Re: [RFC PATCH] configure: deprecate 32 bit build hosts

["Alex Bennée" <alex.bennee@linaro.org>]

Peter Maydell <peter.maydell@linaro.org> writes:

> On Thu, 26 Sep 2019 at 00:31, Alex Bennée <alex.bennee@linaro.org> wrote:
>>
>> The 32 bit hosts are already a second class citizen especially with
>> support for running 64 bit guests under TCG. We are also limited by
>> testing as actual working 32 bit machines are getting quite rare in
>> developers personal menageries. For TCG supporting newer types like
>> Int128 is a lot harder with 32 bit calling conventions compared to
>> their larger bit sized cousins. Fundamentally address space is the
>> most useful thing for the translator to have even for a 32 bit guest a
>> 32 bit host is quite constrained.
>>
>> As far as I'm aware 32 bit KVM users are even less numerous. Even
>> ILP32 doesn't make much sense given the address space QEMU needs to
>> manage.
>
> For KVM we should wait until the kernel chooses to drop support,
> I think.

I can certainly do that - although I'd still like to know who actually
uses 32 bit kvm support these days.

>
>> @@ -745,19 +744,22 @@ case "$cpu" in
>>    ;;
>>    armv*b|armv*l|arm)
>>      cpu="arm"
>> -    supported_cpu="yes"
>>    ;;
>
> I'll leave others to voice opinions about their architectures,
> but I still have 32-bit arm in my test set for builds, and
> I'm pretty sure we have users (raspi users, for a start).

raspi is probably the most common one because of the 32 bit userspace
they use even though they are running on 64 bit chips.

>
>
> thanks
> -- PMM


--
Alex Bennée