Method add_serial_device

vmm/src/device_manager.rs:2223–2271

(
        &mut self,
        interrupt_manager: &dyn InterruptManager<GroupConfig = LegacyIrqGroupConfig>,
        serial_writer: Option<Box<dyn io::Write + Send>>,
    )

    #[cfg(target_arch = "x86_64")]
    fn add_serial_device(
        &mut self,
        interrupt_manager: &dyn InterruptManager<GroupConfig = LegacyIrqGroupConfig>,
        serial_writer: Option<Box<dyn io::Write + Send>>,
    ) -> DeviceManagerResult<Arc<Mutex<Serial>>> {
        // Serial is tied to IRQ #4
        let serial_irq = 4;

        let id = String::from(SERIAL_DEVICE_NAME);

        let interrupt_group = interrupt_manager
            .create_group(LegacyIrqGroupConfig {
                irq: serial_irq as InterruptIndex,
            })
            .map_err(DeviceManagerError::CreateInterruptGroup)?;

        let serial = Arc::new(Mutex::new(Serial::new(
            id.clone(),
            interrupt_group,
            serial_writer,
            state_from_id(self.snapshot.as_ref(), id.as_str())
                .map_err(DeviceManagerError::RestoreGetState)?,
        )));

        self.bus_devices
            .push(Arc::clone(&serial) as Arc<dyn BusDeviceSync>);

        self.address_manager
            .allocator
            .lock()
            .unwrap()
            .allocate_io_addresses(Some(GuestAddress(0x3f8)), 0x8, None)
            .ok_or(DeviceManagerError::AllocateIoPort)?;

        self.address_manager
            .io_bus
            .insert(serial.clone(), 0x3f8, 0x8)
            .map_err(DeviceManagerError::BusError)?;

        // Fill the device tree with a new node. In case of restore, we
        // know there is nothing to do, so we can simply override the
        // existing entry.
        self.device_tree
            .lock()
            .unwrap()
            .insert(id.clone(), device_node!(id, serial));

        Ok(serial)
    }

    #[cfg(target_arch = "aarch64")]
    fn add_serial_device(