Re: [kvm-unit-tests PATCH v7 4/4] s390x: SCLP unit test

[David Hildenbrand <david@redhat.com>]

On 13.01.20 13:33, Claudio Imbrenda wrote:
> On Mon, 13 Jan 2020 12:00:00 +0100
> David Hildenbrand <david@redhat.com> wrote:
> 
>>> +/**
>>> + * Test some bits in the instruction format that are specified to
>>> be ignored.
>>> + */
>>> +static void test_instbits(void)
>>> +{
>>> +	SCCBHeader *h = (SCCBHeader *)pagebuf;
>>> +	int cc;
>>> +
>>> +	expect_pgm_int();
>>> +	sclp_mark_busy();
>>> +	h->length = 8;
>>> +	sclp_setup_int();
>>> +
>>> +	asm volatile(
>>> +		"       .insn   rre,0xb2204200,%1,%2\n"  /* servc
>>> %1,%2 */
>>> +		"       ipm     %0\n"
>>> +		"       srl     %0,28"
>>> +		: "=&d" (cc) : "d" (valid_code), "a"
>>> (__pa(pagebuf))
>>> +		: "cc", "memory");
>>> +	if (lc->pgm_int_code) {
>>> +		sclp_handle_ext();
>>> +		cc = 1;
>>> +	} else if (!cc)
>>> +		  
>>
>> I wonder if something like the following would be possible:
>>
>> expect_pgm_int();
>> ...
>> asm volatiole();
>> ...
>> sclp_wait_busy();
>> check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
> 
> we do not expect a specification exception, if that happens it's
> a bug and the test should rightfully fail.

Which one do we expect? (you're not checking for a specific one, should
you?)

> 
>> We would have to clear "sclp_busy" when we get a progam interrupt on a
>> servc instruction - shouldn't be too hard to add to the program
>> exception handler.
> 
> Sure that could be done, but is it worth it to rework the program
> interrupt handler only for one unit test?

Good point. I don't like this particular code, but I can live with it :)

-- 
Thanks,

David / dhildenb