[PATCH v2 10/16] s390/vfio-ap: Transition device migration state from RESUMING to STOP

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

Leaving the RESUMING state terminates a data transfer of the internal
state of the vfio-ap device on the source host to the vfio-ap device on the
target host. This state transition indicates the vfio_ap driver should
complete the incorporation of data written to the data transfer FD into the
into the vfio-ap device. Since a vfio-ap device does not virtualize a
physical device, there is no internal device state to
incorporate; so, the only thing left to do is release the migration files
used to help facilitate the migration process.

Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_migration.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index ce16028e50a4..ebb3b78b1e19 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -915,10 +915,20 @@ vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev,
 		return migf->filp;
 	}
 
+	/*
+	 * Terminates the data transfer session of the vfio-ap device state
+	 * between the source and target hosts. Since the vfio-ap device does
+	 * not virtualize a DMA device, there is no internal device state to
+	 * incorporate into the vfio-ap device on the target; so, the only
+	 * thing left to do is release the migration files used to process
+	 * the vfio device migration. Note that this state transition is for
+	 * the vfio-ap device on the target host.
+	 */
 	if (cur_state == VFIO_DEVICE_STATE_RESUMING &&
 	    new_state == VFIO_DEVICE_STATE_STOP) {
-		/* TODO */
-		return ERR_PTR(-EOPNOTSUPP);
+		vfio_ap_release_mig_files(matrix_mdev);
+
+		return NULL;
 	}
 
 	if (cur_state == VFIO_DEVICE_STATE_STOP_COPY &&
-- 
2.52.0