Re: [RFC PATCH] docs/about/deprecated: Deprecate 32-bit host systems
On 31/1/23 00:33, Richard Henderson wrote:
On 1/30/23 13:14, Philippe Mathieu-Daudé wrote:
> On 30/1/23 20:19, Richard Henderson wrote:
>
>> But I do question whether we need to support 64-bit guests on 32-bit
>> hosts at all.
>> Retaining 32-bit on 32-bit allows arm32 to emulate i686, which I
>> suspect, but have no proof, is the limit of what users actually want.
>
> I presume you implicitly restrict that to user emulation, right?
No, there's no specific reason to eliminate e.g. qemu-system-i386. or
any other 32-bit guest. Though quite often such hardware doesn't really
have enough ram to do a good job, that's not a technical argument against.
I am not concerned by the RAM limit but by the community maintenance
cost. As of 2023, QEMU v7.2.0 is usable on 32-bit. Fixes will be
backported in the v7.2.x stable releases. Maybe this is enough for
32-bit host users; and planning the unavailability of features released
in v8.2 or v9.0 for 32-bit hosts doesn't seem unreasonable.
Stefan Weil once posted stats of Win32 vs Win64 binary downloads from
last year IIRC, and Win32 is still consumed (but maybe the difference
comes from mirrors or users always downloading both versions).
> WRT i686, if your example is "i686 useremu on non-x86
embedded router"
> then any 32-bit host is potentially interested, not only arm32.
arm32 was merely an example -- the other 32-bit hosts are i686, mips,
ppc. But we don't have many of them.
> I remember being able to run armhf binaries on armel hosts (and vice
> versa) was useful 7 years ago.
Fair enough.
> Today I have no clue, we could poll the community and some distributions.
Sure.
r~