Re: [Qemu-devel] Proposal for deprecating unsupported host OSes & architecutures

[Paolo Bonzini <pbonzini@redhat.com>]

On 16/03/2017 16:55, Peter Maydell wrote:
>> IOW, I think there is a reasonable 3 tier set here
>>
>>  1. Stuff we actively test builds & thus guarantee will work for
>>     any QEMU release going forward.
>>
>>  2. Stuff we don't actively test, but generally assume is mostly
>>     working, and likely to be fixed if & when problems are found
>>
>>  3. Stuff we don't actively test,  assume is probably broken
>>     and unlikely to be fixed if reported
>>
>> Stuff in tier 3 should be candidate for deletion. Stuff in tier
>> 2 shouldn't be removed, but it might drop into tier 3 at some
>> point if people stop caring about fixing problems when found.
>> Conversely tier 2 might rise to tier 1 if CI turns up.
>
> I don't really want a tier 2. Either we support it enough
> to at least be able to run "make && make check" on some
> representative system, or we don't support it at all.
> Code which we have but are really reluctant to touch because
> we don't even test it builds (like bsd-user/) is really bad
> for preventing cleanups.

I think we should further differentiate between bsd-user/ and softmmu.
System emulation is just another program where we mostly compile to C
standard + POSIX or C standard + Win32.  There are certainly places
where we use Linux-specific extensions but it's not that special.
Neither BSD nor Solaris are particularly hard to support there.

On the other hand, bsd-user is extremely BSD specific, and ought to have
CI.  I think there should be a tier 2 for system emulation (which
doesn't mean that anything there shouldn't be moved to tier 3 and
eventually removed), but there shouldn't be a tier 2 for user-mode
emulation.

In particular, I believe that we should remove bsd-user from 2.10 unless
the downstream BSD port is merged back (and CI is provided).  There is
no point in keeping the current half-baked code without thread support.

Paolo