cloud-hypervisor/vm-virtio/src/console.rs

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// Copyright 2019 Intel Corporation. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
use epoll;
use libc::EFD_NONBLOCK;
use std;
use std::cmp;
use std::collections::VecDeque;
use std::io;
use std::io::Write;
use std::os::unix::io::AsRawFd;
use std::result;
use std::sync::{Arc, Mutex, RwLock};
use std::thread;
use super::Error as DeviceError;
use super::{
ActivateError, ActivateResult, DeviceEventT, Queue, VirtioDevice, VirtioDeviceType,
VirtioInterruptType, VIRTIO_F_VERSION_1,
};
use crate::VirtioInterrupt;
use std::sync::atomic::{AtomicU64, Ordering};
use vm_memory::{ByteValued, Bytes, GuestMemoryMmap};
use vmm_sys_util::eventfd::EventFd;
const QUEUE_SIZE: u16 = 256;
const NUM_QUEUES: usize = 2;
const QUEUE_SIZES: &[u16] = &[QUEUE_SIZE; NUM_QUEUES];
// New descriptors are pending on the virtio queue.
const INPUT_QUEUE_EVENT: DeviceEventT = 0;
const OUTPUT_QUEUE_EVENT: DeviceEventT = 1;
// Some input from the VMM is ready to be injected into the VM.
const INPUT_EVENT: DeviceEventT = 2;
// The device has been dropped.
const KILL_EVENT: DeviceEventT = 3;
// Console configuration change event is triggered.
const CONFIG_EVENT: DeviceEventT = 4;
//Console size feature bit
const VIRTIO_CONSOLE_F_SIZE: u64 = 0;
#[derive(Copy, Clone, Debug, Default)]
#[repr(C)]
pub struct VirtioConsoleConfig {
cols: u16,
rows: u16,
max_nr_ports: u32,
emerg_wr: u32,
}
// Safe because it only has data and has no implicit padding.
unsafe impl ByteValued for VirtioConsoleConfig {}
struct ConsoleEpollHandler {
queues: Vec<Queue>,
mem: Arc<RwLock<GuestMemoryMmap>>,
interrupt_cb: Arc<VirtioInterrupt>,
in_buffer: Arc<Mutex<VecDeque<u8>>>,
out: Box<dyn io::Write + Send>,
input_queue_evt: EventFd,
output_queue_evt: EventFd,
input_evt: EventFd,
config_evt: EventFd,
kill_evt: EventFd,
}
impl ConsoleEpollHandler {
/*
* Each port of virtio console device has one receive
* queue. One or more empty buffers are placed by the
* dirver in the receive queue for incoming data. Here,
* we place the input data to these empty buffers.
*/
fn process_input_queue(&mut self) -> bool {
let mut in_buffer = self.in_buffer.lock().unwrap();
let count = in_buffer.len();
let recv_queue = &mut self.queues[0]; //receiveq
let mut used_desc_heads = [(0, 0); QUEUE_SIZE as usize];
let mut used_count = 0;
let mut write_count = 0;
let mem = self.mem.read().unwrap();
for avail_desc in recv_queue.iter(&mem) {
let len;
let limit = cmp::min(write_count + avail_desc.len as u32, count as u32);
let source_slice = in_buffer
.drain(write_count as usize..limit as usize)
.collect::<Vec<u8>>();
let write_result = mem.write_slice(&source_slice[..], avail_desc.addr);
match write_result {
Ok(_) => {
len = limit - write_count; //avail_desc.len;
write_count = limit;
}
Err(e) => {
error!("Failed to write slice: {:?}", e);
break;
}
}
used_desc_heads[used_count] = (avail_desc.index, len);
used_count += 1;
if write_count >= count as u32 {
break;
}
}
for &(desc_index, len) in &used_desc_heads[..used_count] {
recv_queue.add_used(&mem, desc_index, len);
}
used_count > 0
}
/*
* Each port of virtio console device has one transmit
* queue. For outgoing data, characters are placed in
* the transmit queue by the driver. Therefore, here
* we read data from the transmit queue and flush them
* to the referenced address.
*/
fn process_output_queue(&mut self) -> bool {
let trans_queue = &mut self.queues[1]; //transmitq
let mut used_desc_heads = [(0, 0); QUEUE_SIZE as usize];
let mut used_count = 0;
let mem = self.mem.read().unwrap();
for avail_desc in trans_queue.iter(&mem) {
let len;
let _ = mem.write_to(avail_desc.addr, &mut self.out, avail_desc.len as usize);
let _ = self.out.flush();
len = avail_desc.len;
used_desc_heads[used_count] = (avail_desc.index, len);
used_count += 1;
}
for &(desc_index, len) in &used_desc_heads[..used_count] {
trans_queue.add_used(&mem, desc_index, len);
}
used_count > 0
}
fn signal_used_queue(&self) -> result::Result<(), DeviceError> {
(self.interrupt_cb)(&VirtioInterruptType::Queue, Some(&self.queues[0])).map_err(|e| {
error!("Failed to signal used queue: {:?}", e);
DeviceError::FailedSignalingUsedQueue(e)
})
}
fn run(&mut self) -> result::Result<(), DeviceError> {
// Create the epoll file descriptor
let epoll_fd = epoll::create(true).map_err(DeviceError::EpollCreateFd)?;
// Add events
epoll::ctl(
epoll_fd,
epoll::ControlOptions::EPOLL_CTL_ADD,
self.input_queue_evt.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(INPUT_QUEUE_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_fd,
epoll::ControlOptions::EPOLL_CTL_ADD,
self.output_queue_evt.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(OUTPUT_QUEUE_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_fd,
epoll::ControlOptions::EPOLL_CTL_ADD,
self.input_evt.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(INPUT_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_fd,
epoll::ControlOptions::EPOLL_CTL_ADD,
self.config_evt.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, u64::from(CONFIG_EVENT)),
)
.map_err(DeviceError::EpollCtl)?;
epoll::ctl(
epoll_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)?;
const EPOLL_EVENTS_LEN: usize = 100;
let mut events = vec![epoll::Event::new(epoll::Events::empty(), 0); EPOLL_EVENTS_LEN];
'epoll: loop {
let num_events = match epoll::wait(epoll_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 {
INPUT_QUEUE_EVENT => {
if let Err(e) = self.input_queue_evt.read() {
error!("Failed to get queue event: {:?}", e);
break 'epoll;
}
}
OUTPUT_QUEUE_EVENT => {
if let Err(e) = self.output_queue_evt.read() {
error!("Failed to get queue event: {:?}", e);
break 'epoll;
} else {
self.process_output_queue();
}
}
INPUT_EVENT => {
if let Err(e) = self.input_evt.read() {
error!("Failed to get input event: {:?}", e);
break 'epoll;
} else if self.process_input_queue() {
if let Err(e) = self.signal_used_queue() {
error!("Failed to signal used queue: {:?}", e);
break 'epoll;
}
}
}
CONFIG_EVENT => {
if let Err(e) = self.config_evt.read() {
error!("Failed to get config event: {:?}", e);
break 'epoll;
} else if let Err(e) =
(self.interrupt_cb)(&VirtioInterruptType::Config, None)
{
error!("Failed to signal console driver: {:?}", e);
}
}
KILL_EVENT => {
debug!("KILL_EVENT received, stopping epoll loop");
break 'epoll;
}
_ => {
error!("Unknown event for virtio-console");
}
}
}
}
Ok(())
}
}
/// Input device.
pub struct ConsoleInput {
input_evt: EventFd,
config_evt: EventFd,
in_buffer: Arc<Mutex<VecDeque<u8>>>,
config: Arc<Mutex<VirtioConsoleConfig>>,
acked_features: AtomicU64,
}
impl ConsoleInput {
pub fn queue_input_bytes(&self, input: &[u8]) {
let mut in_buffer = self.in_buffer.lock().unwrap();
in_buffer.extend(input);
let _ = self.input_evt.write(1);
}
pub fn update_console_size(&self, cols: u16, rows: u16) {
if self
.acked_features
.fetch_and(1u64 << VIRTIO_CONSOLE_F_SIZE, Ordering::SeqCst)
!= 0
{
self.config.lock().unwrap().update_console_size(cols, rows);
//Send the interrupt to the driver
let _ = self.config_evt.write(1);
}
}
}
impl VirtioConsoleConfig {
pub fn new(cols: u16, rows: u16) -> Self {
VirtioConsoleConfig {
cols,
rows,
max_nr_ports: 1u32,
emerg_wr: 0u32,
}
}
pub fn update_console_size(&mut self, cols: u16, rows: u16) {
self.cols = cols;
self.rows = rows;
}
}
/// Virtio device for exposing console to the guest OS through virtio.
pub struct Console {
kill_evt: Option<EventFd>,
avail_features: u64,
acked_features: u64,
config: Arc<Mutex<VirtioConsoleConfig>>,
input: Arc<ConsoleInput>,
out: Option<Box<dyn io::Write + Send>>,
}
impl Console {
/// Create a new virtio console device that gets random data from /dev/urandom.
pub fn new(
out: Option<Box<dyn io::Write + Send>>,
cols: u16,
rows: u16,
) -> io::Result<(Console, Arc<ConsoleInput>)> {
let avail_features = 1u64 << VIRTIO_F_VERSION_1 | 1u64 << VIRTIO_CONSOLE_F_SIZE;
let input_evt = EventFd::new(EFD_NONBLOCK).unwrap();
let config_evt = EventFd::new(EFD_NONBLOCK).unwrap();
let console_config = Arc::new(Mutex::new(VirtioConsoleConfig::new(cols, rows)));
let console_input = Arc::new(ConsoleInput {
input_evt,
config_evt,
in_buffer: Arc::new(Mutex::new(VecDeque::new())),
config: console_config.clone(),
acked_features: AtomicU64::new(0),
});
Ok((
Console {
kill_evt: None,
avail_features,
acked_features: 0u64,
config: console_config,
input: console_input.clone(),
out,
},
console_input,
))
}
}
impl Drop for Console {
fn drop(&mut self) {
if let Some(kill_evt) = self.kill_evt.take() {
// Ignore the result because there is nothing we can do about it.
let _ = kill_evt.write(1);
}
}
}
impl VirtioDevice for Console {
fn device_type(&self) -> u32 {
VirtioDeviceType::TYPE_CONSOLE as u32
}
fn queue_max_sizes(&self) -> &[u16] {
QUEUE_SIZES
}
fn features(&self, page: u32) -> u32 {
match page {
// Get the lower 32-bits of the features bitfield.
0 => self.avail_features as u32,
// Get the upper 32-bits of the features bitfield.
1 => (self.avail_features >> 32) as u32,
_ => {
warn!("Received request for unknown features page.");
0u32
}
}
}
fn ack_features(&mut self, page: u32, value: u32) {
let mut v = match page {
0 => u64::from(value),
1 => u64::from(value) << 32,
_ => {
warn!("Cannot acknowledge unknown features page.");
0u64
}
};
// Check if the guest is ACK'ing a feature that we didn't claim to have.
let unrequested_features = v & !self.avail_features;
if unrequested_features != 0 {
warn!("Received acknowledge request for unknown feature.");
// Don't count these features as acked.
v &= !unrequested_features;
}
self.acked_features |= v;
}
fn read_config(&self, offset: u64, mut data: &mut [u8]) {
let config = self.config.lock().unwrap();
let config_slice = config.as_slice();
let config_len = config_slice.len() as u64;
if offset >= config_len {
error!("Failed to read config space");
return;
}
if let Some(end) = offset.checked_add(data.len() as u64) {
// This write can't fail, offset and end are checked against config_len.
data.write_all(&config_slice[offset as usize..cmp::min(end, config_len) as usize])
.unwrap();
}
}
fn write_config(&mut self, _offset: u64, _data: &[u8]) {
warn!("No device specific configration requires write");
}
fn activate(
&mut self,
mem: Arc<RwLock<GuestMemoryMmap>>,
interrupt_cb: Arc<VirtioInterrupt>,
queues: Vec<Queue>,
mut queue_evts: Vec<EventFd>,
) -> ActivateResult {
if queues.len() != NUM_QUEUES || queue_evts.len() != NUM_QUEUES {
error!(
"Cannot perform activate. Expected {} queue(s), got {}",
NUM_QUEUES,
queues.len()
);
return Err(ActivateError::BadActivate);
}
let (self_kill_evt, kill_evt) =
match EventFd::new(EFD_NONBLOCK).and_then(|e| Ok((e.try_clone()?, e))) {
Ok(v) => v,
Err(e) => {
error!("failed creating kill EventFd pair: {}", e);
return Err(ActivateError::BadActivate);
}
};
self.kill_evt = Some(self_kill_evt);
self.input
.acked_features
.store(self.acked_features, Ordering::Relaxed);
if (self.acked_features & (1u64 << VIRTIO_CONSOLE_F_SIZE)) != 0 {
if let Err(e) = (interrupt_cb)(&VirtioInterruptType::Config, None) {
error!("Failed to signal console driver: {:?}", e);
}
}
if let Some(out) = self.out.take() {
let mut handler = ConsoleEpollHandler {
queues,
mem,
interrupt_cb,
in_buffer: self.input.in_buffer.clone(),
out,
input_queue_evt: queue_evts.remove(0),
output_queue_evt: queue_evts.remove(0),
input_evt: self.input.input_evt.try_clone().unwrap(),
config_evt: self.input.config_evt.try_clone().unwrap(),
kill_evt,
};
let worker_result = thread::Builder::new()
.name("virtio_console".to_string())
.spawn(move || handler.run());
if let Err(e) = worker_result {
error!("failed to spawn virtio_console worker: {}", e);
return Err(ActivateError::BadActivate);;
}
return Ok(());
}
Err(ActivateError::BadActivate)
}
}