Re: [PATCH v26 00/20] i386 cleanup PART 2

From: Claudio Fontana <cfontana@suse.de>
To: "Philippe Mathieu-Daudé" <f4bug@amsat.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Daniel P . Berrange" <berrange@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>,
	Thomas Huth <thuth@redhat.com>, Jim Fehlig <jfehlig@suse.com>,
	Roman Bolshakov <r.bolshakov@yadro.com>,
	qemu-devel@nongnu.org
Subject: Re: [PATCH v26 00/20] i386 cleanup PART 2
Date: Mon, 8 Mar 2021 16:03:30 +0100	[thread overview]
Message-ID: <9a451974-3d46-64b7-e7ef-c70a05e534cc@suse.de> (raw)
In-Reply-To: <f3700214-baed-e03a-d4e1-028758b07054@amsat.org>

On 3/8/21 3:57 PM, Philippe Mathieu-Daudé wrote:
> On 3/8/21 2:52 PM, Claudio Fontana wrote:
>> On 3/8/21 2:27 PM, Philippe Mathieu-Daudé wrote:
>>> Hi Claudio,
>>>
>>> On 3/8/21 1:57 PM, Claudio Fontana wrote:
>>>> Hi,
>>>>
>>>> anything else for me to do here?
>>>>
>>>> The latest rebased state of this series should be always available here:
>>>>
>>>> https://gitlab.com/hw-claudio/qemu/-/tree/i386_cleanup_8
>>>>
>>>> When it comes to the ARM cleanup series,
>>>> I would like to have the tests pass for ARM, before doing even more changes, could you help me there Philippe?
>>>>
>>>> Maybe applying some of your changes on top would fix the failures? I tried, for example with the arm-cpu-features ones, but it didn't work for me..
>>>
>>> TBH I wrote these patches during my personal spare time and this
>>> became a real Pandora box that drained too much energy. I prefer
>>> to step back and focus on finishing smaller tasks before burning
>>> out. That said I appreciate your effort and am interested in
>>> following / reviewing your work.
>>>
>>> Regards,
>>>
>>> Phil.
>>>
>>
>> Thanks Philippe for sharing this, and I agree completely, it is very draining.
>>
>> The effort of making tests happy that run in artificial environments in particular often feels to me
>> as too disconnected from actually ensuring that there is no real run time regression.
>>
>> qtest_enabled() (implicitly, or explicitly via open-ended else statements) is another painful variable to keep in mind in cpu and machine code, so it is not helpful in my view.
>>
>> I'll try to push more to get the tests running again, if you have any comment or idea, feel free to just point me in the right direction,
>> that is very valuable to me, even without working code.
> 
> Basically I gave up after realizing from Daniel reviews that we need
> QMP commands to query QEMU at runtime its built-in features, so we
> have build-agnostic tests easier to maintain. I agree this is the
> best way to resolve this particular case, but also scale for various
> other cases.
> 

Well, yes, but in order to get things to work, even just a kvm-build fix would be good until we have the perfect solution, no?

We also fixed the tcg tests when doing this for i386, so I think we can fix these issues for arm too.

But this doesn't mean that we don't need the QMP commands to query QEMU at runtime for its "built-in"/module-loaded features.
We need that too, and I suspect this will be more and more needed by libvirt, as QEMU modularizes.

I just think the two things could proceed in parallel..

Ciao,

Claudio