Re: [RFC 0/6] scripts: Rewrite simpletrace printer in Rust

["Alex Bennée" <alex.bennee@linaro.org>]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Mon, May 27, 2024 at 04:14:15PM +0800, Zhao Liu wrote:
>> Hi maintainers and list,
>> 
>> This RFC series attempts to re-implement simpletrace.py with Rust, which
>> is the 1st task of Paolo's GSoC 2024 proposal.
>> 
>> There are two motivations for this work:
>> 1. This is an open chance to discuss how to integrate Rust into QEMU.
>
> I don't think this proposal really triggers that discussion to any
> great extent, because 'simpletrace.py' is not a part of the QEMU
> codebase in any meaningul way. It is a standalone python script
> that just happens to live in the qemu.git repository.
>
> The difficult questions around Rust integration will arise when we
> want to have Rust used to /replace/ some existing non-optional
> functionality. IOW, if Rust were to become a mandatory dep of QEMU
> that could not be avoided.

We hope to post some PoC device models in Rust soon with exactly that
debate in mind.

> In fact I kinda wonder whether this Rust simpletrace code could
> simply be its own git repo under gitlab.com/qemu-project/....,
> rather than put into the monolithic QEMU repo ? That just makes
> it a "normal" Rust project and no questions around integration
> with QEMU's traditional build system would arise.

Do we export the necessary bits for external projects to use? I don't
think we've had the equivalent of a qemu-devel package yet and doing so
start implying externally visible versioning and deprecation policies
for QEMU APIs and data formats.

TCG plugins have a header based API but currently everyone builds
against their local checkout and we are fairly liberal about bumping the
API versions.


>
>
> With regards,
> Daniel

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro