// 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.
//! Handles IPC for controlling the main VM process.
//!
//! The VM Control IPC protocol is synchronous, meaning that each `VmRequest` sent over a connection
//! will receive a `VmResponse` for that request next time data is received over that connection.
//!
//! The wire message format is a little-endian C-struct of fixed size, along with a file descriptor
//! if the request type expects one.
use std::fmt::{self, Display};
use std::fs::File;
use std::io::{Seek, SeekFrom};
use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
use libc::{EINVAL, EIO, ENODEV};
use byteorder::{LittleEndian, WriteBytesExt};
use kvm::Vm;
use msg_socket::{MsgOnSocket, MsgReceiver, MsgResult, MsgSender, MsgSocket};
use resources::{GpuMemoryDesc, SystemAllocator};
use sys_util::{
error, net::UnixSeqpacket, Error as SysError, GuestAddress, MemoryMapping, MmapError, Result,
};
/// A file descriptor either borrowed or owned by this.
#[derive(Debug)]
pub enum MaybeOwnedFd {
/// Owned by this enum variant, and will be destructed automatically if not moved out.
Owned(File),
/// A file descriptor borrwed by this enum.
Borrowed(RawFd),
}
impl AsRawFd for MaybeOwnedFd {
fn as_raw_fd(&self) -> RawFd {
match self {
MaybeOwnedFd::Owned(f) => f.as_raw_fd(),
MaybeOwnedFd::Borrowed(fd) => *fd,
}
}
}
// When sent, it could be owned or borrowed. On the receiver end, it always owned.
impl MsgOnSocket for MaybeOwnedFd {
fn msg_size() -> usize {
0usize
}
fn max_fd_count() -> usize {
1usize
}
unsafe fn read_from_buffer(buffer: &[u8], fds: &[RawFd]) -> MsgResult<(Self, usize)> {
let (fd, size) = RawFd::read_from_buffer(buffer, fds)?;
let file = File::from_raw_fd(fd);
Ok((MaybeOwnedFd::Owned(file), size))
}
fn write_to_buffer(&self, buffer: &mut [u8], fds: &mut [RawFd]) -> MsgResult<usize> {
let fd = self.as_raw_fd();
fd.write_to_buffer(buffer, fds)
}
}
/// Mode of execution for the VM.
#[derive(Debug)]
pub enum VmRunMode {
/// The default run mode indicating the VCPUs are running.
Running,
/// Indicates that the VCPUs are suspending execution until the `Running` mode is set.
Suspending,
/// Indicates that the VM is exiting all processes.
Exiting,
}
impl Display for VmRunMode {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use self::VmRunMode::*;
match self {
Running => write!(f, "running"),
Suspending => write!(f, "suspending"),
Exiting => write!(f, "exiting"),
}
}
}
impl Default for VmRunMode {
fn default() -> Self {
VmRunMode::Running
}
}
#[derive(MsgOnSocket, Debug)]
pub enum DiskControlCommand {
/// Resize a disk to `new_size` in bytes.
Resize { new_size: u64 },
}
impl Display for DiskControlCommand {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use self::DiskControlCommand::*;
match self {
Resize { new_size } => write!(f, "disk_resize {}", new_size),
}
}
}
#[derive(MsgOnSocket, Debug)]
pub enum DiskControlResult {
Ok,
Err(SysError),
}
#[derive(MsgOnSocket, Debug)]
pub enum UsbControlCommand {
AttachDevice {
bus: u8,
addr: u8,
vid: u16,
pid: u16,
fd: Option<MaybeOwnedFd>,
},
DetachDevice {
port: u8,
},
ListDevice {
port: u8,
},
}
#[derive(MsgOnSocket, Debug)]
pub enum UsbControlResult {
Ok { port: u8 },
NoAvailablePort,
NoSuchDevice,
NoSuchPort,
FailedToOpenDevice,
Device { port: u8, vid: u16, pid: u16 },
}
impl Display for UsbControlResult {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use self::UsbControlResult::*;
match self {
Ok { port } => write!(f, "ok {}", port),
NoAvailablePort => write!(f, "no_available_port"),
NoSuchDevice => write!(f, "no_such_device"),
NoSuchPort => write!(f, "no_such_port"),
FailedToOpenDevice => write!(f, "failed_to_open_device"),
Device { port, vid, pid } => write!(f, "device {} {:04x} {:04x}", port, vid, pid),
}
}
}
pub type DiskControlRequestSocket = MsgSocket<DiskControlCommand, DiskControlResult>;
pub type DiskControlResponseSocket = MsgSocket<DiskControlResult, DiskControlCommand>;
pub type UsbControlSocket = MsgSocket<UsbControlCommand, UsbControlResult>;
pub type VmControlRequestSocket = MsgSocket<VmRequest, VmResponse>;
pub type VmControlResponseSocket = MsgSocket<VmResponse, VmRequest>;
/// A request to the main process to perform some operation on the VM.
///
/// Unless otherwise noted, each request should expect a `VmResponse::Ok` to be received on success.
#[derive(MsgOnSocket, Debug)]
pub enum VmRequest {
/// Set the size of the VM's balloon in bytes.
BalloonAdjust(u64),
/// Break the VM's run loop and exit.
Exit,
/// Suspend the VM's VCPUs until resume.
Suspend,
/// Resume the VM's VCPUs that were previously suspended.
Resume,
/// Register shared memory represented by the given fd into guest address space. The response
/// variant is `VmResponse::RegisterMemory`.
RegisterMemory(MaybeOwnedFd, usize),
/// Unregister the given memory slot that was previously registereed with `RegisterMemory`.
UnregisterMemory(u32),
/// Allocate GPU buffer of a given size/format and register the memory into guest address space.
/// The response variant is `VmResponse::AllocateAndRegisterGpuMemory`
AllocateAndRegisterGpuMemory {
width: u32,
height: u32,
format: u32,
},
/// Send a command to a disk chosen by `disk_index`.
/// `disk_index` is a 0-based count of `--disk`, `--rwdisk`, and `-r` command-line options.
DiskCommand {
disk_index: usize,
command: DiskControlCommand,
},
/// Command to use controller.
UsbCommand(UsbControlCommand),
}
fn register_memory(
vm: &mut Vm,
allocator: &mut SystemAllocator,
fd: &dyn AsRawFd,
size: usize,
) -> Result<(u64, u32)> {
let mmap = match MemoryMapping::from_fd(fd, size) {
Ok(v) => v,
Err(MmapError::SystemCallFailed(e)) => return Err(e),
_ => return Err(SysError::new(EINVAL)),
};
let addr = match allocator.allocate_device_addresses(size as u64) {
Some(a) => a,
None => return Err(SysError::new(EINVAL)),
};
let slot = match vm.add_device_memory(GuestAddress(addr), mmap, false, false) {
Ok(v) => v,
Err(e) => return Err(e),
};
Ok((addr >> 12, slot))
}
impl VmRequest {
/// Executes this request on the given Vm and other mutable state.
///
/// # Arguments
/// * `vm` - The `Vm` to perform the request on.
/// * `allocator` - Used to allocate addresses.
/// * `run_mode` - Out argument that is set to a run mode if one was requested.
///
/// This does not return a result, instead encapsulating the success or failure in a
/// `VmResponse` with the intended purpose of sending the response back over the socket that
/// received this `VmRequest`.
pub fn execute(
&self,
vm: &mut Vm,
sys_allocator: &mut SystemAllocator,
run_mode: &mut Option<VmRunMode>,
balloon_host_socket: &UnixSeqpacket,
disk_host_sockets: &[DiskControlRequestSocket],
usb_control_socket: &UsbControlSocket,
) -> VmResponse {
match *self {
VmRequest::Exit => {
*run_mode = Some(VmRunMode::Exiting);
VmResponse::Ok
}
VmRequest::Suspend => {
*run_mode = Some(VmRunMode::Suspending);
VmResponse::Ok
}
VmRequest::Resume => {
*run_mode = Some(VmRunMode::Running);
VmResponse::Ok
}
VmRequest::RegisterMemory(ref fd, size) => {
match register_memory(vm, sys_allocator, fd, size) {
Ok((pfn, slot)) => VmResponse::RegisterMemory { pfn, slot },
Err(e) => VmResponse::Err(e),
}
}
VmRequest::UnregisterMemory(slot) => match vm.remove_device_memory(slot) {
Ok(_) => VmResponse::Ok,
Err(e) => VmResponse::Err(e),
},
VmRequest::BalloonAdjust(num_pages) => {
let mut buf = [0u8; 8];
// write_u64 can't fail as the buffer is 8 bytes long.
(&mut buf[0..])
.write_u64::<LittleEndian>(num_pages)
.unwrap();
match balloon_host_socket.send(&buf) {
Ok(_) => VmResponse::Ok,
Err(_) => VmResponse::Err(SysError::last()),
}
}
VmRequest::AllocateAndRegisterGpuMemory {
width,
height,
format,
} => {
let (mut fd, desc) = match sys_allocator.gpu_memory_allocator() {
Some(gpu_allocator) => match gpu_allocator.allocate(width, height, format) {
Ok(v) => v,
Err(e) => return VmResponse::Err(e),
},
None => return VmResponse::Err(SysError::new(ENODEV)),
};
// Determine size of buffer using 0 byte seek from end. This is preferred over
// `stride * height` as it's not limited to packed pixel formats.
let size = match fd.seek(SeekFrom::End(0)) {
Ok(v) => v,
Err(e) => return VmResponse::Err(SysError::from(e)),
};
match register_memory(vm, sys_allocator, &fd, size as usize) {
Ok((pfn, slot)) => VmResponse::AllocateAndRegisterGpuMemory {
fd: MaybeOwnedFd::Owned(fd),
pfn,
slot,
desc,
},
Err(e) => VmResponse::Err(e),
}
}
VmRequest::DiskCommand {
disk_index,
ref command,
} => {
// Forward the request to the block device process via its control socket.
if let Some(sock) = disk_host_sockets.get(disk_index) {
if let Err(e) = sock.send(command) {
error!("disk socket send failed: {}", e);
VmResponse::Err(SysError::new(EINVAL))
} else {
match sock.recv() {
Ok(DiskControlResult::Ok) => VmResponse::Ok,
Ok(DiskControlResult::Err(e)) => VmResponse::Err(e),
Err(e) => {
error!("disk socket recv failed: {}", e);
VmResponse::Err(SysError::new(EINVAL))
}
}
}
} else {
VmResponse::Err(SysError::new(ENODEV))
}
}
VmRequest::UsbCommand(ref cmd) => {
let res = usb_control_socket.send(cmd);
if let Err(e) = res {
error!("fail to send command to usb control socket: {}", e);
return VmResponse::Err(SysError::new(EIO));
}
match usb_control_socket.recv() {
Ok(response) => VmResponse::UsbResponse(response),
Err(e) => {
error!("fail to recv command from usb control socket: {}", e);
VmResponse::Err(SysError::new(EIO))
}
}
}
}
}
}
/// Indication of success or failure of a `VmRequest`.
///
/// Success is usually indicated `VmResponse::Ok` unless there is data associated with the response.
#[derive(MsgOnSocket, Debug)]
pub enum VmResponse {
/// Indicates the request was executed successfully.
Ok,
/// Indicates the request encountered some error during execution.
Err(SysError),
/// The request to register memory into guest address space was successfully done at page frame
/// number `pfn` and memory slot number `slot`.
RegisterMemory { pfn: u64, slot: u32 },
/// The request to allocate and register GPU memory into guest address space was successfully
/// done at page frame number `pfn` and memory slot number `slot` for buffer with `desc`.
AllocateAndRegisterGpuMemory {
fd: MaybeOwnedFd,
pfn: u64,
slot: u32,
desc: GpuMemoryDesc,
},
/// Results of usb control commands.
UsbResponse(UsbControlResult),
}
impl Display for VmResponse {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use self::VmResponse::*;
match self {
Ok => write!(f, "ok"),
Err(e) => write!(f, "error: {}", e),
RegisterMemory { pfn, slot } => write!(
f,
"memory registered to page frame number {:#x} and memory slot {}",
pfn, slot
),
AllocateAndRegisterGpuMemory { pfn, slot, .. } => write!(
f,
"gpu memory allocated and registered to page frame number {:#x} and memory slot {}",
pfn, slot
),
UsbResponse(result) => write!(f, "usb control request get result {:?}", result),
}
}
}