Re: [RFC PATCH 0/8] i386/sev: Use C API of Rust SEV library

[Stefan Hajnoczi <stefanha@gmail.com>]

On Fri, 15 Sept 2023 at 09:50, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> On Fri, 15 Sept 2023 at 10:54, Daniel P. Berrangé <berrange@redhat.com> wrote:
> > My summary, is that I'd personally be in favour of opening the door
> > to Rust code as a mandatory pre-requisite for QEMU, at the very least
> > for system emulators. Not because this particular series is compelling,
> > but because I think Rust could be more beneficial to QEMU over the long
> > term than we expect. In terms of consuming it though, if we're going
> > to replace existing QEMU functionality, then I think we need to bundle
> > the Rust code and natively integrate it into the build system, as we
> > have recently started doing with our python deps, to detach ourselves
> > from the limits of what distros ship.
>
> I'm not against this, but there is a fair amount of work here
> in figuring out how exactly to integrate Rust components
> into the build system, questions like what our minimum required
> rust version would be, liasing with downstream distros to
> check that what we're proposing isn't a nightmare for them
> to package, etc.

Those details are similar to what librsvg2, libblkio, and other
libraries (like the sev crate in this patch series) have had to solve.

libblkio uses meson as the build system and has C tests that cover the
C API. Cargo is still used to build the Rust code. It is possible to
integrate the two and I think QEMU could take that approach. It's a
little ugly to glue together the two build systems, but it has been
shown to work.

Finding the minimum Rust version across QEMU's support matrix is doable.

Stefan