def METHOD_NAME(
    id, serial, mdts, downstream_bus, upstream_bus, controller_slot, subsystem=None
):
    args = {
        "id": id,
        "serial": serial,
        "bus": downstream_bus,
        "mdts": mdts,
        "ioeventfd": "on",
    }
    if subsystem:
        args["subsys"] = subsystem
    return [
        "-device",
        f"xio3130-downstream,id={downstream_bus},bus={upstream_bus},chassis=2,slot={controller_slot}",
        "-device",
        ",".join(["nvme"] + [f"{k}={v}" for k, v in args.items()]),
    ]