linux-kernel - [PATCH 09/12] s390/vfio-ap: check for TAPQ response codes 0x35 and 0x36

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Message-Id: <20230815184333.6554-10-akrowiak@linux.ibm.com>
Date:   Tue, 15 Aug 2023 14:43:30 -0400
From:   Tony Krowiak <akrowiak@...ux.ibm.com>
To:     linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     jjherne@...ux.ibm.com, freude@...ux.ibm.com,
        borntraeger@...ibm.com, cohuck@...hat.com, mjrosato@...ux.ibm.com,
        pasic@...ux.ibm.com, alex.williamson@...hat.com,
        kwankhede@...dia.com, fiuczy@...ux.ibm.com,
        Viktor Mihajlovski <mihajlov@...ux.ibm.com>
Subject: [PATCH 09/12] s390/vfio-ap: check for TAPQ response codes 0x35 and 0x36

Check for response codes 0x35 and 0x36 which are asynchronous return codes
indicating a failure of the guest to associate a secret with a queue. Since
there can be no interaction with this queue from the guest (i.e., the vcpus
are out of SIE for hot unplug, the guest is being shut down or an emulated
subsystem reset of the guest is taking place), let's go ahead and re-issue
the ZAPQ to reset and zeroize the queue.

Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@...ux.ibm.com>
Reviewed-by: Halil Pasic <pasic@...ux.ibm.com>
Tested-by: Viktor Mihajlovski <mihajlov@...ux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 43dea259fe23..8bda52c46df0 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1612,6 +1612,16 @@ static int apq_status_check(int apqn, struct ap_queue_status *status)
 	case AP_RESPONSE_RESET_IN_PROGRESS:
 	case AP_RESPONSE_BUSY:
 		return -EBUSY;
+	case AP_RESPONSE_ASSOC_SECRET_NOT_UNIQUE:
+	case AP_RESPONSE_ASSOC_FAILED:
+		/*
+		 * These asynchronous response codes indicate a PQAP(AAPQ)
+		 * instruction to associate a secret with the guest failed. All
+		 * subsequent AP instructions will end with the asynchronous
+		 * response code until the AP queue is reset; so, let's return
+		 * a value indicating a reset needs to be performed again.
+		 */
+		return -EAGAIN;
 	default:
 		WARN(true,
 		     "failed to verify reset of queue %02x.%04x: TAPQ rc=%u\n",
@@ -1648,7 +1658,8 @@ static void apq_reset_check(struct work_struct *reset_work)
 		} else {
 			if (q->reset_status.response_code == AP_RESPONSE_RESET_IN_PROGRESS ||
 			    q->reset_status.response_code == AP_RESPONSE_BUSY ||
-			    q->reset_status.response_code == AP_RESPONSE_STATE_CHANGE_IN_PROGRESS) {
+			    q->reset_status.response_code == AP_RESPONSE_STATE_CHANGE_IN_PROGRESS ||
+			    ret == -EAGAIN) {
 				status = ap_zapq(q->apqn, 0);
 				memcpy(&q->reset_status, &status, sizeof(status));
 				continue;
-- 
2.39.3