Re: [Qemu-devel] [PATCH 2/7] Acceptance Tests: introduce arch parameter and attribute

[Cleber Rosa <crosa@redhat.com>]

On 10/4/18 7:56 PM, Murilo Opsfelder Araujo wrote:
> Hi, Cleber.
> 
> On Thu, Oct 04, 2018 at 11:14:24AM -0400, Cleber Rosa wrote:
>> On a number of different scenarios, such as when choosing a QEMU
>> binary to be used on tests (or a image to use to boot a test VM), it's
>> useful to define the architecture that should be used.
>>
>> This introduces both a test parameter and a test instance attribute,
>> that will contain such a value.
>>
>> The selection of the default QEMU binary, if one is not given
>> explicitly, has also been changed to look at the arch attribute.
>>
>> Signed-off-by: Cleber Rosa <crosa@redhat.com>
>> ---
>>  docs/devel/testing.rst                    | 18 ++++++++++++++++++
>>  tests/acceptance/avocado_qemu/__init__.py | 13 ++++++++++---
>>  2 files changed, 28 insertions(+), 3 deletions(-)
>>
>> diff --git a/docs/devel/testing.rst b/docs/devel/testing.rst
>> index 727c4019b5..4178ae5022 100644
>> --- a/docs/devel/testing.rst
>> +++ b/docs/devel/testing.rst
>> @@ -659,6 +659,17 @@ vm
>>  A QEMUMachine instance, initially configured according to the given
>>  ``qemu_bin`` parameter.
>>
>> +arch
>> +~~~~
>> +
>> +The architecture that will be used on a number of different
>> +scenarios.  For instance, when a QEMU binary is not explicitly given,
>> +the one selected will depend on this attribute.
>> +
>> +The ``arch`` attribute will be set to the test parameter of the same
>> +name, and if one is not given explicitly, it will default to the
>> +system architecture (as given by ``uname``).
>> +
>>  qemu_bin
>>  ~~~~~~~~
>>
>> @@ -681,6 +692,13 @@ like the following:
>>
>>    PARAMS (key=qemu_bin, path=*, default=x86_64-softmmu/qemu-system-x86_64) => 'x86_64-softmmu/qemu-system-x86_64
>>
>> +arch
>> +~~~~
>> +
>> +The architecture that will be used on a number of different scenarios.
>> +This parameter has a direct relation with the ``arch`` attribute.  If
>> +not given, it will default to None.
>> +
>>  qemu_bin
>>  ~~~~~~~~
>>
>> diff --git a/tests/acceptance/avocado_qemu/__init__.py b/tests/acceptance/avocado_qemu/__init__.py
>> index d8d5b48dac..9329d9b9ec 100644
>> --- a/tests/acceptance/avocado_qemu/__init__.py
>> +++ b/tests/acceptance/avocado_qemu/__init__.py
>> @@ -23,16 +23,22 @@ def is_readable_executable_file(path):
>>      return os.path.isfile(path) and os.access(path, os.R_OK | os.X_OK)
>>
>>
>> -def pick_default_qemu_bin():
>> +def pick_default_qemu_bin(arch=None):
>>      """
>>      Picks the path of a QEMU binary, starting either in the current working
>>      directory or in the source tree root directory.
>>
>> +    :param arch: the arch to use when looking for a QEMU binary (the target
>> +                 will match the arch given).  If None (the default) arch
>> +                 will be the current host system arch (as given by
>> +                 :func:`os.uname`).
>> +    :param arch: str
> 
> Do you mean
> 
>     :type arch: str
> 
> ?
> 

Hi Murilo,

Yes, thanks for catching that.

>>      :returns: the path to the default QEMU binary or None if one could not
>>                be found
>>      :rtype: str or None
>>      """
>> -    arch = os.uname()[4]
>> +    if arch is None:
>> +        arch = os.uname()[4]
>>      qemu_bin_relative_path = os.path.join("%s-softmmu" % arch,
>>                                            "qemu-system-%s" % arch)
> 
> On ppc64le systems, this can lead to an unexisting path.
> 
> For instance, os.uname() returns:
> 
>     >>> os.uname()
>     ('Linux', 'localhost', '4.15.0-34-generic', '#37-Ubuntu SMP Mon Aug 27 15:18:58 UTC 2018', 'ppc64le')
> 
> Then, qemu_bin_relative_path would be set to:
> 
>     ppc64le-softmmu/qemu-system-ppc64le
> 
> However, the correct path is:
> 
>     ppc64-softmmu/qemu-system-ppc64
> 
> I'm not sure if ppc64le is the only case where the target name is different from
> the OS architecture.
> 
> If you decide not to handle this now, at least add a FIXME, if possible.
> 

You're correct, but this behavior is also unrelated to the *this*
specific change (the uname() based arch was already being used). Because
of that I'd rather send the fix in another series.

To track the fix I've created the following card:

https://trello.com/c/0quVUfKi/48-support-target-binary-selection-on-ppc64le

Thanks!
- Cleber.

>>      if is_readable_executable_file(qemu_bin_relative_path):
>> @@ -47,8 +53,9 @@ def pick_default_qemu_bin():
>>  class Test(avocado.Test):
>>      def setUp(self):
>>          self.vm = None
>> +        self.arch = self.params.get('arch', default=os.uname()[4])
>>          self.qemu_bin = self.params.get('qemu_bin',
>> -                                        default=pick_default_qemu_bin())
>> +                                        default=pick_default_qemu_bin(self.arch))
>>          if self.qemu_bin is None:
>>              self.cancel("No QEMU binary defined or found in the source tree")
>>          self.vm = QEMUMachine(self.qemu_bin)
>> --
>> 2.17.1
>>
>>
> 
> --
> Murilo
>