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

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

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
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