[PATCH 1/2] docs/about: Deprecate 32-bit x86 hosts and qemu-system-i386

[Philippe Mathieu-Daudé]

On 28/2/23 09:59, Michael S. Tsirkin wrote:
> On Mon, Feb 27, 2023 at 10:21:14AM -1000, Richard Henderson wrote:
>> On 2/27/23 10:12, Michael S. Tsirkin wrote:
>>> On Mon, Feb 27, 2023 at 11:50:07AM +0000, Daniel P. Berrangé wrote:
>>>> I feel like we should have separate deprecation entries for the
>>>> i686 host support, and for qemu-system-i386 emulator binary, as
>>>> although they're related they are independant features with
>>>> differing impact. eg removing qemu-system-i386 affects all
>>>> host architectures, not merely 32-bit x86 host, so I think we
>>>> can explain the impact more clearly if we separate them.
>>>
>>> Removing qemu-system-i386 seems ok to me - I think qemu-system-x86_64 is
>>> a superset.
>>>
>>> Removing support for building on 32 bit systems seems like a pity - it's
>>> one of a small number of ways to run 64 bit binaries on 32 bit systems,
>>> and the maintainance overhead is quite small.
>>
>> It's not that small.  It only works for single-threaded system mode.  It
>> silently does not honor atomicity for user-only mode, which is perhaps worse
>> not working at all.

Will the same occur with 64-bit hosts when we introduce a 128-bit 
target? If so, there is no much code we'll be able to drop,

> We should probably block multi-threading on 32 bit then.

so this sound a user experience fix.