linux-kernel - [PATCH 3/3] s390/vfio-ap: Wire in the vfio_device

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Date:   Tue, 30 May 2023 18:35:38 -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, pasic@...ux.ibm.com, farman@...ux.ibm.com,
        mjrosato@...ux.ibm.com, alex.williamson@...hat.com,
        borntraeger@...ux.ibm.com
Subject: [PATCH 3/3] s390/vfio-ap: Wire in the vfio_device_ops request callback

The mdev device is being removed, so pass the request to userspace to
ask for a graceful cleanup. This should free up the thread that
would otherwise loop waiting for the device to be fully released.

Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 44f159136891..a8f58e133e6e 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1736,6 +1736,26 @@ static void vfio_ap_mdev_close_device(struct vfio_device *vdev)
 	vfio_ap_mdev_unset_kvm(matrix_mdev);
 }
 
+static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
+{
+	struct device *dev = vdev->dev;
+	struct ap_matrix_mdev *matrix_mdev;
+
+	matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
+
+	if (matrix_mdev->req_trigger) {
+		if (!(count % 10))
+			dev_notice_ratelimited(dev,
+					       "Relaying device request to user (#%u)\n",
+					       count);
+
+		eventfd_signal(matrix_mdev->req_trigger, 1);
+	} else if (count == 0) {
+		dev_notice(dev,
+			   "No device request registered, blocked until released by user\n");
+	}
+}
+
 static int vfio_ap_mdev_get_device_info(unsigned long arg)
 {
 	unsigned long minsz;
@@ -1955,6 +1975,7 @@ static const struct vfio_device_ops vfio_ap_matrix_dev_ops = {
 	.bind_iommufd = vfio_iommufd_emulated_bind,
 	.unbind_iommufd = vfio_iommufd_emulated_unbind,
 	.attach_ioas = vfio_iommufd_emulated_attach_ioas,
+	.request = vfio_ap_mdev_request
 };
 
 static struct mdev_driver vfio_ap_matrix_driver = {
-- 
2.31.1