From: Tony Krowiak <akrowiak@linux.ibm.com>
Date: Tue, 1 Feb 2022 10:52:29 -0500
Subject: s390/vfio-ap: hot plug/unplug of AP devices when probed/removed
Git-commit: 09d31ff78793ff007ec3b0a26000fcf29ad4928b
Patch-mainline: v6.0-rc1
References: bsc#1205701

When an AP queue device is probed or removed, if the mediated device is
attached to a KVM guest, the mediated device's adapter, domain and
control domain bitmaps must be filtered to update the guest's APCB and if
any changes are detected, the guest's APCB must then be hot plugged into
the guest to reflect those changes to the guest.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/s390/crypto/vfio_ap_ops.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 561e68f69955..8346ad4f1942 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1787,9 +1787,11 @@ int vfio_ap_mdev_probe_queue(struct ap_device *apdev)
 
 	if (matrix_mdev) {
 		vfio_ap_mdev_link_queue(matrix_mdev, q);
-		vfio_ap_mdev_filter_matrix(matrix_mdev->matrix.apm,
-					   matrix_mdev->matrix.aqm,
-					   matrix_mdev);
+
+		if (vfio_ap_mdev_filter_matrix(matrix_mdev->matrix.apm,
+					       matrix_mdev->matrix.aqm,
+					       matrix_mdev))
+			vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 	}
 	dev_set_drvdata(&apdev->device, q);
 	release_update_locks_for_mdev(matrix_mdev);
@@ -1799,7 +1801,7 @@ int vfio_ap_mdev_probe_queue(struct ap_device *apdev)
 
 void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
 {
-	unsigned long apid;
+	unsigned long apid, apqi;
 	struct vfio_ap_queue *q;
 	struct ap_matrix_mdev *matrix_mdev;
 
@@ -1812,8 +1814,17 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
 		vfio_ap_unlink_queue_fr_mdev(q);
 
 		apid = AP_QID_CARD(q->apqn);
-		if (test_bit_inv(apid, q->matrix_mdev->shadow_apcb.apm))
-			clear_bit_inv(apid, q->matrix_mdev->shadow_apcb.apm);
+		apqi = AP_QID_QUEUE(q->apqn);
+
+		/*
+		 * If the queue is assigned to the guest's APCB, then remove
+		 * the adapter's APID from the APCB and hot it into the guest.
+		 */
+		if (test_bit_inv(apid, matrix_mdev->shadow_apcb.apm) &&
+		    test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm)) {
+			clear_bit_inv(apid, matrix_mdev->shadow_apcb.apm);
+			vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+		}
 	}
 
 	vfio_ap_mdev_reset_queue(q, 1);