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

[David Hildenbrand <david@redhat.com>]

> +/**
> + * 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 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.

> +	report(cc == 0, "Instruction format ignored bits");
> +}
> +
> +/**
> + * Find a valid READ INFO command code; not all codes are always allowed, and
> + * probing should be performed in the right order.
> + */
> +static void find_valid_sclp_code(void)
> +{
> +	const unsigned int commands[] = { SCLP_CMDW_READ_SCP_INFO_FORCED,
> +					  SCLP_CMDW_READ_SCP_INFO };
> +	SCCBHeader *h = (SCCBHeader *)pagebuf;
> +	int i, cc;
> +
> +	for (i = 0; i < ARRAY_SIZE(commands); i++) {
> +		sclp_mark_busy();
> +		memset(h, 0, sizeof(*h));
> +		h->length = 4096;
> +
> +		valid_code = commands[i];
> +		cc = sclp_service_call(commands[i], h);
> +		if (cc)
> +			break;
> +		if (h->response_code == SCLP_RC_NORMAL_READ_COMPLETION)
> +			return;
> +		if (h->response_code != SCLP_RC_INVALID_SCLP_COMMAND)
> +			break;
> +	}
> +	valid_code = 0;

This can be dropped because ...

> +	report_abort("READ_SCP_INFO failed");

... you abort here.


-- 
Thanks,

David / dhildenb