mirror of
https://github.com/cloud-hypervisor/cloud-hypervisor.git
synced 2024-08-22 07:51:16 +00:00
The implementation of the virtio-balloon was slightly wrong as it was generating the GPA (Guest Physical Address) from the PFN (Page Frame Number) which was a u32. That means the GPA was created as a u32, and later a cast was done to extend it to a u64 type. Unfortunately, by doing so, the GPA was wrong if the value was supposedly more than 32 bits. That's why the PFN is casted into a u64 before the GPA is generated, which creates the GPA on 64 bits directly. Additionally, this patch simplifies the process_queue() function, relying on multiple vm-memory helpers. Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
594 lines
21 KiB
Rust
594 lines
21 KiB
Rust
// Copyright (c) 2020 Ant Financial
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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use super::Error as DeviceError;
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use super::{
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ActivateError, ActivateResult, DeviceEventT, Queue, VirtioDevice, VirtioDeviceType,
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VIRTIO_F_VERSION_1,
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};
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use crate::vm_memory::GuestMemory;
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use crate::{VirtioInterrupt, VirtioInterruptType};
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use libc::EFD_NONBLOCK;
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use std::cmp;
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use std::fs::File;
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use std::io::{self, Write};
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use std::mem::size_of;
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use std::os::unix::io::{AsRawFd, FromRawFd};
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use std::result;
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use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
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use std::sync::mpsc;
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use std::sync::{Arc, Mutex};
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use std::thread;
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use vm_memory::{
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Address, ByteValued, Bytes, GuestAddress, GuestAddressSpace, GuestMemoryAtomic,
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GuestMemoryError, GuestMemoryMmap,
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};
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use vm_migration::{Migratable, MigratableError, Pausable, Snapshottable, Transportable};
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use vmm_sys_util::eventfd::EventFd;
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const QUEUE_SIZE: u16 = 128;
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const NUM_QUEUES: usize = 2;
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const QUEUE_SIZES: &[u16] = &[QUEUE_SIZE; NUM_QUEUES];
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// Get resize event.
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const RESIZE_EVENT: DeviceEventT = 0;
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// New descriptors are pending on the virtio queue.
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const INFLATE_QUEUE_EVENT: DeviceEventT = 1;
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// New descriptors are pending on the virtio queue.
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const DEFLATE_QUEUE_EVENT: DeviceEventT = 2;
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// The device has been dropped.
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const KILL_EVENT: DeviceEventT = 3;
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// The device should be paused.
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const PAUSE_EVENT: DeviceEventT = 4;
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// Page shift in the host.
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const PAGE_SHIFT: u32 = 12;
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// Size of a PFN in the balloon interface.
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const VIRTIO_BALLOON_PFN_SHIFT: u64 = 12;
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#[derive(Debug)]
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pub enum Error {
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// Guest gave us bad memory addresses.
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GuestMemory(GuestMemoryError),
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// Guest gave us a write only descriptor that protocol says to read from.
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UnexpectedWriteOnlyDescriptor,
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// Guest sent us invalid request.
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InvalidRequest,
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// Madvise fail.
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MadviseFail(std::io::Error),
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// Failed to EventFd write.
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EventFdWriteFail(std::io::Error),
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// Failed to EventFd try_clone.
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EventFdTryCloneFail(std::io::Error),
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// Failed to MpscRecv.
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MpscRecvFail(mpsc::RecvError),
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// Resize invalid argument
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ResizeInval(String),
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// process_queue got wrong ev_type
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ProcessQueueWrongEvType(u16),
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// Fail tp signal
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FailedSignal(io::Error),
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}
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// Got from include/uapi/linux/virtio_balloon.h
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#[repr(C, packed)]
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#[derive(Copy, Clone, Debug, Default)]
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struct VirtioBalloonConfig {
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// Number of pages host wants Guest to give up.
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num_pages: u32,
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// Number of pages we've actually got in balloon.
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actual: u32,
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}
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// Safe because it only has data and has no implicit padding.
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unsafe impl ByteValued for VirtioBalloonConfig {}
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struct VirtioBalloonResizeReceiver {
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size: Arc<AtomicU64>,
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tx: mpsc::Sender<Result<(), Error>>,
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evt: EventFd,
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}
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impl VirtioBalloonResizeReceiver {
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fn get_size(&self) -> u64 {
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self.size.load(Ordering::SeqCst)
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}
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fn send(&self, r: Result<(), Error>) -> Result<(), mpsc::SendError<Result<(), Error>>> {
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self.tx.send(r)
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}
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}
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struct VirtioBalloonResize {
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size: Arc<AtomicU64>,
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tx: mpsc::Sender<Result<(), Error>>,
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rx: mpsc::Receiver<Result<(), Error>>,
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evt: EventFd,
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}
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impl VirtioBalloonResize {
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pub fn new() -> io::Result<Self> {
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let (tx, rx) = mpsc::channel();
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Ok(Self {
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size: Arc::new(AtomicU64::new(0)),
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tx,
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rx,
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evt: EventFd::new(EFD_NONBLOCK)?,
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})
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}
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pub fn get_receiver(&self) -> Result<VirtioBalloonResizeReceiver, Error> {
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Ok(VirtioBalloonResizeReceiver {
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size: self.size.clone(),
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tx: self.tx.clone(),
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evt: self.evt.try_clone().map_err(Error::EventFdTryCloneFail)?,
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})
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}
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pub fn work(&self, size: u64) -> Result<(), Error> {
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self.size.store(size, Ordering::SeqCst);
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self.evt.write(1).map_err(Error::EventFdWriteFail)?;
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self.rx.recv().map_err(Error::MpscRecvFail)?
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}
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}
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struct BalloonEpollHandler {
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config: Arc<Mutex<VirtioBalloonConfig>>,
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resize_receiver: VirtioBalloonResizeReceiver,
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queues: Vec<Queue>,
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mem: GuestMemoryAtomic<GuestMemoryMmap>,
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interrupt_cb: Arc<dyn VirtioInterrupt>,
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inflate_queue_evt: EventFd,
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deflate_queue_evt: EventFd,
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kill_evt: EventFd,
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pause_evt: EventFd,
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}
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impl BalloonEpollHandler {
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fn signal(
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&self,
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int_type: &VirtioInterruptType,
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queue: Option<&Queue>,
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) -> result::Result<(), Error> {
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self.interrupt_cb.trigger(int_type, queue).map_err(|e| {
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error!("Failed to signal used queue: {:?}", e);
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Error::FailedSignal(e)
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})
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}
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fn process_queue(&mut self, ev_type: u16) -> result::Result<(), Error> {
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let queue_index = match ev_type {
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INFLATE_QUEUE_EVENT => 0,
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DEFLATE_QUEUE_EVENT => 1,
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_ => return Err(Error::ProcessQueueWrongEvType(ev_type)),
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};
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let mut used_desc_heads = [0; QUEUE_SIZE as usize];
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let mut used_count = 0;
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let mem = self.mem.memory();
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for avail_desc in self.queues[queue_index].iter(&mem) {
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used_desc_heads[used_count] = avail_desc.index;
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used_count += 1;
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let data_chunk_size = size_of::<u32>();
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// The head contains the request type which MUST be readable.
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if avail_desc.is_write_only() {
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error!("The head contains the request type is not right");
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return Err(Error::UnexpectedWriteOnlyDescriptor);
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}
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if avail_desc.len as usize % data_chunk_size != 0 {
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error!("the request size {} is not right", avail_desc.len);
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return Err(Error::InvalidRequest);
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}
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let mut offset = 0u64;
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while offset < avail_desc.len as u64 {
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let addr = avail_desc.addr.checked_add(offset).unwrap();
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let pfn: u32 = mem.read_obj(addr).map_err(Error::GuestMemory)?;
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offset += data_chunk_size as u64;
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let gpa = (pfn as u64) << VIRTIO_BALLOON_PFN_SHIFT;
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if let Ok(hva) = mem.get_host_address(GuestAddress(gpa)) {
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let advice = match ev_type {
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INFLATE_QUEUE_EVENT => libc::MADV_DONTNEED,
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DEFLATE_QUEUE_EVENT => libc::MADV_WILLNEED,
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_ => return Err(Error::ProcessQueueWrongEvType(ev_type)),
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};
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// Need unsafe to do syscall madvise
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let res = unsafe {
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libc::madvise(
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hva as *mut libc::c_void,
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(1 << PAGE_SHIFT) as libc::size_t,
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advice,
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)
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};
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if res != 0 {
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return Err(Error::MadviseFail(io::Error::last_os_error()));
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}
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} else {
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error!("Address 0x{:x} is not available", gpa);
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return Err(Error::InvalidRequest);
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}
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}
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}
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for &desc_index in &used_desc_heads[..used_count] {
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self.queues[queue_index].add_used(&mem, desc_index, 0);
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}
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if used_count > 0 {
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self.signal(&VirtioInterruptType::Queue, Some(&self.queues[queue_index]))?;
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}
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Ok(())
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}
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fn run(&mut self, paused: Arc<AtomicBool>) -> result::Result<(), DeviceError> {
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// Create the epoll file descriptor
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let epoll_fd = epoll::create(true).map_err(DeviceError::EpollCreateFd)?;
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// Use 'File' to enforce closing on 'epoll_fd'
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let epoll_file = unsafe { File::from_raw_fd(epoll_fd) };
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// Add events
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epoll::ctl(
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epoll_file.as_raw_fd(),
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epoll::ControlOptions::EPOLL_CTL_ADD,
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self.resize_receiver.evt.as_raw_fd(),
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epoll::Event::new(epoll::Events::EPOLLIN, u64::from(RESIZE_EVENT)),
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)
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.map_err(DeviceError::EpollCtl)?;
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epoll::ctl(
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epoll_file.as_raw_fd(),
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epoll::ControlOptions::EPOLL_CTL_ADD,
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self.inflate_queue_evt.as_raw_fd(),
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epoll::Event::new(epoll::Events::EPOLLIN, u64::from(INFLATE_QUEUE_EVENT)),
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)
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.map_err(DeviceError::EpollCtl)?;
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epoll::ctl(
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epoll_file.as_raw_fd(),
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epoll::ControlOptions::EPOLL_CTL_ADD,
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self.deflate_queue_evt.as_raw_fd(),
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epoll::Event::new(epoll::Events::EPOLLIN, u64::from(DEFLATE_QUEUE_EVENT)),
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)
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.map_err(DeviceError::EpollCtl)?;
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epoll::ctl(
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epoll_file.as_raw_fd(),
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epoll::ControlOptions::EPOLL_CTL_ADD,
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self.kill_evt.as_raw_fd(),
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epoll::Event::new(epoll::Events::EPOLLIN, u64::from(KILL_EVENT)),
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)
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.map_err(DeviceError::EpollCtl)?;
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epoll::ctl(
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epoll_file.as_raw_fd(),
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epoll::ControlOptions::EPOLL_CTL_ADD,
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self.pause_evt.as_raw_fd(),
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epoll::Event::new(epoll::Events::EPOLLIN, u64::from(PAUSE_EVENT)),
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)
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.map_err(DeviceError::EpollCtl)?;
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const EPOLL_EVENTS_LEN: usize = 100;
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let mut events = vec![epoll::Event::new(epoll::Events::empty(), 0); EPOLL_EVENTS_LEN];
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'epoll: loop {
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let num_events = match epoll::wait(epoll_file.as_raw_fd(), -1, &mut events[..]) {
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Ok(res) => res,
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Err(e) => {
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if e.kind() == io::ErrorKind::Interrupted {
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// It's well defined from the epoll_wait() syscall
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// documentation that the epoll loop can be interrupted
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// before any of the requested events occurred or the
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// timeout expired. In both those cases, epoll_wait()
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// returns an error of type EINTR, but this should not
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// be considered as a regular error. Instead it is more
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// appropriate to retry, by calling into epoll_wait().
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continue;
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}
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return Err(DeviceError::EpollWait(e));
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}
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};
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for event in events.iter().take(num_events) {
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let ev_type = event.data as u16;
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match ev_type {
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RESIZE_EVENT => {
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if let Err(e) = self.resize_receiver.evt.read() {
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return Err(DeviceError::EpollHander(format!(
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"Failed to get resize event: {:?}",
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e
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)));
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}
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let mut signal_error = false;
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let r = {
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let mut config = self.config.lock().unwrap();
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config.num_pages =
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(self.resize_receiver.get_size() >> PAGE_SHIFT) as u32;
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if let Err(e) = self.signal(&VirtioInterruptType::Config, None) {
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signal_error = true;
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Err(e)
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} else {
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Ok(())
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}
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};
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if let Err(e) = &r {
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// This error will send back to resize caller.
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error!("Handle resize event get error: {:?}", e);
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}
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if let Err(e) = self.resize_receiver.send(r) {
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return Err(DeviceError::EpollHander(format!(
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"Sending \"resize\" generated error: {:?}",
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e
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)));
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}
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if signal_error {
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return Err(DeviceError::EpollHander(String::from("Signal get error")));
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}
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}
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INFLATE_QUEUE_EVENT => {
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if let Err(e) = self.inflate_queue_evt.read() {
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return Err(DeviceError::EpollHander(format!(
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"Failed to get inflate queue event: {:?}",
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e
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)));
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} else if let Err(e) = self.process_queue(ev_type) {
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return Err(DeviceError::EpollHander(format!(
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"Failed to signal used inflate queue: {:?}",
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e
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)));
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}
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}
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DEFLATE_QUEUE_EVENT => {
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if let Err(e) = self.deflate_queue_evt.read() {
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return Err(DeviceError::EpollHander(format!(
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"Failed to get deflate queue event: {:?}",
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e
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)));
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} else if let Err(e) = self.process_queue(ev_type) {
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return Err(DeviceError::EpollHander(format!(
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"Failed to signal used deflate queue: {:?}",
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e
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)));
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}
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}
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KILL_EVENT => {
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debug!("kill_evt received, stopping epoll loop");
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break 'epoll;
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}
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PAUSE_EVENT => {
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debug!("PAUSE_EVENT received, pausing virtio-balloon epoll loop");
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// We loop here to handle spurious park() returns.
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// Until we have not resumed, the paused boolean will
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// be true.
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while paused.load(Ordering::SeqCst) {
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thread::park();
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}
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}
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_ => {
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return Err(DeviceError::EpollHander(String::from(
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"Unknown event for virtio-mem",
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)));
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}
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}
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}
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}
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Ok(())
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}
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}
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// Virtio device for exposing entropy to the guest OS through virtio.
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pub struct Balloon {
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id: String,
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resize: VirtioBalloonResize,
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kill_evt: Option<EventFd>,
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pause_evt: Option<EventFd>,
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avail_features: u64,
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pub acked_features: u64,
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config: Arc<Mutex<VirtioBalloonConfig>>,
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queue_evts: Option<Vec<EventFd>>,
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interrupt_cb: Option<Arc<dyn VirtioInterrupt>>,
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epoll_threads: Option<Vec<thread::JoinHandle<result::Result<(), DeviceError>>>>,
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paused: Arc<AtomicBool>,
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}
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impl Balloon {
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// Create a new virtio-balloon.
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pub fn new(id: String) -> io::Result<Self> {
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let avail_features = 1u64 << VIRTIO_F_VERSION_1;
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let config = VirtioBalloonConfig::default();
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Ok(Balloon {
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id,
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resize: VirtioBalloonResize::new()?,
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kill_evt: None,
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pause_evt: None,
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avail_features,
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acked_features: 0u64,
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config: Arc::new(Mutex::new(config)),
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queue_evts: None,
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interrupt_cb: None,
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epoll_threads: None,
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paused: Arc::new(AtomicBool::new(false)),
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})
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}
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pub fn resize(&self, size: u64) -> Result<(), Error> {
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self.resize.work(size)
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}
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}
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impl Drop for Balloon {
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fn drop(&mut self) {
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if let Some(kill_evt) = self.kill_evt.take() {
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// Ignore the result because there is nothing we can do about it.
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let _ = kill_evt.write(1);
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}
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}
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}
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impl VirtioDevice for Balloon {
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fn device_type(&self) -> u32 {
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VirtioDeviceType::TYPE_BALLOON as u32
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}
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fn queue_max_sizes(&self) -> &[u16] {
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QUEUE_SIZES
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}
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fn features(&self) -> u64 {
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self.avail_features
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}
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fn ack_features(&mut self, value: u64) {
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let mut v = value;
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// Check if the guest is ACK'ing a feature that we didn't claim to have.
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let unrequested_features = v & !self.avail_features;
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if unrequested_features != 0 {
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warn!("Received acknowledge request for unknown feature.");
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// Don't count these features as acked.
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v &= !unrequested_features;
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}
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self.acked_features |= v;
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}
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fn read_config(&self, offset: u64, mut data: &mut [u8]) {
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let config = self.config.lock().unwrap();
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let config_slice = config.as_slice();
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let config_len = config_slice.len() as u64;
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if offset >= config_len {
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error!("Failed to read config space");
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return;
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}
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if let Some(end) = offset.checked_add(data.len() as u64) {
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// 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!("virtio-balloon device configuration is read-only");
|
|
}
|
|
|
|
fn activate(
|
|
&mut self,
|
|
mem: GuestMemoryAtomic<GuestMemoryMmap>,
|
|
interrupt_cb: Arc<dyn 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) = EventFd::new(EFD_NONBLOCK)
|
|
.and_then(|e| Ok((e.try_clone()?, e)))
|
|
.map_err(|e| {
|
|
error!("failed creating kill EventFd pair: {}", e);
|
|
ActivateError::BadActivate
|
|
})?;
|
|
self.kill_evt = Some(self_kill_evt);
|
|
|
|
let (self_pause_evt, pause_evt) = EventFd::new(EFD_NONBLOCK)
|
|
.and_then(|e| Ok((e.try_clone()?, e)))
|
|
.map_err(|e| {
|
|
error!("failed creating pause EventFd pair: {}", e);
|
|
ActivateError::BadActivate
|
|
})?;
|
|
self.pause_evt = Some(self_pause_evt);
|
|
|
|
self.interrupt_cb = Some(interrupt_cb.clone());
|
|
|
|
let mut tmp_queue_evts: Vec<EventFd> = Vec::new();
|
|
for queue_evt in queue_evts.iter() {
|
|
// Save the queue EventFD as we need to return it on reset
|
|
// but clone it to pass into the thread.
|
|
tmp_queue_evts.push(queue_evt.try_clone().map_err(|e| {
|
|
error!("failed to clone queue EventFd: {}", e);
|
|
ActivateError::BadActivate
|
|
})?);
|
|
}
|
|
self.queue_evts = Some(tmp_queue_evts);
|
|
|
|
let mut handler = BalloonEpollHandler {
|
|
config: self.config.clone(),
|
|
resize_receiver: self.resize.get_receiver().map_err(|e| {
|
|
error!("failed to clone resize EventFd: {:?}", e);
|
|
ActivateError::BadActivate
|
|
})?,
|
|
queues,
|
|
mem,
|
|
interrupt_cb,
|
|
inflate_queue_evt: queue_evts.remove(0),
|
|
deflate_queue_evt: queue_evts.remove(0),
|
|
kill_evt,
|
|
pause_evt,
|
|
};
|
|
|
|
let paused = self.paused.clone();
|
|
let mut epoll_threads = Vec::new();
|
|
thread::Builder::new()
|
|
.name("virtio_balloon".to_string())
|
|
.spawn(move || handler.run(paused))
|
|
.map(|thread| epoll_threads.push(thread))
|
|
.map_err(|e| {
|
|
error!("failed to clone virtio-balloon epoll thread: {}", e);
|
|
ActivateError::BadActivate
|
|
})?;
|
|
self.epoll_threads = Some(epoll_threads);
|
|
|
|
Ok(())
|
|
}
|
|
|
|
fn reset(&mut self) -> Option<(Arc<dyn VirtioInterrupt>, Vec<EventFd>)> {
|
|
// We first must resume the virtio thread if it was paused.
|
|
if self.pause_evt.take().is_some() {
|
|
self.resume().ok()?;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
// Return the interrupt and queue EventFDs
|
|
Some((
|
|
self.interrupt_cb.take().unwrap(),
|
|
self.queue_evts.take().unwrap(),
|
|
))
|
|
}
|
|
}
|
|
|
|
virtio_pausable!(Balloon);
|
|
impl Snapshottable for Balloon {
|
|
fn id(&self) -> String {
|
|
self.id.clone()
|
|
}
|
|
}
|
|
impl Transportable for Balloon {}
|
|
impl Migratable for Balloon {}
|