Struct devices::Bus

pub struct Bus {
    devices: Arc<Mutex<BTreeMap<BusRange, BusEntry>>>,
    access_id: usize,
    bus_type: BusType,
}

A device container for routing reads and writes over some address space.

This doesn’t have any restrictions on what kind of device or address space this applies to. The only restriction is that no two devices can overlap in this address space.

Fields

devices: Arc<Mutex<BTreeMap<BusRange, BusEntry>>>

access_id: usize

bus_type: BusType

Implementations

impl Bus

pub fn new(bus_type: BusType) -> Bus

Constructs an a bus with an empty address space.

pub fn get_bus_type(&self) -> BusType

Gets the bus type

pub fn set_access_id(&mut self, id: usize)

Sets the id that will be used for BusAccessInfo.

fn first_before(&self, addr: u64) -> Option<(BusRange, BusEntry)>

fn get_device(&self, addr: u64) -> Option<(u64, u64, BusEntry)>

fn unique_devices(&self) -> Vec<BusDeviceEntry>

There is no unique ID for device instances. For now we use the Arc pointers to dedup them.

See virtio-gpu for an example of a single device instance with multiple bus entries.

TODO: Add a unique ID to BusDevice and use that instead of pointers.

fn unique_devices_with_snapshot_key(&self) -> Vec<(String, BusDeviceEntry)>

Same as unique_devices, but also calculates the “snapshot key” for each device.

The keys are used to associate a particular device with data in a serialized snapshot. The keys need to be stable across multiple runs of the same crosvm binary.

It is most convienent to calculate all the snapshot keys at once, because the keys are dependant on the order of devices on the bus.

pub fn sleep_devices(&self) -> Result<()>

pub fn wake_devices(&self) -> Result<()>

pub fn snapshot_devices(&self, snapshot_writer: &SnapshotWriter) -> Result<()>

pub fn restore_devices(&self, snapshot_reader: &SnapshotReader) -> Result<()>

pub fn insert( &self, device: Arc<Mutex<dyn BusDevice>>, base: u64, len: u64 ) -> Result<(), Error>

Puts the given device at the given address space.

pub fn insert_sync( &self, device: Arc<dyn BusDeviceSync>, base: u64, len: u64 ) -> Result<(), Error>

Puts the given device that implements BusDeviceSync at the given address space. Devices that implement BusDeviceSync manage thread safety internally, and thus can be written to by multiple threads simultaneously.

pub fn remove(&self, base: u64, len: u64) -> Result<(), Error>

Remove the given device at the given address space.

pub fn read(&self, addr: u64, data: &mut [u8]) -> bool

Reads data from the device that owns the range containing addr and puts it into data.

Returns true on success, otherwise data is filled with zeroes.

pub fn write(&self, addr: u64, data: &[u8]) -> bool

Writes data to the device that owns the range containing addr.

Returns true on success, otherwise data is untouched.

Trait Implementations

impl Clone for Bus

fn clone(&self) -> Bus

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for Bus

fn default() -> Self

Returns the “default value” for a type.