linux-kernel - [RFC PATCH v2] s390/vfio-ap: Notify userspace that guest's AP config changed when mdev removed

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250304200812.54556-1-rreyes@linux.ibm.com>
Date: Tue,  4 Mar 2025 15:08:12 -0500
From: Rorie Reyes <rreyes@...ux.ibm.com>
To: linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc: hca@...ux.ibm.com, borntraeger@...ibm.com, agordeev@...ux.ibm.com,
        gor@...ux.ibm.com, pasic@...ux.ibm.com, jjherne@...ux.ibm.com,
        alex.williamson@...hat.com, akrowiak@...ux.ibm.com,
        rreyes@...ux.ibm.com
Subject: [RFC PATCH v2] 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@...ux.ibm.com>
---
This patch is based on the s390/features branch

V1 -> V2:
- replaced get_update_locks_for_kvm() with get_update_locks_for_mdev
- removed else statements that were unnecessary
- Addressed review comments for commit messages/details
---
 drivers/s390/crypto/vfio_ap_ops.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 571f5dcb49c5..ae2bc5c1d445 100644
--- 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 +2074,9 @@ 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)
-- 
2.48.1