Re: [PATCH v2 1/3] tests/acceptance: avocado_qemu: Introduce the 'accel' test parameter

[Wainer dos Santos Moschetta <wainersm@redhat.com>]

On 1/11/20 6:56 AM, Thomas Huth wrote:
> On 10/01/2020 21.02, Wainer dos Santos Moschetta wrote:
>> Hi Thomas,
>>
>> On 12/18/19 4:48 PM, Thomas Huth wrote:
>>> On 18/12/2019 18.00, Wainer dos Santos Moschetta wrote:
>>>> The test case may need to boot the VM with an accelerator that
>>>> isn't actually enabled on the QEMU binary and/or present in the host. In
>>>> this case the test behavior is undefined, and the best course of
>>>> action is to skip its execution.
>>>>
>>>> This change introduced the 'accel' parameter (and the handler of
>>>> tag with same name) used to indicate the test case requires a
>>>> given accelerator available. It was implemented a mechanism to
>>>> skip the test case if the accelerator is not available. Moreover,
>>>>    the QEMU --accel argument is set automatically to any VM
>>>> launched if the parameter is present.
>>>>
>>>> Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
>>>> ---
>>>>    docs/devel/testing.rst                    | 16 ++++++++++++++++
>>>>    tests/acceptance/avocado_qemu/__init__.py | 23 +++++++++++++++++++++++
>>>>    2 files changed, 39 insertions(+)
>>>>
>>>> diff --git a/docs/devel/testing.rst b/docs/devel/testing.rst
>>>> index 27f286858a..6c2e0718e1 100644
>>>> --- a/docs/devel/testing.rst
>>>> +++ b/docs/devel/testing.rst
>>>> @@ -757,6 +757,17 @@ name.  If one is not given explicitly, it will
>>>> either be set to
>>>>    ``None``, or, if the test is tagged with one (and only one)
>>>>    ``:avocado: tags=machine:VALUE`` tag, it will be set to ``VALUE``.
>>>>    +accel
>>>> +~~~~~
>>>> +The accelerator that will be set to all QEMUMachine instances created
>>>> +by the test.
>>>> +
>>>> +The ``accel`` attribute will be set to the test parameter of the same
>>>> +name.  If one is not given explicitly, it will either be set to
>>>> +``None``, or, if the test is tagged with one (and only one)
>>>> +``:avocado: tags=accel:VALUE`` tag, it will be set to ``VALUE``.
>>>> Currently
>>>> +``VALUE`` should be either ``kvm`` or ``tcg``.
>>>> +
>>>>    qemu_bin
>>>>    ~~~~~~~~
>>>>    @@ -798,6 +809,11 @@ machine
>>>>    The machine type that will be set to all QEMUMachine instances created
>>>>    by the test.
>>>>    +accel
>>>> +~~~~~
>>>> +The accelerator that will be set to all QEMUMachine instances created
>>>> +by the test. In case the accelerator is not available (both QEMU
>>>> +binary and the host system are checked) then the test is canceled.
>>>>      qemu_bin
>>>>    ~~~~~~~~
>>>> diff --git a/tests/acceptance/avocado_qemu/__init__.py
>>>> b/tests/acceptance/avocado_qemu/__init__.py
>>>> index 6618ea67c1..aff32668d9 100644
>>>> --- a/tests/acceptance/avocado_qemu/__init__.py
>>>> +++ b/tests/acceptance/avocado_qemu/__init__.py
>>>> @@ -20,6 +20,7 @@ SRC_ROOT_DIR =
>>>> os.path.join(os.path.dirname(__file__), '..', '..', '..')
>>>>    sys.path.append(os.path.join(SRC_ROOT_DIR, 'python'))
>>>>      from qemu.machine import QEMUMachine
>>>> +from qemu.accel import kvm_available, tcg_available
>>>>      def is_readable_executable_file(path):
>>>>        return os.path.isfile(path) and os.access(path, os.R_OK | os.X_OK)
>>>> @@ -111,6 +112,8 @@ class Test(avocado.Test):
>>>>          def setUp(self):
>>>>            self._vms = {}
>>>> +        # VM argumments that are mapped from parameters
>>>> +        self._param_to_vm_args = []
>>>>              self.arch = self.params.get('arch',
>>>>                                       
>>>> default=self._get_unique_tag_val('arch'))
>>>> @@ -124,10 +127,30 @@ class Test(avocado.Test):
>>>>            if self.qemu_bin is None:
>>>>                self.cancel("No QEMU binary defined or found in the
>>>> source tree")
>>>>    +        self.accel = self.params.get('accel',
>>>> +
>>>> default=self._get_unique_tag_val('accel'))
>>>> +        if self.accel:
>>>> +            avail = False
>>>> +            if self.accel == 'kvm':
>>>> +                if kvm_available(self.arch, self.qemu_bin):
>>>> +                    self._param_to_vm_args.append('-enable-kvm')
>>> Could you please use "-accel kvm" instead? "-accel" is now our official
>>> way to configure an accelerator ... so we should not use the old
>>> wrappers in new code anymore if possible.
>> Sure, I am going to adjust that on v3.
>>>    Thanks,
>>>     Thomas
>>>
>>>
>>> PS: Travis supports KVM now, too (with some tweaking of the permissions)
>>> ... maybe we should now try to get some QEMU tests running with KVM
>>> there, too...
>> I heard that but I failed miserably to enable nested virt on Travis.
>> Actually I was expecting it enabled by default but not the case. I did
>> not find documentation so I tried some tweaks like setting
>> 'sudo:required' and using bionic but none of that worked out.
>>
>> Do you know what needs to be done?
> Yes, I recently enabled it for the kvm-unit-tests ... and yes, it's a
> bit ugly: The user has to be in the "kvm" group which is not the case
> for the user that runs the travis scripts. Tweaking the access rights of
> /dev/kvm unfortunately does not work (at least not directly via chmod
> o+rwx /dev/kvm ... but maybe there is a way via udev or something
> similar?), so I ended up with:
>
>        sudo chgrp kvm /usr/bin/qemu-system-*
>        sudo chmod g+s /usr/bin/qemu-system-*
>
> With that, the kvm-unit-tests are running now fine with KVM on Travis.

Hi Thomas,

Thanks for pointing out how you did setup Travis+KVM on kvm-unit-tests.

I just sent a v3. You can see that I changed the Travis's acceptance 
tests builder to run on Ubuntu Bionic, and tweaked the access rights 
(chmod o+rw /dev/kvm) which, unlike on kvm-unit-tests, it is enough to 
make KVM available for the acceptance tests.

- Wainer

>
>   Thomas