[PATCH v5 04/15] s390/vfio-ap: Reset migration state in VFIO_DEVICE_RESET ioctl handler

[Anthony Krowiak]

According to the VFIO migration specifications, userspace must issue a
VFIO_DEVICE_RESET ioctl if a vfio device enters an error state or fails a
state transition to recover the device and return its migration state to
RUNNING. This patch adds a function that is called when a VFIO_DEVICE_RESET
is issued that releases the migration files and frees the storage allocated
for maintaining the migration state.

Signed-off-by: Anthony Krowiak <akrowiak@xxxxxxxxxxxxx>
---
 drivers/s390/crypto/vfio_ap_migration.c | 54 +++++++++++++++++++++++++
 drivers/s390/crypto/vfio_ap_ops.c       |  4 ++
 drivers/s390/crypto/vfio_ap_private.h   |  1 +
 3 files changed, 59 insertions(+)

diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index 9187cfe26da7..45557f433652 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -150,3 +150,57 @@ void vfio_ap_release_migration_data(struct ap_matrix_mdev *matrix_mdev)
 	kfree(matrix_mdev->mig_data);
 	matrix_mdev->mig_data = NULL;
 }
+
+static void vfio_ap_release_mig_files(struct ap_matrix_mdev *matrix_mdev)
+{
+	struct vfio_ap_migration_data *mig_data;
+
+	/*
+	 * The fput call does not call .release synchronously while the
+	 * mdevs_lock mutex is held, so there is no problem with incurring a
+	 * deadlock situation if fput is executed in this function.
+	 */
+	lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+	mig_data = matrix_mdev->mig_data;
+	if (!mig_data)
+		return;
+
+	if (mig_data->stop_copy_mig_file.filp) {
+		fput(mig_data->stop_copy_mig_file.filp);
+		mig_data->stop_copy_mig_file.filp = NULL;
+	}
+
+	kfree(mig_data->stop_copy_mig_file.ap_config);
+	mig_data->stop_copy_mig_file.ap_config = NULL;
+	mig_data->stop_copy_mig_file.config_sz = 0;
+
+	if (mig_data->resuming_mig_file.filp) {
+		fput(mig_data->resuming_mig_file.filp);
+		mig_data->resuming_mig_file.filp = NULL;
+	}
+
+	kfree(mig_data->resuming_mig_file.ap_config);
+	mig_data->resuming_mig_file.ap_config = NULL;
+	mig_data->resuming_mig_file.config_sz = 0;
+}
+
+/**
+ * vfio_ap_reset_migration_state - Reset the vfio-ap migration state
+ *
+ * @matrix_mdev: pointer to the object maintaining the vfio-ap device state
+ *
+ * Called during VFIO_DEVICE_RESET to clean up any active migration
+ * state and reset the device to RUNNING state as required by the VFIO
+ * migration specification.
+ */
+void vfio_ap_reset_migration_state(struct ap_matrix_mdev *matrix_mdev)
+{
+	lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+	if (!matrix_mdev->mig_data)
+		return;
+
+	vfio_ap_release_mig_files(matrix_mdev);
+	matrix_mdev->mig_data->mig_state = VFIO_DEVICE_STATE_RUNNING;
+}
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 47aca908701d..678bdd4c82e9 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -2332,6 +2332,10 @@ static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
 		break;
 	case VFIO_DEVICE_RESET:
 		ret = vfio_ap_mdev_reset_queues(matrix_mdev);
+		if (ret == 0) {
+			/* Reset migration state per VFIO migration spec */
+			vfio_ap_reset_migration_state(matrix_mdev);
+		}
 		break;
 	case VFIO_DEVICE_GET_IRQ_INFO:
 		ret = vfio_ap_get_irq_info(arg);
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index a2a713f93674..1fbdfcce5a11 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -175,5 +175,6 @@ void vfio_ap_on_scan_complete(struct ap_config_info *new_config_info,
 void vfio_ap_init_migration_capabilities(struct ap_matrix_mdev *matrix_mdev);
 int vfio_ap_init_migration_data(struct ap_matrix_mdev *matrix_mdev);
 void vfio_ap_release_migration_data(struct ap_matrix_mdev *matrix_mdev);
+void vfio_ap_reset_migration_state(struct ap_matrix_mdev *matrix_mdev);
 
 #endif /* _VFIO_AP_PRIVATE_H_ */
-- 
2.53.0