Re: [PATCH] tests/acceptance: test hot(un)plug of ccw devices

[Thomas Huth <thuth@redhat.com>]

On 03/12/2020 16.39, Cornelia Huck wrote:
> Hotplug a virtio-net-ccw device, and then hotunplug it again.

Good idea! ... is it also possible with a pci device?

> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
> 
> This is on top of "tests/acceptance: enhance s390x devices test"
> 
> ---
>  tests/acceptance/machine_s390_ccw_virtio.py | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/tests/acceptance/machine_s390_ccw_virtio.py b/tests/acceptance/machine_s390_ccw_virtio.py
> index 53b8484f8f9c..487c25c31d3c 100644
> --- a/tests/acceptance/machine_s390_ccw_virtio.py
> +++ b/tests/acceptance/machine_s390_ccw_virtio.py
> @@ -97,3 +97,17 @@ class S390CCWVirtioMachine(Test):
>          exec_command_and_wait_for_pattern(self,
>                                            'cat /sys/bus/pci/devices/000a\:00\:00.0/function_id',
>                                            '0x0000000c')
> +        # add another device
> +        self.vm.command('device_add', driver='virtio-net-ccw',
> +                        devno='fe.0.4711', id='xxx')

Could we use a different id, please? xxx sounds so ... well, use your
imagination.

> +        exec_command_and_wait_for_pattern(self, 'dmesg | tail -n 1', 'CRW')

That looks like it could be a little bit racy ... what if the kernel outputs
another log message by chance, so that tail -n 1 reports that instead.

I think it would be better to clear the dmesg log ("dmesg -c") before
plugging, and then look at all the new output of "dmesg" without using
"tail" afterwards.

> +        exec_command_and_wait_for_pattern(self, 'ls /sys/bus/ccw/devices/',
> +                                          '0.0.4711')
> +        # and detach it again
> +        self.vm.command('device_del', id='xxx')
> +        self.vm.event_wait(name='DEVICE_DELETED',
> +                           match={'data': {'device': 'xxx'}})
> +        exec_command_and_wait_for_pattern(self, 'dmesg | tail -n 1', 'CRW')

dito

> +        exec_command_and_wait_for_pattern(self,
> +                                          'ls /sys/bus/ccw/devices/0.0.4711',
> +                                          'No such file or directory')
> 

 Thomas


PS: Another idea for a test: Looks like that initrd also has a
virtio-balloon driver ... we could maybe start with "-device
virito-balloon", then change the size of the balloon and check whether the
MemTotal in /proc/meminfo changed...