Re: [RFC PATCH v1 0/6] Implement ARM PL011 in Rust

[Manos Pitsidianakis <manos.pitsidianakis@linaro.org>]

On Tue, 11 Jun 2024 13:57, "Daniel P. Berrangé" <berrange@redhat.com> wrote:
>On Mon, Jun 10, 2024 at 11:29:36PM +0300, Manos Pitsidianakis wrote:
>> On Mon, 10 Jun 2024 22:37, Pierrick Bouvier <pierrick.bouvier@linaro.org> wrote:
>> > Hello Manos,
>> > 
>> > On 6/10/24 11:22, Manos Pitsidianakis wrote:
>> > > 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.
>
>snip
>
>> > Maybe it could be better if build.rs file was *not* needed for new
>> > devices/folders, and could be abstracted as a detail of the python
>> > wrapper script instead of something that should be committed.
>> 
>> 
>> That'd mean you cannot work on the rust files with a LanguageServer, you
>> cannot run cargo build or cargo check or cargo clippy, etc. That's why I
>> left the alternative choice of including a manually generated bindings file
>> (generated.rs.inc)
>
>I would not expect QEMU developers to be running 'cargo <anything>'
>directly at all.
>
>QEMU's build system is 'meson' + 'ninja' with a 'configure' + 'make'
>convenience facade.
>
>Any use of 'cargo' would be an internal impl detail of meson rules
>for building rust code, and developers should still exclusively work
>with 'make' or 'ninja' to run builds & tests.

No, that's not true. If I wrote the pl011 device with this workflow I'd 
just waste time using meson. Part of the development is making sure the 
library type checks, compiles, using cargo to run style formatting, to 
check for lints, perhaps run tests. Doing this only through meson is an 
unnecessary complication.

To compile and run QEMU with a rust component, sure, you'd use meson.