Re: [kvm-unit-tests PATCH v2 1/4] s390x: lib: Add SCLP toplogy nested level

Pierre Morel
2021-08-12T15:05:30Z

On 8/12/21 2:56 PM, Cornelia Huck wrote:
> On Tue, Aug 10 2021, Pierre Morel <pmorel@linux.ibm.com> wrote:
>
>> The maximum CPU Topology nested level is available with the SCLP
>> READ_INFO command inside the byte at offset 15 of the ReadInfo
>> structure.
>>
>> Let's return this information to check the number of topology nested
>> information available with the STSI 15.1.x instruction.
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
>> ---
>> lib/s390x/sclp.c | 6 ++++++
>> lib/s390x/sclp.h | 4 +++-
>> 2 files changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
>> index 9502d161..ee379ddf 100644
>> --- a/lib/s390x/sclp.c
>> +++ b/lib/s390x/sclp.c
>> @@ -123,6 +123,12 @@ int sclp_get_cpu_num(void)
>> return read_info->entries_cpu;
>> }
>>
>> +int sclp_get_stsi_parm(void)
>> +{
>> + assert(read_info);
>> + return read_info->stsi_parm;
>
> Is this a generic "stsi parm", or always the concrete topology nested
> level? IOW, is that name good, or too generic?

It is the name used in the documentation, but for now only the 3 bits
5-7 are used for the maximum value of the selector 2 of the STSI
instruction allowed by the machine.

>
>> +}
>> +
>> CPUEntry *sclp_get_cpu_entries(void)
>> {
>> assert(read_info);
>

--
Pierre Morel
IBM Lab Boeblingen