RustInQemu: Difference between revisions

Latest revision as of 12:50, 2 May 2025

For the old RustInQemu page, see RustInQemu/2022

Active effort

Current state
Documentation
Past updates: January 2025 | November 2024

Past efforts

[RFC v3 00/32] Rust binding for QAPI and qemu-ga QMP handler examples
on patchew on lore
Subject: [RFC 0/6] scripts: Rewrite simpletrace printer in Rust
Date: Mon, 27 May 2024 16:14:15 +0800
RFC v1

Work in progress

Paolo

Waiting for Meson 1.8.1: "objects:", rustdoc,
Later: pinned_init... maybe use MaybeUninit as a first step?

Manos

Zhao

Kevin

Executing async code, block driver implementations
- https://lore.kernel.org/qemu-devel/20250211214328.640374-1-kwolf@redhat.com/

Bugs

Add BQL abstraction for tests - avoid running them with "--test-threads 1"
Distros would prefer to link libstd dynamically; Rust-enabled QEMU binaries are huge

Possible project targets

Nice things to have

Remove need for manual "meson subprojects update --reset" when updating packagefiles/
Improve tool integration
- Run code checks a la "meson test --suite codecheck"? (clippy and rustfmt)
Place rustdoc output for master somewhere?
split qemu_api into multiple crates
distros need dynamically linked libstd
- rewrite all main()s in Rust and use -C prefer-dynamic?
- or should Meson be able to link C programs with rlibs?

New code to write

more QOM procedural macros
- generate qdev properties
- generate parts of TypeInfo?
- monomorphization of T: IsA<Class> to &T (like the momo crate)
feature parity for pl011
safe object creation with pinned_init, originating from Linux)
Generic Rust<->C interop, Error (https://github.com/bonzini/rust-qemu)
DMA (investigate vm-memory?)
Trace/log (Summer of Code)

Improved clippy coverage in CI?

run clippy as part of "make check"
add to CI a fallible job that runs on nightly clippy with -Dclippy::complexity -Dclippy::perf -Dclippy::suspicious -Dclippy::style -Dunknown_lints. the job should generally pass, and if a new lint triggers it probably should be added to Cargo.toml as either "allow" (rare) or "deny" (possibly after adding #[allow()] to the source).

Miscellanea

qemu-bridge-helper.c Re-write SUID C executable with useful features.

Bindings

visitors/QOM properties, could be interesting for hw/sensor/tmp105.c...
complete vmstate bindings (needs const_refs_static in Rust 1.83.0, Zhao+Paolo have a prototype)

Devices

hw/block/pflash_cfi01.c, hw/block/pflash_cfi02.c (claimed, WIP)
- needs block bindings
hw/timer/i8254.c (claimed, WIP)
hw/mem/nvdimm.c (suggested by Manos)

@@ Line 1: / Line 1: @@
 For the old RustInQemu page, see [[RustInQemu/2022]]
-== Active efforts in 2024 ==
+== Active effort ==
+* [https://lore.kernel.org/qemu-devel/d3d1944e-2482-4aa7-b621-596246a08107@gnu.org/ Current state]
+* [https://www.qemu.org/docs/master/devel/rust.html Documentation]
+* Past updates: [https://lore.kernel.org/qemu-devel/17ad81c3-98fc-44c2-8f65-f5e2cc07030b@gnu.org/ January 2025] |  [https://lore.kernel.org/all/cc40943e-dec1-4890-a1d9-579350ce296f@pbonzini.local/ November 2024]
+== Past efforts ==
+* <code>[RFC v3 00/32] Rust binding for QAPI and qemu-ga QMP handler examples</code><br />[https://patchew.org/QEMU/20210907121943.3498701-1-marcandre.lureau@redhat.com/ on patchew] [https://lore.kernel.org/qemu-devel/20210907121943.3498701-1-marcandre.lureau@redhat.com/ on lore]
 * <code>Subject: [RFC 0/6] scripts: Rewrite simpletrace printer in Rust</code><br /><code>Date: Mon, 27 May 2024 16:14:15 +0800</code><br />[https://lore.kernel.org/qemu-devel/20240527081421.2258624-1-zhao1.liu@intel.com/ RFC v1]
-* ARM PL011 UART device model in Rust<br /><code>Subject: [RFC PATCH v1 0/6] Implement ARM PL011 in Rust</code><br /><code>Date: Mon, 10 Jun 2024 21:22:35 +0300</code><br />[https://lore.kernel.org/qemu-devel/cover.rust-pl011-rfc-v1.git.manos.pitsidianakis@linaro.org/ RFC v1] [https://lore.kernel.org/qemu-devel/rust-pl011-rfc-v6.git.manos.pitsidianakis@linaro.org/ v6]
-** Meson and configure integration
-** Bindings generation
-After some discussion we decided to use rustc directly without going through cargo and each external crate becomes a Meson subproject. Meson 1.5.0+'s support for <tt>method = cargo</tt> is pretty good for host-compiled packages, but it doesn't work for dependencies of build-compiled packages (i.e. dependencies of procedural macros). This is tracked by https://github.com/mesonbuild/meson/issues/11121. Until then, meson.build files for procedural macros and their dependencies have to be written by hand. (Currently _all_ dependencies use hand-written meson.build).
+== Work in progress ==
+=== Paolo ===
+* Waiting for Meson 1.8.1: "objects:", rustdoc,
+* Later: pinned_init... maybe use MaybeUninit as a first step?
-While cargo would be fine as an interim solution, using Meson to compile the Rust code removes some moving parts. The extra cost of writing meson.build files for dependencies is expected to be small and will mostly happen upfront.
+=== Manos ===
+=== Zhao ===
-== Past efforts ==
-* <code>[RFC v3 00/32] Rust binding for QAPI and qemu-ga QMP handler examples</code><br />[https://patchew.org/QEMU/20210907121943.3498701-1-marcandre.lureau@redhat.com/ on patchew] [https://lore.kernel.org/qemu-devel/20210907121943.3498701-1-marcandre.lureau@redhat.com/ on lore]
+=== Kevin ===
+* Executing async code, block driver implementations
+** https://lore.kernel.org/qemu-devel/20250211214328.640374-1-kwolf@redhat.com/
-== Minimum supported version ==
+== Bugs ==
-* 1.56.0: 2021 edition
+* Add BQL abstraction for tests - avoid running them with "--test-threads 1"
-* 1.59.0: const <tt>CStr::from_bytes_with_nul_unchecked</tt> (needed by cstr crate, see below)
+* [https://github.com/mesonbuild/meson/issues/8828 Distros would prefer to link libstd dynamically]; Rust-enabled QEMU binaries are huge
-* 1.64.0: <tt>std::ffi::c_*</tt> (can use libc or std::os::raw)
-* 1.74.0: Clippy can be configured in Cargo.toml
-* 1.77.0: C string literals, offset_of!
-**alternative: cstr crate, [https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=10a22a9b8393abd7b541d8fc844bc0df with_offsets macro]
-* only generate bindings.rs.inc once
+== Possible project targets ==
-* disabling the cast_ptr_alignment lint is too broad
-* update bundled meson to 1.5.0
-* add support for --rustc and RUSTC environment variables
-* remove --no-include-path-detection from bindgen invocation
-* rename subprojects to use Meson 1.5.0+ convention and add meson.override_dependency() call
-* add support for cross compilation of Rust subprojects (<tt>native: true</tt> for deps of procedural macro crates)
-* fix licenses for Rust subprojects
-== Posted ==
+=== Nice things to have ===
-* Enable use of rustc 1.63.0
+* Remove need for manual "meson subprojects update --reset" when updating packagefiles/
-** fix cfgs for proc-macro2
+* Improve tool integration
-** core::ffi (stable in 1.64.0)
+** Run code checks a la "meson test --suite codecheck"? (clippy and rustfmt)
-** "if let" usage in bilge-impl needs to be patched out (stable in 1.65.0)
+* Place rustdoc output for master somewhere?
-** std::sync::OnceLock (stable in 1.70.0)
+* split qemu_api into multiple crates
-** MaybeUninit::zeroed() (stable in 1.75.0 in const context)
+* distros need dynamically linked libstd
-** c"" literals (stable in 1.77.0)
+** rewrite all main()s in Rust and use [https://github.com/mesonbuild/meson/issues/14224 -C prefer-dynamic]?
-** offset_of! (stable in 1.77.0)
+** or should Meson be able to link C programs with rlibs?
-* Enable use of older bindgen
-** What to do about Ubuntu 22.04? Bindgen 0.59.x does not have --allowlist-file
-* Install rustc/bindgen in all containers
-== TODO ==
+=== New code to write===
-* Easy integration with clippy
+* more QOM procedural macros
-* Easy integration with rustfmt
+** generate qdev properties
-* More CI
+** generate parts of TypeInfo?
-** Rustfmt checks?
+** monomorphization of <tt>T: IsA&lt;Class&gt;</tt> to <tt>&T</tt> (like the momo crate)
-** Run nightly clippy
+* feature parity for pl011
-* use MaybeUninit in instance_init (long-term: investigate [https://docs.rs/pinned-init/ pinned_init crate, originating from Linux])
+* safe object creation with [https://docs.rs/pinned-init/ pinned_init, originating from Linux])
-** MemoryRegion (creation)
+* Generic Rust<->C interop, Error (https://github.com/bonzini/rust-qemu)
-* module structure should resemble the C part of the tree?
+* DMA (investigate vm-memory?)
-* bindings
+* Trace/log (Summer of Code)
-** MemoryRegion (callbacks)
-** Chardev (callbacks, functions)
-** DMA (investigate vm-memory?)
-* other experiments at https://github.com/bonzini/rust-qemu
-** Generic Rust<->C interop, Error, QOM reference counting
-* more QOM procedural macros (currently <tt>#[derive(Object)]</tt>)
-** generate qdev properties?
-** generate class_init methods?
-== Ideas for lints without breaking CI ==
+=== Improved clippy coverage in CI? ===
-See https://github.com/bonzini/rust-qemu/commit/95b25f7c5f4e2694a85a5503050cc98da7562c7c
+* run clippy as part of "make check"
-* run clippy as part of "make check", possibly only if Rust is newer than some version (1.74.0 so that clippy can be configured in Cargo.toml?)
-* deny many individual lints, do not deny groups (complexity, perf, style, suspicious) on regular builds. allow unknown_lints.
 * add to CI a fallible job that runs on nightly clippy with <tt>-Dclippy::complexity -Dclippy::perf -Dclippy::suspicious -Dclippy::style -Dunknown_lints</tt>. the job should generally pass, and if a new lint triggers it probably should be added to Cargo.toml as either "allow" (rare) or "deny" (possibly after adding #[allow()] to the source).
-== Possible project targets ==
 === Miscellanea  ===
-- <code>qemu-bridge-helper.c</code> Re-write SUID C executable with useful features.
+* <code>qemu-bridge-helper.c</code> Re-write SUID C executable with useful features.
-=== Devices  ===
+=== Bindings ===
-- <code>hw/block/pflash_cfi01.c</code>, <code>hw/block/pflash_cfi02.c</code> (claimed, WIP)
+* visitors/QOM properties, could be interesting for <code>hw/sensor/tmp105.c</code>...
+* complete vmstate bindings (needs const_refs_static in Rust 1.83.0, Zhao+Paolo have a prototype)
-- <code>hw/mem/nvdimm.c</code> (suggested by [[User:Manos|Manos]])
+=== Devices  ===
-- <code>hw/timer/i8254.c</code> (claimed, WIP)
+* <code>hw/block/pflash_cfi01.c</code>, <code>hw/block/pflash_cfi02.c</code> (claimed, WIP)
+** needs block bindings
+* <code>hw/timer/i8254.c</code> (claimed, WIP)
+* <code>hw/mem/nvdimm.c</code> (suggested by [[User:Manos|Manos]])
 [[Category:RustInQemu]]