refactor: Introduce VIRTIO_DEFAULT_FEATURES

This constant contains all the virtio features that all devices offer by
default, so that we can avoid repeating them for each device. For now,
its just VIRTIO_F_VERSION_1.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

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

@@ -23,9 +23,9 @@ use super::{
     VIRTIO_BALLOON_S_MEMTOT, VIRTIO_BALLOON_S_MINFLT, VIRTIO_BALLOON_S_SWAP_IN,
     VIRTIO_BALLOON_S_SWAP_OUT,
 };
+use crate::devices::virtio::VIRTIO_DEFAULT_FEATURES;
 use crate::devices::virtio::balloon::BalloonError;
 use crate::devices::virtio::device::{IrqTrigger, IrqType};
-use crate::devices::virtio::generated::virtio_config::VIRTIO_F_VERSION_1;
 use crate::logger::IncMetric;
 use crate::utils::u64_to_usize;
 use crate::vstate::memory::{Address, ByteValued, Bytes, GuestAddress, GuestMemoryMmap};
@@ -206,7 +206,7 @@ impl Balloon {
         stats_polling_interval_s: u16,
         restored_from_file: bool,
     ) -> Result<Balloon, BalloonError> {
-        let mut avail_features = 1u64 << VIRTIO_F_VERSION_1;
+        let mut avail_features = VIRTIO_DEFAULT_FEATURES;
 
         if deflate_on_oom {
             avail_features |= 1u64 << VIRTIO_BALLOON_F_DEFLATE_ON_OOM;
@@ -727,7 +727,7 @@ pub(crate) mod tests {
                 let mut balloon = Balloon::new(0, *deflate_on_oom, *stats_interval, false).unwrap();
                 assert_eq!(balloon.device_type(), TYPE_BALLOON);
 
-                let features: u64 = (1u64 << VIRTIO_F_VERSION_1)
+                let features: u64 = VIRTIO_DEFAULT_FEATURES
                     | (u64::from(*deflate_on_oom) << VIRTIO_BALLOON_F_DEFLATE_ON_OOM)
                     | ((u64::from(*stats_interval)) << VIRTIO_BALLOON_F_STATS_VQ);
 

src/vmm/src/devices/virtio/block/vhost_user/device.rs

@@ -16,14 +16,13 @@ use super::{NUM_QUEUES, QUEUE_SIZE, VhostUserBlockError};
 use crate::devices::virtio::block::CacheType;
 use crate::devices::virtio::device::{DeviceState, IrqTrigger, IrqType, VirtioDevice};
 use crate::devices::virtio::generated::virtio_blk::{VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_RO};
-use crate::devices::virtio::generated::virtio_config::VIRTIO_F_VERSION_1;
 use crate::devices::virtio::generated::virtio_ring::VIRTIO_RING_F_EVENT_IDX;
 use crate::devices::virtio::queue::Queue;
 use crate::devices::virtio::vhost_user::{VhostUserHandleBackend, VhostUserHandleImpl};
 use crate::devices::virtio::vhost_user_metrics::{
     VhostUserDeviceMetrics, VhostUserMetricsPerDevice,
 };
-use crate::devices::virtio::{ActivateError, TYPE_BLOCK};
+use crate::devices::virtio::{ActivateError, TYPE_BLOCK, VIRTIO_DEFAULT_FEATURES};
 use crate::logger::{IncMetric, StoreMetric, log_dev_preview_warning};
 use crate::utils::u64_to_usize;
 use crate::vmm_config::drive::BlockDeviceConfig;
@@ -32,7 +31,7 @@ use crate::vstate::memory::GuestMemoryMmap;
 /// Block device config space size in bytes.
 const BLOCK_CONFIG_SPACE_SIZE: u32 = 60;
 
-const AVAILABLE_FEATURES: u64 = (1 << VIRTIO_F_VERSION_1)
+const AVAILABLE_FEATURES: u64 = VIRTIO_DEFAULT_FEATURES
     | (1 << VIRTIO_RING_F_EVENT_IDX)
     // vhost-user specific bit. Not defined in standart virtio spec.
     // Specifies ability of frontend to negotiate protocol features.

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

@@ -27,10 +27,9 @@ use crate::devices::virtio::device::{DeviceState, IrqTrigger, IrqType, VirtioDev
 use crate::devices::virtio::generated::virtio_blk::{
     VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_RO, VIRTIO_BLK_ID_BYTES,
 };
-use crate::devices::virtio::generated::virtio_config::VIRTIO_F_VERSION_1;
 use crate::devices::virtio::generated::virtio_ring::VIRTIO_RING_F_EVENT_IDX;
 use crate::devices::virtio::queue::Queue;
-use crate::devices::virtio::{ActivateError, TYPE_BLOCK};
+use crate::devices::virtio::{ActivateError, TYPE_BLOCK, VIRTIO_DEFAULT_FEATURES};
 use crate::logger::{IncMetric, error, warn};
 use crate::rate_limiter::{BucketUpdate, RateLimiter};
 use crate::utils::u64_to_usize;
@@ -295,7 +294,7 @@ impl VirtioBlock {
             .map_err(VirtioBlockError::RateLimiter)?
             .unwrap_or_default();
 
-        let mut avail_features = (1u64 << VIRTIO_F_VERSION_1) | (1u64 << VIRTIO_RING_F_EVENT_IDX);
+        let mut avail_features = VIRTIO_DEFAULT_FEATURES | (1u64 << VIRTIO_RING_F_EVENT_IDX);
 
         if config.cache_type == CacheType::Writeback {
             avail_features |= 1u64 << VIRTIO_BLK_F_FLUSH;
@@ -769,7 +768,7 @@ mod tests {
 
             assert_eq!(block.device_type(), TYPE_BLOCK);
 
-            let features: u64 = (1u64 << VIRTIO_F_VERSION_1) | (1u64 << VIRTIO_RING_F_EVENT_IDX);
+            let features: u64 = VIRTIO_DEFAULT_FEATURES | (1u64 << VIRTIO_RING_F_EVENT_IDX);
 
             assert_eq!(
                 block.avail_features_by_page(0),

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

@@ -10,6 +10,7 @@
 use std::any::Any;
 
 use self::queue::QueueError;
+use crate::devices::virtio::generated::virtio_config::VIRTIO_F_VERSION_1;
 use crate::devices::virtio::net::TapError;
 
 pub mod balloon;
@@ -61,6 +62,9 @@ pub const TYPE_BALLOON: u32 = 5;
 /// queue events.
 pub const NOTIFY_REG_OFFSET: u32 = 0x50;
 
+/// The set of virtio features that every Firecracker device offers.
+pub const VIRTIO_DEFAULT_FEATURES: u64 = 1 << VIRTIO_F_VERSION_1;
+
 /// Errors triggered when activating a VirtioDevice.
 #[derive(Debug, thiserror::Error, displaydoc::Display)]
 pub enum ActivateError {

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

@@ -16,7 +16,6 @@ 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::generated::virtio_config::VIRTIO_F_VERSION_1;
 use crate::devices::virtio::generated::virtio_net::{
     VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
     VIRTIO_NET_F_GUEST_UFO, VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_TSO6, VIRTIO_NET_F_HOST_UFO,
@@ -32,7 +31,7 @@ use crate::devices::virtio::net::{
     MAX_BUFFER_SIZE, NET_QUEUE_SIZES, NetError, NetQueue, RX_INDEX, TX_INDEX, generated,
 };
 use crate::devices::virtio::queue::{DescriptorChain, Queue};
-use crate::devices::virtio::{ActivateError, TYPE_NET};
+use crate::devices::virtio::{ActivateError, TYPE_NET, VIRTIO_DEFAULT_FEATURES};
 use crate::devices::{DeviceError, report_net_event_fail};
 use crate::dumbo::pdu::arp::ETH_IPV4_FRAME_LEN;
 use crate::dumbo::pdu::ethernet::{EthernetFrame, PAYLOAD_OFFSET};
@@ -275,15 +274,15 @@ impl Net {
         rx_rate_limiter: RateLimiter,
         tx_rate_limiter: RateLimiter,
     ) -> Result<Self, NetError> {
-        let mut avail_features = (1 << VIRTIO_NET_F_GUEST_CSUM)
+        let mut avail_features = VIRTIO_DEFAULT_FEATURES
+            | (1 << VIRTIO_NET_F_GUEST_CSUM)
             | (1 << VIRTIO_NET_F_CSUM)
             | (1 << VIRTIO_NET_F_GUEST_TSO4)
             | (1 << VIRTIO_NET_F_GUEST_TSO6)
             | (1 << VIRTIO_NET_F_GUEST_UFO)
             | (1 << VIRTIO_NET_F_HOST_TSO4)
             | (1 << VIRTIO_NET_F_HOST_TSO6)
             | (1 << VIRTIO_NET_F_HOST_UFO)
-            | (1 << VIRTIO_F_VERSION_1)
             | (1 << VIRTIO_NET_F_MRG_RXBUF)
             | (1 << VIRTIO_RING_F_EVENT_IDX);
 
@@ -1116,7 +1115,8 @@ pub mod tests {
         set_mac(&mut net, MacAddr::from_str("11:22:33:44:55:66").unwrap());
 
         // Test `features()` and `ack_features()`.
-        let features = (1 << VIRTIO_NET_F_GUEST_CSUM)
+        let features = VIRTIO_DEFAULT_FEATURES
+            | (1 << VIRTIO_NET_F_GUEST_CSUM)
             | (1 << VIRTIO_NET_F_CSUM)
             | (1 << VIRTIO_NET_F_GUEST_TSO4)
             | (1 << VIRTIO_NET_F_GUEST_TSO6)
@@ -1125,7 +1125,6 @@ pub mod tests {
             | (1 << VIRTIO_NET_F_HOST_TSO4)
             | (1 << VIRTIO_NET_F_HOST_TSO6)
             | (1 << VIRTIO_NET_F_HOST_UFO)
-            | (1 << VIRTIO_F_VERSION_1)
             | (1 << VIRTIO_NET_F_MRG_RXBUF)
             | (1 << VIRTIO_RING_F_EVENT_IDX);
 

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

@@ -13,11 +13,10 @@ use super::metrics::METRICS;
 use super::{RNG_NUM_QUEUES, RNG_QUEUE};
 use crate::devices::DeviceError;
 use crate::devices::virtio::device::{DeviceState, IrqTrigger, IrqType, VirtioDevice};
-use crate::devices::virtio::generated::virtio_config::VIRTIO_F_VERSION_1;
 use crate::devices::virtio::iov_deque::IovDequeError;
 use crate::devices::virtio::iovec::IoVecBufferMut;
 use crate::devices::virtio::queue::{FIRECRACKER_MAX_QUEUE_SIZE, Queue};
-use crate::devices::virtio::{ActivateError, TYPE_RNG};
+use crate::devices::virtio::{ActivateError, TYPE_RNG, VIRTIO_DEFAULT_FEATURES};
 use crate::logger::{IncMetric, debug, error};
 use crate::rate_limiter::{RateLimiter, TokenType};
 use crate::vstate::memory::GuestMemoryMmap;
@@ -72,7 +71,7 @@ impl Entropy {
         let irq_trigger = IrqTrigger::new()?;
 
         Ok(Self {
-            avail_features: 1 << VIRTIO_F_VERSION_1,
+            avail_features: VIRTIO_DEFAULT_FEATURES,
             acked_features: 0u64,
             activate_event,
             device_state: DeviceState::Inactive,
@@ -312,6 +311,7 @@ mod tests {
     use super::*;
     use crate::check_metric_after_block;
     use crate::devices::virtio::device::VirtioDevice;
+    use crate::devices::virtio::generated::virtio_config::VIRTIO_F_VERSION_1;
     use crate::devices::virtio::queue::VIRTQ_DESC_F_WRITE;
     use crate::devices::virtio::test_utils::test::{
         VirtioTestDevice, VirtioTestHelper, create_virtio_mem,
@@ -397,7 +397,7 @@ mod tests {
     fn test_virtio_device_features() {
         let mut entropy_dev = default_entropy();
 
-        let features = 1 << VIRTIO_F_VERSION_1;
+        let features = VIRTIO_DEFAULT_FEATURES;
 
         assert_eq!(
             entropy_dev.avail_features_by_page(0),

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

@@ -29,12 +29,12 @@ use super::super::super::DeviceError;
 use super::defs::uapi;
 use super::packet::{VSOCK_PKT_HDR_SIZE, VsockPacketRx, VsockPacketTx};
 use super::{VsockBackend, defs};
-use crate::devices::virtio::ActivateError;
 use crate::devices::virtio::device::{DeviceState, IrqTrigger, IrqType, VirtioDevice};
-use crate::devices::virtio::generated::virtio_config::{VIRTIO_F_IN_ORDER, VIRTIO_F_VERSION_1};
+use crate::devices::virtio::generated::virtio_config::VIRTIO_F_IN_ORDER;
 use crate::devices::virtio::queue::Queue as VirtQueue;
 use crate::devices::virtio::vsock::VsockError;
 use crate::devices::virtio::vsock::metrics::METRICS;
+use crate::devices::virtio::{ActivateError, VIRTIO_DEFAULT_FEATURES};
 use crate::logger::IncMetric;
 use crate::utils::byte_order;
 use crate::vstate::memory::{Bytes, GuestMemoryMmap};
@@ -49,8 +49,7 @@ pub(crate) const VIRTIO_VSOCK_EVENT_TRANSPORT_RESET: u32 = 0;
 /// - VIRTIO_F_VERSION_1: the device conforms to at least version 1.0 of the VirtIO spec.
 /// - VIRTIO_F_IN_ORDER: the device returns used buffers in the same order that the driver makes
 ///   them available.
-pub(crate) const AVAIL_FEATURES: u64 =
-    (1 << VIRTIO_F_VERSION_1 as u64) | (1 << VIRTIO_F_IN_ORDER as u64);
+pub(crate) const AVAIL_FEATURES: u64 = VIRTIO_DEFAULT_FEATURES | (1 << VIRTIO_F_IN_ORDER as u64);
 
 /// Structure representing the vsock device.
 #[derive(Debug)]