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virtio-devices: vsock: Port to EpollHelper

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Migrate to EpollHelper so as to remove code that is duplicated between
multiple virtio devices.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This commit is contained in:
Sebastien Boeuf 2020-08-11 18:38:21 +02:00 committed by Rob Bradford
parent 01e7bd7276
commit 8fbc4b4004
2 changed files with 113 additions and 217 deletions
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303
virtio-devices/src/vsock/device.rs
View File

@ -12,8 +12,9 @@ use super::{VsockBackend, VsockPacket};
use crate::Error as DeviceError;
use crate::VirtioInterrupt;
use crate::{
ActivateError, ActivateResult, DeviceEventT, Queue, VirtioDevice, VirtioDeviceType,
VirtioInterruptType, VIRTIO_F_IN_ORDER, VIRTIO_F_IOMMU_PLATFORM, VIRTIO_F_VERSION_1,
ActivateError, ActivateResult, EpollHelper, EpollHelperError, EpollHelperHandler, Queue,
VirtioDevice, VirtioDeviceType, VirtioInterruptType, EPOLL_HELPER_EVENT_LAST,
VIRTIO_F_IN_ORDER, VIRTIO_F_IOMMU_PLATFORM, VIRTIO_F_VERSION_1,
};
use anyhow::anyhow;
/// This is the `VirtioDevice` implementation for our vsock device. It handles the virtio-level
@ -37,9 +38,8 @@ use anyhow::anyhow;
///
use byteorder::{ByteOrder, LittleEndian};
use libc::EFD_NONBLOCK;
use std::fs::File;
use std::io;
use std::os::unix::io::{AsRawFd, FromRawFd};
use std::os::unix::io::AsRawFd;
use std::path::PathBuf;
use std::result;
use std::sync::atomic::{AtomicBool, Ordering};
@ -57,18 +57,13 @@ const NUM_QUEUES: usize = 3;
const QUEUE_SIZES: &[u16] = &[QUEUE_SIZE; NUM_QUEUES];
// New descriptors are pending on the rx queue.
pub const RX_QUEUE_EVENT: DeviceEventT = 0;
pub const RX_QUEUE_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 1;
// New descriptors are pending on the tx queue.
pub const TX_QUEUE_EVENT: DeviceEventT = 1;
pub const TX_QUEUE_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 2;
// New descriptors are pending on the event queue.
pub const EVT_QUEUE_EVENT: DeviceEventT = 2;
pub const EVT_QUEUE_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 3;
// Notification coming from the backend.
pub const BACKEND_EVENT: DeviceEventT = 3;
// The device has been dropped.
pub const KILL_EVENT: DeviceEventT = 4;
// The device should be paused.
const PAUSE_EVENT: DeviceEventT = 5;
pub const EVENTS_LEN: usize = 6;
pub const BACKEND_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 4;
/// The `VsockEpollHandler` implements the runtime logic of our vsock device:
/// 1. Respond to TX queue events by wrapping virtio buffers into `VsockPacket`s, then sending those
@ -198,142 +193,64 @@ where
}
}
fn run(&mut self, paused: Arc<AtomicBool>) -> result::Result<(), DeviceError> {
// Create the epoll file descriptor
let epoll_fd = epoll::create(true).map_err(DeviceError::EpollCreateFd)?;
// Use 'File' to enforce closing on 'epoll_fd'
let epoll_file = unsafe { File::from_raw_fd(epoll_fd) };
// Add events
epoll::ctl(
epoll_file.as_raw_fd(),
epoll::ControlOptions::EPOLL_CTL_ADD,
self.queue_evts[0].as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(RX_QUEUE_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_file.as_raw_fd(),
epoll::ControlOptions::EPOLL_CTL_ADD,
self.queue_evts[1].as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(TX_QUEUE_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_file.as_raw_fd(),
epoll::ControlOptions::EPOLL_CTL_ADD,
self.queue_evts[2].as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(EVT_QUEUE_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_file.as_raw_fd(),
epoll::ControlOptions::EPOLL_CTL_ADD,
self.backend.read().unwrap().get_polled_fd(),
epoll::Event::new(
self.backend.read().unwrap().get_polled_evset(),
u64::from(BACKEND_EVENT),
),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_file.as_raw_fd(),
epoll::ControlOptions::EPOLL_CTL_ADD,
self.kill_evt.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(KILL_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_file.as_raw_fd(),
epoll::ControlOptions::EPOLL_CTL_ADD,
self.pause_evt.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(PAUSE_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
let mut events = vec![epoll::Event::new(epoll::Events::empty(), 0); EVENTS_LEN];
// Before jumping into the epoll loop, check if the device is expected
// to be in a paused state. This is helpful for the restore code path
// as the device thread should not start processing anything before the
// device has been resumed.
while paused.load(Ordering::SeqCst) {
thread::park();
}
'epoll: loop {
let num_events = match epoll::wait(epoll_file.as_raw_fd(), -1, &mut events[..]) {
Ok(res) => res,
Err(e) => {
if e.kind() == io::ErrorKind::Interrupted {
// It's well defined from the epoll_wait() syscall
// documentation that the epoll loop can be interrupted
// before any of the requested events occurred or the
// timeout expired. In both those cases, epoll_wait()
// returns an error of type EINTR, but this should not
// be considered as a regular error. Instead it is more
// appropriate to retry, by calling into epoll_wait().
continue;
}
return Err(DeviceError::EpollWait(e));
}
};
for event in events.iter().take(num_events) {
let evset = match epoll::Events::from_bits(event.events) {
Some(evset) => evset,
None => {
let evbits = event.events;
warn!("epoll: ignoring unknown event set: 0x{:x}", evbits);
continue;
}
};
let ev_type = event.data as DeviceEventT;
if self.handle_event(ev_type, evset, paused.clone())? {
break 'epoll;
}
}
}
fn run(&mut self, paused: Arc<AtomicBool>) -> result::Result<(), EpollHelperError> {
let mut helper = EpollHelper::new(&self.kill_evt, &self.pause_evt)?;
helper.add_event(self.queue_evts[0].as_raw_fd(), RX_QUEUE_EVENT)?;
helper.add_event(self.queue_evts[1].as_raw_fd(), TX_QUEUE_EVENT)?;
helper.add_event(self.queue_evts[2].as_raw_fd(), EVT_QUEUE_EVENT)?;
helper.add_event(self.backend.read().unwrap().get_polled_fd(), BACKEND_EVENT)?;
helper.run(paused, self)?;
Ok(())
}
}
pub fn handle_event(
&mut self,
device_event: DeviceEventT,
evset: epoll::Events,
paused: Arc<AtomicBool>,
) -> Result<bool, DeviceError> {
match device_event {
impl<B> EpollHelperHandler for VsockEpollHandler<B>
where
B: VsockBackend,
{
fn handle_event(&mut self, _helper: &mut EpollHelper, event: &epoll::Event) -> bool {
let evset = match epoll::Events::from_bits(event.events) {
Some(evset) => evset,
None => {
let evbits = event.events;
warn!("epoll: ignoring unknown event set: 0x{:x}", evbits);
return false;
}
};
let ev_type = event.data as u16;
match ev_type {
RX_QUEUE_EVENT => {
debug!("vsock: RX queue event");
if let Err(e) = self.queue_evts[0].read() {
error!("Failed to get RX queue event: {:?}", e);
return Err(DeviceError::FailedReadingQueue {
event_type: "rx queue event",
underlying: e,
});
return true;
} else if self.backend.read().unwrap().has_pending_rx() {
self.process_rx()?;
if let Err(e) = self.process_rx() {
error!("Failed to process RX queue: {:?}", e);
return true;
}
}
}
TX_QUEUE_EVENT => {
debug!("vsock: TX queue event");
if let Err(e) = self.queue_evts[1].read() {
error!("Failed to get TX queue event: {:?}", e);
return Err(DeviceError::FailedReadingQueue {
event_type: "tx queue event",
underlying: e,
});
return true;
} else {
self.process_tx()?;
if let Err(e) = self.process_tx() {
error!("Failed to process TX queue: {:?}", e);
return true;
}
// The backend may have queued up responses to the packets we sent during TX queue
// processing. If that happened, we need to fetch those responses and place them
// into RX buffers.
if self.backend.read().unwrap().has_pending_rx() {
self.process_rx()?;
if let Err(e) = self.process_rx() {
error!("Failed to process RX queue: {:?}", e);
return true;
}
}
}
}
@ -341,10 +258,7 @@ where
debug!("vsock: EVT queue event");
if let Err(e) = self.queue_evts[2].read() {
error!("Failed to get EVT queue event: {:?}", e);
return Err(DeviceError::FailedReadingQueue {
event_type: "evt queue event",
underlying: e,
});
return true;
}
}
BACKEND_EVENT => {
@ -355,39 +269,24 @@ where
// In particular, if `self.backend.send_pkt()` halted the TX queue processing (by
// reurning an error) at some point in the past, now is the time to try walking the
// TX queue again.
self.process_tx()?;
if let Err(e) = self.process_tx() {
error!("Failed to process TX queue: {:?}", e);
return true;
}
if self.backend.read().unwrap().has_pending_rx() {
self.process_rx()?;
if let Err(e) = self.process_rx() {
error!("Failed to process RX queue: {:?}", e);
return true;
}
}
}
KILL_EVENT => {
debug!("KILL_EVENT received, stopping epoll loop");
return Ok(true);
}
PAUSE_EVENT => {
debug!("PAUSE_EVENT received, pausing virtio-vsock epoll loop");
// We loop here to handle spurious park() returns.
// Until we have not resumed, the paused boolean will
// be true.
while paused.load(Ordering::SeqCst) {
thread::park();
}
// Drain pause event after the device has been resumed.
// This ensures the pause event has been seen by each
// and every thread related to this virtio device.
let _ = self.pause_evt.read();
}
other => {
_ => {
error!("Unknown event for virtio-vsock");
return Err(DeviceError::UnknownEvent {
device: "vsock",
event: other,
});
return true;
}
}
Ok(false)
false
}
}
@ -402,7 +301,7 @@ pub struct Vsock<B: VsockBackend> {
acked_features: u64,
queue_evts: Option<Vec<EventFd>>,
interrupt_cb: Option<Arc<dyn VirtioInterrupt>>,
epoll_threads: Option<Vec<thread::JoinHandle<result::Result<(), DeviceError>>>>,
epoll_threads: Option<Vec<thread::JoinHandle<result::Result<(), EpollHelperError>>>>,
paused: Arc<AtomicBool>,
path: PathBuf,
}
@ -840,13 +739,13 @@ mod tests {
let test_ctx = TestContext::new();
let mut ctx = test_ctx.create_epoll_handler_context();
match ctx.handler.handle_event(
TX_QUEUE_EVENT,
epoll::Events::EPOLLIN,
Arc::new(AtomicBool::new(false)),
) {
Err(DeviceError::FailedReadingQueue { .. }) => (),
other => panic!("{:?}", other),
let events = epoll::Events::EPOLLIN;
let event = epoll::Event::new(events, TX_QUEUE_EVENT as u64);
let mut epoll_helper =
EpollHelper::new(&ctx.handler.kill_evt, &ctx.handler.pause_evt).unwrap();
if !ctx.handler.handle_event(&mut epoll_helper, &event) {
panic!("handle_event() should have failed");
}
}
}
@ -907,13 +806,14 @@ mod tests {
let test_ctx = TestContext::new();
let mut ctx = test_ctx.create_epoll_handler_context();
ctx.handler.backend.write().unwrap().set_pending_rx(false);
match ctx.handler.handle_event(
RX_QUEUE_EVENT,
epoll::Events::EPOLLIN,
Arc::new(AtomicBool::new(false)),
) {
Err(DeviceError::FailedReadingQueue { .. }) => (),
other => panic!("{:?}", other),
let events = epoll::Events::EPOLLIN;
let event = epoll::Event::new(events, RX_QUEUE_EVENT as u64);
let mut epoll_helper =
EpollHelper::new(&ctx.handler.kill_evt, &ctx.handler.pause_evt).unwrap();
if !ctx.handler.handle_event(&mut epoll_helper, &event) {
panic!("handle_event() should have failed");
}
}
}
@ -925,13 +825,14 @@ mod tests {
let test_ctx = TestContext::new();
let mut ctx = test_ctx.create_epoll_handler_context();
ctx.handler.backend.write().unwrap().set_pending_rx(false);
match ctx.handler.handle_event(
EVT_QUEUE_EVENT,
epoll::Events::EPOLLIN,
Arc::new(AtomicBool::new(false)),
) {
Err(DeviceError::FailedReadingQueue { .. }) => (),
other => panic!("{:?}", other),
let events = epoll::Events::EPOLLIN;
let event = epoll::Event::new(events, EVT_QUEUE_EVENT as u64);
let mut epoll_helper =
EpollHelper::new(&ctx.handler.kill_evt, &ctx.handler.pause_evt).unwrap();
if !ctx.handler.handle_event(&mut epoll_helper, &event) {
panic!("handle_event() should have failed");
}
}
}
@ -946,13 +847,12 @@ mod tests {
let mut ctx = test_ctx.create_epoll_handler_context();
ctx.handler.backend.write().unwrap().set_pending_rx(true);
ctx.handler
.handle_event(
BACKEND_EVENT,
epoll::Events::EPOLLIN,
Arc::new(AtomicBool::new(false)),
)
.unwrap();
let events = epoll::Events::EPOLLIN;
let event = epoll::Event::new(events, BACKEND_EVENT as u64);
let mut epoll_helper =
EpollHelper::new(&ctx.handler.kill_evt, &ctx.handler.pause_evt).unwrap();
ctx.handler.handle_event(&mut epoll_helper, &event);
// The backend should've received this event.
assert_eq!(
@ -973,13 +873,12 @@ mod tests {
let mut ctx = test_ctx.create_epoll_handler_context();
ctx.handler.backend.write().unwrap().set_pending_rx(false);
ctx.handler
.handle_event(
BACKEND_EVENT,
epoll::Events::EPOLLIN,
Arc::new(AtomicBool::new(false)),
)
.unwrap();
let events = epoll::Events::EPOLLIN;
let event = epoll::Event::new(events, BACKEND_EVENT as u64);
let mut epoll_helper =
EpollHelper::new(&ctx.handler.kill_evt, &ctx.handler.pause_evt).unwrap();
ctx.handler.handle_event(&mut epoll_helper, &event);
// The backend should've received this event.
assert_eq!(
@ -998,13 +897,13 @@ mod tests {
let test_ctx = TestContext::new();
let mut ctx = test_ctx.create_epoll_handler_context();
match ctx.handler.handle_event(
0xff,
epoll::Events::EPOLLIN,
Arc::new(AtomicBool::new(false)),
) {
Err(DeviceError::UnknownEvent { .. }) => (),
other => panic!("{:?}", other),
let events = epoll::Events::EPOLLIN;
let event = epoll::Event::new(events, 0xff);
let mut epoll_helper =
EpollHelper::new(&ctx.handler.kill_evt, &ctx.handler.pause_evt).unwrap();
if !ctx.handler.handle_event(&mut epoll_helper, &event) {
panic!("handle_event() should have failed");
}
}
}

27
virtio-devices/src/vsock/mod.rs
View File

@ -161,10 +161,11 @@ mod tests {
use super::packet::VSOCK_PKT_HDR_SIZE;
use super::*;
use crate::device::{VirtioInterrupt, VirtioInterruptType};
use crate::epoll_helper::EpollHelperHandler;
use crate::EpollHelper;
use libc::EFD_NONBLOCK;
use std::os::unix::io::AsRawFd;
use std::path::PathBuf;
use std::sync::atomic::AtomicBool;
use std::sync::{Arc, RwLock};
use vm_memory::{GuestAddress, GuestMemoryAtomic, GuestMemoryMmap};
use vm_virtio::queue::testing::VirtQueue as GuestQ;
@ -339,23 +340,19 @@ mod tests {
impl<'a> EpollHandlerContext<'a> {
pub fn signal_txq_event(&mut self) {
self.handler.queue_evts[1].write(1).unwrap();
self.handler
.handle_event(
TX_QUEUE_EVENT,
epoll::Events::EPOLLIN,
Arc::new(AtomicBool::new(false)),
)
.unwrap();
let events = epoll::Events::EPOLLIN;
let event = epoll::Event::new(events, TX_QUEUE_EVENT as u64);
let mut epoll_helper =
EpollHelper::new(&self.handler.kill_evt, &self.handler.pause_evt).unwrap();
self.handler.handle_event(&mut epoll_helper, &event);
}
pub fn signal_rxq_event(&mut self) {
self.handler.queue_evts[0].write(1).unwrap();
self.handler
.handle_event(
RX_QUEUE_EVENT,
epoll::Events::EPOLLIN,
Arc::new(AtomicBool::new(false)),
)
.unwrap();
let events = epoll::Events::EPOLLIN;
let event = epoll::Event::new(events, RX_QUEUE_EVENT as u64);
let mut epoll_helper =
EpollHelper::new(&self.handler.kill_evt, &self.handler.pause_evt).unwrap();
self.handler.handle_event(&mut epoll_helper, &event);
}
}
}