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// Copyright 2017 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
use std::os::raw::c_ulonglong;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Arc;
use sync::Mutex;
use sys_util::{EventFd, PollContext, PollToken};
use vhost::Vhost;
use super::{Error, Result};
use crate::pci::MsixConfig;
use crate::virtio::{Queue, INTERRUPT_STATUS_USED_RING};
/// Worker that takes care of running the vhost device. This mainly involves forwarding interrupts
/// from the vhost driver to the guest VM because crosvm only supports the virtio-mmio transport,
/// which requires a bit to be set in the interrupt status register before triggering the interrupt
/// and the vhost driver doesn't do this for us.
pub struct Worker<T: Vhost> {
queues: Vec<Queue>,
vhost_handle: T,
vhost_interrupt: Vec<EventFd>,
interrupt_status: Arc<AtomicUsize>,
interrupt_evt: EventFd,
interrupt_resample_evt: EventFd,
msix_config: Option<Arc<Mutex<MsixConfig>>>,
acked_features: u64,
}
impl<T: Vhost> Worker<T> {
pub fn new(
queues: Vec<Queue>,
vhost_handle: T,
vhost_interrupt: Vec<EventFd>,
interrupt_status: Arc<AtomicUsize>,
interrupt_evt: EventFd,
interrupt_resample_evt: EventFd,
msix_config: Option<Arc<Mutex<MsixConfig>>>,
acked_features: u64,
) -> Worker<T> {
Worker {
queues,
vhost_handle,
vhost_interrupt,
interrupt_status,
interrupt_evt,
interrupt_resample_evt,
msix_config,
acked_features,
}
}
fn signal_used_queue(&self, vector: u16) {
if let Some(msix_config) = &self.msix_config {
let mut msix_config = msix_config.lock();
if msix_config.enabled() {
msix_config.trigger(vector);
return;
}
}
self.interrupt_status
.fetch_or(INTERRUPT_STATUS_USED_RING as usize, Ordering::SeqCst);
self.interrupt_evt.write(1).unwrap();
}
pub fn run<F>(
&mut self,
queue_evts: Vec<EventFd>,
queue_sizes: &[u16],
kill_evt: EventFd,
activate_vqs: F,
) -> Result<()>
where
F: FnOnce(&T) -> Result<()>,
{
// Preliminary setup for vhost net.
self.vhost_handle
.set_owner()
.map_err(Error::VhostSetOwner)?;
let avail_features = self
.vhost_handle
.get_features()
.map_err(Error::VhostGetFeatures)?;
let features: c_ulonglong = self.acked_features & avail_features;
self.vhost_handle
.set_features(features)
.map_err(Error::VhostSetFeatures)?;
self.vhost_handle
.set_mem_table()
.map_err(Error::VhostSetMemTable)?;
for (queue_index, queue) in self.queues.iter().enumerate() {
self.vhost_handle
.set_vring_num(queue_index, queue.max_size)
.map_err(Error::VhostSetVringNum)?;
self.vhost_handle
.set_vring_addr(
queue_sizes[queue_index],
queue.actual_size(),
queue_index,
0,
queue.desc_table,
queue.used_ring,
queue.avail_ring,
None,
)
.map_err(Error::VhostSetVringAddr)?;
self.vhost_handle
.set_vring_base(queue_index, 0)
.map_err(Error::VhostSetVringBase)?;
self.vhost_handle
.set_vring_call(queue_index, &self.vhost_interrupt[queue_index])
.map_err(Error::VhostSetVringCall)?;
self.vhost_handle
.set_vring_kick(queue_index, &queue_evts[queue_index])
.map_err(Error::VhostSetVringKick)?;
}
activate_vqs(&self.vhost_handle)?;
#[derive(PollToken)]
enum Token {
VhostIrqi { index: usize },
InterruptResample,
Kill,
}
let poll_ctx: PollContext<Token> = PollContext::build_with(&[
(&self.interrupt_resample_evt, Token::InterruptResample),
(&kill_evt, Token::Kill),
])
.map_err(Error::CreatePollContext)?;
for (index, vhost_int) in self.vhost_interrupt.iter().enumerate() {
poll_ctx
.add(vhost_int, Token::VhostIrqi { index })
.map_err(Error::CreatePollContext)?;
}
'poll: loop {
let events = poll_ctx.wait().map_err(Error::PollError)?;
for event in events.iter_readable() {
match event.token() {
Token::VhostIrqi { index } => {
self.vhost_interrupt[index]
.read()
.map_err(Error::VhostIrqRead)?;
self.signal_used_queue(self.queues[index].vector);
}
Token::InterruptResample => {
let _ = self.interrupt_resample_evt.read();
if self.interrupt_status.load(Ordering::SeqCst) != 0 {
self.interrupt_evt.write(1).unwrap();
}
}
Token::Kill => break 'poll,
}
}
}
Ok(())
}
}
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