s390/vfio-ap: clean up irq resources if possible

The architecture does not specify whether interrupts are disabled as part
of the asynchronous reset or upon return from the PQAP/ZAPQ instruction.
If, however, PQAP/ZAPQ completes with APQSW response code 0 and the
interrupt bit in the status word is also 0, we know the interrupts are
disabled and we can go ahead and clean up the corresponding resources;
otherwise, we must wait until the asynchronous reset has completed.

Signed-off-by: Tony Krowiak <[email protected]>
Suggested-by: Halil Pasic <[email protected]>
Reviewed-by: Jason J. Herne <[email protected]>
Acked-by: Halil Pasic <[email protected]>
Acked-by: Janosch Frank <[email protected]>
Tested-by: Viktor Mihajlovski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Heiko Carstens <[email protected]>

Author: Tony Krowiak

drivers/s390/crypto/vfio_ap_ops.c

@@ -1654,9 +1654,13 @@ static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
 	switch (status.response_code) {
 	case AP_RESPONSE_NORMAL:
 		ret = 0;
-		/* if the reset has not completed, wait for it to take effect */
-		if (!status.queue_empty || status.irq_enabled)
+		if (!status.irq_enabled)
+			vfio_ap_free_aqic_resources(q);
+		if (!status.queue_empty || status.irq_enabled) {
 			ret = apq_reset_check(q);
+			if (status.irq_enabled && ret == 0)
+				vfio_ap_free_aqic_resources(q);
+		}
 		break;
 	case AP_RESPONSE_RESET_IN_PROGRESS:
 		/*
@@ -1675,6 +1679,7 @@ static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
 		 * completed successfully.
 		 */
 		ret = 0;
+		vfio_ap_free_aqic_resources(q);
 		break;
 	default:
 		WARN(true,
@@ -1684,8 +1689,6 @@ static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
 		return -EIO;
 	}
 
-	vfio_ap_free_aqic_resources(q);
-
 	return ret;
 }