Re: [PATCH v3 11/12] meson: Deprecate 32-bit host support

[Richard Henderson <richard.henderson@linaro.org>]

On 2/5/25 10:05, Philippe Mathieu-Daudé wrote:
> On 4/2/25 22:53, Richard Henderson wrote:
>> We deprecated i686 system mode support for qemu 8.0.  However, to
>> make real cleanups to TCG we need to deprecate all 32-bit hosts.
>>
>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>   docs/about/deprecated.rst | 7 +++++++
>>   meson.build               | 8 +++-----
>>   2 files changed, 10 insertions(+), 5 deletions(-)
>>
>> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
>> index 4a3c302962..7c61d0ba16 100644
>> --- a/docs/about/deprecated.rst
>> +++ b/docs/about/deprecated.rst
>> @@ -204,6 +204,13 @@ is going to be so much slower it wouldn't make sense for any serious
>>   instrumentation. Due to implementation differences there will also be
>>   anomalies in things like memory instrumentation.
>> +32-bit host operating systems (since 10.0)
>> +''''''''''''''''''''''''''''''''''''''''''
>> +
>> +Keeping 32-bit host support alive is a substantial burden for the
>> +QEMU project.  Thus QEMU will in future drop the support for all
>> +32-bit host systems.
>> +
>>   System emulator CPUs
>>   --------------------
>> diff --git a/meson.build b/meson.build
>> index aa1ca8355d..3347b0a553 100644
>> --- a/meson.build
>> +++ b/meson.build
>> @@ -4843,14 +4843,12 @@ if host_arch == 'unknown'
>>       message('configure has succeeded and you can continue to build, but')
>>       message('QEMU will use a slow interpreter to emulate the target CPU.')
>>     endif
>> -elif host_arch == 'mips'
>> +elif host_long_bits < 64
>>     message()
>>     warning('DEPRECATED HOST CPU')
>>     message()
>> -  message('Support for CPU host architecture ' + cpu + ' is going to be')
>> -  message('dropped as soon as the QEMU project stops supporting Debian 12')
>> -  message('("Bookworm"). Going forward, the QEMU project will not guarantee')
>> -  message('that QEMU will compile or work on this host CPU.')
>> +  message('Support for 32-bit CPU host architecture ' + cpu + ' is going')
>> +  message('to be dropped in a future QEMU release.')
> 
> This change still allows us to remove 32-bit mips host support before
> the other architectures, right?
No, bookworm goes into LTS in June 2026, which would match QEMU 11.1 release.
If we add this now, we could (selectively) remove 32-bit support earlier than that.


r~