| Message ID | rust-pl011-rfc-v2.git.manos.pitsidianakis@linaro.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Implement ARM PL011 in Rust | expand |
On Tue, Jun 11, 2024 at 01:33:29PM +0300, Manos Pitsidianakis wrote: > > .gitignore | 2 + > .gitlab-ci.d/buildtest.yml | 64 ++-- > MAINTAINERS | 13 + > configure | 12 + > hw/arm/virt.c | 4 + > meson.build | 102 ++++++ > meson_options.txt | 4 + > rust/meson.build | 93 ++++++ > rust/pl011/.cargo/config.toml | 2 + > rust/pl011/.gitignore | 2 + > rust/pl011/Cargo.lock | 120 +++++++ > rust/pl011/Cargo.toml | 66 ++++ > rust/pl011/README.md | 42 +++ > rust/pl011/build.rs | 44 +++ > rust/pl011/deny.toml | 57 ++++ > rust/pl011/meson.build | 7 + > rust/pl011/rustfmt.toml | 1 + > rust/pl011/src/definitions.rs | 95 ++++++ > rust/pl011/src/device.rs | 531 ++++++++++++++++++++++++++++++ > rust/pl011/src/device_class.rs | 95 ++++++ > rust/pl011/src/generated.rs | 5 + > rust/pl011/src/lib.rs | 581 +++++++++++++++++++++++++++++++++ > rust/pl011/src/memory_ops.rs | 38 +++ > rust/rustfmt.toml | 7 + > rust/wrapper.h | 39 +++ > scripts/cargo_wrapper.py | 221 +++++++++++++ > scripts/meson-buildoptions.sh | 6 + Given the priority of getting the build system correct, what's missing here is updates/integration into our standard GitLab CI pipeline. If that can be shown to be working, that'll give alot more confidence in the overall solution. Ideally this should not require anything more than updating the docker container definitions to add in the rust toolchain, plus the appropriate std library build for the given target - we cross compiler for every arch we officially care about. Most of our dockerfiles these days are managed by lcitool, and it has nearly sufficient support for cross compiling with the rust std library. So to start with, this series should modify tests/lcitool/projects/qemu.yml to add - rust - rust-std to the package list, and run 'make lcitool-refresh' to re-create the dockerfiles - see the docs/devel/testing.rst for more info about lcitool if needed. Assuming these 2 rust packages are in the container, I would then expect QEMU to just "do the right thing" when building this rust code. If it does not, then that's a sign of gaps that need closing. Getting rid of the need to use --rust-target-triple will be the immediate gap that needs fixing, as CI just passes --cross-prefix for cross-builds and expects everything to be set from that. The main gap we have is that for Windows I need to update lcitool to pull in the mingw std lib target for rust, which I something I missed when adding rust cross compiler support. With regards, Daniel
Good morning Daniel, On Wed, 12 Jun 2024 11:37, "Daniel P. Berrangé" <berrange@redhat.com> wrote: >On Tue, Jun 11, 2024 at 01:33:29PM +0300, Manos Pitsidianakis wrote: > >> >> .gitignore | 2 + >> .gitlab-ci.d/buildtest.yml | 64 ++-- >> MAINTAINERS | 13 + >> configure | 12 + >> hw/arm/virt.c | 4 + >> meson.build | 102 ++++++ >> meson_options.txt | 4 + >> rust/meson.build | 93 ++++++ >> rust/pl011/.cargo/config.toml | 2 + >> rust/pl011/.gitignore | 2 + >> rust/pl011/Cargo.lock | 120 +++++++ >> rust/pl011/Cargo.toml | 66 ++++ >> rust/pl011/README.md | 42 +++ >> rust/pl011/build.rs | 44 +++ >> rust/pl011/deny.toml | 57 ++++ >> rust/pl011/meson.build | 7 + >> rust/pl011/rustfmt.toml | 1 + >> rust/pl011/src/definitions.rs | 95 ++++++ >> rust/pl011/src/device.rs | 531 ++++++++++++++++++++++++++++++ >> rust/pl011/src/device_class.rs | 95 ++++++ >> rust/pl011/src/generated.rs | 5 + >> rust/pl011/src/lib.rs | 581 +++++++++++++++++++++++++++++++++ >> rust/pl011/src/memory_ops.rs | 38 +++ >> rust/rustfmt.toml | 7 + >> rust/wrapper.h | 39 +++ >> scripts/cargo_wrapper.py | 221 +++++++++++++ >> scripts/meson-buildoptions.sh | 6 + > >Given the priority of getting the build system correct, what's missing >here is updates/integration into our standard GitLab CI pipeline. If >that can be shown to be working, that'll give alot more confidence in >the overall solution. > >Ideally this should not require anything more than updating the docker >container definitions to add in the rust toolchain, plus the appropriate >std library build for the given target - we cross compiler for every >arch we officially care about. > >Most of our dockerfiles these days are managed by lcitool, and it has >nearly sufficient support for cross compiling with the rust std library. >So to start with, this series should modify tests/lcitool/projects/qemu.yml >to add > > - rust > - rust-std > >to the package list, and run 'make lcitool-refresh' to re-create the >dockerfiles - see the docs/devel/testing.rst for more info about >lcitool if needed. > >Assuming these 2 rust packages are in the container, I would then >expect QEMU to just "do the right thing" when building this rust >code. If it does not, then that's a sign of gaps that need closing. > >Getting rid of the need to use --rust-target-triple will be the >immediate gap that needs fixing, as CI just passes --cross-prefix >for cross-builds and expects everything to be set from that. > >The main gap we have is that for Windows I need to update lcitool >to pull in the mingw std lib target for rust, which I something I >missed when adding rust cross compiler support. > Thanks very much for the pointers! I will start dealing with this in the next RFC version. Re: the target triple, I agree 100%. In fact it wasn't my addition, I kept it from the previous rust RFC patchset that was posted on the list some years ago. It should be possible to construct the triplets ourselves and let the user override if they want to as mentioned in another email. The rust project has official Docker images, do you think it's something we could use or is it unnecessary? https://github.com/rust-lang/docker-rust Thanks, Manos
On Thu, Jun 13, 2024 at 08:13:01AM +0300, Manos Pitsidianakis wrote: > Good morning Daniel, > > On Wed, 12 Jun 2024 11:37, "Daniel P. Berrangé" <berrange@redhat.com> wrote: > > On Tue, Jun 11, 2024 at 01:33:29PM +0300, Manos Pitsidianakis wrote: > > > > > > > > .gitignore | 2 + > > > .gitlab-ci.d/buildtest.yml | 64 ++-- > > > MAINTAINERS | 13 + > > > configure | 12 + > > > hw/arm/virt.c | 4 + > > > meson.build | 102 ++++++ > > > meson_options.txt | 4 + > > > rust/meson.build | 93 ++++++ > > > rust/pl011/.cargo/config.toml | 2 + > > > rust/pl011/.gitignore | 2 + > > > rust/pl011/Cargo.lock | 120 +++++++ > > > rust/pl011/Cargo.toml | 66 ++++ > > > rust/pl011/README.md | 42 +++ > > > rust/pl011/build.rs | 44 +++ > > > rust/pl011/deny.toml | 57 ++++ > > > rust/pl011/meson.build | 7 + > > > rust/pl011/rustfmt.toml | 1 + > > > rust/pl011/src/definitions.rs | 95 ++++++ > > > rust/pl011/src/device.rs | 531 ++++++++++++++++++++++++++++++ > > > rust/pl011/src/device_class.rs | 95 ++++++ > > > rust/pl011/src/generated.rs | 5 + > > > rust/pl011/src/lib.rs | 581 +++++++++++++++++++++++++++++++++ > > > rust/pl011/src/memory_ops.rs | 38 +++ > > > rust/rustfmt.toml | 7 + > > > rust/wrapper.h | 39 +++ > > > scripts/cargo_wrapper.py | 221 +++++++++++++ > > > scripts/meson-buildoptions.sh | 6 + > > > > Given the priority of getting the build system correct, what's missing > > here is updates/integration into our standard GitLab CI pipeline. If > > that can be shown to be working, that'll give alot more confidence in > > the overall solution. > > > > Ideally this should not require anything more than updating the docker > > container definitions to add in the rust toolchain, plus the appropriate > > std library build for the given target - we cross compiler for every > > arch we officially care about. > > > > Most of our dockerfiles these days are managed by lcitool, and it has > > nearly sufficient support for cross compiling with the rust std library. > > So to start with, this series should modify tests/lcitool/projects/qemu.yml > > to add > > > > - rust > > - rust-std > > > > to the package list, and run 'make lcitool-refresh' to re-create the > > dockerfiles - see the docs/devel/testing.rst for more info about > > lcitool if needed. > > > > Assuming these 2 rust packages are in the container, I would then > > expect QEMU to just "do the right thing" when building this rust > > code. If it does not, then that's a sign of gaps that need closing. > > > > Getting rid of the need to use --rust-target-triple will be the > > immediate gap that needs fixing, as CI just passes --cross-prefix > > for cross-builds and expects everything to be set from that. > > > > The main gap we have is that for Windows I need to update lcitool > > to pull in the mingw std lib target for rust, which I something I > > missed when adding rust cross compiler support. I've updated lcitool for this gap: https://gitlab.com/libvirt/libvirt-ci/-/merge_requests/492 > The rust project has official Docker images, do you think it's something we > could use or is it unnecessary? > > https://github.com/rust-lang/docker-rust They're irrelevant - we need the containers with the full set of QEMU build dependencies present, and it is the Rust versions that are in the distros that matter to us. With regards, Daniel
On 6/11/24 03:33, Manos Pitsidianakis wrote: > If `cargo` and `bindgen` is installed in your system, you should be able > to build qemu-system-aarch64 with configure flag --enable-rust and > launch an arm virt VM. One of the patches hardcodes the default UART of > the machine to the Rust one, so if something goes wrong you will see it > upon launching qemu-system-aarch64. What version is required? On my stock ubuntu 22.04 system, I get /usr/bin/bindgen aarch64-softmmu_wrapper.h ... error: Found argument '--formatter' which wasn't expected, or isn't valid in this context USAGE: bindgen [FLAGS] [OPTIONS] <header> -- <clang-args>... $ bindgen --version bindgen 0.59.1 r~
On Wed, 19 Jun 2024 06:31, Richard Henderson <richard.henderson@linaro.org> wrote: >On 6/11/24 03:33, Manos Pitsidianakis wrote: >> If `cargo` and `bindgen` is installed in your system, you should be able >> to build qemu-system-aarch64 with configure flag --enable-rust and >> launch an arm virt VM. One of the patches hardcodes the default UART of >> the machine to the Rust one, so if something goes wrong you will see it >> upon launching qemu-system-aarch64. > >What version is required? > >On my stock ubuntu 22.04 system, I get > >/usr/bin/bindgen aarch64-softmmu_wrapper.h ... >error: Found argument '--formatter' which wasn't expected, or isn't valid in this context > >USAGE: > bindgen [FLAGS] [OPTIONS] <header> -- <clang-args>... > >$ bindgen --version >bindgen 0.59.1 I added version checks in the (yet unpublished) next version: (Which we will also need to match with distro ones whenever possible) +# FIXME: Latest stable versions, refine to actual minimum ones. +msrv = { + 'rustc': '1.79.0', + 'cargo': '1.79.0', + 'bindgen': '0.69.4', +} + +# rustup = find_program('rustup', required: false) +foreach bin_dep: msrv.keys() + bin = find_program(bin_dep, required: true) + if bin.version() < msrv[bin_dep] + # TODO verify behavior + if bin == 'bindgen' and get_option('wrap_mode') != 'nodownload' + run_command(cargo, 'install', 'bindgen', capture: true, check: true) + bin = find_program(bin_dep, required: true) + if bin.version() >= msrv[bin_dep] + continue + endif + endif + message() + error(bin_dep + ' version ' + bin.version() + ' is unsupported: Please upgrade to at least ' + msrv[bin_dep]) + endif +endforeach
Changes from v1->v2: - Create bindgen target first, then add commit for device (thanks Pierrick) - Create a special named generated.rs for each target as compilation would fail if more than one targets were defined. The generated.rs target names would clash. - Add more descriptive commit messages - Update MAINTAINERS - Cleanup patch order for better review, hopefully Previous series was <cover.rust-pl011-rfc-v1.git.manos.pitsidianakis@linaro.org> -- Hello everyone, This is an early draft of my work on implementing a very simple device, in this case the ARM PL011 (which in C code resides in hw/char/pl011.c and is used in hw/arm/virt.c). The device is functional, with copied logic from the C code but with effort not to make a direct C to Rust translation. In other words, do not write Rust as a C developer would. That goal is not complete but a best-effort case. To give a specific example, register values are typed but interrupt bit flags are not (but could be). I will leave such minutiae for later iterations. By the way, the wiki page for Rust was revived to keep track of all current series on the mailing list https://wiki.qemu.org/RustInQemu a #qemu-rust IRC channel was also created for rust-specific discussion that might flood #qemu ------------------------------------------------------------------------ A request: keep comments to Rust in relation to the QEMU project and no debates on the merits of the language itself. These are valid concerns, but it'd be better if they were on separate mailing list threads. ------------------------------------------------------------------------ Table of contents: [TOC] - How can I try it? [howcanItryit] - What are the most important points to focus on, at this point? [whatarethemostimportant] - What are the issues with not using the compiler, rustc, directly? [whataretheissueswith] 1. Tooling 2. Rust dependencies - Should QEMU use third-party dependencies? [shouldqemuusethirdparty] - Should QEMU provide wrapping Rust APIs over QEMU internals? [qemuprovidewrappingrustapis] - Will QEMU now depend on Rust and thus not build on my XYZ platform? [qemudependonrustnotbuildonxyz] - How is the compilation structured? [howisthecompilationstructured] - The generated.rs rust file includes a bunch of junk definitions? [generatedrsincludesjunk] - The staticlib artifact contains a bunch of mangled .o objects? [staticlibmangledobjects] How can I try it? ================= [howcanItryit] Back to [TOC] Hopefully applying this patches (or checking out `master` branch from https://gitlab.com/epilys/rust-for-qemu/ ) Tag for this RFC is rust-pl011-rfc-v2 Rustdoc documentation is hosted on https://rust-for-qemu-epilys-aebb06ca9f9adfe6584811c14ae44156501d935ba4.gitlab.io/pl011/index.html If `cargo` and `bindgen` is installed in your system, you should be able to build qemu-system-aarch64 with configure flag --enable-rust and launch an arm virt VM. One of the patches hardcodes the default UART of the machine to the Rust one, so if something goes wrong you will see it upon launching qemu-system-aarch64. To confirm it is there for sure, run e.g. info qom-tree on the monitor and look for x-pl011-rust. What are the most important points to focus on, at this point? ============================================================== [whatarethemostimportant] Back to [TOC] In my opinion, integration of the go-to Rust build system (Cargo and crates.io) with the build system we use in QEMU. This is "easily" done in some definition of the word with a python wrapper script. What are the issues with not using the compiler, rustc, directly? ----------------------------------------------------------------- [whataretheissueswith] Back to [TOC] 1. Tooling Mostly writing up the build-sys tooling to do so. Ideally we'd compile everything without cargo but rustc directly. If we decide we need Rust's `std` library support, we could investigate whether building it from scratch is a good solution. This will only build the bits we need in our devices. 2. Rust dependencies We could go without them completely. I chose deliberately to include one dependency in my UART implementation, `bilge`[0], because it has an elegant way of representing typed bitfields for the UART's registers. [0]: Article: https://hecatia-elegua.github.io/blog/no-more-bit-fiddling/ Crates.io page: https://crates.io/crates/bilge Repository: https://github.com/hecatia-elegua/bilge Should QEMU use third-party dependencies? ----------------------------------------- [shouldqemuusethirdparty] Back to [TOC] In my personal opinion, if we need a dependency we need a strong argument for it. A dependency needs a trusted upstream source, a QEMU maintainer to make sure it us up-to-date in QEMU etc. We already fetch some projects with meson subprojects, so this is not a new reality. Cargo allows you to define "locked" dependencies which is the same as only fetching specific commits by SHA. No suspicious tarballs, and no disappearing dependencies a la left-pad in npm. However, I believe it's worth considering vendoring every dependency by default, if they prove to be few, for the sake of having a local QEMU git clone buildable without network access. Should QEMU provide wrapping Rust APIs over QEMU internals? ----------------------------------------------------------- [qemuprovidewrappingrustapis] Back to [TOC] My personal opinion is no, with the reasoning being that QEMU internals are not documented or stable. However I do not see why creating stable opt-in interfaces is bad. It just needs someone to volunteer to maintain it and ensure there are no breakages through versions. Will QEMU now depend on Rust and thus not build on my XYZ platform? ------------------------------------------------------------------- [qemudependonrustnotbuildonxyz] Back to [TOC] No, worry about this in some years if this experiment takes off. Rust has broad platform support and is present in most distro package managers. In the future we might have gcc support for it as well. For now, Rust will have an experimental status, and will be aimed to those who wish to try it. I leave it to the project leaders to make proper decisions and statements on this if necessary. How is the compilation structured? ================================== [howisthecompilationstructured] Back to [TOC] First, a meson target that runs `bindgen` on a bunch of header files (defined in `rust/wrapper.h`) is created as a target and as a dependency for any rust hardware device that needs it. You can see the generated bindings by running ninja aarch64-softmmu-generated.rs inside your build directory. The devices are defined as dictionaries in rust/meson.build because they depend on the bindgen dependency, which is available much later in the meson process (when the static qemu lib and target emulator executables are defined). A cargo wrapper python script under scripts/ exists to build the crate library, by providing the path to the generated.rs bindings via the environment. Then, the qemu-system-aarch64 binary links against the staticlib archive (i.e. libpl011.a) The generated.rs rust file includes a bunch of junk definitions? ================================================================ [generatedrsincludesjunk] Back to [TOC] Yes, bindgen allows you to block certain types and identifiers from being generated but they are simply too many. I have trimmed some of the fat but vast improvements can be made. The staticlib artifact contains a bunch of mangled .o objects? ============================================================== [staticlibmangledobjects] Back to [TOC] Yes, until we compile without the `std` module library or we compile it manually instead of linking it, we will have some junk in it. -- Manos Pitsidianakis (5): build-sys: Add rust feature option rust: add bindgen step as a meson dependency rust: add PL011 device model DO NOT MERGE: add rustdoc build for gitlab pages DO NOT MERGE: replace TYPE_PL011 with x-pl011-rust in arm virt machine .gitignore | 2 + .gitlab-ci.d/buildtest.yml | 64 ++-- MAINTAINERS | 13 + configure | 12 + hw/arm/virt.c | 4 + meson.build | 102 ++++++ meson_options.txt | 4 + rust/meson.build | 93 ++++++ rust/pl011/.cargo/config.toml | 2 + rust/pl011/.gitignore | 2 + rust/pl011/Cargo.lock | 120 +++++++ rust/pl011/Cargo.toml | 66 ++++ rust/pl011/README.md | 42 +++ rust/pl011/build.rs | 44 +++ rust/pl011/deny.toml | 57 ++++ rust/pl011/meson.build | 7 + rust/pl011/rustfmt.toml | 1 + rust/pl011/src/definitions.rs | 95 ++++++ rust/pl011/src/device.rs | 531 ++++++++++++++++++++++++++++++ rust/pl011/src/device_class.rs | 95 ++++++ rust/pl011/src/generated.rs | 5 + rust/pl011/src/lib.rs | 581 +++++++++++++++++++++++++++++++++ rust/pl011/src/memory_ops.rs | 38 +++ rust/rustfmt.toml | 7 + rust/wrapper.h | 39 +++ scripts/cargo_wrapper.py | 221 +++++++++++++ scripts/meson-buildoptions.sh | 6 + 27 files changed, 2234 insertions(+), 19 deletions(-) create mode 100644 rust/meson.build create mode 100644 rust/pl011/.cargo/config.toml create mode 100644 rust/pl011/.gitignore create mode 100644 rust/pl011/Cargo.lock create mode 100644 rust/pl011/Cargo.toml create mode 100644 rust/pl011/README.md create mode 100644 rust/pl011/build.rs create mode 100644 rust/pl011/deny.toml create mode 100644 rust/pl011/meson.build create mode 120000 rust/pl011/rustfmt.toml create mode 100644 rust/pl011/src/definitions.rs create mode 100644 rust/pl011/src/device.rs create mode 100644 rust/pl011/src/device_class.rs create mode 100644 rust/pl011/src/generated.rs create mode 100644 rust/pl011/src/lib.rs create mode 100644 rust/pl011/src/memory_ops.rs create mode 100644 rust/rustfmt.toml create mode 100644 rust/wrapper.h create mode 100644 scripts/cargo_wrapper.py base-commit: 01782d6b294f95bcde334386f0aaac593cd28c0d