Enum devices::virtio::Queue

pub enum Queue {
    SplitVirtQueue(SplitQueue),
    PackedVirtQueue(PackedQueue),
}

Virtqueue interface representing different types of virtqueues The struct of each queue type is wrapped in the enum variants

Variants

SplitVirtQueue(SplitQueue)

Split virtqueue type in virtio v1.2 spec: https://docs.oasis-open.org/virtio/virtio/v1.2/csd01/virtio-v1.2-csd01.html#x1-350007

PackedVirtQueue(PackedQueue)

Packed virtqueue type in virtio v1.2 spec: https://docs.oasis-open.org/virtio/virtio/v1.2/csd01/virtio-v1.2-csd01.html#x1-720008

Implementations

impl Queue

pub const MAX_SIZE: u16 = 32_768u16

Largest valid number of entries in a virtqueue.

pub async fn next_async( &mut self, eventfd: &mut EventAsync ) -> Result<DescriptorChain, AsyncError>

Asynchronously read the next descriptor chain from the queue. Returns a DescriptorChain when it is awaited.

pub fn peek(&mut self) -> Option<PeekedDescriptorChain<'_>>

Get the first available descriptor chain without removing it from the queue. Call pop() on the returned PeekedDescriptorChain to remove it from the queue.

pub fn pop(&mut self) -> Option<DescriptorChain>

If a new DescriptorChain is available, returns one and removes it from the queue.

pub async fn next_async_interruptable( &mut self, queue_event: &mut EventAsync, stop_rx: &mut Receiver<()> ) -> Result<Option<DescriptorChain>, AsyncError>

Returns None if stop_rx receives a value; otherwise returns the result of waiting for the next descriptor.

pub fn trigger_interrupt(&mut self) -> bool

inject interrupt into guest on this queue return true: interrupt is injected into guest for this queue false: interrupt isn’t injected

pub fn restore( queue_config: &QueueConfig, queue_value: Value, mem: &GuestMemory, event: Event, interrupt: Interrupt ) -> Result<Queue>

Restore queue from snapshot

pub fn vhost_user_reclaim(&mut self, vring_base: u16)

“Reclaim” a queue that was given to a vhost-user backend and is now being taken back using VHOST_USER_GET_VRING_BASE.

The Queue will have stale fields if the vhost-user backend fulfilled any virtqueue requests. This function updates the Queue to pick up where the backend left off.

pub fn next_avail_to_process(&self) -> u16

Getter for the next index of the available ring that device will process.

Not to be confused with the available ring’s index field, which is the next index for the driver to fill.

pub fn vector(&self) -> u16

Getter for vector field

pub fn desc_table(&self) -> GuestAddress

Getter for descriptor area

pub fn avail_ring(&self) -> GuestAddress

Getter for driver area

pub fn used_ring(&self) -> GuestAddress

Getter for device area

pub fn size(&self) -> u16

Return the actual size of the queue, as the driver may not set up a queue as big as the device allows.

pub fn event(&self) -> &Event

Get a reference to the queue’s event.

pub fn interrupt(&self) -> &Interrupt

Get a reference to the queue’s interrupt.

pub fn add_used(&mut self, desc_chain: DescriptorChain, len: u32)

Puts an available descriptor head into the used ring for use by the guest.

pub fn snapshot(&self) -> Result<Value>

Take snapshot of queue’s current status

Trait Implementations

impl Debug for Queue

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.