mirror of
https://github.com/cloud-hypervisor/cloud-hypervisor.git
synced 2024-10-28 07:33:09 +00:00
433 lines
14 KiB
Rust
433 lines
14 KiB
Rust
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// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
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//
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// Copyright © 2020 Intel Corporation
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// Portions Copyright 2017 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE-BSD-3-Clause file.
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use super::Error as DeviceError;
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use super::{
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ActivateError, ActivateResult, EpollHelper, EpollHelperError, EpollHelperHandler, Queue,
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VirtioCommon, VirtioDevice, VirtioDeviceType, EPOLL_HELPER_EVENT_LAST, VIRTIO_F_VERSION_1,
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};
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use crate::seccomp_filters::{get_seccomp_filter, Thread};
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use crate::{VirtioInterrupt, VirtioInterruptType};
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use anyhow::anyhow;
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use seccomp::{SeccompAction, SeccompFilter};
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use std::fs::File;
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use std::io::{self, Read};
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use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
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use std::result;
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use std::sync::atomic::AtomicBool;
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use std::sync::{Arc, Barrier, Mutex};
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use std::thread;
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use std::time::Instant;
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use vm_memory::{Bytes, GuestAddressSpace, GuestMemoryAtomic, GuestMemoryMmap};
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use vm_migration::{
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Migratable, MigratableError, Pausable, Snapshot, SnapshotDataSection, Snapshottable,
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Transportable,
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};
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use vmm_sys_util::eventfd::EventFd;
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const QUEUE_SIZE: u16 = 8;
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const QUEUE_SIZES: &[u16] = &[QUEUE_SIZE];
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// New descriptors are pending on the virtio queue.
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const QUEUE_AVAIL_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 1;
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// Timer expired
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const TIMER_EXPIRED_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 2;
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// Number of seconds to check to see if there has been a ping
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// This needs to match what the driver is using.
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const WATCHDOG_TIMER_INTERVAL: i64 = 15;
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// Number of seconds since last ping to trigger reboot
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const WATCHDOG_TIMEOUT: u64 = WATCHDOG_TIMER_INTERVAL as u64 + 5;
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struct WatchdogEpollHandler {
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queues: Vec<Queue>,
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mem: GuestMemoryAtomic<GuestMemoryMmap>,
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interrupt_cb: Arc<dyn VirtioInterrupt>,
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queue_evt: EventFd,
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kill_evt: EventFd,
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pause_evt: EventFd,
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timer: File,
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last_ping_time: Arc<Mutex<Option<Instant>>>,
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reset_evt: EventFd,
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}
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impl WatchdogEpollHandler {
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// The main queue is very simple - the driver "pings" the device by passing it a (write-only)
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// descriptor. In response the device writes a 1 into the descriptor and returns it to the driver
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fn process_queue(&mut self) -> bool {
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let queue = &mut self.queues[0];
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let mut used_desc_heads = [(0, 0); QUEUE_SIZE as usize];
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let mut used_count = 0;
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let mem = self.mem.memory();
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for avail_desc in queue.iter(&mem) {
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let mut len = 0;
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if avail_desc.is_write_only() && mem.write_obj(1u8, avail_desc.addr).is_ok() {
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len = avail_desc.len;
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// If this is the first "ping" then setup the timer
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if self.last_ping_time.lock().unwrap().is_none() {
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info!(
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"First ping received. Starting timer (every {} seconds)",
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WATCHDOG_TIMER_INTERVAL
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);
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if let Err(e) = timerfd_setup(&self.timer, WATCHDOG_TIMER_INTERVAL) {
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error!("Error programming timer fd: {:?}", e);
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}
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}
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self.last_ping_time.lock().unwrap().replace(Instant::now());
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}
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used_desc_heads[used_count] = (avail_desc.index, len);
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used_count += 1;
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}
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for &(desc_index, len) in &used_desc_heads[..used_count] {
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queue.add_used(&mem, desc_index, len);
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}
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used_count > 0
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}
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fn signal_used_queue(&self) -> result::Result<(), DeviceError> {
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self.interrupt_cb
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.trigger(&VirtioInterruptType::Queue, Some(&self.queues[0]))
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.map_err(|e| {
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error!("Failed to signal used queue: {:?}", e);
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DeviceError::FailedSignalingUsedQueue(e)
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})
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}
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fn run(
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&mut self,
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paused: Arc<AtomicBool>,
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paused_sync: Arc<Barrier>,
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) -> 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.add_event(self.timer.as_raw_fd(), TIMER_EXPIRED_EVENT)?;
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helper.run(paused, paused_sync, self)?;
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Ok(())
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}
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}
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impl EpollHelperHandler for WatchdogEpollHandler {
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fn handle_event(&mut self, _helper: &mut EpollHelper, event: &epoll::Event) -> bool {
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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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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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TIMER_EXPIRED_EVENT => {
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// When reading from the timerfd you get 8 bytes indicating
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// the number of times this event has elapsed since the last read.
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let mut buf = vec![0; 8];
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if let Err(e) = self.timer.read_exact(&mut buf) {
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error!("Error reading from timer fd: {:}", e);
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return true;
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}
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if let Some(last_ping_time) = self.last_ping_time.lock().unwrap().as_ref() {
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let now = Instant::now();
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let gap = now.duration_since(*last_ping_time).as_secs();
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if gap > WATCHDOG_TIMEOUT {
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error!("Watchdog triggered: {} seconds since last ping", gap);
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self.reset_evt.write(1).ok();
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}
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}
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return false;
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}
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_ => {
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error!("Unexpected event: {}", ev_type);
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return true;
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}
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}
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false
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}
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}
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/// Virtio device for exposing a watchdog to the guest
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pub struct Watchdog {
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common: VirtioCommon,
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id: String,
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seccomp_action: SeccompAction,
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reset_evt: EventFd,
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last_ping_time: Arc<Mutex<Option<Instant>>>,
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timer: File,
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}
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#[derive(Serialize, Deserialize)]
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pub struct WatchdogState {
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pub avail_features: u64,
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pub acked_features: u64,
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pub enabled: bool,
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}
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impl Watchdog {
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/// Create a new virtio watchdog device that will reboot VM if the guest hangs
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pub fn new(
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id: String,
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reset_evt: EventFd,
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seccomp_action: SeccompAction,
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) -> io::Result<Watchdog> {
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let avail_features = 1u64 << VIRTIO_F_VERSION_1;
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let timer_fd = timerfd_create().map_err(|e| {
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error!("Failed to create timer fd {}", e);
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e
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})?;
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let timer = unsafe { File::from_raw_fd(timer_fd) };
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Ok(Watchdog {
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common: VirtioCommon {
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device_type: VirtioDeviceType::TYPE_WATCHDOG as u32,
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queue_sizes: QUEUE_SIZES.to_vec(),
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paused_sync: Some(Arc::new(Barrier::new(2))),
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avail_features,
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..Default::default()
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},
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id,
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seccomp_action,
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reset_evt,
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last_ping_time: Arc::new(Mutex::new(None)),
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timer,
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})
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}
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fn state(&self) -> WatchdogState {
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WatchdogState {
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avail_features: self.common.avail_features,
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acked_features: self.common.acked_features,
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enabled: self.last_ping_time.lock().unwrap().is_some(),
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}
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}
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fn set_state(&mut self, state: &WatchdogState) -> io::Result<()> {
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self.common.avail_features = state.avail_features;
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self.common.acked_features = state.acked_features;
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// When restoring enable the watchdog if it was previously enabled. We reset the timer
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// to ensure that we don't unnecesarily reboot due to the offline time.
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if state.enabled {
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self.last_ping_time.lock().unwrap().replace(Instant::now());
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}
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Ok(())
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}
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}
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impl Drop for Watchdog {
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fn drop(&mut self) {
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if let Some(kill_evt) = self.common.kill_evt.take() {
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// Ignore the result because there is nothing we can do about it.
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let _ = kill_evt.write(1);
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}
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}
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}
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fn timerfd_create() -> Result<RawFd, io::Error> {
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let res = unsafe { libc::timerfd_create(libc::CLOCK_MONOTONIC, 0) };
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if res < 0 {
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Err(io::Error::last_os_error())
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} else {
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Ok(res as RawFd)
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}
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}
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fn timerfd_setup(timer: &File, secs: i64) -> Result<(), io::Error> {
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let periodic = libc::itimerspec {
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it_interval: libc::timespec {
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tv_sec: secs,
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tv_nsec: 0,
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},
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it_value: libc::timespec {
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tv_sec: secs,
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tv_nsec: 0,
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},
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};
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let res =
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unsafe { libc::timerfd_settime(timer.as_raw_fd(), 0, &periodic, std::ptr::null_mut()) };
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if res < 0 {
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Err(io::Error::last_os_error())
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} else {
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Ok(())
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}
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}
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impl VirtioDevice for Watchdog {
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fn device_type(&self) -> u32 {
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self.common.device_type
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}
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fn queue_max_sizes(&self) -> &[u16] {
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&self.common.queue_sizes
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}
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fn features(&self) -> u64 {
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self.common.avail_features
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}
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fn ack_features(&mut self, value: u64) {
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self.common.ack_features(value)
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}
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fn activate(
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&mut self,
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mem: GuestMemoryAtomic<GuestMemoryMmap>,
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interrupt_cb: Arc<dyn VirtioInterrupt>,
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queues: Vec<Queue>,
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mut queue_evts: Vec<EventFd>,
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) -> ActivateResult {
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self.common.activate(&queues, &queue_evts, &interrupt_cb)?;
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let kill_evt = self
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.common
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.kill_evt
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.as_ref()
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.unwrap()
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.try_clone()
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.map_err(|e| {
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error!("Failed to clone kill_evt eventfd: {}", e);
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ActivateError::BadActivate
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})?;
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let pause_evt = self
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.common
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.pause_evt
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.as_ref()
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.unwrap()
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.try_clone()
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.map_err(|e| {
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error!("Failed to clone pause_evt eventfd: {}", e);
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ActivateError::BadActivate
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})?;
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let reset_evt = self.reset_evt.try_clone().map_err(|e| {
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error!("Failed to clone reset_evt eventfd: {}", e);
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ActivateError::BadActivate
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})?;
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let timer = self.timer.try_clone().map_err(|e| {
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error!("Failed to clone timer fd: {}", e);
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ActivateError::BadActivate
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})?;
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let mut handler = WatchdogEpollHandler {
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queues,
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mem,
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interrupt_cb,
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queue_evt: queue_evts.remove(0),
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kill_evt,
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pause_evt,
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timer,
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last_ping_time: self.last_ping_time.clone(),
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reset_evt,
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};
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let paused = self.common.paused.clone();
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let paused_sync = self.common.paused_sync.clone();
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let mut epoll_threads = Vec::new();
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// Retrieve seccomp filter for virtio_watchdog thread
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let virtio_watchdog_seccomp_filter =
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get_seccomp_filter(&self.seccomp_action, Thread::VirtioWatchdog)
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.map_err(ActivateError::CreateSeccompFilter)?;
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thread::Builder::new()
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.name("virtio_watchdog".to_string())
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.spawn(move || {
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if let Err(e) = SeccompFilter::apply(virtio_watchdog_seccomp_filter) {
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error!("Error applying seccomp filter: {:?}", e);
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} else if let Err(e) = handler.run(paused, paused_sync.unwrap()) {
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error!("Error running worker: {:?}", e);
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}
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})
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.map(|thread| epoll_threads.push(thread))
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.map_err(|e| {
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error!("failed to clone the virtio-watchdog epoll thread: {}", e);
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ActivateError::BadActivate
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})?;
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self.common.epoll_threads = Some(epoll_threads);
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Ok(())
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}
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fn reset(&mut self) -> Option<(Arc<dyn VirtioInterrupt>, Vec<EventFd>)> {
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self.common.reset()
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}
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}
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impl Pausable for Watchdog {
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fn pause(&mut self) -> result::Result<(), MigratableError> {
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info!("Watchdog paused - disabling timer");
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timerfd_setup(&self.timer, 0)
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.map_err(|e| MigratableError::Pause(anyhow!("Error clearing timer: {:?}", e)))?;
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self.common.pause()
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}
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fn resume(&mut self) -> result::Result<(), MigratableError> {
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// Reset the timer on pause if it was previously used
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if self.last_ping_time.lock().unwrap().is_some() {
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info!(
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"Watchdog resumed - enabling timer (every {} seconds)",
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WATCHDOG_TIMER_INTERVAL
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);
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self.last_ping_time.lock().unwrap().replace(Instant::now());
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timerfd_setup(&self.timer, WATCHDOG_TIMER_INTERVAL)
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.map_err(|e| MigratableError::Resume(anyhow!("Error setting timer: {:?}", e)))?;
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}
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self.common.resume()
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}
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}
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impl Snapshottable for Watchdog {
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fn id(&self) -> String {
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self.id.clone()
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}
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fn snapshot(&mut self) -> std::result::Result<Snapshot, MigratableError> {
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let snapshot =
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serde_json::to_vec(&self.state()).map_err(|e| MigratableError::Snapshot(e.into()))?;
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let mut watchdog_snapshot = Snapshot::new(self.id.as_str());
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watchdog_snapshot.add_data_section(SnapshotDataSection {
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id: format!("{}-section", self.id),
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snapshot,
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});
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Ok(watchdog_snapshot)
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}
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fn restore(&mut self, snapshot: Snapshot) -> std::result::Result<(), MigratableError> {
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if let Some(watchdog_section) = snapshot.snapshot_data.get(&format!("{}-section", self.id))
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{
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let watchdog_state = match serde_json::from_slice(&watchdog_section.snapshot) {
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Ok(state) => state,
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Err(error) => {
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return Err(MigratableError::Restore(anyhow!(
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"Could not deserialize watchdog {}",
|
||
|
error
|
||
|
)))
|
||
|
}
|
||
|
};
|
||
|
|
||
|
return self.set_state(&watchdog_state).map_err(|e| {
|
||
|
MigratableError::Restore(anyhow!("Could not restore watchdog state {:?}", e))
|
||
|
});
|
||
|
}
|
||
|
|
||
|
Err(MigratableError::Restore(anyhow!(
|
||
|
"Could not find watchdog snapshot section"
|
||
|
)))
|
||
|
}
|
||
|
}
|
||
|
|
||
|
impl Transportable for Watchdog {}
|
||
|
impl Migratable for Watchdog {}
|