Re: [Qemu-devel] Drop support for 32bit hosts in qemu? (was: [PULL 1/6] audio/hda: create millisecond timers that handle IO)

[Laurent Vivier]

Le 27/06/2018 à 15:33, Philippe Mathieu-Daudé a écrit :
> On 06/27/2018 06:09 AM, Thomas Huth wrote:
>> On 27.06.2018 10:52, Gerd Hoffmann wrote:
>>>   Hi,
>>>
>>>>> Is QEMU still useful on 32-bit hosts?  Honest question!
>>>>
>>>> I guess it depends on what 32-bit hosts you consider. If you look at only
>>>> x86 vs. x86_64 then probably x86 is not that important any more but for 
>>>> some
>>>> embedded systems/SoCs 32bit might still be common and QEMU useful for those
>>>> (also as host not only emulated).
>>>
>>> Well.  I've used kvm with an 32bit arm soc (cubietruck).  It's very
>>> slow.  And all the arm architecture improvements to support kvm better
>>> are for aarch64 only.
>>>
>>>> Another option might be to not support audio/hda on 32bit hosts. It's not
>>>> nice either but a lot nicer than dropping support for 32bit hosts
>>>> alltogether to fix a problem in device emulation.
>>>
>>> But it also is not useful and a waste of resources to maintain 32bit
>>> host compatibility if nobody actually uses that ...
>>>
>>> For me testbuilds are the only reason to compile qemu for 32bit hosts.
>>> Since years.
>>
>> Well, while that's true for you, me and likely most of us developers,
>> you can not know whether this is also true for all users of qemu. Thus
>> this needs to be announced first for a couple of releases so that people
>> have a chance to speak up whether they still need this or not. As
>> mentioned earlier, embedded devices are often still 32-bit and I know
>> that there really are people who use QEMU on embedded devices.
>>
>> But I think we could at least announce now already that we intend to
>> drop support for 32-bit hosts in the future (maybe not in 2 releases
>> already, but, let's say in 2020? 2020 is already the EOL of Python 2, so
>> that will rule out a bunch of other legacy hosts, too).
> 
> linux-user is certainly widely used on ARMv6 / ARMv7.
> 
> Known user cases:
> 
> - run ARMv7 binaries on ARMv6
> - run armhf binaries on armel
> - run x86-64 binaries on ARMv7
> 

I run i386 binaries on ARMv6.

I use it to run i386 printer driver on my raspberry Pi B+.
Brother doesn't provide the binary for ARM, neither the source.

Thanks,
Laurent