linux-kernel - [PATCH 02/12] s390/vfio-ap: clean up irq resources if possible

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Message-Id: <20230815184333.6554-3-akrowiak@linux.ibm.com>
Date:   Tue, 15 Aug 2023 14:43:23 -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,
        Janosch Frank <frankja@...ux.ibm.com>,
        Viktor Mihajlovski <mihajlov@...ux.ibm.com>
Subject: [PATCH 02/12] 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 <akrowiak@...ux.ibm.com>
Suggested-by: Halil Pasic <pasic@...ux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@...ux.ibm.com>
Acked-by: Halil Pasic <pasic@...ux.ibm.com>
Acked-by: Janosch Frank <frankja@...ux.ibm.com>
Tested-by: Viktor Mihajlovski <mihajlov@...ux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 3fd80533194b..be92ba45226d 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/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;
 }
 
-- 
2.39.3