Re: Rust in Qemu BoF followup: Rust vs. qemu platform support

[Warner Losh <imp@bsdimp.com>]

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On Fri, Sep 17, 2021, 12:39 PM Philippe Mathieu-Daudé <f4bug@amsat.org>
wrote:

> On 9/17/21 6:04 PM, Warner Losh wrote:> wrt FreeBSD:
> >
> > The main focus of the project is on AMD64 (x86_64) and ARM64 (aarc64).
> With
> > ricsv64 being ascendant as well. i386 and armv7 are fading. ppc64 has
> > strong,
> > but episodic, interest as well. The rest are bit players.
> >
> > i386 (i686 really), armv7 and riscv7 are the next tier of interest in
> > FreeBSD
> > land. i386 is confined to 32-bit VMs with only a few legacy hardware
> > deployments
> > still kicking. armv7 is more popular on embedded boards, some of which
> have
> > a need to run qemu.
>
> What part of QEMU is used there, user-emulation (likely IMO) or
> system-emulation (unlikely) or both?
>

System emulation is typical.  User emulation of x86 is the only interesting
thing, but that is less complete than other arch.

> riscv64 has a rust port that's being upstreamed, but not
> > there yet and there's likely interest to run qemu on it for research
> > projects.
> > riscv64 isn't widely deployed but has a lot of developer interest /
> > mindshare.
> > sparc64 was removed from FreeBSD 13 and has been irrelevant for years.
> > ppc 32 bit has some minor interest. mips has been fading fast and stands
> > an excellent chance of being removed before FreeBSD 14 (which is
> currently
> > slated for 2022). PowerPC 64 is hard to talk about... there's interest
> > that comes
> > and goes, but when it's around, it's quite intense. It's quite likely
> > there will
> > be interest to run qemu on ppc64 on FreeBSD, but that's much less
> certain.
> >
> > So it all depends on what having rust means for those platforms that
> > don't have
> > it. Would it be a 'half a loaf' situation where the non-rust bits would
> > be buildable
> > but cool new drivers written in rust won't be? Or will it be so central
> > that rust is
> > table stakes to even start a qemu build? To be honest, I'm not sure this
> > difference
> > would greatly affect the above answer :).
> >
> > Rust works really well on x86_64 and aarch64 (though there's more often
> > a lag
> > on the latter of a few weeks). I know of a rust riscv64 port, but that's
> > just getting
> > ready to upstream. No first-hand or second-hand clue on the rest.
> >
> > FreeBSD tl;dr: x86_64 and aarch64 are must have. i386, armv7 and riscv64
> are
> > really nice to have. ppc64 might also be in that list, but that's less
> > certain. The rest
> > have little to no relevance.
>
> Thanks for gathering this useful info!
>

You are welcome.

Warner

> P.S I've been poking at people to get our QEMU aarch64 CI story in better
> > shape than it is today... I'll have to continue to prompt those
> > interested...
> >
>

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