Skip to content

Cleanups for Clippy and Windows #310

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Jan 28, 2025
Merged

Cleanups for Clippy and Windows #310

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
a929d90
chore: stop using deprecated MIN/MAX constants
bonzini Jan 28, 2025
f27f29a
chore: fix doc comment indentation
bonzini Jan 28, 2025
ca82e34
volatile_memory: avoid undefined symbols on Windows
bonzini Jan 28, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 16 additions & 8 deletions src/volatile_memory.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,12 +16,15 @@
//! doing with that hunk of memory.
//!
//! For the purposes of maintaining safety, volatile memory has some rules of its own:
//!
//! 1. No references or slices to volatile memory (`&` or `&mut`).
//!
//! 2. Access should always been done with a volatile read or write.
//! The First rule is because having references of any kind to memory considered volatile would
//! violate pointer aliasing. The second is because unvolatile accesses are inherently undefined if
//! done concurrently without synchronization. With volatile access we know that the compiler has
//! not reordered or elided the access.
//!
//! The First rule is because having references of any kind to memory considered volatile would
//! violate pointer aliasing. The second is because unvolatile accesses are inherently undefined if
//! done concurrently without synchronization. With volatile access we know that the compiler has
//! not reordered or elided the access.

use std::cmp::min;
use std::io::{self, Read, Write};
Expand Down Expand Up @@ -85,7 +88,7 @@ pub type Result<T> = result::Result<T, Error>;
/// # use vm_memory::volatile_memory::compute_offset;
/// #
/// assert_eq!(108, compute_offset(100, 8).unwrap());
/// assert!(compute_offset(std::usize::MAX, 6).is_err());
/// assert!(compute_offset(usize::MAX, 6).is_err());
/// ```
pub fn compute_offset(base: usize, offset: usize) -> Result<usize> {
match base.checked_add(offset) {
Expand Down Expand Up @@ -315,9 +318,14 @@ pub struct PtrGuard {
#[allow(clippy::len_without_is_empty)]
impl PtrGuard {
#[allow(unused_variables)]
fn new(mmap: Option<&MmapInfo>, addr: *mut u8, prot: i32, len: usize) -> Self {
fn new(mmap: Option<&MmapInfo>, addr: *mut u8, write: bool, len: usize) -> Self {
#[cfg(all(feature = "xen", unix))]
let (addr, _slice) = {
let prot = if write {
libc::PROT_WRITE
} else {
libc::PROT_READ
};
let slice = MmapInfo::mmap(mmap, addr, prot, len);
(slice.addr(), slice)
};
Expand All @@ -332,7 +340,7 @@ impl PtrGuard {
}

fn read(mmap: Option<&MmapInfo>, addr: *mut u8, len: usize) -> Self {
Self::new(mmap, addr, libc::PROT_READ, len)
Self::new(mmap, addr, false, len)
}

/// Returns a non-mutable pointer to the beginning of the slice.
Expand All @@ -353,7 +361,7 @@ pub struct PtrGuardMut(PtrGuard);
#[allow(clippy::len_without_is_empty)]
impl PtrGuardMut {
fn write(mmap: Option<&MmapInfo>, addr: *mut u8, len: usize) -> Self {
Self(PtrGuard::new(mmap, addr, libc::PROT_WRITE, len))
Self(PtrGuard::new(mmap, addr, true, len))
}

/// Returns a mutable pointer to the beginning of the slice. Mutable accesses performed
Expand Down