feat(virtio-net): increase max queue size to 512

Increase of the queue size helps with keeping both
vmm thread and guest busy at hight network load and
improves performance.

Signed-off-by: Egor Lazarchuk <[email protected]>

Author: ShadowCurse

src/vmm/src/devices/virtio/net/device.rs

@@ -14,6 +14,7 @@ use libc::{iovec, EAGAIN};
 use log::error;
 use vmm_sys_util::eventfd::EventFd;
 
+use super::NET_QUEUE_MAX_SIZE;
 use crate::devices::virtio::device::{DeviceState, IrqTrigger, IrqType, VirtioDevice};
 use crate::devices::virtio::gen::virtio_blk::VIRTIO_F_VERSION_1;
 use crate::devices::virtio::gen::virtio_net::{
@@ -104,7 +105,7 @@ pub struct RxBuffers {
     pub min_buffer_size: u32,
     // An [`IoVecBufferMut`] covering all the memory we have available for receiving network
     // frames.
-    pub iovec: IoVecBufferMut,
+    pub iovec: IoVecBufferMut<NET_QUEUE_MAX_SIZE>,
     // A map of which part of the memory belongs to which `DescriptorChain` object
     pub parsed_descriptors: VecDeque<ParsedDescriptorChain>,
     // Buffers that we have used and they are ready to be given back to the guest.

src/vmm/src/devices/virtio/net/mod.rs

@@ -5,13 +5,13 @@
 
 use std::io;
 
-use crate::devices::virtio::queue::FIRECRACKER_MAX_QUEUE_SIZE;
-
+/// Maximum size of the queue for network device.
+pub const NET_QUEUE_MAX_SIZE: u16 = 512;
 /// Maximum size of the frame buffers handled by this device.
 pub const MAX_BUFFER_SIZE: usize = 65562;
 /// The number of queues of the network device.
 pub const NET_NUM_QUEUES: usize = 2;
-pub const NET_QUEUE_SIZES: [u16; NET_NUM_QUEUES] = [FIRECRACKER_MAX_QUEUE_SIZE; NET_NUM_QUEUES];
+pub const NET_QUEUE_SIZES: [u16; NET_NUM_QUEUES] = [NET_QUEUE_MAX_SIZE; NET_NUM_QUEUES];
 /// The index of the rx queue from Net device queues/queues_evts vector.
 pub const RX_INDEX: usize = 0;
 /// The index of the tx queue from Net device queues/queues_evts vector.