Re: [kvm-unit-tests PATCH] s390x/skey: Skip the "iske" test when running under z/VM 6

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 11.04.19 07:53, Thomas Huth wrote:
> There is a known bug of z/VM 6 which causes the "iske" test to fail.
> Since it is still sometimes useful to run the kvm-unit-tests in such
> a nested environment, let's rather skip the "iske" test there instead
> of always reporting a failure.

I have seen the skey test fail as well, but only on 6.3. IIRC 6.4 was good.
Do you have a bug number or an offical statement whatever (I did not found 
one).

In general 

Ack.



> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  s390x/skey.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 51 insertions(+), 4 deletions(-)
> 
> diff --git a/s390x/skey.c b/s390x/skey.c
> index f4894f1..b1e11af 100644
> --- a/s390x/skey.c
> +++ b/s390x/skey.c
> @@ -70,9 +70,51 @@ static void test_set(void)
>  	       skey.str.acc == ret.str.acc && skey.str.fp == ret.str.fp);
>  }
> 
> +static inline int stsi(void *addr, int fc, int sel1, int sel2)
> +{
> +	register int r0 asm("0") = (fc << 28) | sel1;
> +	register int r1 asm("1") = sel2;
> +	int rc = 0;
> +
> +	asm volatile(
> +		"	stsi	0(%3)\n"
> +		"	jz	0f\n"
> +		"	lhi	%1,-1\n"
> +		"0:\n"
> +		: "+d" (r0), "+d" (rc)
> +		: "d" (r1), "a" (addr)
> +		: "cc", "memory");
> +
> +	return rc;
> +}
> +
> +/* Returns true if we are running under z/VM 6.x */
> +static bool check_for_zvm6(void)
> +{
> +	int dcbt;	/* Descriptor block count */
> +	int nr;
> +	static const unsigned char zvm6[] = {
> +		/* This is "z/VM    6" in EBCDIC */
> +		0xa9, 0x61, 0xe5, 0xd4, 0x40, 0x40, 0x40, 0x40, 0xf6
> +	};
> +
> +	if (stsi(pagebuf, 3, 2, 2))
> +		return false;
> +
> +	dcbt = pagebuf[31] & 0xf;
> +
> +	for (nr = 0; nr < dcbt; nr++) {
> +		if (!memcmp(&pagebuf[32 + nr * 64 + 24], zvm6, sizeof(zvm6)))
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
>  static void test_priv(void)
>  {
>  	union skey skey;
> +	bool is_zvm6 = check_for_zvm6();
> 
>  	memset(pagebuf, 0, PAGE_SIZE * 2);
>  	report_prefix_push("privileged");
> @@ -87,10 +129,15 @@ static void test_priv(void)
>  	report("skey did not change on exception", skey.str.acc != 3);
> 
>  	report_prefix_push("iske");
> -	expect_pgm_int();
> -	enter_pstate();
> -	get_storage_key(page0);
> -	check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
> +	if (is_zvm6) {
> +		/* There is a known bug with z/VM 6, so skip the test there */
> +		report_skip("not working on z/VM 6");
> +	} else {
> +		expect_pgm_int();
> +		enter_pstate();
> +		get_storage_key(page0);
> +		check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
> +	}
>  	report_prefix_pop();
> 
>  	report_prefix_pop();
>