cloud-hypervisor/block_util/src/lib.rs
dependabot[bot] 1d55de9c74 build: Bump virtio-bindings from 0.1.0 to 0.2.0
Bumps [virtio-bindings](https://github.com/rust-vmm/vm-virtio) from 0.1.0 to 0.2.0.
- [Release notes](https://github.com/rust-vmm/vm-virtio/releases)
- [Commits](https://github.com/rust-vmm/vm-virtio/compare/virtio-queue-v0.1.0...virtio-bindings-v0.2.0)

---
updated-dependencies:
- dependency-name: virtio-bindings
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
2023-02-23 00:59:32 +00:00

723 lines
24 KiB
Rust

// Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//
// Portions 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-BSD-3-Clause file.
//
// Copyright © 2020 Intel Corporation
//
// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
#[macro_use]
extern crate log;
pub mod async_io;
pub mod fixed_vhd_async;
pub mod fixed_vhd_sync;
pub mod qcow_sync;
pub mod raw_async;
pub mod raw_sync;
pub mod vhd;
pub mod vhdx_sync;
use crate::async_io::{AsyncIo, AsyncIoError, AsyncIoResult};
use io_uring::{opcode, IoUring, Probe};
use smallvec::SmallVec;
use std::alloc::{alloc_zeroed, dealloc, Layout};
use std::cmp;
use std::collections::VecDeque;
use std::convert::TryInto;
use std::fs::File;
use std::io::{self, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write};
use std::os::linux::fs::MetadataExt;
use std::path::Path;
use std::result;
use std::sync::Arc;
use std::sync::MutexGuard;
use std::time::Instant;
use thiserror::Error;
use versionize::{VersionMap, Versionize, VersionizeResult};
use versionize_derive::Versionize;
use virtio_bindings::virtio_blk::*;
use virtio_queue::DescriptorChain;
use vm_memory::{
bitmap::AtomicBitmap, bitmap::Bitmap, ByteValued, Bytes, GuestAddress, GuestMemory,
GuestMemoryError, GuestMemoryLoadGuard,
};
use vm_virtio::{AccessPlatform, Translatable};
use vmm_sys_util::eventfd::EventFd;
type GuestMemoryMmap = vm_memory::GuestMemoryMmap<AtomicBitmap>;
const SECTOR_SHIFT: u8 = 9;
pub const SECTOR_SIZE: u64 = 0x01 << SECTOR_SHIFT;
#[derive(Error, Debug)]
pub enum Error {
#[error("Guest gave us bad memory addresses")]
GuestMemory(GuestMemoryError),
#[error("Guest gave us offsets that would have overflowed a usize")]
CheckedOffset(GuestAddress, usize),
#[error("Guest gave us a write only descriptor that protocol says to read from")]
UnexpectedWriteOnlyDescriptor,
#[error("Guest gave us a read only descriptor that protocol says to write to")]
UnexpectedReadOnlyDescriptor,
#[error("Guest gave us too few descriptors in a descriptor chain")]
DescriptorChainTooShort,
#[error("Guest gave us a descriptor that was too short to use")]
DescriptorLengthTooSmall,
#[error("Getting a block's metadata fails for any reason")]
GetFileMetadata,
#[error("The requested operation would cause a seek beyond disk end")]
InvalidOffset,
#[error("The requested operation does not support multiple descriptors")]
TooManyDescriptors,
}
fn build_device_id(disk_path: &Path) -> result::Result<String, Error> {
let blk_metadata = match disk_path.metadata() {
Err(_) => return Err(Error::GetFileMetadata),
Ok(m) => m,
};
// This is how kvmtool does it.
let device_id = format!(
"{}{}{}",
blk_metadata.st_dev(),
blk_metadata.st_rdev(),
blk_metadata.st_ino()
);
Ok(device_id)
}
pub fn build_disk_image_id(disk_path: &Path) -> Vec<u8> {
let mut default_disk_image_id = vec![0; VIRTIO_BLK_ID_BYTES as usize];
match build_device_id(disk_path) {
Err(_) => {
warn!("Could not generate device id. We'll use a default.");
}
Ok(m) => {
// The kernel only knows to read a maximum of VIRTIO_BLK_ID_BYTES.
// This will also zero out any leftover bytes.
let disk_id = m.as_bytes();
let bytes_to_copy = cmp::min(disk_id.len(), VIRTIO_BLK_ID_BYTES as usize);
default_disk_image_id[..bytes_to_copy].clone_from_slice(&disk_id[..bytes_to_copy])
}
}
default_disk_image_id
}
#[derive(Error, Debug)]
pub enum ExecuteError {
#[error("Bad request: {0}")]
BadRequest(Error),
#[error("Falied to flush: {0}")]
Flush(io::Error),
#[error("Failed to read: {0}")]
Read(GuestMemoryError),
#[error("Failed to seek: {0}")]
Seek(io::Error),
#[error("Failed to write: {0}")]
Write(GuestMemoryError),
#[error("Unsupported request: {0}")]
Unsupported(u32),
#[error("Failed to submit io uring: {0}")]
SubmitIoUring(io::Error),
#[error("Failed to get guest address: {0}")]
GetHostAddress(GuestMemoryError),
#[error("Failed to async read: {0}")]
AsyncRead(AsyncIoError),
#[error("Failed to async write: {0}")]
AsyncWrite(AsyncIoError),
#[error("failed to async flush: {0}")]
AsyncFlush(AsyncIoError),
#[error("Failed allocating a temporary buffer: {0}")]
TemporaryBufferAllocation(io::Error),
}
impl ExecuteError {
pub fn status(&self) -> u32 {
match *self {
ExecuteError::BadRequest(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::Flush(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::Read(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::Seek(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::Write(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::Unsupported(_) => VIRTIO_BLK_S_UNSUPP,
ExecuteError::SubmitIoUring(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::GetHostAddress(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::AsyncRead(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::AsyncWrite(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::AsyncFlush(_) => VIRTIO_BLK_S_IOERR,
ExecuteError::TemporaryBufferAllocation(_) => VIRTIO_BLK_S_IOERR,
}
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum RequestType {
In,
Out,
Flush,
GetDeviceId,
Unsupported(u32),
}
pub fn request_type(
mem: &GuestMemoryMmap,
desc_addr: GuestAddress,
) -> result::Result<RequestType, Error> {
let type_ = mem.read_obj(desc_addr).map_err(Error::GuestMemory)?;
match type_ {
VIRTIO_BLK_T_IN => Ok(RequestType::In),
VIRTIO_BLK_T_OUT => Ok(RequestType::Out),
VIRTIO_BLK_T_FLUSH => Ok(RequestType::Flush),
VIRTIO_BLK_T_GET_ID => Ok(RequestType::GetDeviceId),
t => Ok(RequestType::Unsupported(t)),
}
}
fn sector(mem: &GuestMemoryMmap, desc_addr: GuestAddress) -> result::Result<u64, Error> {
const SECTOR_OFFSET: usize = 8;
let addr = match mem.checked_offset(desc_addr, SECTOR_OFFSET) {
Some(v) => v,
None => return Err(Error::CheckedOffset(desc_addr, SECTOR_OFFSET)),
};
mem.read_obj(addr).map_err(Error::GuestMemory)
}
#[derive(Debug)]
pub struct AlignedOperation {
origin_ptr: u64,
aligned_ptr: u64,
size: usize,
layout: Layout,
}
#[derive(Debug)]
pub struct Request {
pub request_type: RequestType,
pub sector: u64,
pub data_descriptors: SmallVec<[(GuestAddress, u32); 1]>,
pub status_addr: GuestAddress,
pub writeback: bool,
pub aligned_operations: SmallVec<[AlignedOperation; 1]>,
pub start: Instant,
}
impl Request {
pub fn parse(
desc_chain: &mut DescriptorChain<GuestMemoryLoadGuard<GuestMemoryMmap>>,
access_platform: Option<&Arc<dyn AccessPlatform>>,
) -> result::Result<Request, Error> {
let hdr_desc = desc_chain
.next()
.ok_or(Error::DescriptorChainTooShort)
.map_err(|e| {
error!("Missing head descriptor");
e
})?;
// The head contains the request type which MUST be readable.
if hdr_desc.is_write_only() {
return Err(Error::UnexpectedWriteOnlyDescriptor);
}
let hdr_desc_addr = hdr_desc
.addr()
.translate_gva(access_platform, hdr_desc.len() as usize);
let mut req = Request {
request_type: request_type(desc_chain.memory(), hdr_desc_addr)?,
sector: sector(desc_chain.memory(), hdr_desc_addr)?,
data_descriptors: SmallVec::with_capacity(1),
status_addr: GuestAddress(0),
writeback: true,
aligned_operations: SmallVec::with_capacity(1),
start: Instant::now(),
};
let status_desc;
let mut desc = desc_chain
.next()
.ok_or(Error::DescriptorChainTooShort)
.map_err(|e| {
error!("Only head descriptor present: request = {:?}", req);
e
})?;
if !desc.has_next() {
status_desc = desc;
// Only flush requests are allowed to skip the data descriptor.
if req.request_type != RequestType::Flush {
error!("Need a data descriptor: request = {:?}", req);
return Err(Error::DescriptorChainTooShort);
}
} else {
req.data_descriptors.reserve_exact(1);
while desc.has_next() {
if desc.is_write_only() && req.request_type == RequestType::Out {
return Err(Error::UnexpectedWriteOnlyDescriptor);
}
if !desc.is_write_only() && req.request_type == RequestType::In {
return Err(Error::UnexpectedReadOnlyDescriptor);
}
if !desc.is_write_only() && req.request_type == RequestType::GetDeviceId {
return Err(Error::UnexpectedReadOnlyDescriptor);
}
req.data_descriptors.push((
desc.addr()
.translate_gva(access_platform, desc.len() as usize),
desc.len(),
));
desc = desc_chain
.next()
.ok_or(Error::DescriptorChainTooShort)
.map_err(|e| {
error!("DescriptorChain corrupted: request = {:?}", req);
e
})?;
}
status_desc = desc;
}
// The status MUST always be writable.
if !status_desc.is_write_only() {
return Err(Error::UnexpectedReadOnlyDescriptor);
}
if status_desc.len() < 1 {
return Err(Error::DescriptorLengthTooSmall);
}
req.status_addr = status_desc
.addr()
.translate_gva(access_platform, status_desc.len() as usize);
Ok(req)
}
pub fn execute<T: Seek + Read + Write>(
&self,
disk: &mut T,
disk_nsectors: u64,
mem: &GuestMemoryMmap,
disk_id: &[u8],
) -> result::Result<u32, ExecuteError> {
disk.seek(SeekFrom::Start(self.sector << SECTOR_SHIFT))
.map_err(ExecuteError::Seek)?;
let mut len = 0;
for (data_addr, data_len) in &self.data_descriptors {
let mut top: u64 = u64::from(*data_len) / SECTOR_SIZE;
if u64::from(*data_len) % SECTOR_SIZE != 0 {
top += 1;
}
top = top
.checked_add(self.sector)
.ok_or(ExecuteError::BadRequest(Error::InvalidOffset))?;
if top > disk_nsectors {
return Err(ExecuteError::BadRequest(Error::InvalidOffset));
}
match self.request_type {
RequestType::In => {
mem.read_exact_from(*data_addr, disk, *data_len as usize)
.map_err(ExecuteError::Read)?;
len += data_len;
}
RequestType::Out => {
mem.write_all_to(*data_addr, disk, *data_len as usize)
.map_err(ExecuteError::Write)?;
if !self.writeback {
disk.flush().map_err(ExecuteError::Flush)?;
}
}
RequestType::Flush => disk.flush().map_err(ExecuteError::Flush)?,
RequestType::GetDeviceId => {
if (*data_len as usize) < disk_id.len() {
return Err(ExecuteError::BadRequest(Error::InvalidOffset));
}
mem.write_slice(disk_id, *data_addr)
.map_err(ExecuteError::Write)?;
}
RequestType::Unsupported(t) => return Err(ExecuteError::Unsupported(t)),
};
}
Ok(len)
}
pub fn execute_async(
&mut self,
mem: &GuestMemoryMmap,
disk_nsectors: u64,
disk_image: &mut dyn AsyncIo,
disk_id: &[u8],
user_data: u64,
) -> result::Result<bool, ExecuteError> {
let sector = self.sector;
let request_type = self.request_type;
let offset = (sector << SECTOR_SHIFT) as libc::off_t;
let mut iovecs: SmallVec<[libc::iovec; 1]> =
SmallVec::with_capacity(self.data_descriptors.len());
for (data_addr, data_len) in &self.data_descriptors {
if *data_len == 0 {
continue;
}
let mut top: u64 = u64::from(*data_len) / SECTOR_SIZE;
if u64::from(*data_len) % SECTOR_SIZE != 0 {
top += 1;
}
top = top
.checked_add(sector)
.ok_or(ExecuteError::BadRequest(Error::InvalidOffset))?;
if top > disk_nsectors {
return Err(ExecuteError::BadRequest(Error::InvalidOffset));
}
let origin_ptr = mem
.get_slice(*data_addr, *data_len as usize)
.map_err(ExecuteError::GetHostAddress)?
.as_ptr();
// Verify the buffer alignment.
// In case it's not properly aligned, an intermediate buffer is
// created with the correct alignment, and a copy from/to the
// origin buffer is performed, depending on the type of operation.
let iov_base = if (origin_ptr as u64) % SECTOR_SIZE != 0 {
let layout =
Layout::from_size_align(*data_len as usize, SECTOR_SIZE as usize).unwrap();
// SAFETY: layout has non-zero size
let aligned_ptr = unsafe { alloc_zeroed(layout) };
if aligned_ptr.is_null() {
return Err(ExecuteError::TemporaryBufferAllocation(
io::Error::last_os_error(),
));
}
// We need to perform the copy beforehand in case we're writing
// data out.
if request_type == RequestType::Out {
// SAFETY: destination buffer has been allocated with
// the proper size.
unsafe {
std::ptr::copy(origin_ptr as *const u8, aligned_ptr, *data_len as usize)
};
}
// Store both origin and aligned pointers for complete_async()
// to process them.
self.aligned_operations.push(AlignedOperation {
origin_ptr: origin_ptr as u64,
aligned_ptr: aligned_ptr as u64,
size: *data_len as usize,
layout,
});
aligned_ptr as *mut libc::c_void
} else {
origin_ptr as *mut libc::c_void
};
let iovec = libc::iovec {
iov_base,
iov_len: *data_len as libc::size_t,
};
iovecs.push(iovec);
}
// Queue operations expected to be submitted.
match request_type {
RequestType::In => {
for (data_addr, data_len) in &self.data_descriptors {
mem.get_slice(*data_addr, *data_len as usize)
.map_err(ExecuteError::GetHostAddress)?
.bitmap()
.mark_dirty(0, *data_len as usize);
}
disk_image
.read_vectored(offset, &iovecs, user_data)
.map_err(ExecuteError::AsyncRead)?;
}
RequestType::Out => {
disk_image
.write_vectored(offset, &iovecs, user_data)
.map_err(ExecuteError::AsyncWrite)?;
}
RequestType::Flush => {
disk_image
.fsync(Some(user_data))
.map_err(ExecuteError::AsyncFlush)?;
}
RequestType::GetDeviceId => {
let (data_addr, data_len) = if self.data_descriptors.len() == 1 {
(self.data_descriptors[0].0, self.data_descriptors[0].1)
} else {
return Err(ExecuteError::BadRequest(Error::TooManyDescriptors));
};
if (data_len as usize) < disk_id.len() {
return Err(ExecuteError::BadRequest(Error::InvalidOffset));
}
mem.write_slice(disk_id, data_addr)
.map_err(ExecuteError::Write)?;
return Ok(false);
}
RequestType::Unsupported(t) => return Err(ExecuteError::Unsupported(t)),
}
Ok(true)
}
pub fn complete_async(&mut self) -> result::Result<(), Error> {
for aligned_operation in self.aligned_operations.drain(..) {
// We need to perform the copy after the data has been read inside
// the aligned buffer in case we're reading data in.
if self.request_type == RequestType::In {
// SAFETY: origin buffer has been allocated with the
// proper size.
unsafe {
std::ptr::copy(
aligned_operation.aligned_ptr as *const u8,
aligned_operation.origin_ptr as *mut u8,
aligned_operation.size,
)
};
}
// Free the temporary aligned buffer.
// SAFETY: aligned_ptr was allocated by alloc_zeroed with the same
// layout
unsafe {
dealloc(
aligned_operation.aligned_ptr as *mut u8,
aligned_operation.layout,
)
};
}
Ok(())
}
pub fn set_writeback(&mut self, writeback: bool) {
self.writeback = writeback
}
}
#[derive(Copy, Clone, Debug, Default, Versionize)]
#[repr(C, packed)]
pub struct VirtioBlockConfig {
pub capacity: u64,
pub size_max: u32,
pub seg_max: u32,
pub geometry: VirtioBlockGeometry,
pub blk_size: u32,
pub physical_block_exp: u8,
pub alignment_offset: u8,
pub min_io_size: u16,
pub opt_io_size: u32,
pub writeback: u8,
pub unused: u8,
pub num_queues: u16,
pub max_discard_sectors: u32,
pub max_discard_seg: u32,
pub discard_sector_alignment: u32,
pub max_write_zeroes_sectors: u32,
pub max_write_zeroes_seg: u32,
pub write_zeroes_may_unmap: u8,
pub unused1: [u8; 3],
}
#[derive(Copy, Clone, Debug, Default, Versionize)]
#[repr(C, packed)]
pub struct VirtioBlockGeometry {
pub cylinders: u16,
pub heads: u8,
pub sectors: u8,
}
// SAFETY: data structure only contain a series of integers
unsafe impl ByteValued for VirtioBlockConfig {}
// SAFETY: data structure only contain a series of integers
unsafe impl ByteValued for VirtioBlockGeometry {}
/// Check if io_uring for block device can be used on the current system, as
/// it correctly supports the expected io_uring features.
pub fn block_io_uring_is_supported() -> bool {
let error_msg = "io_uring not supported:";
// Check we can create an io_uring instance, which effectively verifies
// that io_uring_setup() syscall is supported.
let io_uring = match IoUring::new(1) {
Ok(io_uring) => io_uring,
Err(e) => {
info!("{} failed to create io_uring instance: {}", error_msg, e);
return false;
}
};
let submitter = io_uring.submitter();
let mut probe = Probe::new();
// Check we can register a probe to validate supported operations.
match submitter.register_probe(&mut probe) {
Ok(_) => {}
Err(e) => {
info!("{} failed to register a probe: {}", error_msg, e);
return false;
}
}
// Check IORING_OP_FSYNC is supported
if !probe.is_supported(opcode::Fsync::CODE) {
info!("{} IORING_OP_FSYNC operation not supported", error_msg);
return false;
}
// Check IORING_OP_READV is supported
if !probe.is_supported(opcode::Readv::CODE) {
info!("{} IORING_OP_READV operation not supported", error_msg);
return false;
}
// Check IORING_OP_WRITEV is supported
if !probe.is_supported(opcode::Writev::CODE) {
info!("{} IORING_OP_WRITEV operation not supported", error_msg);
return false;
}
true
}
pub trait AsyncAdaptor<F>
where
F: Read + Write + Seek,
{
fn read_vectored_sync(
&mut self,
offset: libc::off_t,
iovecs: &[libc::iovec],
user_data: u64,
eventfd: &EventFd,
completion_list: &mut VecDeque<(u64, i32)>,
) -> AsyncIoResult<()> {
// Convert libc::iovec into IoSliceMut
let mut slices: SmallVec<[IoSliceMut; 1]> = SmallVec::with_capacity(iovecs.len());
for iovec in iovecs.iter() {
// SAFETY: on Linux IoSliceMut wraps around libc::iovec
slices.push(IoSliceMut::new(unsafe { std::mem::transmute(*iovec) }));
}
let result = {
let mut file = self.file();
// Move the cursor to the right offset
file.seek(SeekFrom::Start(offset as u64))
.map_err(AsyncIoError::ReadVectored)?;
// Read vectored
file.read_vectored(slices.as_mut_slice())
.map_err(AsyncIoError::ReadVectored)?
};
completion_list.push_back((user_data, result as i32));
eventfd.write(1).unwrap();
Ok(())
}
fn write_vectored_sync(
&mut self,
offset: libc::off_t,
iovecs: &[libc::iovec],
user_data: u64,
eventfd: &EventFd,
completion_list: &mut VecDeque<(u64, i32)>,
) -> AsyncIoResult<()> {
// Convert libc::iovec into IoSlice
let mut slices: SmallVec<[IoSlice; 1]> = SmallVec::with_capacity(iovecs.len());
for iovec in iovecs.iter() {
// SAFETY: on Linux IoSlice wraps around libc::iovec
slices.push(IoSlice::new(unsafe { std::mem::transmute(*iovec) }));
}
let result = {
let mut file = self.file();
// Move the cursor to the right offset
file.seek(SeekFrom::Start(offset as u64))
.map_err(AsyncIoError::WriteVectored)?;
// Write vectored
file.write_vectored(slices.as_slice())
.map_err(AsyncIoError::WriteVectored)?
};
completion_list.push_back((user_data, result as i32));
eventfd.write(1).unwrap();
Ok(())
}
fn fsync_sync(
&mut self,
user_data: Option<u64>,
eventfd: &EventFd,
completion_list: &mut VecDeque<(u64, i32)>,
) -> AsyncIoResult<()> {
let result: i32 = {
let mut file = self.file();
// Flush
file.flush().map_err(AsyncIoError::Fsync)?;
0
};
if let Some(user_data) = user_data {
completion_list.push_back((user_data, result));
eventfd.write(1).unwrap();
}
Ok(())
}
fn file(&mut self) -> MutexGuard<F>;
}
pub enum ImageType {
FixedVhd,
Qcow2,
Raw,
Vhdx,
}
const QCOW_MAGIC: u32 = 0x5146_49fb;
const VHDX_SIGN: u64 = 0x656C_6966_7864_6876;
/// Determine image type through file parsing.
pub fn detect_image_type(f: &mut File) -> std::io::Result<ImageType> {
// We must create a buffer aligned on 512 bytes with a size being a
// multiple of 512 bytes as the file might be opened with O_DIRECT flag.
#[repr(align(512))]
struct Sector {
data: [u8; 512],
}
let mut s = Sector { data: [0; 512] };
f.read_exact(&mut s.data)?;
// Check 4 first bytes to get the header value and determine the image type
let image_type = if u32::from_be_bytes(s.data[0..4].try_into().unwrap()) == QCOW_MAGIC {
ImageType::Qcow2
} else if vhd::is_fixed_vhd(f)? {
ImageType::FixedVhd
} else if u64::from_le_bytes(s.data[0..8].try_into().unwrap()) == VHDX_SIGN {
ImageType::Vhdx
} else {
ImageType::Raw
};
Ok(image_type)
}