[PATCH v1 04/20] s390/zcrypt: Rework zcrypt layer to support new flag NOMEMALLOC

[Harald Freudenberger <freude@linux.ibm.com>]

Introduce a new flag parameter for the both cprb send functions
zcrypt_send_cprb() and zcrypt_send_ep11_cprb(). This new
xflags parameter ("execution flags") shall be used to provide
execution hints and flags for this crypto request.

One flag is implemented: The xflag ZCRYPT_XFLAG_NOMEMALLOC
tells the zcrypt_send_*() functions to not allocate memory
via kmalloc() and friends with the goal to not trigger any
IO operations. If this xflag is given, it is also forwarded
to the AP bus functions as AP_MSG_FLAG_MEMPOOL when the
ap_init_apmsg() is invoked.

If the ZCRYPT_XFLAG_NOMEMALLOC is given, the zcrypt layer
does not allocate any memory but may fail to send a crypto
load:
- The number of EP11 targets if given must not exceed 16 APQNs.
- As the flag is passed down to the AP bus functions the
  AP bus uses a limited mem pool (with limited item size)
  to construct the AP msg. The AP bus mem pool may be depleted
  and/or the message size may exceed the item size of the
  AP bus mem pool. Currently the AP bus mem pool is limited
  to 4 mem pool items of 12KB each. On not being able to process
  a crypto request without memory allocation the result will
  be -ENOMEM returned from the zcrypt_send_cprb_*() functions.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
---
 drivers/s390/crypto/zcrypt_api.c      | 65 +++++++++++++++------------
 drivers/s390/crypto/zcrypt_api.h      | 12 ++++-
 drivers/s390/crypto/zcrypt_ccamisc.c  | 16 +++----
 drivers/s390/crypto/zcrypt_ep11misc.c | 10 ++---
 4 files changed, 59 insertions(+), 44 deletions(-)

diff --git a/drivers/s390/crypto/zcrypt_api.c b/drivers/s390/crypto/zcrypt_api.c
index ce5f7cb974b9..f6deb10329e6 100644
--- a/drivers/s390/crypto/zcrypt_api.c
+++ b/drivers/s390/crypto/zcrypt_api.c
@@ -846,7 +846,7 @@ static long zcrypt_rsa_crt(struct ap_perms *perms,
 
 static long _zcrypt_send_cprb(bool userspace, struct ap_perms *perms,
 			      struct zcrypt_track *tr,
-			      struct ica_xcRB *xcrb)
+			      struct ica_xcRB *xcrb, u32 xflags)
 {
 	struct zcrypt_card *zc, *pref_zc;
 	struct zcrypt_queue *zq, *pref_zq;
@@ -861,7 +861,8 @@ static long _zcrypt_send_cprb(bool userspace, struct ap_perms *perms,
 
 	xcrb->status = 0;
 
-	rc = ap_init_apmsg(&ap_msg, 0);
+	rc = ap_init_apmsg(&ap_msg, xflags & ZCRYPT_XFLAG_NOMEMALLOC ?
+			   AP_MSG_FLAG_MEMPOOL : 0);
 	if (rc)
 		goto out;
 
@@ -977,7 +978,7 @@ static long _zcrypt_send_cprb(bool userspace, struct ap_perms *perms,
 	return rc;
 }
 
-long zcrypt_send_cprb(struct ica_xcRB *xcrb)
+long zcrypt_send_cprb(struct ica_xcRB *xcrb, u32 xflags)
 {
 	struct zcrypt_track tr;
 	int rc;
@@ -985,13 +986,14 @@ long zcrypt_send_cprb(struct ica_xcRB *xcrb)
 	memset(&tr, 0, sizeof(tr));
 
 	do {
-		rc = _zcrypt_send_cprb(false, &ap_perms, &tr, xcrb);
+		rc = _zcrypt_send_cprb(false, &ap_perms, &tr, xcrb, xflags);
 	} while (rc == -EAGAIN && ++tr.again_counter < TRACK_AGAIN_MAX);
 
 	/* on ENODEV failure: retry once again after a requested rescan */
 	if (rc == -ENODEV && zcrypt_process_rescan())
 		do {
-			rc = _zcrypt_send_cprb(false, &ap_perms, &tr, xcrb);
+			rc = _zcrypt_send_cprb(false, &ap_perms,
+					       &tr, xcrb, xflags);
 		} while (rc == -EAGAIN && ++tr.again_counter < TRACK_AGAIN_MAX);
 	if (rc == -EAGAIN && tr.again_counter >= TRACK_AGAIN_MAX)
 		rc = -EIO;
@@ -1031,11 +1033,11 @@ static bool is_desired_ep11_queue(unsigned int dev_qid,
 
 static long _zcrypt_send_ep11_cprb(bool userspace, struct ap_perms *perms,
 				   struct zcrypt_track *tr,
-				   struct ep11_urb *xcrb)
+				   struct ep11_urb *xcrb, u32 xflags)
 {
 	struct zcrypt_card *zc, *pref_zc;
 	struct zcrypt_queue *zq, *pref_zq;
-	struct ep11_target_dev *targets;
+	struct ep11_target_dev targetbuf[16], *targets = NULL;
 	unsigned short target_num;
 	unsigned int wgt = 0, pref_wgt = 0;
 	unsigned int func_code = 0, domain;
@@ -1045,36 +1047,39 @@ static long _zcrypt_send_ep11_cprb(bool userspace, struct ap_perms *perms,
 
 	trace_s390_zcrypt_req(xcrb, TP_ZSENDEP11CPRB);
 
-	rc = ap_init_apmsg(&ap_msg, 0);
+	rc = ap_init_apmsg(&ap_msg, xflags & ZCRYPT_XFLAG_NOMEMALLOC ?
+			   AP_MSG_FLAG_MEMPOOL : 0);
 	if (rc)
 		goto out;
 
 	target_num = (unsigned short)xcrb->targets_num;
 
 	/* empty list indicates autoselect (all available targets) */
-	targets = NULL;
+	rc = -ENOMEM;
 	if (target_num != 0) {
 		struct ep11_target_dev __user *uptr;
 
-		targets = kcalloc(target_num, sizeof(*targets), GFP_KERNEL);
-		if (!targets) {
-			func_code = 0;
-			rc = -ENOMEM;
+		if (target_num <= ARRAY_SIZE(targetbuf)) {
+			targets = targetbuf;
+		} else if (xflags & ZCRYPT_XFLAG_NOMEMALLOC) {
 			goto out;
+		} else {
+			targets = kcalloc(target_num,
+					  sizeof(*targets), GFP_KERNEL);
+			if (!targets)
+				goto out;
 		}
-
 		uptr = (struct ep11_target_dev __force __user *)xcrb->targets;
 		if (z_copy_from_user(userspace, targets, uptr,
 				     target_num * sizeof(*targets))) {
-			func_code = 0;
 			rc = -EFAULT;
-			goto out_free;
+			goto out;
 		}
 	}
 
 	rc = prep_ep11_ap_msg(userspace, xcrb, &ap_msg, &func_code, &domain);
 	if (rc)
-		goto out_free;
+		goto out;
 	print_hex_dump_debug("ep11req: ", DUMP_PREFIX_ADDRESS, 16, 1,
 			     ap_msg.msg, ap_msg.len, false);
 
@@ -1082,11 +1087,11 @@ static long _zcrypt_send_ep11_cprb(bool userspace, struct ap_perms *perms,
 		if (ap_msg.flags & AP_MSG_FLAG_ADMIN) {
 			if (!test_bit_inv(domain, perms->adm)) {
 				rc = -ENODEV;
-				goto out_free;
+				goto out;
 			}
 		} else if ((ap_msg.flags & AP_MSG_FLAG_USAGE) == 0) {
 			rc = -EOPNOTSUPP;
-			goto out_free;
+			goto out;
 		}
 	}
 
@@ -1154,7 +1159,7 @@ static long _zcrypt_send_ep11_cprb(bool userspace, struct ap_perms *perms,
 			pr_debug("no match for address ff.ffff => ENODEV\n");
 		}
 		rc = -ENODEV;
-		goto out_free;
+		goto out;
 	}
 
 	qid = pref_zq->queue->qid;
@@ -1168,9 +1173,9 @@ static long _zcrypt_send_ep11_cprb(bool userspace, struct ap_perms *perms,
 	zcrypt_drop_queue(pref_zc, pref_zq, mod, wgt);
 	spin_unlock(&zcrypt_list_lock);
 
-out_free:
-	kfree(targets);
 out:
+	if (targets && targets != targetbuf)
+		kfree(targets);
 	ap_release_apmsg(&ap_msg);
 	if (tr) {
 		tr->last_rc = rc;
@@ -1181,7 +1186,7 @@ static long _zcrypt_send_ep11_cprb(bool userspace, struct ap_perms *perms,
 	return rc;
 }
 
-long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb)
+long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb, u32 xflags)
 {
 	struct zcrypt_track tr;
 	int rc;
@@ -1189,13 +1194,15 @@ long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb)
 	memset(&tr, 0, sizeof(tr));
 
 	do {
-		rc = _zcrypt_send_ep11_cprb(false, &ap_perms, &tr, xcrb);
+		rc = _zcrypt_send_ep11_cprb(false, &ap_perms,
+					    &tr, xcrb, xflags);
 	} while (rc == -EAGAIN && ++tr.again_counter < TRACK_AGAIN_MAX);
 
 	/* on ENODEV failure: retry once again after a requested rescan */
 	if (rc == -ENODEV && zcrypt_process_rescan())
 		do {
-			rc = _zcrypt_send_ep11_cprb(false, &ap_perms, &tr, xcrb);
+			rc = _zcrypt_send_ep11_cprb(false, &ap_perms,
+						    &tr, xcrb, xflags);
 		} while (rc == -EAGAIN && ++tr.again_counter < TRACK_AGAIN_MAX);
 	if (rc == -EAGAIN && tr.again_counter >= TRACK_AGAIN_MAX)
 		rc = -EIO;
@@ -1539,13 +1546,13 @@ static int zsecsendcprb_ioctl(struct ap_perms *perms, unsigned long arg)
 		return -EFAULT;
 
 	do {
-		rc = _zcrypt_send_cprb(true, perms, &tr, &xcrb);
+		rc = _zcrypt_send_cprb(true, perms, &tr, &xcrb, 0);
 	} while (rc == -EAGAIN && ++tr.again_counter < TRACK_AGAIN_MAX);
 
 	/* on ENODEV failure: retry once again after a requested rescan */
 	if (rc == -ENODEV && zcrypt_process_rescan())
 		do {
-			rc = _zcrypt_send_cprb(true, perms, &tr, &xcrb);
+			rc = _zcrypt_send_cprb(true, perms, &tr, &xcrb, 0);
 		} while (rc == -EAGAIN && ++tr.again_counter < TRACK_AGAIN_MAX);
 	if (rc == -EAGAIN && tr.again_counter >= TRACK_AGAIN_MAX)
 		rc = -EIO;
@@ -1569,13 +1576,13 @@ static int zsendep11cprb_ioctl(struct ap_perms *perms, unsigned long arg)
 		return -EFAULT;
 
 	do {
-		rc = _zcrypt_send_ep11_cprb(true, perms, &tr, &xcrb);
+		rc = _zcrypt_send_ep11_cprb(true, perms, &tr, &xcrb, 0);
 	} while (rc == -EAGAIN && ++tr.again_counter < TRACK_AGAIN_MAX);
 
 	/* on ENODEV failure: retry once again after a requested rescan */
 	if (rc == -ENODEV && zcrypt_process_rescan())
 		do {
-			rc = _zcrypt_send_ep11_cprb(true, perms, &tr, &xcrb);
+			rc = _zcrypt_send_ep11_cprb(true, perms, &tr, &xcrb, 0);
 		} while (rc == -EAGAIN && ++tr.again_counter < TRACK_AGAIN_MAX);
 	if (rc == -EAGAIN && tr.again_counter >= TRACK_AGAIN_MAX)
 		rc = -EIO;
diff --git a/drivers/s390/crypto/zcrypt_api.h b/drivers/s390/crypto/zcrypt_api.h
index 4ed481df57ca..06ff697d171c 100644
--- a/drivers/s390/crypto/zcrypt_api.h
+++ b/drivers/s390/crypto/zcrypt_api.h
@@ -76,6 +76,14 @@ struct zcrypt_track {
 #define TRACK_AGAIN_CARD_WEIGHT_PENALTY  1000
 #define TRACK_AGAIN_QUEUE_WEIGHT_PENALTY 10000
 
+/*
+ * Do not allocate memory xflag. To be used with
+ * zcrypt_send_cprb() and zcrypt_send_ep11_cprb().
+ * Currently only available and used for the in-kernel
+ * zcrpyt api.
+ */
+#define ZCRYPT_XFLAG_NOMEMALLOC 0x0001
+
 struct zcrypt_ops {
 	long (*rsa_modexpo)(struct zcrypt_queue *, struct ica_rsa_modexpo *,
 			    struct ap_message *);
@@ -161,8 +169,8 @@ void zcrypt_msgtype_unregister(struct zcrypt_ops *);
 struct zcrypt_ops *zcrypt_msgtype(unsigned char *, int);
 int zcrypt_api_init(void);
 void zcrypt_api_exit(void);
-long zcrypt_send_cprb(struct ica_xcRB *xcRB);
-long zcrypt_send_ep11_cprb(struct ep11_urb *urb);
+long zcrypt_send_cprb(struct ica_xcRB *xcRB, u32 xflags);
+long zcrypt_send_ep11_cprb(struct ep11_urb *urb, u32 xflags);
 void zcrypt_device_status_mask_ext(struct zcrypt_device_status_ext *devstatus);
 int zcrypt_device_status_ext(int card, int queue,
 			     struct zcrypt_device_status_ext *devstatus);
diff --git a/drivers/s390/crypto/zcrypt_ccamisc.c b/drivers/s390/crypto/zcrypt_ccamisc.c
index 43a27cb3db84..521baaea06ff 100644
--- a/drivers/s390/crypto/zcrypt_ccamisc.c
+++ b/drivers/s390/crypto/zcrypt_ccamisc.c
@@ -379,7 +379,7 @@ int cca_genseckey(u16 cardnr, u16 domain,
 	prep_xcrb(&xcrb, cardnr, preqcblk, prepcblk);
 
 	/* forward xcrb with request CPRB and reply CPRB to zcrypt dd */
-	rc = zcrypt_send_cprb(&xcrb);
+	rc = zcrypt_send_cprb(&xcrb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, errno %d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -517,7 +517,7 @@ int cca_clr2seckey(u16 cardnr, u16 domain, u32 keybitsize,
 	prep_xcrb(&xcrb, cardnr, preqcblk, prepcblk);
 
 	/* forward xcrb with request CPRB and reply CPRB to zcrypt dd */
-	rc = zcrypt_send_cprb(&xcrb);
+	rc = zcrypt_send_cprb(&xcrb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -644,7 +644,7 @@ int cca_sec2protkey(u16 cardnr, u16 domain,
 	prep_xcrb(&xcrb, cardnr, preqcblk, prepcblk);
 
 	/* forward xcrb with request CPRB and reply CPRB to zcrypt dd */
-	rc = zcrypt_send_cprb(&xcrb);
+	rc = zcrypt_send_cprb(&xcrb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -872,7 +872,7 @@ int cca_gencipherkey(u16 cardnr, u16 domain, u32 keybitsize, u32 keygenflags,
 	prep_xcrb(&xcrb, cardnr, preqcblk, prepcblk);
 
 	/* forward xcrb with request CPRB and reply CPRB to zcrypt dd */
-	rc = zcrypt_send_cprb(&xcrb);
+	rc = zcrypt_send_cprb(&xcrb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -1038,7 +1038,7 @@ static int _ip_cprb_helper(u16 cardnr, u16 domain,
 	prep_xcrb(&xcrb, cardnr, preqcblk, prepcblk);
 
 	/* forward xcrb with request CPRB and reply CPRB to zcrypt dd */
-	rc = zcrypt_send_cprb(&xcrb);
+	rc = zcrypt_send_cprb(&xcrb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -1249,7 +1249,7 @@ int cca_cipher2protkey(u16 cardnr, u16 domain, const u8 *ckey,
 	prep_xcrb(&xcrb, cardnr, preqcblk, prepcblk);
 
 	/* forward xcrb with request CPRB and reply CPRB to zcrypt dd */
-	rc = zcrypt_send_cprb(&xcrb);
+	rc = zcrypt_send_cprb(&xcrb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -1412,7 +1412,7 @@ int cca_ecc2protkey(u16 cardnr, u16 domain, const u8 *key,
 	prep_xcrb(&xcrb, cardnr, preqcblk, prepcblk);
 
 	/* forward xcrb with request CPRB and reply CPRB to zcrypt dd */
-	rc = zcrypt_send_cprb(&xcrb);
+	rc = zcrypt_send_cprb(&xcrb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -1526,7 +1526,7 @@ int cca_query_crypto_facility(u16 cardnr, u16 domain,
 	prep_xcrb(&xcrb, cardnr, preqcblk, prepcblk);
 
 	/* forward xcrb with request CPRB and reply CPRB to zcrypt dd */
-	rc = zcrypt_send_cprb(&xcrb);
+	rc = zcrypt_send_cprb(&xcrb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
diff --git a/drivers/s390/crypto/zcrypt_ep11misc.c b/drivers/s390/crypto/zcrypt_ep11misc.c
index cb7e6da43602..b60e262bcaa3 100644
--- a/drivers/s390/crypto/zcrypt_ep11misc.c
+++ b/drivers/s390/crypto/zcrypt_ep11misc.c
@@ -636,7 +636,7 @@ static int ep11_query_info(u16 cardnr, u16 domain, u32 query_type,
 		 req, sizeof(*req) + sizeof(*req_pl),
 		 rep, sizeof(*rep) + sizeof(*rep_pl) + buflen);
 
-	rc = zcrypt_send_ep11_cprb(urb);
+	rc = zcrypt_send_ep11_cprb(urb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_ep11_cprb(card=%d dom=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -892,7 +892,7 @@ static int _ep11_genaeskey(u16 card, u16 domain,
 		 req, sizeof(*req) + req_pl_size,
 		 rep, sizeof(*rep) + sizeof(*rep_pl));
 
-	rc = zcrypt_send_ep11_cprb(urb);
+	rc = zcrypt_send_ep11_cprb(urb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_ep11_cprb(card=%d dom=%d) failed, rc=%d\n",
 			       __func__, (int)card, (int)domain, rc);
@@ -1049,7 +1049,7 @@ static int ep11_cryptsingle(u16 card, u16 domain,
 		 req, sizeof(*req) + req_pl_size,
 		 rep, sizeof(*rep) + rep_pl_size);
 
-	rc = zcrypt_send_ep11_cprb(urb);
+	rc = zcrypt_send_ep11_cprb(urb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_ep11_cprb(card=%d dom=%d) failed, rc=%d\n",
 			       __func__, (int)card, (int)domain, rc);
@@ -1212,7 +1212,7 @@ static int _ep11_unwrapkey(u16 card, u16 domain,
 		 req, sizeof(*req) + req_pl_size,
 		 rep, sizeof(*rep) + sizeof(*rep_pl));
 
-	rc = zcrypt_send_ep11_cprb(urb);
+	rc = zcrypt_send_ep11_cprb(urb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_ep11_cprb(card=%d dom=%d) failed, rc=%d\n",
 			       __func__, (int)card, (int)domain, rc);
@@ -1372,7 +1372,7 @@ static int _ep11_wrapkey(u16 card, u16 domain,
 		 req, sizeof(*req) + req_pl_size,
 		 rep, sizeof(*rep) + sizeof(*rep_pl));
 
-	rc = zcrypt_send_ep11_cprb(urb);
+	rc = zcrypt_send_ep11_cprb(urb, 0);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_ep11_cprb(card=%d dom=%d) failed, rc=%d\n",
 			       __func__, (int)card, (int)domain, rc);
-- 
2.43.0