Re: [PATCH 2/3] tests/acceptance/machine_s390_ccw_virtio: Test virtio-rng via /dev/hwrng

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

Hi,

On 12/11/20 2:31 PM, Thomas Huth wrote:
> /dev/hwrng is only functional if virtio-rng is working right, so let's
> add a sanity check for this device node.

Good idea.

>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>   tests/acceptance/machine_s390_ccw_virtio.py | 17 +++++++++++++++--
>   1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/tests/acceptance/machine_s390_ccw_virtio.py b/tests/acceptance/machine_s390_ccw_virtio.py
> index 733a7ca24a..7d0a78139b 100644
> --- a/tests/acceptance/machine_s390_ccw_virtio.py
> +++ b/tests/acceptance/machine_s390_ccw_virtio.py
> @@ -64,9 +64,9 @@ class S390CCWVirtioMachine(Test):
>                            '-append', kernel_command_line,
>                            '-device', 'virtio-net-ccw,devno=fe.1.1111',
>                            '-device',
> -                         'virtio-rng-ccw,devno=fe.2.0000,max_revision=0',
> +                         'virtio-rng-ccw,devno=fe.2.0000,max_revision=0,id=rn1',
>                            '-device',
> -                         'virtio-rng-ccw,devno=fe.3.1234,max_revision=2',
> +                         'virtio-rng-ccw,devno=fe.3.1234,max_revision=2,id=rn2',
>                            '-device', 'zpci,uid=5,target=zzz',
>                            '-device', 'virtio-net-pci,id=zzz',
>                            '-device', 'zpci,uid=0xa,fid=12,target=serial',
> @@ -96,6 +96,19 @@ class S390CCWVirtioMachine(Test):
>           exec_command_and_wait_for_pattern(self,
>                           'cat /sys/bus/ccw/devices/0.3.1234/virtio?/features',
>                           virtio_rng_features)
> +        # check that /dev/hwrng works - and that it's gone after ejecting
> +        exec_command_and_wait_for_pattern(self,
> +                        'dd if=/dev/hwrng of=/tmp/out.dat bs=1k count=10',
> +                        '10+0 records out')
> +        self.clear_guests_dmesg()
> +        self.vm.command('device_del', id='rn1')
> +        self.wait_for_crw_reports()
> +        self.clear_guests_dmesg()
> +        self.vm.command('device_del', id='rn2')
> +        self.wait_for_crw_reports()
> +        exec_command_and_wait_for_pattern(self,
> +                        'dd if=/dev/hwrng of=/tmp/out.dat bs=1k count=10',
> +                        'dd: /dev/hwrng: No such device')

Maybe the expected pattern is too fragile. On my Fedora 33 system, 'dd' 
will print a different message.

What if it checks for the presence of the device file, e.g:

... self, 'test -c /dev/hwrng; echo $?', '1')

- Wainer

>           # verify that we indeed have virtio-net devices (without having the
>           # virtio-net driver handy)
>           exec_command_and_wait_for_pattern(self,