virtio-devices: mem: 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>
This commit is contained in:
Rob Bradford 2020-08-04 12:16:44 +01:00 committed by Sebastien Boeuf
parent d4754e18f9
commit 66efe3cf53

View File

@ -14,16 +14,17 @@
use super::Error as DeviceError;
use super::{
ActivateError, ActivateResult, DescriptorChain, DeviceEventT, Queue, VirtioDevice,
VirtioDeviceType, VIRTIO_F_VERSION_1,
ActivateError, ActivateResult, DescriptorChain, EpollHelper, EpollHelperError,
EpollHelperHandler, Queue, VirtioDevice, VirtioDeviceType, EPOLL_HELPER_EVENT_LAST,
VIRTIO_F_VERSION_1,
};
use crate::{VirtioInterrupt, VirtioInterruptType};
use libc::EFD_NONBLOCK;
use std::cmp;
use std::fs::File;
use std::io;
use std::mem::size_of;
use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
use std::os::unix::io::{AsRawFd, RawFd};
use std::result;
use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
use std::sync::mpsc;
@ -84,13 +85,9 @@ const VIRTIO_MEM_REQ_UNPLUG_ALL: u16 = 2;
const VIRTIO_MEM_REQ_STATE: u16 = 3;
// Get resize event.
const RESIZE_EVENT: DeviceEventT = 0;
const RESIZE_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 1;
// New descriptors are pending on the virtio queue.
const QUEUE_AVAIL_EVENT: DeviceEventT = 1;
// The device has been dropped.
const KILL_EVENT: DeviceEventT = 2;
// The device should be paused.
const PAUSE_EVENT: DeviceEventT = 3;
const QUEUE_AVAIL_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 2;
#[derive(Debug)]
pub enum Error {
@ -592,177 +589,85 @@ impl MemEpollHandler {
used_count > 0
}
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) };
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.resize.evt.as_raw_fd(), RESIZE_EVENT)?;
helper.add_event(self.queue_evt.as_raw_fd(), QUEUE_AVAIL_EVENT)?;
helper.run(paused, self)?;
// Add events
epoll::ctl(
epoll_file.as_raw_fd(),
epoll::ControlOptions::EPOLL_CTL_ADD,
self.resize.evt.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(RESIZE_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
Ok(())
}
}
epoll::ctl(
epoll_file.as_raw_fd(),
epoll::ControlOptions::EPOLL_CTL_ADD,
self.queue_evt.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(QUEUE_AVAIL_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)?;
const EPOLL_EVENTS_LEN: usize = 100;
let mut events = vec![epoll::Event::new(epoll::Events::empty(), 0); EPOLL_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 ev_type = event.data as u16;
match ev_type {
RESIZE_EVENT => {
if let Err(e) = self.resize.evt.read() {
return Err(DeviceError::EpollHander(format!(
"Failed to get resize event: {:?}",
e
)));
impl EpollHelperHandler for MemEpollHandler {
fn handle_event(&mut self, _helper: &mut EpollHelper, event: u16) -> bool {
match event {
RESIZE_EVENT => {
if let Err(e) = self.resize.evt.read() {
error!("Failed to get resize event: {:?}", e);
return true;
} else {
let size = self.resize.get_size();
let mut config = self.config.lock().unwrap();
let mut signal_error = false;
let r = if config.requested_size == size {
Err(Error::ResizeInval(format!(
"Virtio-mem resize {} is same with current config.requested_size",
size
)))
} else if size > config.region_size {
let region_size = config.region_size;
Err(Error::ResizeInval(format!(
"Virtio-mem resize {} is bigger than config.region_size {}",
size, region_size
)))
} else if size % (config.block_size as u64) != 0 {
let block_size = config.block_size;
Err(Error::ResizeInval(format!(
"Virtio-mem resize {} is not aligned with config.block_size {}",
size, block_size
)))
} else {
config.requested_size = size;
let tmp_size = cmp::min(
config.region_size,
config.requested_size + VIRTIO_MEM_USABLE_EXTENT,
);
config.usable_region_size = cmp::max(config.usable_region_size, tmp_size);
if let Err(e) = self.signal(&VirtioInterruptType::Config) {
signal_error = true;
error!("Error signalling config: {:?}", e);
Err(Error::ResizeTriggerFail(e))
} else {
let size = self.resize.get_size();
let mut config = self.config.lock().unwrap();
let mut signal_error = false;
let r = if config.requested_size == size {
Err(Error::ResizeInval(format!("Virtio-mem resize {} is same with current config.requested_size", size)))
} else if size > config.region_size {
let region_size = config.region_size;
Err(Error::ResizeInval(format!(
"Virtio-mem resize {} is bigger than config.region_size {}",
size, region_size
)))
} else if size % (config.block_size as u64) != 0 {
let block_size = config.block_size;
Err(Error::ResizeInval(format!(
"Virtio-mem resize {} is not aligned with config.block_size {}",
size, block_size
)))
} else {
config.requested_size = size;
let tmp_size = cmp::min(
config.region_size,
config.requested_size + VIRTIO_MEM_USABLE_EXTENT,
);
config.usable_region_size =
cmp::max(config.usable_region_size, tmp_size);
if let Err(e) = self.signal(&VirtioInterruptType::Config) {
signal_error = true;
Err(Error::ResizeTriggerFail(e))
} else {
Ok(())
}
};
if let Err(e) = &r {
// This error will send back to resize caller.
error!("Handle resize event get error: {:?}", e);
}
if let Err(e) = self.resize.send(r) {
return Err(DeviceError::EpollHander(format!(
"Sending \"resize\" generated error: {:?}",
e
)));
}
if signal_error {
return Err(DeviceError::EpollHander(String::from(
"Signal get error",
)));
}
Ok(())
}
};
if let Err(e) = self.resize.send(r) {
error!("Sending \"resize\" reponse: {:?}", e);
return true;
}
QUEUE_AVAIL_EVENT => {
if let Err(e) = self.queue_evt.read() {
return Err(DeviceError::EpollHander(format!(
"Failed to get queue event: {:?}",
e
)));
} else if self.process_queue() {
if let Err(e) = self.signal(&VirtioInterruptType::Queue) {
return Err(DeviceError::EpollHander(format!(
"Failed to signal used queue: {:?}",
e
)));
}
}
}
KILL_EVENT => {
debug!("kill_evt received, stopping epoll loop");
break 'epoll;
}
PAUSE_EVENT => {
debug!("PAUSE_EVENT received, pausing virtio-pmem 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();
}
_ => {
return Err(DeviceError::EpollHander(String::from(
"Unknown event for virtio-mem",
)));
if signal_error {
return true;
}
}
}
QUEUE_AVAIL_EVENT => {
if let Err(e) = self.queue_evt.read() {
error!("Failed to get queue event: {:?}", e);
return true;
} else if self.process_queue() {
if let Err(e) = self.signal(&VirtioInterruptType::Queue) {
error!("Failed to signal used queue: {:?}", e);
return true;
}
}
}
_ => {
error!("Unexpected event: {}", event);
return true;
}
}
Ok(())
false
}
}
@ -779,7 +684,7 @@ pub struct Mem {
config: Arc<Mutex<VirtioMemConfig>>,
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>,
}