linux-kernel - [RFC PATCH v3 2/2] s390/vfio-ap: Adding mdev remove notification

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Message-ID: <20250226180605.15810-3-rreyes@linux.ibm.com>
Date: Wed, 26 Feb 2025 13:06:05 -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 v3 2/2] s390/vfio-ap: Adding mdev remove notification

This patch is based on the s390/features branch.

The first patch, b26ed71f9647, was missing a
notification based on the process to remove a
mediated device from the AP configuration. In
the original patch, b26ed71f9647, the guest is
notified immediately for any AP configuration
changes that are queued during the following
processes:
- assign/unassign_adapter
- assign/unassign_domain
- bind/unbind

However, the original patch, b26ed71f9647, was
missing a notification for the process to remove
the entire mediated device.

This patch addresses the missing notification and
successfully notifies the guest when a mediated device
is removed.

Notes:
- Removed eventfd from vfio_ap_mdev_unset_kvm
- Update and release locks along with the eventfd added
to vfio_ap_mdev_request

Signed-off-by: Rorie Reyes <rreyes@...ux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 9a6845064ff3..e0237ea27d7e 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -2056,6 +2056,14 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
 
 	matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
 
+	if (matrix_mdev->kvm) {
+		get_update_locks_for_kvm(matrix_mdev->kvm);
+		kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
+		signal_guest_ap_cfg_changed(matrix_mdev);
+	} else {
+		mutex_lock(&matrix_dev->mdevs_lock);
+	}
+
 	if (matrix_mdev->req_trigger) {
 		if (!(count % 10))
 			dev_notice_ratelimited(dev,
@@ -2067,6 +2075,12 @@ 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");
 	}
+
+	if (matrix_mdev->kvm)
+		release_update_locks_for_kvm(matrix_mdev->kvm);
+	else
+		mutex_unlock(&matrix_dev->mdevs_lock);
+
 }
 
 static int vfio_ap_mdev_get_device_info(unsigned long arg)
-- 
2.48.1