Re: [kvm-unit-tests PATCH v2 3/4] s390x: topology: Check the Perform Topology Function

[Pierre Morel <pmorel@linux.ibm.com>]

On 8/12/21 11:38 AM, Janosch Frank wrote:
> On 8/10/21 6:22 PM, Pierre Morel wrote:
>> We check the PTF instruction.
>>
>> - We do not expect to support vertical polarization.
> 
> KVM does not support vertical polarization and we don't expect it to be
> added in the future?

OK

> 
>>
>> - We do not expect the Modified Topology Change Report to be
>> pending or not at the moment the first PTF instruction with
>> PTF_CHECK function code is done as some code already did run
>> a polarization change may have occur.
> 
> ENOPARSE

OK I find another way to explain:

"
The Topology changes if the topology of the real CPUs backing the vCPUs 
changes.
This can happen between the initialization of the VM and the start of 
the guest.
As a consequence we can not expect the result of the first PTF instruction.
"
...
>> +	/*
>> +	 * In the LPAR we can not assume the state of the polarizatiom
> 
> polarization

yes

> 
>> +	 * at this moment.
>> +	 * Let's skip the tests for LPAR.
>> +	 */
> 
> Any idea what happens on z/VM?
> We don't necessarily need to support z/VM but we at least need to skip
> like we do on lpar :-)

No, I do not know.
Then OK we skip the test for zVM too

> 
> Maybe also add a TODO, so we know we could improve the test?
> 
>> +	if (machine_level < 3)
>> +		goto end;
>> +
> 
> Add comments:
> We're always horizontally polarized in KVM.

OK

> 
>> +	cc = ptf(PTF_REQ_HORIZONTAL, &rc);
>> +	report(cc == 2 && rc == PTF_ERR_ALRDY_POLARIZED,
>> +	       "PTF horizontal already configured");
>> +
> 
> KVM doesn't support vertical polarization.

OK too

> 
>> +	cc = ptf(PTF_REQ_VERTICAL, &rc);
>> +	report(cc == 2 && rc == PTF_ERR_NO_REASON,
>> +	       "PTF vertical non possible");
> 
> s/non/not/

yes, seems I forgot to change this.

...


Thanks,
Pierre

-- 
Pierre Morel
IBM Lab Boeblingen