s390/ap/zcrypt: revisit ap and zcrypt error handling

Revisit the ap queue error handling: Based on discussions and
evaluatios with the firmware folk here is now a rework of the response
code handling for all the AP instructions. The idea is to distinguish
between failures because of some kind of invalid request where a retry
does not make any sense and a failure where another attempt to send
the very same request may succeed. The first case is handled by
returning EINVAL to the userspace application. The second case results
in retries within the zcrypt API controlled by a per message retry
counter.

Revisit the zcrpyt error handling: Similar here, based on discussions
with the firmware people here comes a rework of the handling of all
the reply codes.  Main point here is that there are only very few
cases left, where a zcrypt device queue is switched to offline. It
should never be the case that an AP reply message is 'unknown' to the
device driver as it indicates a total mismatch between device driver
and crypto card firmware. In all other cases, the code distinguishes
between failure because of invalid message (see above - EINVAL) or
failures of the infrastructure (see above - EAGAIN).

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 32 insertions, 56 deletions

diff --git a/drivers/s390/crypto/zcrypt_error.h b/drivers/s390/crypto/zcrypt_error.h
index 54a04f8c38ef..39e626e3a379 100644
--- a/drivers/s390/crypto/zcrypt_error.h
+++ b/drivers/s390/crypto/zcrypt_error.h
@@ -52,7 +52,6 @@ struct error_hdr {
 #define REP82_ERROR_INVALID_COMMAND	    0x30
 #define REP82_ERROR_MALFORMED_MSG	    0x40
 #define REP82_ERROR_INVALID_SPECIAL_CMD	    0x41
-#define REP82_ERROR_INVALID_DOMAIN_PRECHECK 0x42
 #define REP82_ERROR_RESERVED_FIELDO	    0x50 /* old value	*/
 #define REP82_ERROR_WORD_ALIGNMENT	    0x60
 #define REP82_ERROR_MESSAGE_LENGTH	    0x80
@@ -67,7 +66,6 @@ struct error_hdr {
 #define REP82_ERROR_ZERO_BUFFER_LEN	    0xB0
 
 #define REP88_ERROR_MODULE_FAILURE	    0x10
-
 #define REP88_ERROR_MESSAGE_TYPE	    0x20
 #define REP88_ERROR_MESSAGE_MALFORMD	    0x22
 #define REP88_ERROR_MESSAGE_LENGTH	    0x23
@@ -85,78 +83,56 @@ static inline int convert_error(struct zcrypt_queue *zq,
 	int queue = AP_QID_QUEUE(zq->queue->qid);
 
 	switch (ehdr->reply_code) {
-	case REP82_ERROR_OPERAND_INVALID:
-	case REP82_ERROR_OPERAND_SIZE:
-	case REP82_ERROR_EVEN_MOD_IN_OPND:
-	case REP88_ERROR_MESSAGE_MALFORMD:
-	case REP82_ERROR_INVALID_DOMAIN_PRECHECK:
-	case REP82_ERROR_INVALID_DOMAIN_PENDING:
-	case REP82_ERROR_INVALID_SPECIAL_CMD:
-	case REP82_ERROR_FILTERED_BY_HYPERVISOR:
-	//   REP88_ERROR_INVALID_KEY		// '82' CEX2A
-	//   REP88_ERROR_OPERAND		// '84' CEX2A
-	//   REP88_ERROR_OPERAND_EVEN_MOD	// '85' CEX2A
-		/* Invalid input data. */
+	case REP82_ERROR_INVALID_MSG_LEN:	 /* 0x23 */
+	case REP82_ERROR_RESERVD_FIELD:		 /* 0x24 */
+	case REP82_ERROR_FORMAT_FIELD:		 /* 0x29 */
+	case REP82_ERROR_MALFORMED_MSG:		 /* 0x40 */
+	case REP82_ERROR_INVALID_SPECIAL_CMD:	 /* 0x41 */
+	case REP82_ERROR_MESSAGE_LENGTH:	 /* 0x80 */
+	case REP82_ERROR_OPERAND_INVALID:	 /* 0x82 */
+	case REP82_ERROR_OPERAND_SIZE:		 /* 0x84 */
+	case REP82_ERROR_EVEN_MOD_IN_OPND:	 /* 0x85 */
+	case REP82_ERROR_INVALID_DOMAIN_PENDING: /* 0x8A */
+	case REP82_ERROR_FILTERED_BY_HYPERVISOR: /* 0x8B */
+	case REP82_ERROR_PACKET_TRUNCATED:	 /* 0xA0 */
+	case REP88_ERROR_MESSAGE_MALFORMD:	 /* 0x22 */
+	case REP88_ERROR_KEY_TYPE:		 /* 0x34 */
+		/* RY indicates malformed request */
 		ZCRYPT_DBF(DBF_WARN,
-			   "device=%02x.%04x reply=0x%02x => rc=EINVAL\n",
+			   "dev=%02x.%04x RY=0x%02x => rc=EINVAL\n",
 			   card, queue, ehdr->reply_code);
 		return -EINVAL;
-	case REP82_ERROR_MESSAGE_TYPE:
-	//   REP88_ERROR_MESSAGE_TYPE		// '20' CEX2A
+	case REP82_ERROR_MACHINE_FAILURE:	 /* 0x10 */
+	case REP82_ERROR_MESSAGE_TYPE:		 /* 0x20 */
+	case REP82_ERROR_TRANSPORT_FAIL:	 /* 0x90 */
 		/*
-		 * To sent a message of the wrong type is a bug in the
-		 * device driver. Send error msg, disable the device
-		 * and then repeat the request.
+		 * Msg to wrong type or card/infrastructure failure.
+		 * Trigger rescan of the ap bus, trigger retry request.
 		 */
 		atomic_set(&zcrypt_rescan_req, 1);
-		zq->online = 0;
-		pr_err("Cryptographic device %02x.%04x failed and was set offline\n",
-		       card, queue);
-		ZCRYPT_DBF(DBF_ERR,
-			   "device=%02x.%04x reply=0x%02x => online=0 rc=EAGAIN\n",
-			   card, queue, ehdr->reply_code);
-		return -EAGAIN;
-	case REP82_ERROR_TRANSPORT_FAIL:
-		/* Card or infrastructure failure, disable card */
-		atomic_set(&zcrypt_rescan_req, 1);
-		zq->online = 0;
-		pr_err("Cryptographic device %02x.%04x failed and was set offline\n",
-		       card, queue);
 		/* For type 86 response show the apfs value (failure reason) */
-		if (ehdr->type == TYPE86_RSP_CODE) {
+		if (ehdr->reply_code == REP82_ERROR_TRANSPORT_FAIL &&
+		    ehdr->type == TYPE86_RSP_CODE) {
 			struct {
 				struct type86_hdr hdr;
 				struct type86_fmt2_ext fmt2;
 			} __packed * head = reply->msg;
 			unsigned int apfs = *((u32 *)head->fmt2.apfs);
 
-			ZCRYPT_DBF(DBF_ERR,
-				   "device=%02x.%04x reply=0x%02x apfs=0x%x => online=0 rc=EAGAIN\n",
-				   card, queue, apfs, ehdr->reply_code);
+			ZCRYPT_DBF(DBF_WARN,
+				   "dev=%02x.%04x RY=0x%02x apfs=0x%x => bus rescan, rc=EAGAIN\n",
+				   card, queue, ehdr->reply_code, apfs);
 		} else
-			ZCRYPT_DBF(DBF_ERR,
-				   "device=%02x.%04x reply=0x%02x => online=0 rc=EAGAIN\n",
+			ZCRYPT_DBF(DBF_WARN,
+				   "dev=%02x.%04x RY=0x%02x => bus rescan, rc=EAGAIN\n",
 				   card, queue, ehdr->reply_code);
 		return -EAGAIN;
-	case REP82_ERROR_MACHINE_FAILURE:
-	//   REP88_ERROR_MODULE_FAILURE		// '10' CEX2A
-		/* If a card fails disable it and repeat the request. */
-		atomic_set(&zcrypt_rescan_req, 1);
-		zq->online = 0;
-		pr_err("Cryptographic device %02x.%04x failed and was set offline\n",
-		       card, queue);
-		ZCRYPT_DBF(DBF_ERR,
-			   "device=%02x.%04x reply=0x%02x => online=0 rc=EAGAIN\n",
-			   card, queue, ehdr->reply_code);
-		return -EAGAIN;
 	default:
-		zq->online = 0;
-		pr_err("Cryptographic device %02x.%04x failed and was set offline\n",
-		       card, queue);
-		ZCRYPT_DBF(DBF_ERR,
-			   "device=%02x.%04x reply=0x%02x => online=0 rc=EAGAIN\n",
+		/* Assume request is valid and a retry will be worth it */
+		ZCRYPT_DBF(DBF_WARN,
+			   "dev=%02x.%04x RY=0x%02x => rc=EAGAIN\n",
 			   card, queue, ehdr->reply_code);
-		return -EAGAIN;	/* repeat the request on a different device. */
+		return -EAGAIN;
 	}
 }