Fix virtIO on some ppc64le and <12-SP2 machines

[pdostal]

This PR fixing issues with virtIO serial terminal on the PPC64le architecture.

• Related ticket: poo#44696
• Needles: No need
• Verification run: In progress

This is a follow up of #6360, #6351 and #6295.

[mimi1vx]

add_serial_console from where is used ? missing use serial_terminal 'add_serial_console';

[pdostal]

I'll test it later today.

[okurz]

How about

add_serial_console('hvc' . is_sle('<12-SP2') ? 0 : 1) if (get_var('VIRTIO_CONSOLE') && check_var('ARCH', 'ppc64le'));

or what should happen in the "else"-branch?

[richiejp]

Before SLE12-SP2 we need to run agetty on /dev/hvc0 ourselves. After SP2 it is done automatically by systemd AFAIK.

[pdostal]

@okurz a week ago my if() { … } else { … } was 'too complex' and now you write this?

[okurz]

I don't think this will work, do we have that device available on all backends and architectures or only ppc64le?

[richiejp]

IIRC the virtio serial driver always uses the "HVC" serial terminal driver. So it will always get a device called hvcN regardless of the platform.

If not then we need to introduce another variable, but I don't think it is necessary for now.

[mimi1vx]

@okurz only sligty misleading PR name

[pevik]

@pdostal FYI now we have very similar cleanup code in these modules:

tests/shutdown/cleanup_before_shutdown.pm
tests/console/system_prepare.pm
lib/wickedbase.pm
tests/kernel/install_ltp.pm

(well, unlike the others wicked is using hvc2 and hvc1).
I wonder if there is single place in the tests which this code could (and should) be added.
Maybe activate_console()?
@asmorodskyi topic, we were discussing few weeks ago.