viommu_send_req_sync
ret = viommu_send_req_sync(viommu, req, sizeof(*req));
ret = viommu_send_req_sync(vdomain->viommu, &map, sizeof(map));
ret = viommu_send_req_sync(viommu, probe, probe_len);
WARN_ON(viommu_send_req_sync(vdev->viommu, &req, sizeof(req)));