Trait vhost_user_backend::VhostUserBackend

pub trait VhostUserBackend: Send + Sync {
    type Bitmap: Bitmap + 'static;
    type Vring: VringT<GuestMemoryAtomic<GuestMemoryMmap<Self::Bitmap>>>;

    // Required methods
    fn num_queues(&self) -> usize;
    fn max_queue_size(&self) -> usize;
    fn features(&self) -> u64;
    fn protocol_features(&self) -> VhostUserProtocolFeatures;
    fn set_event_idx(&self, enabled: bool);
    fn update_memory(
        &self,
        mem: GuestMemoryAtomic<GuestMemoryMmap<Self::Bitmap>>
    ) -> Result<()>;
    fn handle_event(
        &self,
        device_event: u16,
        evset: EventSet,
        vrings: &[Self::Vring],
        thread_id: usize
    ) -> Result<()>;

    // Provided methods
    fn acked_features(&self, _features: u64) { ... }
    fn get_config(&self, _offset: u32, _size: u32) -> Vec<u8> { ... }
    fn set_config(&self, _offset: u32, _buf: &[u8]) -> Result<()> { ... }
    fn set_backend_req_fd(&self, _backend: Backend) { ... }
    fn queues_per_thread(&self) -> Vec<u64> { ... }
    fn exit_event(&self, _thread_index: usize) -> Option<EventFd> { ... }
}

Trait with interior mutability for vhost user backend servers to implement concrete services.

To support multi-threading and asynchronous IO, we enforce Send + Sync bound.

Required Associated Types

type Bitmap: Bitmap + 'static

type Vring: VringT<GuestMemoryAtomic<GuestMemoryMmap<Self::Bitmap>>>

Required Methods

fn num_queues(&self) -> usize

Get number of queues supported.

fn max_queue_size(&self) -> usize

Get maximum queue size supported.

fn features(&self) -> u64

Get available virtio features.

fn protocol_features(&self) -> VhostUserProtocolFeatures

Get available vhost protocol features.

fn set_event_idx(&self, enabled: bool)

Enable or disable the virtio EVENT_IDX feature

fn update_memory( &self, mem: GuestMemoryAtomic<GuestMemoryMmap<Self::Bitmap>> ) -> Result<()>

Update guest memory regions.

fn handle_event( &self, device_event: u16, evset: EventSet, vrings: &[Self::Vring], thread_id: usize ) -> Result<()>

Handle IO events for backend registered file descriptors.

This function gets called if the backend registered some additional listeners onto specific file descriptors. The library can handle virtqueues on its own, but does not know what to do with events happening on custom listeners.

Provided Methods

fn acked_features(&self, _features: u64)

Set acknowledged virtio features.

fn get_config(&self, _offset: u32, _size: u32) -> Vec<u8>

Get virtio device configuration.

A default implementation is provided as we cannot expect all backends to implement this function.

fn set_config(&self, _offset: u32, _buf: &[u8]) -> Result<()>

Set virtio device configuration.

A default implementation is provided as we cannot expect all backends to implement this function.

fn set_backend_req_fd(&self, _backend: Backend)

Set handler for communicating with the frontend by the backend communication channel.

A default implementation is provided as we cannot expect all backends to implement this function.

fn queues_per_thread(&self) -> Vec<u64>

Get the map to map queue index to worker thread index.

A return value of [2, 2, 4] means: the first two queues will be handled by worker thread 0, the following two queues will be handled by worker thread 1, and the last four queues will be handled by worker thread 2.

fn exit_event(&self, _thread_index: usize) -> Option<EventFd>

Provide an optional exit EventFd for the specified worker thread.

The returned EventFd will be monitored for IO events. When the returned EventFd is written to, the worker thread will exit.

Object Safety

This trait is not object safe.

Implementations on Foreign Types

impl<T: VhostUserBackend> VhostUserBackend for Arc<T>

type Bitmap = <T as VhostUserBackend>::Bitmap

type Vring = <T as VhostUserBackend>::Vring

fn num_queues(&self) -> usize

fn max_queue_size(&self) -> usize

fn features(&self) -> u64

fn acked_features(&self, features: u64)

fn protocol_features(&self) -> VhostUserProtocolFeatures

fn set_event_idx(&self, enabled: bool)

fn get_config(&self, offset: u32, size: u32) -> Vec<u8>

fn set_config(&self, offset: u32, buf: &[u8]) -> Result<()>

fn update_memory( &self, mem: GuestMemoryAtomic<GuestMemoryMmap<Self::Bitmap>> ) -> Result<()>

fn set_backend_req_fd(&self, backend: Backend)

fn queues_per_thread(&self) -> Vec<u64>

fn exit_event(&self, thread_index: usize) -> Option<EventFd>

fn handle_event( &self, device_event: u16, evset: EventSet, vrings: &[Self::Vring], thread_id: usize ) -> Result<()>

impl<T: VhostUserBackendMut> VhostUserBackend for Mutex<T>

type Bitmap = <T as VhostUserBackendMut>::Bitmap

type Vring = <T as VhostUserBackendMut>::Vring

fn num_queues(&self) -> usize

fn max_queue_size(&self) -> usize

fn features(&self) -> u64

fn acked_features(&self, features: u64)

fn protocol_features(&self) -> VhostUserProtocolFeatures

fn set_event_idx(&self, enabled: bool)

fn get_config(&self, offset: u32, size: u32) -> Vec<u8>

fn set_config(&self, offset: u32, buf: &[u8]) -> Result<()>

fn update_memory( &self, mem: GuestMemoryAtomic<GuestMemoryMmap<Self::Bitmap>> ) -> Result<()>

fn set_backend_req_fd(&self, backend: Backend)

fn queues_per_thread(&self) -> Vec<u64>

fn exit_event(&self, thread_index: usize) -> Option<EventFd>

fn handle_event( &self, device_event: u16, evset: EventSet, vrings: &[Self::Vring], thread_id: usize ) -> Result<()>

impl<T: VhostUserBackendMut> VhostUserBackend for RwLock<T>

type Bitmap = <T as VhostUserBackendMut>::Bitmap

type Vring = <T as VhostUserBackendMut>::Vring

fn num_queues(&self) -> usize

fn max_queue_size(&self) -> usize

fn features(&self) -> u64

fn acked_features(&self, features: u64)

fn protocol_features(&self) -> VhostUserProtocolFeatures

fn set_event_idx(&self, enabled: bool)

fn get_config(&self, offset: u32, size: u32) -> Vec<u8>

fn set_config(&self, offset: u32, buf: &[u8]) -> Result<()>

fn update_memory( &self, mem: GuestMemoryAtomic<GuestMemoryMmap<Self::Bitmap>> ) -> Result<()>

fn set_backend_req_fd(&self, backend: Backend)

fn queues_per_thread(&self) -> Vec<u64>

fn exit_event(&self, thread_index: usize) -> Option<EventFd>

fn handle_event( &self, device_event: u16, evset: EventSet, vrings: &[Self::Vring], thread_id: usize ) -> Result<()>

Implementors