// 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.
//! This module implements the virtio wayland used by the guest to access the host's wayland server.
//!
//! The virtio wayland protocol is done over two queues: `in` and `out`. The `in` queue is used for
//! sending commands to the guest that are generated by the host, usually messages from the wayland
//! server. The `out` queue is for commands from the guest, usually requests to allocate shared
//! memory, open a wayland server connection, or send data over an existing connection.
//!
//! Each `WlVfd` represents one virtual file descriptor created by either the guest or the host.
//! Virtual file descriptors contain actual file descriptors, either a shared memory file descriptor
//! or a unix domain socket to the wayland server. In the shared memory case, there is also an
//! associated slot that indicates which KVM memory slot the memory is installed into, as well as a
//! page frame number that the guest can access the memory from.
//!
//! The types starting with `Ctrl` are structures representing the virtio wayland protocol "on the
//! wire." They are decoded and executed in the `execute` function and encoded as some variant of
//! `WlResp` for responses.
//!
//! There is one `WlState` instance that contains every known vfd and the current state of `in`
//! queue. The `in` queue requires extra state to buffer messages to the guest in case the `in`
//! queue is already full. The `WlState` also has a control socket necessary to fulfill certain
//! requests, such as those registering guest memory.
//!
//! The `Worker` is responsible for the poll loop over all possible events, encoding/decoding from
//! the virtio queue, and routing messages in and out of `WlState`. Possible events include the kill
//! event, available descriptors on the `in` or `out` queue, and incoming data on any vfd's socket.
use std::collections::BTreeMap as Map;
use std::os::unix::io::{AsRawFd, RawFd};
use std::path::PathBuf;
use std::thread;
use super::resource_bridge::*;
use super::{Interrupt, InterruptProxyEvent, Queue, VirtioDevice, TYPE_WL, VIRTIO_F_VERSION_1};
use vm_control::{MaybeOwnedFd, VmMemoryControlRequestSocket};
use msg_socket::{MsgOnSocket, MsgReceiver, MsgSocket};
use serde::{Deserialize, Serialize};
use sys_util::net::UnixSeqpacket;
use sys_util::{error, EventFd, GuestMemory, PollContext, PollToken, SharedMemory};
#[derive(Debug, MsgOnSocket)]
pub enum MsgOnSocketRequest {
Create {
// wayland_paths: Map<String, PathBuf>,
vm_socket: MaybeOwnedFd<UnixSeqpacket>,
// resource_bridge: Option<ResourceRequestSocket>,
},
Activate {
shm: MaybeOwnedFd<SharedMemory>,
interrupt: MaybeOwnedFd<UnixSeqpacket>,
interrupt_resample_evt: MaybeOwnedFd<EventFd>,
in_queue: Queue,
out_queue: Queue,
in_queue_evt: MaybeOwnedFd<EventFd>,
out_queue_evt: MaybeOwnedFd<EventFd>,
},
Kill,
}
#[derive(Debug, Serialize, Deserialize)]
pub enum BincodeRequest {
WriteConfig { offset: u64, data: Vec<u8> },
}
pub type Request = poly_msg_socket::Value<MsgOnSocketRequest, BincodeRequest>;
impl From<MsgOnSocketRequest> for Request {
fn from(request: MsgOnSocketRequest) -> Self {
Self::MsgOnSocket(request)
}
}
impl From<BincodeRequest> for Request {
fn from(request: BincodeRequest) -> Self {
Self::Bincode(request)
}
}
#[derive(Debug, MsgOnSocket)]
pub enum MsgOnSocketResponse {
Kill,
}
#[derive(Debug, Deserialize, Serialize)]
pub struct BincodeResponse;
pub type Response = poly_msg_socket::Value<MsgOnSocketResponse, BincodeResponse>;
impl From<MsgOnSocketResponse> for Response {
fn from(response: MsgOnSocketResponse) -> Self {
Self::MsgOnSocket(response)
}
}
impl From<BincodeResponse> for Response {
fn from(response: BincodeResponse) -> Self {
Self::Bincode(response)
}
}
use poly_msg_socket::PolyMsgSocket;
type Socket =
PolyMsgSocket<MsgOnSocketRequest, MsgOnSocketResponse, BincodeRequest, BincodeResponse>;
const VIRTIO_WL_F_TRANS_FLAGS: u32 = 0x01;
// TODO: support arbitrary number of queues
const QUEUE_SIZE: u16 = 16;
const QUEUE_SIZES: &[u16] = &[QUEUE_SIZE, QUEUE_SIZE];
struct Worker {
device_socket: Socket,
interrupt: Interrupt,
interrupt_socket: MsgSocket<(), InterruptProxyEvent>,
shutdown: bool,
}
impl Worker {
fn new(
device_socket: Socket,
interrupt: Interrupt,
interrupt_socket: MsgSocket<(), InterruptProxyEvent>,
) -> Self {
Self {
device_socket,
interrupt,
interrupt_socket,
shutdown: false,
}
}
fn handle_response(&mut self) {
use poly_msg_socket::Value::*;
match self.device_socket.recv() {
Ok(MsgOnSocket(MsgOnSocketResponse::Kill)) => {
self.shutdown = true;
}
Ok(Bincode(BincodeResponse)) => unreachable!(),
Err(e) => {
error!("recv failed: {:?}", e);
}
}
}
fn interrupt(&self) {
use InterruptProxyEvent::*;
match self.interrupt_socket.recv() {
Ok(SignalUsedQueue(value)) => self.interrupt.signal_used_queue(value).unwrap(),
Ok(SignalConfigChanged) => self.interrupt.signal_config_changed().unwrap(),
Ok(InterruptResample) => self.interrupt.interrupt_resample().unwrap(),
Err(e) => {
eprintln!("recv error: {}", e);
panic!("recv error: {}", e)
}
}
}
fn kill(&self) {
if let Err(e) = self.device_socket.send(poly_msg_socket::Value::MsgOnSocket(
MsgOnSocketRequest::Kill,
)) {
error!("failed to send Kill message: {}", e);
}
}
fn run(mut self, kill_evt: EventFd) {
#[derive(Debug, PollToken)]
enum Token {
Device,
Interrupt,
Kill,
}
let poll_ctx: PollContext<Token> = match PollContext::build_with(&[
(&self.device_socket, Token::Device),
(&self.interrupt_socket, Token::Interrupt),
(&kill_evt, Token::Kill),
]) {
Ok(pc) => pc,
Err(e) => {
error!("failed creating PollContext: {}", e);
return;
}
};
while !self.shutdown {
let events = match poll_ctx.wait() {
Ok(v) => v,
Err(e) => {
error!("failed polling for events: {}", e);
break;
}
};
for event in &events {
match event.token() {
Token::Device => self.handle_response(),
Token::Interrupt => self.interrupt(),
Token::Kill => self.kill(),
}
}
}
}
}
pub struct Controller {
kill_evt: Option<EventFd>,
worker_thread: Option<thread::JoinHandle<()>>,
use_transition_flags: bool,
socket: Option<Socket>,
}
impl Controller {
pub fn create(
wayland_paths: Map<String, PathBuf>,
vm_socket: VmMemoryControlRequestSocket,
resource_bridge: Option<ResourceRequestSocket>,
socket: Socket,
) -> Result<Controller, poly_msg_socket::Error> {
socket.send(MsgOnSocketRequest::Create {
// wayland_paths,
vm_socket: MaybeOwnedFd::new_borrowed(&vm_socket),
// resource_bridge,
})?;
Ok(Controller {
kill_evt: None,
worker_thread: None,
use_transition_flags: false,
socket: Some(socket),
})
}
}
impl Drop for Controller {
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);
}
if let Some(worker_thread) = self.worker_thread.take() {
let _ = worker_thread.join();
}
}
}
impl VirtioDevice for Controller {
fn keep_fds(&self) -> Vec<RawFd> {
let mut keep_fds = Vec::new();
if let Some(ref kill_evt) = self.kill_evt {
keep_fds.push(kill_evt.as_raw_fd());
}
if let Some(ref socket) = self.socket {
keep_fds.push(socket.as_raw_fd());
}
keep_fds
}
fn device_type(&self) -> u32 {
TYPE_WL
}
fn queue_max_sizes(&self) -> &[u16] {
QUEUE_SIZES
}
fn features(&self) -> u64 {
1 << VIRTIO_WL_F_TRANS_FLAGS | 1 << VIRTIO_F_VERSION_1
}
fn ack_features(&mut self, value: u64) {
if value & (1 << VIRTIO_WL_F_TRANS_FLAGS) != 0 {
self.use_transition_flags = true;
}
}
fn activate(
&mut self,
mem: GuestMemory,
interrupt: Interrupt,
mut queues: Vec<Queue>,
queue_evts: Vec<EventFd>,
) {
if queues.len() != QUEUE_SIZES.len() || queue_evts.len() != QUEUE_SIZES.len() {
return;
}
let (self_kill_evt, kill_evt) = match EventFd::new().and_then(|e| Ok((e.try_clone()?, e))) {
Ok(v) => v,
Err(e) => {
error!("failed creating kill EventFd pair: {}", e);
return;
}
};
self.kill_evt = Some(self_kill_evt);
if let Some(socket) = self.socket.take() {
let use_transition_flags = self.use_transition_flags;
let (ours, theirs) = UnixSeqpacket::pair().expect("pair failed");
if let Err(e) = socket.send(MsgOnSocketRequest::Activate {
shm: MaybeOwnedFd::new_borrowed(&mem),
interrupt: MaybeOwnedFd::new_borrowed(&theirs),
interrupt_resample_evt: MaybeOwnedFd::new_borrowed(interrupt.get_resample_evt()),
in_queue: queues.remove(0),
out_queue: queues.remove(0),
in_queue_evt: MaybeOwnedFd::new_borrowed(&queue_evts[0]),
out_queue_evt: MaybeOwnedFd::new_borrowed(&queue_evts[1]),
}) {
error!("failed to send Activate: {}", e);
return;
}
let worker_result =
thread::Builder::new()
.name("virtio_wl".to_string())
.spawn(move || {
Worker::new(socket, interrupt, MsgSocket::new(ours)).run(kill_evt);
});
match worker_result {
Err(e) => {
error!("failed to spawn virtio_wl worker: {}", e);
return;
}
Ok(join_handle) => {
self.worker_thread = Some(join_handle);
}
}
}
}
}