Re: [RFC PATCH v2 0/5] Implement ARM PL011 in Rust

["Daniel P. Berrangé" <berrange@redhat.com>]

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
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