chore: prepare virtio for multiple transport options

bchalios · bchalios · commit 7c28b2a6ddc9 · 2025-05-07T11:26:33.000+02:00
This is just code organization changes. Create a new module under
`virtio`, called `transport`. For the time being the only transport
supported is `mmio`. Also, move `IrqInterrupt` type within the MMIO
transport code, as it is MMIO specific.

Signed-off-by: Babis Chalios &lt;bchalios@amazon.es&gt;
diff --git a/src/vmm/src/builder.rs b/src/vmm/src/builder.rs
@@ -44,9 +44,9 @@ use crate::devices::legacy::{EventFdTrigger, SerialEventsWrapper, SerialWrapper}
 use crate::devices::virtio::balloon::Balloon;
 use crate::devices::virtio::block::device::Block;
 use crate::devices::virtio::device::VirtioDevice;
-use crate::devices::virtio::mmio::MmioTransport;
 use crate::devices::virtio::net::Net;
 use crate::devices::virtio::rng::Entropy;
+use crate::devices::virtio::transport::mmio::MmioTransport;
 use crate::devices::virtio::vsock::{Vsock, VsockUnixBackend};
 #[cfg(feature = "gdb")]
 use crate::gdb;
diff --git a/src/vmm/src/device_manager/mmio.rs b/src/vmm/src/device_manager/mmio.rs
@@ -30,9 +30,9 @@ use crate::devices::pseudo::BootTimer;
 use crate::devices::virtio::balloon::Balloon;
 use crate::devices::virtio::block::device::Block;
 use crate::devices::virtio::device::VirtioDevice;
-use crate::devices::virtio::mmio::MmioTransport;
 use crate::devices::virtio::net::Net;
 use crate::devices::virtio::rng::Entropy;
+use crate::devices::virtio::transport::mmio::MmioTransport;
 use crate::devices::virtio::vsock::{TYPE_VSOCK, Vsock, VsockUnixBackend};
 use crate::devices::virtio::{TYPE_BALLOON, TYPE_BLOCK, TYPE_NET, TYPE_RNG};
 #[cfg(target_arch = "x86_64")]
@@ -223,7 +223,7 @@ impl MMIODeviceManager {
         device_info: &MMIODeviceInfo,
     ) -> Result<(), MmioError> {
         // as per doc, [virtio_mmio.]device=<size>@<baseaddr>:<irq> needs to be appended
-        // to kernel command line for virtio mmio devices to get recongnized
+        // to kernel command line for virtio mmio devices to get recognized
         // the size parameter has to be transformed to KiB, so dividing hexadecimal value in
         // bytes to 1024; further, the '{}' formatting rust construct will automatically
         // transform it to decimal
@@ -530,8 +530,9 @@ mod tests {
     use super::*;
     use crate::Vm;
     use crate::devices::virtio::ActivateError;
-    use crate::devices::virtio::device::{IrqTrigger, VirtioDevice};
+    use crate::devices::virtio::device::VirtioDevice;
     use crate::devices::virtio::queue::Queue;
+    use crate::devices::virtio::transport::mmio::IrqTrigger;
     use crate::test_utils::multi_region_mem_raw;
     use crate::vstate::kvm::Kvm;
     use crate::vstate::memory::{GuestAddress, GuestMemoryMmap};
diff --git a/src/vmm/src/device_manager/persist.rs b/src/vmm/src/device_manager/persist.rs
@@ -25,7 +25,6 @@ use crate::devices::virtio::block::BlockError;
 use crate::devices::virtio::block::device::Block;
 use crate::devices::virtio::block::persist::{BlockConstructorArgs, BlockState};
 use crate::devices::virtio::device::VirtioDevice;
-use crate::devices::virtio::mmio::MmioTransport;
 use crate::devices::virtio::net::Net;
 use crate::devices::virtio::net::persist::{
     NetConstructorArgs, NetPersistError as NetError, NetState,
@@ -35,6 +34,7 @@ use crate::devices::virtio::rng::Entropy;
 use crate::devices::virtio::rng::persist::{
     EntropyConstructorArgs, EntropyPersistError as EntropyError, EntropyState,
 };
+use crate::devices::virtio::transport::mmio::MmioTransport;
 use crate::devices::virtio::vsock::persist::{
     VsockConstructorArgs, VsockState, VsockUdsConstructorArgs,
 };
diff --git a/src/vmm/src/devices/bus.rs b/src/vmm/src/devices/bus.rs
@@ -56,7 +56,7 @@ use event_manager::{EventOps, Events, MutEventSubscriber};
 use super::legacy::RTCDevice;
 use super::legacy::{I8042Device, SerialDevice};
 use super::pseudo::BootTimer;
-use super::virtio::mmio::MmioTransport;
+use super::virtio::transport::mmio::MmioTransport;
 
 #[derive(Debug)]
 pub enum BusDevice {
diff --git a/src/vmm/src/devices/virtio/balloon/device.rs b/src/vmm/src/devices/virtio/balloon/device.rs
@@ -24,8 +24,8 @@ use super::{
     VIRTIO_BALLOON_S_SWAP_OUT,
 };
 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::devices::virtio::transport::mmio::{IrqTrigger, IrqType};
 use crate::logger::IncMetric;
 use crate::utils::u64_to_usize;
 use crate::vstate::memory::{Address, ByteValued, Bytes, GuestAddress, GuestMemoryMmap};
diff --git a/src/vmm/src/devices/virtio/balloon/test_utils.rs b/src/vmm/src/devices/virtio/balloon/test_utils.rs
@@ -10,7 +10,7 @@ use crate::devices::virtio::{balloon::BALLOON_NUM_QUEUES, balloon::Balloon};
 #[cfg(test)]
 pub fn invoke_handler_for_queue_event(b: &mut Balloon, queue_index: usize) {
     use crate::devices::virtio::balloon::{DEFLATE_INDEX, INFLATE_INDEX, STATS_INDEX};
-    use crate::devices::virtio::device::IrqType;
+    use crate::devices::virtio::transport::mmio::IrqType;
 
     assert!(queue_index < BALLOON_NUM_QUEUES);
     // Trigger the queue event.
diff --git a/src/vmm/src/devices/virtio/block/device.rs b/src/vmm/src/devices/virtio/block/device.rs
@@ -8,8 +8,9 @@ use super::BlockError;
 use super::persist::{BlockConstructorArgs, BlockState};
 use super::vhost_user::device::{VhostUserBlock, VhostUserBlockConfig};
 use super::virtio::device::{VirtioBlock, VirtioBlockConfig};
-use crate::devices::virtio::device::{IrqTrigger, VirtioDevice};
+use crate::devices::virtio::device::VirtioDevice;
 use crate::devices::virtio::queue::Queue;
+use crate::devices::virtio::transport::mmio::IrqTrigger;
 use crate::devices::virtio::{ActivateError, TYPE_BLOCK};
 use crate::rate_limiter::BucketUpdate;
 use crate::snapshot::Persist;
diff --git a/src/vmm/src/devices/virtio/block/vhost_user/device.rs b/src/vmm/src/devices/virtio/block/vhost_user/device.rs
@@ -14,11 +14,12 @@ use vmm_sys_util::eventfd::EventFd;
 
 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::device::{DeviceState, 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::transport::mmio::{IrqTrigger, IrqType};
 use crate::devices::virtio::vhost_user::{VhostUserHandleBackend, VhostUserHandleImpl};
 use crate::devices::virtio::vhost_user_metrics::{
     VhostUserDeviceMetrics, VhostUserMetricsPerDevice,
@@ -34,7 +35,7 @@ const BLOCK_CONFIG_SPACE_SIZE: u32 = 60;
 
 const AVAILABLE_FEATURES: u64 = (1 << VIRTIO_F_VERSION_1)
     | (1 << VIRTIO_RING_F_EVENT_IDX)
-    // vhost-user specific bit. Not defined in standart virtio spec.
+    // vhost-user specific bit. Not defined in standard virtio spec.
     // Specifies ability of frontend to negotiate protocol features.
     | VhostUserVirtioFeatures::PROTOCOL_FEATURES.bits()
     // We always try to negotiate readonly with the backend.
@@ -375,7 +376,7 @@ mod tests {
 
     use super::*;
     use crate::devices::virtio::block::virtio::device::FileEngineType;
-    use crate::devices::virtio::mmio::VIRTIO_MMIO_INT_CONFIG;
+    use crate::devices::virtio::transport::mmio::VIRTIO_MMIO_INT_CONFIG;
     use crate::devices::virtio::vhost_user::tests::create_mem;
     use crate::test_utils::create_tmp_socket;
     use crate::vstate::memory::GuestAddress;
diff --git a/src/vmm/src/devices/virtio/block/virtio/device.rs b/src/vmm/src/devices/virtio/block/virtio/device.rs
@@ -23,13 +23,14 @@ use super::request::*;
 use super::{BLOCK_QUEUE_SIZES, SECTOR_SHIFT, SECTOR_SIZE, VirtioBlockError, io as block_io};
 use crate::devices::virtio::block::CacheType;
 use crate::devices::virtio::block::virtio::metrics::{BlockDeviceMetrics, BlockMetricsPerDevice};
-use crate::devices::virtio::device::{DeviceState, IrqTrigger, IrqType, VirtioDevice};
+use crate::devices::virtio::device::{DeviceState, VirtioDevice};
 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::transport::mmio::{IrqTrigger, IrqType};
 use crate::devices::virtio::{ActivateError, TYPE_BLOCK};
 use crate::logger::{IncMetric, error, warn};
 use crate::rate_limiter::{BucketUpdate, RateLimiter};
@@ -826,7 +827,7 @@ mod tests {
             block.read_config(0, actual_config_space.as_mut_slice());
             assert_eq!(actual_config_space, expected_config_space);
 
-            // If priviledged user writes to `/dev/mem`, in block config space - byte by byte.
+            // If privileged user writes to `/dev/mem`, in block config space - byte by byte.
             let expected_config_space = ConfigSpace {
                 capacity: 0x1122334455667788,
             };
diff --git a/src/vmm/src/devices/virtio/block/virtio/persist.rs b/src/vmm/src/devices/virtio/block/virtio/persist.rs
@@ -16,9 +16,10 @@ use crate::devices::virtio::TYPE_BLOCK;
 use crate::devices::virtio::block::persist::BlockConstructorArgs;
 use crate::devices::virtio::block::virtio::device::FileEngineType;
 use crate::devices::virtio::block::virtio::metrics::BlockMetricsPerDevice;
-use crate::devices::virtio::device::{DeviceState, IrqTrigger};
+use crate::devices::virtio::device::DeviceState;
 use crate::devices::virtio::generated::virtio_blk::VIRTIO_BLK_F_RO;
 use crate::devices::virtio::persist::VirtioDeviceState;
+use crate::devices::virtio::transport::mmio::IrqTrigger;
 use crate::rate_limiter::RateLimiter;
 use crate::rate_limiter::persist::RateLimiterState;
 use crate::snapshot::Persist;
diff --git a/src/vmm/src/devices/virtio/block/virtio/test_utils.rs b/src/vmm/src/devices/virtio/block/virtio/test_utils.rs
@@ -16,10 +16,10 @@ use crate::devices::virtio::block::virtio::device::FileEngineType;
 #[cfg(test)]
 use crate::devices::virtio::block::virtio::io::FileEngine;
 use crate::devices::virtio::block::virtio::{CacheType, VirtioBlock};
-#[cfg(test)]
-use crate::devices::virtio::device::IrqType;
 use crate::devices::virtio::queue::{Queue, VIRTQ_DESC_F_NEXT, VIRTQ_DESC_F_WRITE};
 use crate::devices::virtio::test_utils::{VirtQueue, VirtqDesc};
+#[cfg(test)]
+use crate::devices::virtio::transport::mmio::IrqType;
 use crate::rate_limiter::RateLimiter;
 use crate::vmm_config::{RateLimiterConfig, TokenBucketConfig};
 use crate::vstate::memory::{Bytes, GuestAddress};
diff --git a/src/vmm/src/devices/virtio/device.rs b/src/vmm/src/devices/virtio/device.rs
@@ -7,15 +7,15 @@
 
 use std::fmt;
 use std::sync::Arc;
-use std::sync::atomic::{AtomicU32, Ordering};
+use std::sync::atomic::AtomicU32;
 
 use vmm_sys_util::eventfd::EventFd;
 
 use super::ActivateError;
-use super::mmio::{VIRTIO_MMIO_INT_CONFIG, VIRTIO_MMIO_INT_VRING};
 use super::queue::{Queue, QueueError};
+use super::transport::mmio::IrqTrigger;
 use crate::devices::virtio::AsAny;
-use crate::logger::{error, warn};
+use crate::logger::warn;
 use crate::vstate::memory::GuestMemoryMmap;
 
 /// Enum that indicates if a VirtioDevice is inactive or has been activated
@@ -44,46 +44,6 @@ impl DeviceState {
     }
 }
 
-/// The 2 types of interrupt sources in MMIO transport.
-#[derive(Debug)]
-pub enum IrqType {
-    /// Interrupt triggered by change in config.
-    Config,
-    /// Interrupt triggered by used vring buffers.
-    Vring,
-}
-
-/// Helper struct that is responsible for triggering guest IRQs
-#[derive(Debug)]
-pub struct IrqTrigger {
-    pub(crate) irq_status: Arc<AtomicU32>,
-    pub(crate) irq_evt: EventFd,
-}
-
-impl IrqTrigger {
-    pub fn new() -> std::io::Result<Self> {
-        Ok(Self {
-            irq_status: Arc::new(AtomicU32::new(0)),
-            irq_evt: EventFd::new(libc::EFD_NONBLOCK)?,
-        })
-    }
-
-    pub fn trigger_irq(&self, irq_type: IrqType) -> Result<(), std::io::Error> {
-        let irq = match irq_type {
-            IrqType::Config => VIRTIO_MMIO_INT_CONFIG,
-            IrqType::Vring => VIRTIO_MMIO_INT_VRING,
-        };
-        self.irq_status.fetch_or(irq, Ordering::SeqCst);
-
-        self.irq_evt.write(1).map_err(|err| {
-            error!("Failed to send irq to the guest: {:?}", err);
-            err
-        })?;
-
-        Ok(())
-    }
-}
-
 /// Trait for virtio devices to be driven by a virtio transport.
 ///
 /// The lifecycle of a virtio device is to be moved to a virtio transport, which will then query the
@@ -200,47 +160,6 @@ impl fmt::Debug for dyn VirtioDevice {
 pub(crate) mod tests {
     use super::*;
 
-    impl IrqTrigger {
-        pub fn has_pending_irq(&self, irq_type: IrqType) -> bool {
-            if let Ok(num_irqs) = self.irq_evt.read() {
-                if num_irqs == 0 {
-                    return false;
-                }
-
-                let irq_status = self.irq_status.load(Ordering::SeqCst);
-                return matches!(
-                    (irq_status, irq_type),
-                    (VIRTIO_MMIO_INT_CONFIG, IrqType::Config)
-                        | (VIRTIO_MMIO_INT_VRING, IrqType::Vring)
-                );
-            }
-
-            false
-        }
-    }
-
-    #[test]
-    fn irq_trigger() {
-        let irq_trigger = IrqTrigger::new().unwrap();
-        assert_eq!(irq_trigger.irq_status.load(Ordering::SeqCst), 0);
-
-        // Check that there are no pending irqs.
-        assert!(!irq_trigger.has_pending_irq(IrqType::Config));
-        assert!(!irq_trigger.has_pending_irq(IrqType::Vring));
-
-        // Check that trigger_irq() correctly generates irqs.
-        irq_trigger.trigger_irq(IrqType::Config).unwrap();
-        assert!(irq_trigger.has_pending_irq(IrqType::Config));
-        irq_trigger.irq_status.store(0, Ordering::SeqCst);
-        irq_trigger.trigger_irq(IrqType::Vring).unwrap();
-        assert!(irq_trigger.has_pending_irq(IrqType::Vring));
-
-        // Check trigger_irq() failure case (irq_evt is full).
-        irq_trigger.irq_evt.write(u64::MAX - 1).unwrap();
-        irq_trigger.trigger_irq(IrqType::Config).unwrap_err();
-        irq_trigger.trigger_irq(IrqType::Vring).unwrap_err();
-    }
-
     #[derive(Debug)]
     struct MockVirtioDevice {
         acked_features: u64,
diff --git a/src/vmm/src/devices/virtio/mod.rs b/src/vmm/src/devices/virtio/mod.rs
@@ -18,12 +18,12 @@ pub mod device;
 pub mod generated;
 mod iov_deque;
 pub mod iovec;
-pub mod mmio;
 pub mod net;
 pub mod persist;
 pub mod queue;
 pub mod rng;
 pub mod test_utils;
+pub mod transport;
 pub mod vhost_user;
 pub mod vhost_user_metrics;
 pub mod vsock;
diff --git a/src/vmm/src/devices/virtio/net/device.rs b/src/vmm/src/devices/virtio/net/device.rs
@@ -15,7 +15,7 @@ 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::device::{DeviceState, 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,
@@ -32,6 +32,7 @@ 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::transport::mmio::{IrqTrigger, IrqType};
 use crate::devices::virtio::{ActivateError, TYPE_NET};
 use crate::devices::{DeviceError, report_net_event_fail};
 use crate::dumbo::pdu::arp::ETH_IPV4_FRAME_LEN;
@@ -1053,6 +1054,7 @@ pub mod tests {
     };
     use crate::devices::virtio::queue::VIRTQ_DESC_F_WRITE;
     use crate::devices::virtio::test_utils::VirtQueue;
+    use crate::devices::virtio::transport::mmio::IrqType;
     use crate::dumbo::EthernetFrame;
     use crate::dumbo::pdu::arp::{ETH_IPV4_FRAME_LEN, EthIPv4ArpFrame};
     use crate::dumbo::pdu::ethernet::ETHERTYPE_ARP;
diff --git a/src/vmm/src/devices/virtio/net/test_utils.rs b/src/vmm/src/devices/virtio/net/test_utils.rs
@@ -104,7 +104,7 @@ impl TapTrafficSimulator {
 
         let send_addr_ptr = &mut storage as *mut libc::sockaddr_storage;
 
-        // SAFETY: `sock_addr` is a valid pointer and safe to derference.
+        // SAFETY: `sock_addr` is a valid pointer and safe to dereference.
         unsafe {
             let sock_addr: *mut libc::sockaddr_ll = send_addr_ptr.cast::<libc::sockaddr_ll>();
             (*sock_addr).sll_family = libc::sa_family_t::try_from(libc::AF_PACKET).unwrap();
@@ -223,7 +223,7 @@ pub fn if_index(tap: &Tap) -> i32 {
 
 /// Enable the tap interface.
 pub fn enable(tap: &Tap) {
-    // Disable IPv6 router advertisment requests
+    // Disable IPv6 router advertisement requests
     Command::new("sh")
         .arg("-c")
         .arg(format!(
@@ -311,7 +311,7 @@ pub mod test {
     use event_manager::{EventManager, SubscriberId, SubscriberOps};
 
     use crate::check_metric_after_block;
-    use crate::devices::virtio::device::{IrqType, VirtioDevice};
+    use crate::devices::virtio::device::VirtioDevice;
     use crate::devices::virtio::net::device::vnet_hdr_len;
     use crate::devices::virtio::net::generated::ETH_HLEN;
     use crate::devices::virtio::net::test_utils::{
@@ -320,6 +320,7 @@ pub mod test {
     use crate::devices::virtio::net::{MAX_BUFFER_SIZE, Net, RX_INDEX, TX_INDEX};
     use crate::devices::virtio::queue::{VIRTQ_DESC_F_NEXT, VIRTQ_DESC_F_WRITE};
     use crate::devices::virtio::test_utils::{VirtQueue, VirtqDesc};
+    use crate::devices::virtio::transport::mmio::IrqType;
     use crate::logger::IncMetric;
     use crate::vstate::memory::{Address, Bytes, GuestAddress, GuestMemoryMmap};
 
diff --git a/src/vmm/src/devices/virtio/persist.rs b/src/vmm/src/devices/virtio/persist.rs
@@ -12,8 +12,8 @@ use serde::{Deserialize, Serialize};
 use super::queue::QueueError;
 use crate::devices::virtio::device::VirtioDevice;
 use crate::devices::virtio::generated::virtio_ring::VIRTIO_RING_F_EVENT_IDX;
-use crate::devices::virtio::mmio::MmioTransport;
 use crate::devices::virtio::queue::Queue;
+use crate::devices::virtio::transport::mmio::MmioTransport;
 use crate::snapshot::Persist;
 use crate::vstate::memory::{GuestAddress, GuestMemoryMmap};
 
@@ -261,10 +261,10 @@ mod tests {
     use crate::devices::virtio::block::virtio::VirtioBlock;
     use crate::devices::virtio::block::virtio::device::FileEngineType;
     use crate::devices::virtio::block::virtio::test_utils::default_block_with_path;
-    use crate::devices::virtio::mmio::tests::DummyDevice;
     use crate::devices::virtio::net::Net;
     use crate::devices::virtio::net::test_utils::default_net;
     use crate::devices::virtio::test_utils::default_mem;
+    use crate::devices::virtio::transport::mmio::tests::DummyDevice;
     use crate::devices::virtio::vsock::{Vsock, VsockUnixBackend};
     use crate::snapshot::Snapshot;
 
diff --git a/src/vmm/src/devices/virtio/rng/device.rs b/src/vmm/src/devices/virtio/rng/device.rs
diff --git a/src/vmm/src/devices/virtio/transport/mmio.rs b/src/vmm/src/devices/virtio/transport/mmio.rs
diff --git a/src/vmm/src/devices/virtio/transport/mod.rs b/src/vmm/src/devices/virtio/transport/mod.rs
diff --git a/src/vmm/src/devices/virtio/vhost_user.rs b/src/vmm/src/devices/virtio/vhost_user.rs
diff --git a/src/vmm/src/devices/virtio/vsock/device.rs b/src/vmm/src/devices/virtio/vsock/device.rs
