[PATCH v10 04/15] s390/vfio-ap: Reset migration state in VFIO_DEVICE_RESET ioctl handler

[Anthony Krowiak <akrowiak@linux.ibm.com>]

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 any open migration file buffers and resets the
migration state to RUNNING.

Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_migration.c | 20 ++++++++++++++++++++
 drivers/s390/crypto/vfio_ap_ops.c       | 11 +++++++++++
 drivers/s390/crypto/vfio_ap_private.h   |  1 +
 3 files changed, 32 insertions(+)

diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index ba86a1afbb33..5d898be0d058 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -216,3 +216,23 @@ void vfio_ap_release_migration_data(struct ap_matrix_mdev *matrix_mdev)
 	kfree(matrix_mdev->mig_data);
 	matrix_mdev->mig_data = NULL;
 }
+
+/**
+ * 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 9cbc5ecb19d5..635c8a20af86 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -2320,6 +2320,17 @@ static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
 		break;
 	case VFIO_DEVICE_RESET:
 		ret = vfio_ap_mdev_reset_queues(matrix_mdev);
+		/*
+		 * Reset the migration state unconditionally, regardless of
+		 * whether the hardware queue reset succeeded. The migration
+		 * state tracks the AP configuration transfer lifecycle and is
+		 * independent of the hardware queue reset outcome. The VFIO
+		 * migration spec designates VFIO_DEVICE_RESET as the mechanism
+		 * to return device_state to RUNNING (e.g. to recover from
+		 * ERROR), so the migration state must be cleaned up even when
+		 * one or more queues fail to reset.
+		 */
+		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 aa8a22585204..c6e577064e7e 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -174,5 +174,6 @@ void vfio_ap_on_scan_complete(struct ap_config_info *new_config_info,
 
 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