Struct devices::virtio::queue::QueueConfig

pub struct QueueConfig {
    activated: bool,
    max_size: u16,
    size: u16,
    ready: bool,
    vector: u16,
    features: u64,
    acked_features: u64,
    desc_table: GuestAddress,
    avail_ring: GuestAddress,
    used_ring: GuestAddress,
    next_avail: Wrapping<u16>,
    next_used: Wrapping<u16>,
}

A virtio queue’s parameters.

QueueConfig can be converted into a running Queue by calling QueueConfig::activate().

Fields

activated: bool

Whether this queue has already been activated.

max_size: u16

The maximal size in elements offered by the device

size: u16

The queue size in elements the driver selected. This is always guaranteed to be a power of two less than or equal to max_size, as required for split virtqueues. These invariants are enforced by set_size().

ready: bool

Indicates if the queue is finished with configuration

vector: u16

MSI-X vector for the queue. Don’t care for INTx

features: u64

Ring features (e.g. VIRTIO_RING_F_EVENT_IDX, VIRTIO_F_RING_PACKED) offered by the device

acked_features: u64

desc_table: GuestAddress

Guest physical address of the descriptor table

avail_ring: GuestAddress

Guest physical address of the available ring (driver area)

TODO(b/290657008): update field and accessor names to match the current virtio spec

used_ring: GuestAddress

Guest physical address of the used ring (device area)

next_avail: Wrapping<u16>

Initial available ring index when the queue is activated.

next_used: Wrapping<u16>

Initial used ring index when the queue is activated.

Implementations

impl QueueConfig

pub fn new(max_size: u16, features: u64) -> Self

Constructs a virtio queue configuration with the given max_size.

pub fn max_size(&self) -> u16

Returns the maximum size of this queue.

pub fn size(&self) -> u16

Returns the currently configured size of the queue.

pub fn set_size(&mut self, val: u16)

Sets the queue size.

pub fn vector(&self) -> u16

Returns the currently configured interrupt vector.

pub fn set_vector(&mut self, val: u16)

Sets the interrupt vector for this queue.

pub fn desc_table(&self) -> GuestAddress

Getter for descriptor area

pub fn set_desc_table(&mut self, val: GuestAddress)

Setter for descriptor area

pub fn avail_ring(&self) -> GuestAddress

Getter for driver area

pub fn set_avail_ring(&mut self, val: GuestAddress)

Setter for driver area

pub fn used_ring(&self) -> GuestAddress

Getter for device area

pub fn set_used_ring(&mut self, val: GuestAddress)

Setter for device area

pub fn next_avail(&self) -> Wrapping<u16>

Getter for next_avail index

pub fn set_next_avail(&mut self, val: Wrapping<u16>)

Setter for next_avail index

pub fn next_used(&self) -> Wrapping<u16>

Getter for next_used index

pub fn set_next_used(&mut self, val: Wrapping<u16>)

Setter for next_used index

pub fn acked_features(&self) -> u64

Returns the features that have been acknowledged by the driver.

pub fn ack_features(&mut self, features: u64)

Acknowledges that this set of features should be enabled on this queue.

pub fn ready(&self) -> bool

Return whether the driver has enabled this queue.

pub fn set_ready(&mut self, enable: bool)

Signal that the driver has completed queue configuration.

pub fn activate(&mut self, mem: &GuestMemory, event: Event) -> Result<Queue>

Convert the queue configuration into an active queue.

pub fn reset(&mut self)

Reset queue to a clean state

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

Take snapshot of queue configuration

pub fn restore(&mut self, data: Value) -> Result<()>

Restore queue configuration from snapshot