Re: [PATCH v4 10/12] qtest/qmp-cmd-test: Make test build-independent from accelerator

[Markus Armbruster]

Philippe Mathieu-Daudé <philmd@redhat.com> writes:

> On 4/29/21 7:43 AM, Markus Armbruster wrote:
>> Philippe Mathieu-Daudé <philmd@redhat.com> writes:
>> 
>>> Now than we can probe if the TCG accelerator is available
>>> at runtime with a QMP command, do it once at the beginning
>>> and only register the tests we can run.
>>> We can then replace the #ifdef'ry by a runtime check.
>>>
>>> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> 
>> Please read the last remark first.  The other ones are detail; feel free
>> to skip them until we're done with the last one.
>> 
>>> ---
>>>  tests/qtest/qmp-cmd-test.c | 18 ++++++++++++++----
>>>  1 file changed, 14 insertions(+), 4 deletions(-)
>
>>> +    tcg_accel_available = qtest_has_accel("tcg");
>>> +
>> 
>> When does tcg_accel_available differ from defined(CONFIG_TCG)?
>
> qtest_has_accel("tcg") is a runtime check, while defined(CONFIG_TCG)
> is build-time.

Let me rephrase my question: under what conditions can the values of
qtest_has_accel("tcg") and defined(CONFIG_TCG) differ?

> Having tests doing runtime checking allow to:
>
> - have easier reviews, having less #ifdef'ry
> - build them once for all targets
> - build them once for all ./configure options
>   (thinking about CI, the a single job could build the tests, then
>   we run them using the QEMU binaries from other jobs)
> - use the same binaries to test the built binary and the distribution
>   installed one
> - remove the dependencies between tests and binaries
>
>> 
>>>      g_test_init(&argc, &argv, NULL);
>>>  
>>>      qmp_schema_init(&schema);
>>