[PATCH 6.1.y 1/2] s390/vfio-ap: wait for response code 05 to clear on queue reset

[Sasha Levin <sashal@kernel.org>]

From: Tony Krowiak <akrowiak@linux.ibm.com>

[ Upstream commit 411b0109daa52d1cc5be39635631e22a5590c5d8 ]

Response code 05, AP busy, is a valid response code for a ZAPQ or TAPQ.
Instead of returning error -EIO when a ZAPQ fails with response code 05,
let's wait until the queue is no longer busy and try the ZAPQ again.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Tested-by: Viktor Mihajlovski <mihajlov@linux.ibm.com>
Link: https://lore.kernel.org/r/20230815184333.6554-4-akrowiak@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

[Backport to 6.1: keep the existing bounded queue-reset implementation
and handle AP_RESPONSE_BUSY through its reset-in-progress retry path.
Drop the apq_status_check() hunk because that helper is absent here; do
not introduce the newer reset helpers or their prerequisite refactors.

Prepare for 4400270ec034 ("s390/vfio-ap: fix stale pqap_hook pointer on
error in vfio_ap_mdev_set_kvm()") by changing the existing
vfio_ap_mdev_reset_queues() argument from a queue table to its matrix
mdev. Keep the same table traversal and error propagation. The adapter
and domain hot-unplug paths reset their detached queue tables directly
with the existing single-queue helper before unlinking, preserving the
reset order, retry count, and ignored aggregate return value. No new
functions are introduced.]

Stable-dep-of: 4400270ec034 ("s390/vfio-ap: fix stale pqap_hook pointer on error in vfio_ap_mdev_set_kvm()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/s390/crypto/vfio_ap_ops.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 11fe917fbd9d4..5016c157a3010 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -30,7 +30,7 @@
 #define AP_QUEUE_UNASSIGNED "unassigned"
 #define AP_QUEUE_IN_USE "in use"
 
-static int vfio_ap_mdev_reset_queues(struct ap_queue_table *qtable);
+static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev);
 static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
 static const struct vfio_device_ops vfio_ap_matrix_dev_ops;
 static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q, unsigned int retry);
@@ -781,7 +781,7 @@ static void vfio_ap_mdev_remove(struct mdev_device *mdev)
 
 	mutex_lock(&matrix_dev->guests_lock);
 	mutex_lock(&matrix_dev->mdevs_lock);
-	vfio_ap_mdev_reset_queues(&matrix_mdev->qtable);
+	vfio_ap_mdev_reset_queues(matrix_mdev);
 	vfio_ap_mdev_unlink_fr_queues(matrix_mdev);
 	list_del(&matrix_mdev->node);
 	mutex_unlock(&matrix_dev->mdevs_lock);
@@ -1048,7 +1048,8 @@ static void vfio_ap_mdev_hot_unplug_adapter(struct ap_matrix_mdev *matrix_mdev,
 		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 	}
 
-	vfio_ap_mdev_reset_queues(qtable);
+	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode)
+		vfio_ap_mdev_reset_queue(q, 1);
 
 	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode) {
 		vfio_ap_unlink_mdev_fr_queue(q);
@@ -1231,7 +1232,8 @@ static void vfio_ap_mdev_hot_unplug_domain(struct ap_matrix_mdev *matrix_mdev,
 		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 	}
 
-	vfio_ap_mdev_reset_queues(qtable);
+	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode)
+		vfio_ap_mdev_reset_queue(q, 1);
 
 	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode) {
 		vfio_ap_unlink_mdev_fr_queue(q);
@@ -1577,7 +1579,7 @@ static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev)
 		get_update_locks_for_kvm(kvm);
 
 		kvm_arch_crypto_clear_masks(kvm);
-		vfio_ap_mdev_reset_queues(&matrix_mdev->qtable);
+		vfio_ap_mdev_reset_queues(matrix_mdev);
 		kvm_put_kvm(kvm);
 		matrix_mdev->kvm = NULL;
 
@@ -1619,6 +1621,7 @@ static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
 		ret = 0;
 		break;
 	case AP_RESPONSE_RESET_IN_PROGRESS:
+	case AP_RESPONSE_BUSY:
 		if (retry--) {
 			msleep(20);
 			goto retry_zapq;
@@ -1659,8 +1662,9 @@ static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
 	return ret;
 }
 
-static int vfio_ap_mdev_reset_queues(struct ap_queue_table *qtable)
+static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev)
 {
+	struct ap_queue_table *qtable = &matrix_mdev->qtable;
 	int ret, loop_cursor, rc = 0;
 	struct vfio_ap_queue *q;
 
@@ -1730,7 +1734,7 @@ static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
 		ret = vfio_ap_mdev_get_device_info(arg);
 		break;
 	case VFIO_DEVICE_RESET:
-		ret = vfio_ap_mdev_reset_queues(&matrix_mdev->qtable);
+		ret = vfio_ap_mdev_reset_queues(matrix_mdev);
 		break;
 	default:
 		ret = -EOPNOTSUPP;
-- 
2.53.0