fn process_vm_request<V: VmArch + 'static, Vcpu: VcpuArch + 'static>(
state: &mut ControlLoopState<'_, V, Vcpu>,
id: usize,
tube: &Tube,
request: VmRequest,
add_tubes: &mut Vec<TaggedControlTube>
) -> Result<(Option<VmResponse>, bool, Option<VmRunMode>)>