[PATCH v2 05/20] s390/zcrypt: Introduce cprb mempool for cca misc functions

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

Introduce a cprb mempool for the zcrypt cca misc functions
(zcrypt_ccamisc.*) do some preparation rework to support
a do-not-allocate path through some zcrypt cca misc functions.

The mempool is by default space for 4 cprbs with each 16KB.
For CCA a CPRB needs to hold the request and the reply, so
the pool items only support requests/replies with a limit of
about 8KB. The minimal number of items in the mempool can get
adjusted via module parameter zcrypt.cca_cprbpool_min_items
on module load.

This is only part of an rework to support a new xflag
ZCRYPT_XFLAG_NOMEMALLOC but not yet complete.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
---
 drivers/s390/crypto/zcrypt_api.c     |  13 ++-
 drivers/s390/crypto/zcrypt_api.h     |   2 +
 drivers/s390/crypto/zcrypt_ccamisc.c | 116 ++++++++++++++++++++-------
 drivers/s390/crypto/zcrypt_ccamisc.h |   1 +
 4 files changed, 101 insertions(+), 31 deletions(-)

diff --git a/drivers/s390/crypto/zcrypt_api.c b/drivers/s390/crypto/zcrypt_api.c
index 659fe7afb67e..d7915c3fe3c0 100644
--- a/drivers/s390/crypto/zcrypt_api.c
+++ b/drivers/s390/crypto/zcrypt_api.c
@@ -50,6 +50,10 @@ MODULE_DESCRIPTION("Cryptographic Coprocessor interface, " \
 		   "Copyright IBM Corp. 2001, 2012");
 MODULE_LICENSE("GPL");
 
+unsigned int zcrypt_cca_cprbpool_min_items = 4;
+module_param_named(cca_cprbpool_min_items, zcrypt_cca_cprbpool_min_items, uint, 0440);
+MODULE_PARM_DESC(cca_cprbpool_min_items, "CCA CPRB pool minimal items.");
+
 /*
  * zcrypt tracepoint functions
  */
@@ -2159,7 +2163,11 @@ int __init zcrypt_api_init(void)
 
 	rc = zcdn_init();
 	if (rc)
-		goto out;
+		goto out_zcdn_init_failed;
+
+	rc = zcrypt_ccamisc_init();
+	if (rc)
+		goto out_ccamisc_init_failed;
 
 	/* Register the request sprayer. */
 	rc = misc_register(&zcrypt_misc_device);
@@ -2172,7 +2180,10 @@ int __init zcrypt_api_init(void)
 	return 0;
 
 out_misc_register_failed:
+	zcrypt_ccamisc_exit();
+out_ccamisc_init_failed:
 	zcdn_exit();
+out_zcdn_init_failed:
 	zcrypt_debug_exit();
 out:
 	return rc;
diff --git a/drivers/s390/crypto/zcrypt_api.h b/drivers/s390/crypto/zcrypt_api.h
index 8550a1eceb05..d2640ea5d080 100644
--- a/drivers/s390/crypto/zcrypt_api.h
+++ b/drivers/s390/crypto/zcrypt_api.h
@@ -144,6 +144,8 @@ extern atomic_t zcrypt_rescan_req;
 extern spinlock_t zcrypt_list_lock;
 extern struct list_head zcrypt_card_list;
 
+extern unsigned int zcrypt_cca_cprbpool_min_items;
+
 #define for_each_zcrypt_card(_zc) \
 	list_for_each_entry(_zc, &zcrypt_card_list, list)
 
diff --git a/drivers/s390/crypto/zcrypt_ccamisc.c b/drivers/s390/crypto/zcrypt_ccamisc.c
index 521baaea06ff..2c2ca2d67e2d 100644
--- a/drivers/s390/crypto/zcrypt_ccamisc.c
+++ b/drivers/s390/crypto/zcrypt_ccamisc.c
@@ -11,6 +11,7 @@
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
 #include <linux/init.h>
+#include <linux/mempool.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/random.h>
@@ -40,6 +41,16 @@ struct cca_info_list_entry {
 static LIST_HEAD(cca_info_list);
 static DEFINE_SPINLOCK(cca_info_list_lock);
 
+/*
+ * Cprb memory pool held for urgent cases where no memory
+ * can be allocated via kmalloc. This pool is only used
+ * when alloc_and_prep_cprbmem() is called with the xflag
+ * ZCRYPT_XFLAG_NOMEMALLOC. The cprb memory needs to hold
+ * space for request AND reply!
+ */
+#define CPRB_MEMPOOL_ITEM_SIZE (16 * 1024)
+static mempool_t *cprb_mempool;
+
 /*
  * Simple check if the token is a valid CCA secure AES data key
  * token. If keybitsize is given, the bitsize of the key is
@@ -219,9 +230,10 @@ EXPORT_SYMBOL(cca_check_sececckeytoken);
 static int alloc_and_prep_cprbmem(size_t paramblen,
 				  u8 **p_cprb_mem,
 				  struct CPRBX **p_req_cprb,
-				  struct CPRBX **p_rep_cprb)
+				  struct CPRBX **p_rep_cprb,
+				  u32 xflags)
 {
-	u8 *cprbmem;
+	u8 *cprbmem = NULL;
 	size_t cprbplusparamblen = sizeof(struct CPRBX) + paramblen;
 	struct CPRBX *preqcblk, *prepcblk;
 
@@ -229,7 +241,15 @@ static int alloc_and_prep_cprbmem(size_t paramblen,
 	 * allocate consecutive memory for request CPRB, request param
 	 * block, reply CPRB and reply param block
 	 */
-	cprbmem = kcalloc(2, cprbplusparamblen, GFP_KERNEL);
+	if (xflags & ZCRYPT_XFLAG_NOMEMALLOC) {
+		if (cprb_mempool &&
+		    2 * cprbplusparamblen <= CPRB_MEMPOOL_ITEM_SIZE) {
+			cprbmem = mempool_alloc_preallocated(cprb_mempool);
+			memset(cprbmem, 0, 2 * cprbplusparamblen);
+		}
+	} else {
+		cprbmem = kcalloc(2, cprbplusparamblen, GFP_KERNEL);
+	}
 	if (!cprbmem)
 		return -ENOMEM;
 
@@ -261,11 +281,15 @@ static int alloc_and_prep_cprbmem(size_t paramblen,
  * with zeros before freeing (useful if there was some
  * clear key material in there).
  */
-static void free_cprbmem(void *mem, size_t paramblen, int scrub)
+static void free_cprbmem(void *mem, size_t paramblen, bool scrub, u32 xflags)
 {
 	if (scrub)
 		memzero_explicit(mem, 2 * (sizeof(struct CPRBX) + paramblen));
-	kfree(mem);
+
+	if (xflags & ZCRYPT_XFLAG_NOMEMALLOC)
+		mempool_free(mem, cprb_mempool);
+	else
+		kfree(mem);
 }
 
 /*
@@ -330,9 +354,11 @@ int cca_genseckey(u16 cardnr, u16 domain,
 			} keyblock;
 		} lv3;
 	} __packed * prepparm;
+	const u32 xflags = 0;
 
 	/* get already prepared memory for 2 cprbs with param block each */
-	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem, &preqcblk, &prepcblk);
+	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem,
+				    &preqcblk, &prepcblk, xflags);
 	if (rc)
 		return rc;
 
@@ -379,7 +405,7 @@ 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, 0);
+	rc = zcrypt_send_cprb(&xcrb, xflags);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, errno %d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -424,7 +450,7 @@ int cca_genseckey(u16 cardnr, u16 domain,
 	memcpy(seckey, prepparm->lv3.keyblock.tok, SECKEYBLOBSIZE);
 
 out:
-	free_cprbmem(mem, PARMBSIZE, 0);
+	free_cprbmem(mem, PARMBSIZE, false, xflags);
 	return rc;
 }
 EXPORT_SYMBOL(cca_genseckey);
@@ -471,9 +497,11 @@ int cca_clr2seckey(u16 cardnr, u16 domain, u32 keybitsize,
 			} keyblock;
 		} lv3;
 	} __packed * prepparm;
+	const u32 xflags = 0;
 
 	/* get already prepared memory for 2 cprbs with param block each */
-	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem, &preqcblk, &prepcblk);
+	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem,
+				    &preqcblk, &prepcblk, xflags);
 	if (rc)
 		return rc;
 
@@ -517,7 +545,7 @@ 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, 0);
+	rc = zcrypt_send_cprb(&xcrb, xflags);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -563,7 +591,7 @@ int cca_clr2seckey(u16 cardnr, u16 domain, u32 keybitsize,
 		memcpy(seckey, prepparm->lv3.keyblock.tok, SECKEYBLOBSIZE);
 
 out:
-	free_cprbmem(mem, PARMBSIZE, 1);
+	free_cprbmem(mem, PARMBSIZE, true, xflags);
 	return rc;
 }
 EXPORT_SYMBOL(cca_clr2seckey);
@@ -617,9 +645,11 @@ int cca_sec2protkey(u16 cardnr, u16 domain,
 			} ckb;
 		} lv3;
 	} __packed * prepparm;
+	const u32 xflags = 0;
 
 	/* get already prepared memory for 2 cprbs with param block each */
-	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem, &preqcblk, &prepcblk);
+	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem,
+				    &preqcblk, &prepcblk, xflags);
 	if (rc)
 		return rc;
 
@@ -644,7 +674,7 @@ 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, 0);
+	rc = zcrypt_send_cprb(&xcrb, xflags);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -712,7 +742,7 @@ int cca_sec2protkey(u16 cardnr, u16 domain,
 		*protkeylen = prepparm->lv3.ckb.len;
 
 out:
-	free_cprbmem(mem, PARMBSIZE, 0);
+	free_cprbmem(mem, PARMBSIZE, true, xflags);
 	return rc;
 }
 EXPORT_SYMBOL(cca_sec2protkey);
@@ -811,9 +841,11 @@ int cca_gencipherkey(u16 cardnr, u16 domain, u32 keybitsize, u32 keygenflags,
 		} kb;
 	} __packed * prepparm;
 	struct cipherkeytoken *t;
+	const u32 xflags = 0;
 
 	/* get already prepared memory for 2 cprbs with param block each */
-	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem, &preqcblk, &prepcblk);
+	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem,
+				    &preqcblk, &prepcblk, xflags);
 	if (rc)
 		return rc;
 
@@ -872,7 +904,7 @@ 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, 0);
+	rc = zcrypt_send_cprb(&xcrb, xflags);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -923,7 +955,7 @@ int cca_gencipherkey(u16 cardnr, u16 domain, u32 keybitsize, u32 keygenflags,
 	*keybufsize = t->len;
 
 out:
-	free_cprbmem(mem, PARMBSIZE, 0);
+	free_cprbmem(mem, PARMBSIZE, false, xflags);
 	return rc;
 }
 EXPORT_SYMBOL(cca_gencipherkey);
@@ -987,9 +1019,11 @@ static int _ip_cprb_helper(u16 cardnr, u16 domain,
 	} __packed * prepparm;
 	struct cipherkeytoken *t;
 	int complete = strncmp(rule_array_2, "COMPLETE", 8) ? 0 : 1;
+	const u32 xflags = 0;
 
 	/* get already prepared memory for 2 cprbs with param block each */
-	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem, &preqcblk, &prepcblk);
+	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem,
+				    &preqcblk, &prepcblk, xflags);
 	if (rc)
 		return rc;
 
@@ -1038,7 +1072,7 @@ 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, 0);
+	rc = zcrypt_send_cprb(&xcrb, xflags);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -1077,7 +1111,7 @@ static int _ip_cprb_helper(u16 cardnr, u16 domain,
 	*key_token_size = t->len;
 
 out:
-	free_cprbmem(mem, PARMBSIZE, 0);
+	free_cprbmem(mem, PARMBSIZE, false, xflags);
 	return rc;
 }
 
@@ -1217,9 +1251,11 @@ int cca_cipher2protkey(u16 cardnr, u16 domain, const u8 *ckey,
 		} kb;
 	} __packed * prepparm;
 	int keytoklen = ((struct cipherkeytoken *)ckey)->len;
+	const u32 xflags = 0;
 
 	/* get already prepared memory for 2 cprbs with param block each */
-	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem, &preqcblk, &prepcblk);
+	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem,
+				    &preqcblk, &prepcblk, xflags);
 	if (rc)
 		return rc;
 
@@ -1249,7 +1285,7 @@ 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, 0);
+	rc = zcrypt_send_cprb(&xcrb, xflags);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -1323,7 +1359,7 @@ int cca_cipher2protkey(u16 cardnr, u16 domain, const u8 *ckey,
 		*protkeylen = prepparm->vud.ckb.keylen;
 
 out:
-	free_cprbmem(mem, PARMBSIZE, 0);
+	free_cprbmem(mem, PARMBSIZE, true, xflags);
 	return rc;
 }
 EXPORT_SYMBOL(cca_cipher2protkey);
@@ -1380,9 +1416,11 @@ int cca_ecc2protkey(u16 cardnr, u16 domain, const u8 *key,
 		/* followed by a key block */
 	} __packed * prepparm;
 	int keylen = ((struct eccprivkeytoken *)key)->len;
+	const u32 xflags = 0;
 
 	/* get already prepared memory for 2 cprbs with param block each */
-	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem, &preqcblk, &prepcblk);
+	rc = alloc_and_prep_cprbmem(PARMBSIZE, &mem,
+				    &preqcblk, &prepcblk, xflags);
 	if (rc)
 		return rc;
 
@@ -1412,7 +1450,7 @@ 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, 0);
+	rc = zcrypt_send_cprb(&xcrb, xflags);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -1470,7 +1508,7 @@ int cca_ecc2protkey(u16 cardnr, u16 domain, const u8 *key,
 		*protkeytype = PKEY_KEYTYPE_ECC;
 
 out:
-	free_cprbmem(mem, PARMBSIZE, 0);
+	free_cprbmem(mem, PARMBSIZE, true, xflags);
 	return rc;
 }
 EXPORT_SYMBOL(cca_ecc2protkey);
@@ -1503,9 +1541,11 @@ int cca_query_crypto_facility(u16 cardnr, u16 domain,
 		u8  subfunc_code[2];
 		u8  lvdata[];
 	} __packed * prepparm;
+	const u32 xflags = 0;
 
 	/* get already prepared memory for 2 cprbs with param block each */
-	rc = alloc_and_prep_cprbmem(parmbsize, &mem, &preqcblk, &prepcblk);
+	rc = alloc_and_prep_cprbmem(parmbsize, &mem,
+				    &preqcblk, &prepcblk, xflags);
 	if (rc)
 		return rc;
 
@@ -1526,7 +1566,7 @@ 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, 0);
+	rc = zcrypt_send_cprb(&xcrb, xflags);
 	if (rc) {
 		ZCRYPT_DBF_ERR("%s zcrypt_send_cprb (cardnr=%d domain=%d) failed, rc=%d\n",
 			       __func__, (int)cardnr, (int)domain, rc);
@@ -1573,7 +1613,7 @@ int cca_query_crypto_facility(u16 cardnr, u16 domain,
 	}
 
 out:
-	free_cprbmem(mem, parmbsize, 0);
+	free_cprbmem(mem, parmbsize, false, xflags);
 	return rc;
 }
 EXPORT_SYMBOL(cca_query_crypto_facility);
@@ -1959,7 +1999,23 @@ int cca_findcard2(u32 **apqns, u32 *nr_apqns, u16 cardnr, u16 domain,
 }
 EXPORT_SYMBOL(cca_findcard2);
 
-void __exit zcrypt_ccamisc_exit(void)
+int __init zcrypt_ccamisc_init(void)
+{
+	/* Pre-allocate a small memory pool for cca cprbs. */
+	cprb_mempool = mempool_create_kmalloc_pool(zcrypt_cca_cprbpool_min_items,
+						   CPRB_MEMPOOL_ITEM_SIZE);
+	if (IS_ERR(cprb_mempool)) {
+		ZCRYPT_DBF_ERR("%s mempool_create(%d,%d) failed: %ld\n",
+			       __func__, zcrypt_cca_cprbpool_min_items,
+			       CPRB_MEMPOOL_ITEM_SIZE, PTR_ERR(cprb_mempool));
+		cprb_mempool = NULL;
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void zcrypt_ccamisc_exit(void)
 {
 	mkvp_cache_free();
+	mempool_destroy(cprb_mempool);
 }
diff --git a/drivers/s390/crypto/zcrypt_ccamisc.h b/drivers/s390/crypto/zcrypt_ccamisc.h
index 26bdca702523..273edf2bb036 100644
--- a/drivers/s390/crypto/zcrypt_ccamisc.h
+++ b/drivers/s390/crypto/zcrypt_ccamisc.h
@@ -272,6 +272,7 @@ struct cca_info {
  */
 int cca_get_info(u16 card, u16 dom, struct cca_info *ci, int verify);
 
+int zcrypt_ccamisc_init(void);
 void zcrypt_ccamisc_exit(void);
 
 #endif /* _ZCRYPT_CCAMISC_H_ */
-- 
2.43.0