
+	case PK_STATE_NO_KEY:
+		rc = -ENOKEY;
+		goto out;
+	case PK_STATE_CONVERT_IN_PROGRESS:
+		rc = -EKEYEXPIRED;
+		goto out;
+	case PK_STATE_VALID:
+		break;
+	default:
+		rc = pk_state < 0 ? pk_state : -EIO;
+		goto out;
+	}
+
+	/* Call the 'real' crypt function based on the xts prot key type. */
 	switch (ctx->fc) {
 	case CPACF_KM_PXTS_128:
 	case CPACF_KM_PXTS_256:
-		return paes_xts_crypt(req, modifier);
+		rc = xts_paes_do_crypt_2keys(ctx, req_ctx, maysleep);
+		break;
 	case CPACF_KM_PXTS_128_FULL:
 	case CPACF_KM_PXTS_256_FULL:
-		return paes_xts_crypt_full(req, modifier);
+		rc = xts_paes_do_crypt_fullkey(ctx, req_ctx, maysleep);
+		break;
 	default:
-		return -EINVAL;
+		rc = -EINVAL;
 	}
-}
 
-static int xts_paes_encrypt(struct skcipher_request *req)
-{
-	return xts_paes_crypt(req, 0);
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static int xts_paes_decrypt(struct skcipher_request *req)
+static inline int xts_paes_crypt(struct skcipher_request *req, unsigned long modifier)
 {
-	return xts_paes_crypt(req, CPACF_DECRYPT);
-}
+	struct s390_pxts_req_ctx *req_ctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk *walk = &req_ctx->walk;
+	int rc;
 
-static struct skcipher_alg xts_paes_alg = {
-	.base.cra_name		=	"xts(paes)",
-	.base.cra_driver_name	=	"xts-paes-s390",
-	.base.cra_priority	=	402,	/* ecb-paes-s390 + 1 */
-	.base.cra_blocksize	=	AES_BLOCK_SIZE,
-	.base.cra_ctxsize	=	sizeof(struct s390_pxts_ctx),
-	.base.cra_module	=	THIS_MODULE,
-	.base.cra_list		=	LIST_HEAD_INIT(xts_paes_alg.base.cra_list),
-	.init			=	xts_paes_init,
-	.exit			=	xts_paes_exit,
-	.min_keysize		=	2 * PAES_MIN_KEYSIZE,
-	.max_keysize		=	2 * PAES_MAX_KEYSIZE,
-	.ivsize			=	AES_BLOCK_SIZE,
-	.setkey			=	xts_paes_set_key,
-	.encrypt		=	xts_paes_encrypt,
-	.decrypt		=	xts_paes_decrypt,
-};
+	/*
+	 * First try synchronous. If this fails for any reason
+	 * schedule this request asynchronous via crypto engine.
+	 */
 
-static int ctr_paes_init(struct crypto_skcipher *tfm)
-{
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	rc = skcipher_walk_virt(walk, req, false);
+	if (rc)
+		goto out;
 
-	ctx->kb.key = NULL;
-	spin_lock_init(&ctx->pk_lock);
+	req_ctx->modifier = modifier;
+	req_ctx->param_init_done = false;
 
-	return 0;
-}
+	rc = xts_paes_do_crypt(ctx, req_ctx, false);
+	if (rc != -EKEYEXPIRED) {
+		if (rc)
+			skcipher_walk_done(walk, rc);
+		goto out;
+	}
 
-static void ctr_paes_exit(struct crypto_skcipher *tfm)
-{
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	rc = crypto_transfer_skcipher_request_to_engine(paes_crypto_engine, req);
+	if (rc)
+		goto out;
+
+	rc = -EINPROGRESS;
 
-	_free_kb_keybuf(&ctx->kb);
+out:
+	if (rc != -EINPROGRESS)
+		memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static inline int __ctr_paes_set_key(struct s390_paes_ctx *ctx)
+static int xts_paes_encrypt(struct skcipher_request *req)
 {
-	unsigned long fc;
-	int rc;
-
-	rc = __paes_convert_key(ctx);
-	if (rc)
-		return rc;
-
-	/* Pick the correct function code based on the protected key type */
-	fc = (ctx->pk.type == PKEY_KEYTYPE_AES_128) ? CPACF_KMCTR_PAES_128 :
-		(ctx->pk.type == PKEY_KEYTYPE_AES_192) ? CPACF_KMCTR_PAES_192 :
-		(ctx->pk.type == PKEY_KEYTYPE_AES_256) ?
-		CPACF_KMCTR_PAES_256 : 0;
-
-	/* Check if the function code is available */
-	ctx->fc = (fc && cpacf_test_func(&kmctr_functions, fc)) ? fc : 0;
+	return xts_paes_crypt(req, 0);
+}
 
-	return ctx->fc ? 0 : -EINVAL;
+static int xts_paes_decrypt(struct skcipher_request *req)
+{
+	return xts_paes_crypt(req, CPACF_DECRYPT);
 }
 
-static int ctr_paes_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			    unsigned int key_len)
+static int xts_paes_init(struct crypto_skcipher *tfm)
 {
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
-	int rc;
+	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	_free_kb_keybuf(&ctx->kb);
-	rc = _key_to_kb(&ctx->kb, in_key, key_len);
-	if (rc)
-		return rc;
+	memset(ctx, 0, sizeof(*ctx));
+	spin_lock_init(&ctx->pk_lock);
+
+	crypto_skcipher_set_reqsize(tfm, sizeof(struct s390_pxts_req_ctx));
 
-	return __ctr_paes_set_key(ctx);
+	return 0;
 }
 
-static unsigned int __ctrblk_init(u8 *ctrptr, u8 *iv, unsigned int nbytes)
+static void xts_paes_exit(struct crypto_skcipher *tfm)
 {
-	unsigned int i, n;
+	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	/* only use complete blocks, max. PAGE_SIZE */
-	memcpy(ctrptr, iv, AES_BLOCK_SIZE);
-	n = (nbytes > PAGE_SIZE) ? PAGE_SIZE : nbytes & ~(AES_BLOCK_SIZE - 1);
-	for (i = (n / AES_BLOCK_SIZE) - 1; i > 0; i--) {
-		memcpy(ctrptr + AES_BLOCK_SIZE, ctrptr, AES_BLOCK_SIZE);
-		crypto_inc(ctrptr + AES_BLOCK_SIZE, AES_BLOCK_SIZE);
-		ctrptr += AES_BLOCK_SIZE;
-	}
-	return n;
+	memzero_explicit(ctx, sizeof(*ctx));
 }
 
-static int ctr_paes_crypt(struct skcipher_request *req)
+static int xts_paes_do_one_request(struct crypto_engine *engine, void *areq)
 {
+	struct skcipher_request *req = skcipher_request_cast(areq);
+	struct s390_pxts_req_ctx *req_ctx = skcipher_request_ctx(req);
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
-	u8 buf[AES_BLOCK_SIZE], *ctrptr;
-	struct {
-		u8 key[PAES_256_PROTKEY_SIZE];
-	} param;
-	struct skcipher_walk walk;
-	unsigned int nbytes, n, k;
-	int rc, locked;
-
-	rc = skcipher_walk_virt(&walk, req, false);
-	if (rc)
-		return rc;
-
-	spin_lock_bh(&ctx->pk_lock);
-	memcpy(param.key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
-	spin_unlock_bh(&ctx->pk_lock);
+	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk *walk = &req_ctx->walk;
+	int rc;
 
-	locked = mutex_trylock(&ctrblk_lock);
+	/* walk has already been prepared */
 
-	while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
-		n = AES_BLOCK_SIZE;
-		if (nbytes >= 2*AES_BLOCK_SIZE && locked)
-			n = __ctrblk_init(ctrblk, walk.iv, nbytes);
-		ctrptr = (n > AES_BLOCK_SIZE) ? ctrblk : walk.iv;
-		k = cpacf_kmctr(ctx->fc, &param, walk.dst.virt.addr,
-				walk.src.virt.addr, n, ctrptr);
-		if (k) {
-			if (ctrptr == ctrblk)
-				memcpy(walk.iv, ctrptr + k - AES_BLOCK_SIZE,
-				       AES_BLOCK_SIZE);
-			crypto_inc(walk.iv, AES_BLOCK_SIZE);
-			rc = skcipher_walk_done(&walk, nbytes - k);
-		}
-		if (k < n) {
-			if (__paes_convert_key(ctx)) {
-				if (locked)
-					mutex_unlock(&ctrblk_lock);
-				return skcipher_walk_done(&walk, -EIO);
-			}
-			spin_lock_bh(&ctx->pk_lock);
-			memcpy(param.key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
-			spin_unlock_bh(&ctx->pk_lock);
-		}
+	rc = xts_paes_do_crypt(ctx, req_ctx, true);
+	if (rc != -EKEYEXPIRED) {
+		if (rc)
+			skcipher_walk_done(walk, rc);
+		goto complete;
 	}
-	if (locked)
-		mutex_unlock(&ctrblk_lock);
+
 	/*
-	 * final block may be < AES_BLOCK_SIZE, copy only nbytes
+	 * Protected key expired, conversion is in process.
+	 * Trigger a re-schedule of this request by returning
+	 * -ENOSPC ("hardware queue is full") to the crypto engine.
+	 * To avoid immediately re-invocation of this callback,
+	 * tell the scheduler to voluntarily give up the CPU here.
 	 */
-	if (nbytes) {
-		memset(buf, 0, AES_BLOCK_SIZE);
-		memcpy(buf, walk.src.virt.addr, nbytes);
-		while (1) {
-			if (cpacf_kmctr(ctx->fc, &param, buf,
-					buf, AES_BLOCK_SIZE,
-					walk.iv) == AES_BLOCK_SIZE)
-				break;
-			if (__paes_convert_key(ctx))
-				return skcipher_walk_done(&walk, -EIO);
-			spin_lock_bh(&ctx->pk_lock);
-			memcpy(param.key, ctx->pk.protkey, PAES_256_PROTKEY_SIZE);
-			spin_unlock_bh(&ctx->pk_lock);
-		}
-		memcpy(walk.dst.virt.addr, buf, nbytes);
-		crypto_inc(walk.iv, AES_BLOCK_SIZE);
-		rc = skcipher_walk_done(&walk, nbytes);
-	}
-
+	yield();
+	pr_debug("rescheduling request\n");
+	return -ENOSPC;
+
+complete:
+	memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("request complete with rc=%d\n", rc);
+	local_bh_disable();
+	crypto_finalize_skcipher_request(engine, req, rc);
+	local_bh_enable();
 	return rc;
 }
 
-static struct skcipher_alg ctr_paes_alg = {
-	.base.cra_name		=	"ctr(paes)",
-	.base.cra_driver_name	=	"ctr-paes-s390",
-	.base.cra_priority	=	402,	/* ecb-paes-s390 + 1 */
-	.base.cra_blocksize	=	1,
-	.base.cra_ctxsize	=	sizeof(struct s390_paes_ctx),
-	.base.cra_module	=	THIS_MODULE,
-	.base.cra_list		=	LIST_HEAD_INIT(ctr_paes_alg.base.cra_list),
-	.init			=	ctr_paes_init,
-	.exit			=	ctr_paes_exit,
-	.min_keysize		=	PAES_MIN_KEYSIZE,
-	.max_keysize		=	PAES_MAX_KEYSIZE,
-	.ivsize			=	AES_BLOCK_SIZE,
-	.setkey			=	ctr_paes_set_key,
-	.encrypt		=	ctr_paes_crypt,
-	.decrypt		=	ctr_paes_crypt,
-	.chunksize		=	AES_BLOCK_SIZE,
+static struct skcipher_engine_alg xts_paes_alg = {
+	.base = {
+		.base.cra_name	      =	"xts(paes)",
+		.base.cra_driver_name =	"xts-paes-s390",
+		.base.cra_priority    =	402,	/* ecb-paes-s390 + 1 */
+		.base.cra_blocksize   =	AES_BLOCK_SIZE,
+		.base.cra_ctxsize     =	sizeof(struct s390_pxts_ctx),
+		.base.cra_module      =	THIS_MODULE,
+		.base.cra_list	      =	LIST_HEAD_INIT(xts_paes_alg.base.base.cra_list),
+		.init		      =	xts_paes_init,
+		.exit		      =	xts_paes_exit,
+		.min_keysize	      =	2 * PAES_MIN_KEYSIZE,
+		.max_keysize	      =	2 * PAES_MAX_KEYSIZE,
+		.ivsize		      =	AES_BLOCK_SIZE,
+		.setkey		      =	xts_paes_setkey,
+		.encrypt	      =	xts_paes_encrypt,
+		.decrypt	      =	xts_paes_decrypt,
+	},
+	.op = {
+		.do_one_request	      = xts_paes_do_one_request,
+	},
+};
+
+/*
+ * alg register, unregister, module init, exit
+ */
+
+static struct miscdevice paes_dev = {
+	.name	= "paes",
+	.minor	= MISC_DYNAMIC_MINOR,
 };
 
-static inline void __crypto_unregister_skcipher(struct skcipher_alg *alg)
+static inline void __crypto_unregister_skcipher(struct skcipher_engine_alg *alg)
 {
-	if (!list_empty(&alg->base.cra_list))
-		crypto_unregister_skcipher(alg);
+	if (!list_empty(&alg->base.base.cra_list))
+		crypto_engine_unregister_skcipher(alg);
 }
 
 static void paes_s390_fini(void)
 {
+	if (paes_crypto_engine) {
+		crypto_engine_stop(paes_crypto_engine);
+		crypto_engine_exit(paes_crypto_engine);
+	}
 	__crypto_unregister_skcipher(&ctr_paes_alg);
 	__crypto_unregister_skcipher(&xts_paes_alg);
 	__crypto_unregister_skcipher(&cbc_paes_alg);
 	__crypto_unregister_skcipher(&ecb_paes_alg);
 	if (ctrblk)
-		free_page((unsigned long) ctrblk);
+		free_page((unsigned long)ctrblk);
+	misc_deregister(&paes_dev);
 }
 
 static int __init paes_s390_init(void)
 {
 	int rc;
 
+	/* register a simple paes pseudo misc device */
+	rc = misc_register(&paes_dev);
+	if (rc)
+		return rc;
+
+	/* with this pseudo devie alloc and start a crypto engine */
+	paes_crypto_engine =
+		crypto_engine_alloc_init_and_set(paes_dev.this_device,
+						 true, NULL, false, MAX_QLEN);
+	if (!paes_crypto_engine) {
+		rc = -ENOMEM;
+		goto out_err;
+	}
+	rc = crypto_engine_start(paes_crypto_engine);
+	if (rc) {
+		crypto_engine_exit(paes_crypto_engine);
+		paes_crypto_engine = NULL;
+		goto out_err;
+	}
+
 	/* Query available functions for KM, KMC and KMCTR */
 	cpacf_query(CPACF_KM, &km_functions);
 	cpacf_query(CPACF_KMC, &kmc_functions);
@@ -927,40 +1563,45 @@  static int __init paes_s390_init(void)
 	if (cpacf_test_func(&km_functions, CPACF_KM_PAES_128) ||
 	    cpacf_test_func(&km_functions, CPACF_KM_PAES_192) ||
 	    cpacf_test_func(&km_functions, CPACF_KM_PAES_256)) {
-		rc = crypto_register_skcipher(&ecb_paes_alg);
+		rc = crypto_engine_register_skcipher(&ecb_paes_alg);
 		if (rc)
 			goto out_err;
+		pr_debug("%s registered\n", ecb_paes_alg.base.base.cra_driver_name);
 	}
 
 	if (cpacf_test_func(&kmc_functions, CPACF_KMC_PAES_128) ||
 	    cpacf_test_func(&kmc_functions, CPACF_KMC_PAES_192) ||
 	    cpacf_test_func(&kmc_functions, CPACF_KMC_PAES_256)) {
-		rc = crypto_register_skcipher(&cbc_paes_alg);
+		rc = crypto_engine_register_skcipher(&cbc_paes_alg);
 		if (rc)
 			goto out_err;
+		pr_debug("%s registered\n", cbc_paes_alg.base.base.cra_driver_name);
 	}
 
 	if (cpacf_test_func(&km_functions, CPACF_KM_PXTS_128) ||
 	    cpacf_test_func(&km_functions, CPACF_KM_PXTS_256)) {
-		rc = crypto_register_skcipher(&xts_paes_alg);
+		rc = crypto_engine_register_skcipher(&xts_paes_alg);
 		if (rc)
 			goto out_err;
+		pr_debug("%s registered\n", xts_paes_alg.base.base.cra_driver_name);
 	}
 
 	if (cpacf_test_func(&kmctr_functions, CPACF_KMCTR_PAES_128) ||
 	    cpacf_test_func(&kmctr_functions, CPACF_KMCTR_PAES_192) ||
 	    cpacf_test_func(&kmctr_functions, CPACF_KMCTR_PAES_256)) {
-		ctrblk = (u8 *) __get_free_page(GFP_KERNEL);
+		ctrblk = (u8 *)__get_free_page(GFP_KERNEL);
 		if (!ctrblk) {
 			rc = -ENOMEM;
 			goto out_err;
 		}
-		rc = crypto_register_skcipher(&ctr_paes_alg);
+		rc = crypto_engine_register_skcipher(&ctr_paes_alg);
 		if (rc)
 			goto out_err;
+		pr_debug("%s registered\n", ctr_paes_alg.base.base.cra_driver_name);
 	}
 
 	return 0;
+
 out_err:
 	paes_s390_fini();
 	return rc;