Re: [PATCH preview 0/5] rust: allow minimum version of 1.83

[Zhao Liu <zhao1.liu@intel.com>]

> This series does not cover enabling the newer compiler in CI because,
> while both Debian and Ubuntu have a new-enough Rust compiler to support
> 1.77, they pose problems for this further bump.  For Debian, the bookworm
> release probably will not have new compilers and is supported by QEMU
> for roughly two more years.  For Ubuntu, the situation is a bit weird
> because while Ubuntu 22.04 had new Rust compilers added until the summer
> of 2024, Ubuntu 24.04 is not adding packages for new versions.
> 
> A possible plan here is to split the configuration between "enable Rust"
> and "enable all devices written in Rust" as soon as new devices are
> contributed that are written in Rust.  This way, the C versions of
> the pl011 and HPET devices can be used but the new boards/devices would
> only be available on Debian or Ubuntu by using rustup.

"enable Rust" supports v1.77 and "enable all devices written in Rust"
supports v1.83, correct?

If so, do we need two versions of vmstate? one is for v1.77 (that HPET &
pl011 can use), and another one is for v1.83 (newer devices based on
v1.83 can use).

The current vmstate builder is excellent, but I'm concerned it might not
land soon. Can we find a compromise?

Thanks,
Zhao