1 files changed, 1273 insertions, 542 deletions

diff --git a/arch/s390/crypto/paes_s390.c b/arch/s390/crypto/paes_s390.c
index 511093713a6f..8a340c16acb4 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 <schwidefsky@de.ibm.com>
  *		Harald Freudenberger <freude@de.ibm.com>
  */
@@ -13,16 +13,18 @@
 #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/atomic.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 +46,61 @@ 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;
+
+	/* nr of requests enqueued via crypto engine which use this tfm ctx */
+	atomic_t via_engine_ctr;
+
+	/* 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;
+
+	/* nr of requests enqueued via crypto engine which use this tfm ctx */
+	atomic_t via_engine_ctr;
+
+	/* 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 +129,370 @@ 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)
+/*
+ * paes_ctx_setkey() - Set key value into context, maybe construct
+ * a clear key token digestible by pkey from a clear key value.
+ */
+static inline int paes_ctx_setkey(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)
+/*
+ * pxts_ctx_setkey() - Set key value into context, maybe construct
+ * a clear key token digestible by pkey from a clear key value.
+ */
+static inline int pxts_ctx_setkey(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;
+	int rc, i;
+
+	pk->len = sizeof(pk->protkey);
+
+	/*
+	 * In case of a busy card retry with increasing delay
+	 * of 200, 400, 800 and 1600 ms - in total 3 s.
+	 */
+	for (rc = -EIO, i = 0; rc && i < 5; 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);
 	}
-	memzero_explicit(kb->keybuf, sizeof(kb->keybuf));
+
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-struct s390_paes_ctx {
-	struct key_blob kb;
+/*
+ * (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 tfm context.
+ * Please note this function may be invoked concurrently with the very
+ * same tfm context. The pk_lock spinlock in the context ensures an
+ * atomic update of the pk and the pk state but does not guarantee any
+ * order of update. So a fresh converted valid protected key may get
+ * updated with an 'old' expired key value. As the cpacf instructions
+ * detect this, refuse to operate with an invalid key and the calling
+ * code triggers a (re-)conversion this does no harm. This may lead to
+ * unnecessary additional conversion but never to invalid data on en-
+ * or decrypt operations.
+ */
+static int paes_convert_key(struct s390_paes_ctx *ctx)
+{
 	struct paes_protkey pk;
-	spinlock_t pk_lock;
-	unsigned long fc;
-};
+	int rc;
 
-struct s390_pxts_ctx {
-	struct key_blob kb;
-	struct paes_protkey pk[2];
-	spinlock_t pk_lock;
-	unsigned long fc;
-};
+	spin_lock_bh(&ctx->pk_lock);
+	ctx->pk_state = PK_STATE_CONVERT_IN_PROGRESS;
+	spin_unlock_bh(&ctx->pk_lock);
 
-static inline int __paes_keyblob2pkey(const u8 *key, unsigned int keylen,
-				      struct paes_protkey *pk)
-{
-	int i, rc = -EIO;
+	rc = convert_key(ctx->keybuf, ctx->keylen, &pk);
 
-	/* 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;
-		}
-		rc = pkey_key2protkey(key, keylen, pk->protkey, &pk->len,
-				      &pk->type);
+	/* update context */
+	spin_lock_bh(&ctx->pk_lock);
+	if (rc) {
+		ctx->pk_state = rc;
+	} else {
+		ctx->pk_state = PK_STATE_VALID;
+		ctx->pk = pk;
 	}
+	spin_unlock_bh(&ctx->pk_lock);
 
+	memzero_explicit(&pk, sizeof(pk));
+	pr_debug("rc=%d\n", rc);
 	return rc;
 }
 
-static inline int __paes_convert_key(struct s390_paes_ctx *ctx)
+/*
+ * (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 tfm context.
+ * See also comments on function paes_convert_key.
+ */
+static int pxts_convert_key(struct s390_pxts_ctx *ctx)
 {
-	struct paes_protkey pk;
+	struct paes_protkey pk0, pk1;
+	size_t split_keylen;
 	int rc;
 
-	pk.len = sizeof(pk.protkey);
-	rc = __paes_keyblob2pkey(ctx->kb.key, ctx->kb.keylen, &pk);
+	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, &pk0);
 	if (rc)
-		return rc;
+		goto out;
+
+	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);
-	memcpy(&ctx->pk, &pk, sizeof(pk));
+	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);
 
-	return 0;
+	memzero_explicit(&pk0, sizeof(pk0));
+	memzero_explicit(&pk1, sizeof(pk1));
+	pr_debug("rc=%d\n", rc);
+	return rc;
 }
 
-static int ecb_paes_init(struct crypto_skcipher *tfm)
-{
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+/*
+ * PAES ECB implementation
+ */
 
-	ctx->kb.key = NULL;
-	spin_lock_init(&ctx->pk_lock);
+struct ecb_param {
+	u8 key[PAES_256_PROTKEY_SIZE];
+} __packed;
 
-	return 0;
-}
+struct s390_pecb_req_ctx {
+	unsigned long modifier;
+	struct skcipher_walk walk;
+	bool param_init_done;
+	struct ecb_param param;
+};
 
-static void ecb_paes_exit(struct crypto_skcipher *tfm)
+static int ecb_paes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			   unsigned int key_len)
 {
 	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
-
-	_free_kb_keybuf(&ctx->kb);
-}
-
-static inline int __ecb_paes_set_key(struct s390_paes_ctx *ctx)
-{
-	unsigned long fc;
+	long fc;
 	int rc;
 
-	rc = __paes_convert_key(ctx);
+	/* set raw key into context */
+	rc = paes_ctx_setkey(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;
-
-	_free_kb_keybuf(&ctx->kb);
-	rc = _key_to_kb(&ctx->kb, in_key, key_len);
+	struct ecb_param *param = &req_ctx->param;
+	struct skcipher_walk *walk = &req_ctx->walk;
+	unsigned int nbytes, n, k;
+	int pk_state, rc = 0;
+
+	if (!req_ctx->param_init_done) {
+		/* fetch and check protected key state */
+		spin_lock_bh(&ctx->pk_lock);
+		pk_state = ctx->pk_state;
+		switch (pk_state) {
+		case PK_STATE_NO_KEY:
+			rc = -ENOKEY;
+			break;
+		case PK_STATE_CONVERT_IN_PROGRESS:
+			rc = -EKEYEXPIRED;
+			break;
+		case PK_STATE_VALID:
+			memcpy(param->key, ctx->pk.protkey, sizeof(param->key));
+			req_ctx->param_init_done = true;
+			break;
+		default:
+			rc = pk_state < 0 ? pk_state : -EIO;
+			break;
+		}
+		spin_unlock_bh(&ctx->pk_lock);
+	}
 	if (rc)
-		return rc;
+		goto out;
 
-	return __ecb_paes_set_key(ctx);
+	/*
+	 * Note that in case of partial processing or failure the walk
+	 * is NOT unmapped here. So a follow up task may reuse the walk
+	 * or in case of unrecoverable failure needs to unmap it.
+	 */
+	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, sizeof(param->key));
+			spin_unlock_bh(&ctx->pk_lock);
+		}
+	}
+
+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);
+	/*
+	 * Attempt synchronous encryption first. If it fails, schedule the request
+	 * asynchronously via the crypto engine. To preserve execution order,
+	 * once a request is queued to the engine, further requests using the same
+	 * tfm will also be routed through the 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);
-		}
+	/* Try synchronous operation if no active engine usage */
+	if (!atomic_read(&ctx->via_engine_ctr)) {
+		rc = ecb_paes_do_crypt(ctx, req_ctx, false);
+		if (rc == 0)
+			goto out;
+	}
+
+	/*
+	 * If sync operation failed or key expired or there are already
+	 * requests enqueued via engine, fallback to async. Mark tfm as
+	 * using engine to serialize requests.
+	 */
+	if (rc == 0 || rc == -EKEYEXPIRED) {
+		atomic_inc(&ctx->via_engine_ctr);
+		rc = crypto_transfer_skcipher_request_to_engine(paes_crypto_engine, req);
+		if (rc != -EINPROGRESS)
+			atomic_dec(&ctx->via_engine_ctr);
 	}
+
+	if (rc != -EINPROGRESS)
+		skcipher_walk_done(walk, rc);
+
+out:
+	if (rc != -EINPROGRESS)
+		memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("rc=%d\n", rc);
 	return rc;
 }
 
@@ -310,112 +506,256 @@ 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;
+	/* walk has already been prepared */
+
+	rc = ecb_paes_do_crypt(ctx, req_ctx, true);
+	if (rc == -EKEYEXPIRED) {
+		/*
+		 * 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.
+		 */
+		cond_resched();
+		pr_debug("rescheduling request\n");
+		return -ENOSPC;
+	} else if (rc) {
+		skcipher_walk_done(walk, 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;
+	memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("request complete with rc=%d\n", rc);
+	local_bh_disable();
+	atomic_dec(&ctx->via_engine_ctr);
+	crypto_finalize_skcipher_request(engine, req, rc);
+	local_bh_enable();
+	return rc;
+}
 
-	/* Check if the function code is available */
-	ctx->fc = (fc && cpacf_test_func(&kmc_functions, fc)) ? fc : 0;
+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,
+	},
+};
 
-	return ctx->fc ? 0 : -EINVAL;
-}
+/*
+ * 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_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			    unsigned int key_len)
+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 = paes_ctx_setkey(ctx, in_key, key_len);
 	if (rc)
-		return rc;
+		goto out;
 
-	return __cbc_paes_set_key(ctx);
+	/* 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;
+
+	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);
+	int pk_state, rc = 0;
+
+	if (!req_ctx->param_init_done) {
+		/* fetch and check protected key state */
+		spin_lock_bh(&ctx->pk_lock);
+		pk_state = ctx->pk_state;
+		switch (pk_state) {
+		case PK_STATE_NO_KEY:
+			rc = -ENOKEY;
+			break;
+		case PK_STATE_CONVERT_IN_PROGRESS:
+			rc = -EKEYEXPIRED;
+			break;
+		case PK_STATE_VALID:
+			memcpy(param->key, ctx->pk.protkey, sizeof(param->key));
+			req_ctx->param_init_done = true;
+			break;
+		default:
+			rc = pk_state < 0 ? pk_state : -EIO;
+			break;
+		}
+		spin_unlock_bh(&ctx->pk_lock);
+	}
 	if (rc)
-		return rc;
+		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);
 
-	while ((nbytes = walk.nbytes) != 0) {
+	/*
+	 * Note that in case of partial processing or failure the walk
+	 * is NOT unmapped here. So a follow up task may reuse the walk
+	 * or in case of unrecoverable failure needs to unmap it.
+	 */
+	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, sizeof(param->key));
 			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;
+
+	/*
+	 * Attempt synchronous encryption first. If it fails, schedule the request
+	 * asynchronously via the crypto engine. To preserve execution order,
+	 * once a request is queued to the engine, further requests using the same
+	 * tfm will also be routed through the engine.
+	 */
+
+	rc = skcipher_walk_virt(walk, req, false);
+	if (rc)
+		goto out;
+
+	req_ctx->modifier = modifier;
+	req_ctx->param_init_done = false;
+
+	/* Try synchronous operation if no active engine usage */
+	if (!atomic_read(&ctx->via_engine_ctr)) {
+		rc = cbc_paes_do_crypt(ctx, req_ctx, false);
+		if (rc == 0)
+			goto out;
+	}
+
+	/*
+	 * If sync operation failed or key expired or there are already
+	 * requests enqueued via engine, fallback to async. Mark tfm as
+	 * using engine to serialize requests.
+	 */
+	if (rc == 0 || rc == -EKEYEXPIRED) {
+		atomic_inc(&ctx->via_engine_ctr);
+		rc = crypto_transfer_skcipher_request_to_engine(paes_crypto_engine, req);
+		if (rc != -EINPROGRESS)
+			atomic_dec(&ctx->via_engine_ctr);
+	}
+
+	if (rc != -EINPROGRESS)
+		skcipher_walk_done(walk, rc);
+
+out:
+	if (rc != -EINPROGRESS)
+		memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("rc=%d\n", rc);
 	return rc;
 }
 
@@ -429,496 +769,882 @@ 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);
-
-	rc = __paes_keyblob2pkey(ctx->kb.key, ctx->kb.keylen, &pk0);
-	if (rc)
-		return rc;
+	/* walk has already been prepared */
+
+	rc = cbc_paes_do_crypt(ctx, req_ctx, true);
+	if (rc == -EKEYEXPIRED) {
+		/*
+		 * 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.
+		 */
+		cond_resched();
+		pr_debug("rescheduling request\n");
+		return -ENOSPC;
+	} else if (rc) {
+		skcipher_walk_done(walk, rc);
+	}
 
-	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;
+	memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("request complete with rc=%d\n", rc);
+	local_bh_disable();
+	atomic_dec(&ctx->via_engine_ctr);
+	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 = paes_ctx_setkey(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;
-		break;
-	case PKEY_KEYTYPE_AES_256:
-		fc = CPACF_KM_PXTS_256;
+		fc = CPACF_KMCTR_PAES_128;
 		break;
-	case PKEY_KEYTYPE_AES_XTS_128:
-		fc = CPACF_KM_PXTS_128_FULL;
+	case PKEY_KEYTYPE_AES_192:
+		fc = CPACF_KMCTR_PAES_192;
 		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;
+
+out:
+	pr_debug("rc=%d\n", rc);
+	return rc;
+}
+
+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 = 0;
+
+	if (!req_ctx->param_init_done) {
+		/* fetch and check protected key state */
+		spin_lock_bh(&ctx->pk_lock);
+		pk_state = ctx->pk_state;
+		switch (pk_state) {
+		case PK_STATE_NO_KEY:
+			rc = -ENOKEY;
+			break;
+		case PK_STATE_CONVERT_IN_PROGRESS:
+			rc = -EKEYEXPIRED;
+			break;
+		case PK_STATE_VALID:
+			memcpy(param->key, ctx->pk.protkey, sizeof(param->key));
+			req_ctx->param_init_done = true;
+			break;
+		default:
+			rc = pk_state < 0 ? pk_state : -EIO;
+			break;
+		}
+		spin_unlock_bh(&ctx->pk_lock);
+	}
+	if (rc)
+		goto out;
+
+	locked = mutex_trylock(&ctrblk_lock);
+
+	/*
+	 * Note that in case of partial processing or failure the walk
+	 * is NOT unmapped here. So a follow up task may reuse the walk
+	 * or in case of unrecoverable failure needs to unmap it.
+	 */
+	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, sizeof(param->key));
+			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, sizeof(param->key));
+			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;
+
+	/*
+	 * Attempt synchronous encryption first. If it fails, schedule the request
+	 * asynchronously via the crypto engine. To preserve execution order,
+	 * once a request is queued to the engine, further requests using the same
+	 * tfm will also be routed through the engine.
+	 */
+
+	rc = skcipher_walk_virt(walk, req, false);
+	if (rc)
+		goto out;
+
+	req_ctx->param_init_done = false;
+
+	/* Try synchronous operation if no active engine usage */
+	if (!atomic_read(&ctx->via_engine_ctr)) {
+		rc = ctr_paes_do_crypt(ctx, req_ctx, false);
+		if (rc == 0)
+			goto out;
+	}
+
+	/*
+	 * If sync operation failed or key expired or there are already
+	 * requests enqueued via engine, fallback to async. Mark tfm as
+	 * using engine to serialize requests.
+	 */
+	if (rc == 0 || rc == -EKEYEXPIRED) {
+		atomic_inc(&ctx->via_engine_ctr);
+		rc = crypto_transfer_skcipher_request_to_engine(paes_crypto_engine, req);
+		if (rc != -EINPROGRESS)
+			atomic_dec(&ctx->via_engine_ctr);
+	}
+
+	if (rc != -EINPROGRESS)
+		skcipher_walk_done(walk, rc);
+
+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;
 
-	return ctx->fc ? 0 : -EINVAL;
+	/* walk has already been prepared */
+
+	rc = ctr_paes_do_crypt(ctx, req_ctx, true);
+	if (rc == -EKEYEXPIRED) {
+		/*
+		 * 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.
+		 */
+		cond_resched();
+		pr_debug("rescheduling request\n");
+		return -ENOSPC;
+	} else if (rc) {
+		skcipher_walk_done(walk, rc);
+	}
+
+	memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("request complete with rc=%d\n", rc);
+	local_bh_disable();
+	atomic_dec(&ctx->via_engine_ctr);
+	crypto_finalize_skcipher_request(engine, req, rc);
+	local_bh_enable();
+	return rc;
 }
 
-static int xts_paes_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			    unsigned int in_keylen)
+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 = pxts_ctx_setkey(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;
+	int rc = 0;
 
-	rc = skcipher_walk_virt(&walk, req, false);
-	if (rc)
-		return rc;
+	/*
+	 * The calling function xts_paes_do_crypt() ensures the
+	 * protected key state is always PK_STATE_VALID when this
+	 * function is invoked.
+	 */
 
 	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) {
+	/*
+	 * Note that in case of partial processing or failure the walk
+	 * is NOT unmapped here. So a follow up task may reuse the walk
+	 * or in case of unrecoverable failure needs to unmap it.
+	 */
+	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);
+	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);
+	}
+
+	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;
-	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;
+	int rc = 0;
 
-	rc = skcipher_walk_virt(&walk, req, false);
-	if (rc)
-		return rc;
+	/*
+	 * The calling function xts_paes_do_crypt() ensures the
+	 * protected key state is always PK_STATE_VALID when this
+	 * function is invoked.
+	 */
 
 	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) {
+	/*
+	 * Note that in case of partial processing or failure the walk
+	 * is NOT unmapped here. So a follow up task may reuse the walk
+	 * or in case of unrecoverable failure needs to unmap it.
+	 */
+	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 = 0;
+
+	/* fetch and check protected key state */
+	spin_lock_bh(&ctx->pk_lock);
+	pk_state = ctx->pk_state;
+	switch (pk_state) {
+	case PK_STATE_NO_KEY:
+		rc = -ENOKEY;
+		break;
+	case PK_STATE_CONVERT_IN_PROGRESS:
+		rc = -EKEYEXPIRED;
+		break;
+	case PK_STATE_VALID:
+		break;
+	default:
+		rc = pk_state < 0 ? pk_state : -EIO;
+		break;
+	}
+	spin_unlock_bh(&ctx->pk_lock);
+	if (rc)
+		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,
-};
+	/*
+	 * Attempt synchronous encryption first. If it fails, schedule the request
+	 * asynchronously via the crypto engine. To preserve execution order,
+	 * once a request is queued to the engine, further requests using the same
+	 * tfm will also be routed through the 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;
-}
+	/* Try synchronous operation if no active engine usage */
+	if (!atomic_read(&ctx->via_engine_ctr)) {
+		rc = xts_paes_do_crypt(ctx, req_ctx, false);
+		if (rc == 0)
+			goto out;
+	}
 
-static void ctr_paes_exit(struct crypto_skcipher *tfm)
-{
-	struct s390_paes_ctx *ctx = crypto_skcipher_ctx(tfm);
+	/*
+	 * If sync operation failed or key expired or there are already
+	 * requests enqueued via engine, fallback to async. Mark tfm as
+	 * using engine to serialize requests.
+	 */
+	if (rc == 0 || rc == -EKEYEXPIRED) {
+		atomic_inc(&ctx->via_engine_ctr);
+		rc = crypto_transfer_skcipher_request_to_engine(paes_crypto_engine, req);
+		if (rc != -EINPROGRESS)
+			atomic_dec(&ctx->via_engine_ctr);
+	}
+
+	if (rc != -EINPROGRESS)
+		skcipher_walk_done(walk, rc);
 
-	_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);
 
-	return __ctr_paes_set_key(ctx);
+	crypto_skcipher_set_reqsize(tfm, sizeof(struct s390_pxts_req_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);
-
-	locked = mutex_trylock(&ctrblk_lock);
+	struct s390_pxts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk *walk = &req_ctx->walk;
+	int rc;
 
-	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);
-		}
-	}
-	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 (__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);
+	/* walk has already been prepared */
+
+	rc = xts_paes_do_crypt(ctx, req_ctx, true);
+	if (rc == -EKEYEXPIRED) {
+		/*
+		 * 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.
+		 */
+		cond_resched();
+		pr_debug("rescheduling request\n");
+		return -ENOSPC;
+	} else if (rc) {
+		skcipher_walk_done(walk, rc);
 	}
 
+	memzero_explicit(&req_ctx->param, sizeof(req_ctx->param));
+	pr_debug("request complete with rc=%d\n", rc);
+	local_bh_disable();
+	atomic_dec(&ctx->via_engine_ctr);
+	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,
+	},
 };
 
-static inline void __crypto_unregister_skcipher(struct skcipher_alg *alg)
+/*
+ * 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_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 +1653,45 @@ 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;