Re: [RFC PATCH] docs/about/deprecated: Deprecate 32-bit host systems

[Philippe Mathieu-Daudé]

(Cc'ing Huacai & Jiaxun).

On 17/2/23 17:38, Paolo Bonzini wrote:
> On 2/17/23 11:47, Daniel P. Berrangé wrote:
> > On Fri, Feb 17, 2023 at 11:36:41AM +0100, Markus Armbruster wrote:
> > > I feel the discussion petered out without a conclusion.
> > >
> > > I don't think letting the status quo win by inertia is a good outcome
> > > here.
> > >
> > > Which 32-bit hosts are still useful, and why?
> >
> > Which 32-bit hosts does Linux still provide KVM  support for.
>
> All except ARM: MIPS, x86, PPC and RISC-V.
>
> I would like to remove x86, but encountered some objections.
>
> MIPS, nobody is really using it I think.

32-bit was added in 2014, commit 222e7d11e7 ("target-mips: Enable KVM
support in build system"). I'm not aware of anybody using it (even
testing it). I don't have hardware to test it (neither time).
We are still cross-compiling it although.

64-bit support was added recently (see commit aa2953fd16 "configure:
Add KVM target support for MIPS64") and is used (see commit fbc5884ce2
"meson.build: Re-enable KVM support for MIPS" from 2020), however I
tend to see it more as hobbyist use than production one. Besides it
is listed as 'Odd Fixes' in MAINTAINERS (still 2020, commit 134f7f7da1
"MAINTAINERS: Reactivate MIPS KVM CPUs").

> So that leaves PPC and RISC-V.
>
> > If any, is there an EOL date for Linux 32-bit KVM support ?
>
> No, and I don't think there's going to be one.
>
> Paolo