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virtio-devices: pmem: Port to EpollHelper
Migrate to EpollHelper so as to remove code that is duplicated between multiple virtio devices. Signed-off-by: Rob Bradford <robert.bradford@intel.com>
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@ -8,8 +8,9 @@
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use super::Error as DeviceError;
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use super::{
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ActivateError, ActivateResult, DescriptorChain, DeviceEventT, Queue, UserspaceMapping,
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VirtioDevice, VirtioDeviceType, VIRTIO_F_IOMMU_PLATFORM, VIRTIO_F_VERSION_1,
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ActivateError, ActivateResult, DescriptorChain, EpollHelper, EpollHelperError,
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EpollHelperHandler, Queue, UserspaceMapping, VirtioDevice, VirtioDeviceType,
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EPOLL_HELPER_EVENT_LAST, VIRTIO_F_IOMMU_PLATFORM, VIRTIO_F_VERSION_1,
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};
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use crate::{VirtioInterrupt, VirtioInterruptType};
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use anyhow::anyhow;
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@ -19,7 +20,7 @@ use std::fmt::{self, Display};
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use std::fs::File;
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use std::io;
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use std::mem::size_of;
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use std::os::unix::io::{AsRawFd, FromRawFd};
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use std::os::unix::io::AsRawFd;
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use std::result;
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use std::sync::atomic::{AtomicBool, Ordering};
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use std::sync::Arc;
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@ -43,11 +44,7 @@ const VIRTIO_PMEM_RESP_TYPE_OK: u32 = 0;
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const VIRTIO_PMEM_RESP_TYPE_EIO: u32 = 1;
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// New descriptors are pending on the virtio queue.
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const QUEUE_AVAIL_EVENT: DeviceEventT = 0;
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// The device has been dropped.
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const KILL_EVENT: DeviceEventT = 1;
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// The device should be paused.
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const PAUSE_EVENT: DeviceEventT = 2;
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const QUEUE_AVAIL_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 1;
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#[derive(Copy, Clone, Debug, Default, Deserialize)]
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#[repr(C, packed)]
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@ -244,106 +241,35 @@ impl PmemEpollHandler {
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})
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}
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fn run(&mut self, paused: Arc<AtomicBool>) -> result::Result<(), DeviceError> {
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// Create the epoll file descriptor
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let epoll_fd = epoll::create(true).map_err(DeviceError::EpollCreateFd)?;
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// Use 'File' to enforce closing on 'epoll_fd'
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let epoll_file = unsafe { File::from_raw_fd(epoll_fd) };
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fn run(&mut self, paused: Arc<AtomicBool>) -> result::Result<(), EpollHelperError> {
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let mut helper = EpollHelper::new(&self.kill_evt, &self.pause_evt)?;
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helper.add_event(self.queue_evt.as_raw_fd(), QUEUE_AVAIL_EVENT)?;
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helper.run(paused, self)?;
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// Add events
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epoll::ctl(
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epoll_file.as_raw_fd(),
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epoll::ControlOptions::EPOLL_CTL_ADD,
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self.queue_evt.as_raw_fd(),
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epoll::Event::new(epoll::Events::EPOLLIN, u64::from(QUEUE_AVAIL_EVENT)),
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)
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.map_err(DeviceError::EpollCtl)?;
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epoll::ctl(
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epoll_file.as_raw_fd(),
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epoll::ControlOptions::EPOLL_CTL_ADD,
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self.kill_evt.as_raw_fd(),
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epoll::Event::new(epoll::Events::EPOLLIN, u64::from(KILL_EVENT)),
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)
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.map_err(DeviceError::EpollCtl)?;
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Ok(())
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}
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}
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epoll::ctl(
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epoll_file.as_raw_fd(),
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epoll::ControlOptions::EPOLL_CTL_ADD,
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self.pause_evt.as_raw_fd(),
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epoll::Event::new(epoll::Events::EPOLLIN, u64::from(PAUSE_EVENT)),
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)
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.map_err(DeviceError::EpollCtl)?;
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const EPOLL_EVENTS_LEN: usize = 100;
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let mut events = vec![epoll::Event::new(epoll::Events::empty(), 0); EPOLL_EVENTS_LEN];
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// Before jumping into the epoll loop, check if the device is expected
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// to be in a paused state. This is helpful for the restore code path
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// as the device thread should not start processing anything before the
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// device has been resumed.
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while paused.load(Ordering::SeqCst) {
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thread::park();
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}
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'epoll: loop {
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let num_events = match epoll::wait(epoll_file.as_raw_fd(), -1, &mut events[..]) {
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Ok(res) => res,
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Err(e) => {
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if e.kind() == io::ErrorKind::Interrupted {
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// It's well defined from the epoll_wait() syscall
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// documentation that the epoll loop can be interrupted
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// before any of the requested events occurred or the
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// timeout expired. In both those cases, epoll_wait()
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// returns an error of type EINTR, but this should not
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// be considered as a regular error. Instead it is more
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// appropriate to retry, by calling into epoll_wait().
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continue;
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}
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return Err(DeviceError::EpollWait(e));
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}
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};
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for event in events.iter().take(num_events) {
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let ev_type = event.data as u16;
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match ev_type {
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QUEUE_AVAIL_EVENT => {
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if let Err(e) = self.queue_evt.read() {
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error!("Failed to get queue event: {:?}", e);
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break 'epoll;
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} else if self.process_queue() {
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if let Err(e) = self.signal_used_queue() {
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error!("Failed to signal used queue: {:?}", e);
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break 'epoll;
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}
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}
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}
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KILL_EVENT => {
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debug!("kill_evt received, stopping epoll loop");
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break 'epoll;
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}
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PAUSE_EVENT => {
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debug!("PAUSE_EVENT received, pausing virtio-pmem epoll loop");
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// We loop here to handle spurious park() returns.
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// Until we have not resumed, the paused boolean will
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// be true.
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while paused.load(Ordering::SeqCst) {
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thread::park();
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}
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// Drain pause event after the device has been resumed.
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// This ensures the pause event has been seen by each
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// and every thread related to this virtio device.
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let _ = self.pause_evt.read();
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}
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_ => {
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error!("Unknown event for virtio-block");
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impl EpollHelperHandler for PmemEpollHandler {
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fn handle_event(&mut self, _helper: &mut EpollHelper, event: u16) -> bool {
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match event {
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QUEUE_AVAIL_EVENT => {
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if let Err(e) = self.queue_evt.read() {
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error!("Failed to get queue event: {:?}", e);
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return true;
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} else if self.process_queue() {
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if let Err(e) = self.signal_used_queue() {
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error!("Failed to signal used queue: {:?}", e);
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return true;
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}
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}
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}
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_ => {
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error!("Unexpected event: {}", event);
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return true;
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}
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}
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Ok(())
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false
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}
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}
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@ -357,7 +283,7 @@ pub struct Pmem {
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config: VirtioPmemConfig,
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queue_evts: Option<Vec<EventFd>>,
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interrupt_cb: Option<Arc<dyn VirtioInterrupt>>,
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epoll_threads: Option<Vec<thread::JoinHandle<result::Result<(), DeviceError>>>>,
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epoll_threads: Option<Vec<thread::JoinHandle<result::Result<(), EpollHelperError>>>>,
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paused: Arc<AtomicBool>,
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mapping: UserspaceMapping,
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