Re: [kvm-unit-tests PATCH v4 3/4] s390x: topology: Check the Perform Topology Function

Pierre Morel
2022-02-15T08:48:14Z

On 2/9/22 12:37, Nico Boehr wrote:
> On Tue, 2022-02-08 at 14:27 +0100, Pierre Morel wrote:
>> We check the PTF instruction.
>
> You could test some very basic things as well:
>
> - you get a privileged pgm int in problem state,
> - reserved bits in first operand cause specification pgm int,
> - reserved FC values result in a specification pgm int,
> - second operand is ignored.

Which second operand?

>
>>
>> - We do not expect to support vertical polarization.
>>
>> - We do not expect the Modified Topology Change Report to be
> [...]
>
> Forgive me if I'm missing something, but why _Modified_ Topology Change
> Report?
>
>> diff --git a/s390x/topology.c b/s390x/topology.c
>> new file mode 100644
>> index 00000000..a1f9ce51
>> --- /dev/null
>> +++ b/s390x/topology.c
>
> [...]
>
>> +static int ptf(unsigned long fc, unsigned long *rc)
>> +{
>> +       int cc;
>> +
>> +       asm volatile(
>> +               "       .insn   rre,0xb9a20000,%1,0\n"
>> +               "       ipm     %0\n"
>> +               "       srl     %0,28\n"
>> +               : "=d" (cc), "+d" (fc)
>> +               : "d" (fc)
>
> Why list fc here again?
>
>

--
Pierre Morel
IBM Lab Boeblingen