From: Avihai Horon <avih...@nvidia.com> When migrating a VFIO device that supports pre-copy, it is transitioned to STOP_COPY twice: once in vfio_vmstate_change() and second time in vfio_save_complete_precopy().
The second transition is harmless, as it's a STOP_COPY->STOP_COPY no-op transition. However, with the newly added VFIO migration QAPI event, the STOP_COPY event is undesirably emitted twice. Prevent this by returning early in vfio_migration_set_state() if new_state is the same as current device state. Note that the STOP_COPY transition in vfio_save_complete_precopy() is essential for VFIO devices that don't support pre-copy, for migrating an already stopped guest and for snapshots. Signed-off-by: Avihai Horon <avih...@nvidia.com> Reviewed-by: Cédric Le Goater <c...@redhat.com> Signed-off-by: Cédric Le Goater <c...@redhat.com> --- hw/vfio/migration.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index af579b868d7caa726fde1eeb73c832ebc3136a7a..56edffaf6251e28e39ef32991394697abb1b9e55 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -150,6 +150,10 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, g_strdup_printf("%s: Failed setting device state to %s.", vbasedev->name, mig_state_to_str(new_state)); + if (new_state == migration->device_state) { + return 0; + } + feature->argsz = sizeof(buf); feature->flags = VFIO_DEVICE_FEATURE_SET | VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE; -- 2.45.1