s390/vfio-ap: Notify userspace that guest's AP config changed when mdev removed

The guest's AP configuration is cleared when the mdev is removed, so
userspace must be notified that the AP configuration has changed. To this
end, this patch:

* Removes call to 'signal_guest_ap_cfg_changed()' function from the
  'vfio_ap_mdev_unset_kvm()' function because it has no affect given it is
  called after the mdev fd is closed.

* Adds call to 'signal_guest_ap_cfg_changed()' function to the
  'vfio_ap_mdev_request()' function to notify userspace that the guest's
  AP configuration has changed before signaling the request to remove the
  mdev.

Minor change - Fixed an indentation issue in function
'signal_guest_ap_cfg_changed()'

Fixes: 07d89045bffe ("s390/vfio-ap: Signal eventfd when guest AP configuration is changed")
Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Link: https://lore.kernel.org/r/20250304200812.54556-1-rreyes@linux.ibm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 571f5dcb49c5174bfdd24ebba84c61923449b582..bc8669b5c3041a29a41a54f3a2ace0308ebf6c4f 100644 (file)
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -652,8 +652,8 @@ static void vfio_ap_matrix_init(struct ap_config_info *info,
 
 static void signal_guest_ap_cfg_changed(struct ap_matrix_mdev *matrix_mdev)
 {
-               if (matrix_mdev->cfg_chg_trigger)
-                       eventfd_signal(matrix_mdev->cfg_chg_trigger);
+       if (matrix_mdev->cfg_chg_trigger)
+               eventfd_signal(matrix_mdev->cfg_chg_trigger);
 }
 
 static void vfio_ap_mdev_update_guest_apcb(struct ap_matrix_mdev *matrix_mdev)
@@ -1870,7 +1870,6 @@ 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);
-               signal_guest_ap_cfg_changed(matrix_mdev);
                vfio_ap_mdev_reset_queues(matrix_mdev);
                kvm_put_kvm(kvm);
                matrix_mdev->kvm = NULL;
@@ -2057,6 +2056,13 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
 
        matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
 
+       get_update_locks_for_mdev(matrix_mdev);
+
+       if (matrix_mdev->kvm) {
+               kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
+               signal_guest_ap_cfg_changed(matrix_mdev);
+       }
+
        if (matrix_mdev->req_trigger) {
                if (!(count % 10))
                        dev_notice_ratelimited(dev,
@@ -2068,6 +2074,8 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
                dev_notice(dev,
                           "No device request registered, blocked until released by user\n");
        }
+
+       release_update_locks_for_mdev(matrix_mdev);
 }
 
 static int vfio_ap_mdev_get_device_info(unsigned long arg)