On 10/15/20 3:56 PM, Thomas Huth wrote:
> On 15/10/2020 14.40, Janosch Frank wrote:
>> On 10/14/20 9:27 PM, Collin Walling wrote:
>>> The DIAGNOSE 0x0318 instruction, unique to s390x, is a privileged call
>>> that must be intercepted via SIE, handled in userspace, and the
>>> information set by the instruction is communicated back to KVM.
>>
>> It might be nice to have a few words in here about what information can
>> be set via the diag.
>>
>>>
>>> To test the instruction interception, an ad-hoc handler is defined which
>>> simply has a VM execute the instruction and then userspace will extract
>>> the necessary info. The handler is defined such that the instruction
>>> invocation occurs only once. It is up the the caller to determine how the
>>> info returned by this handler should be used.
>>>
>>> The diag318 info is communicated from userspace to KVM via a sync_regs
>>> call. This is tested during a sync_regs test, where the diag318 info is
>>> requested via the handler, then the info is stored in the appropriate
>>> register in KVM via a sync registers call.
>>>
>>> The diag318 info is checked to be 0 after a normal and clear reset.
>>>
>>> If KVM does not support diag318, then the tests will print a message
>>> stating that diag318 was skipped, and the asserts will simply test
>>> against a value of 0.
>>>
>>> Signed-off-by: Collin Walling <walling@linux.ibm.com>
>>
>> Checkpatch throws lots of errors on this patch.
>> Could you check if my workflow misteriously introduced windows line
>> endings or if they were introduced on your side?
> 
> How did you feed the patch into checkpatch? IIRC mails are often sent with
> CR-LF line endings by default - it's "git am" that is converting the line
> endings back to the Unix default. So for running a patch through checkpatch,
> you might need to do "git am" first and then export it again.

Uh right, that's why I asked in the first place
With git am checkpatch is a lot happier and it would be even happier if
I would have looked at the V1 and not at the RFC I reviewed on Monday...

> 
>>> +uint64_t get_diag318_info(void)
>>> +{
>>> +	static uint64_t diag318_info;
>>> +	static bool printed_skip;
>>> +
>>> +	/*
>>> +	 * If KVM does not support diag318, then return 0 to
>>> +	 * ensure tests do not break.
>>> +	 */
>>> +	if (!kvm_check_cap(KVM_CAP_S390_DIAG318)) {
>>> +		if (!printed_skip) {
>>> +			fprintf(stdout, "KVM_CAP_S390_DIAG318 not supported. "
>>
>> Whitespace after .
>>
>>> +				"Skipping diag318 test.\n");
> 
> It's a multi-line text, so the whitespace is needed, isn't it?

I missed that second line as it is indented to the stdout and not to the
first string.

> 
>>> +			printed_skip = true;
>>> +		}
>>> +		return 0;
>>> +	}
> 
>  Thomas
>