Re: [kvm-unit-tests PATCH v4 1/8] s390x: Add more tests for MSCH

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

On 2/24/22 16:43, Nico Boehr wrote:
> We already have some coverage for MSCH, but there are more cases to test
> for:
> 
> - invalid SCHIB structure. We cover that by setting reserved bits 0, 1,
>    6 and 7 in the flags of the PMCW.
>    Older QEMU versions require this bit to always be zero on msch,
>    which is why this test may fail. A fix is available in QEMU master
>    commit 2df59b73e086 ("s390x/css: fix PMCW invalid mask").
> - a pointer to an unaligned SCHIB. We cover misalignment by 1
>    and 2 bytes. Using pointer to valid memory avoids messing up
>    random memory in case of test failures.
> 
> Here's the QEMU PMCW invalid mask fix: https://lists.nongnu.org/archive/html/qemu-s390x/2021-12/msg00100.html
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>

Here too I gave my R-B already a long time ago didn't I ?

Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>

> ---
>   s390x/css.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 58 insertions(+)
> 
> diff --git a/s390x/css.c b/s390x/css.c
> index 881206ba1cef..396007ed0074 100644
> --- a/s390x/css.c
> +++ b/s390x/css.c
> @@ -27,6 +27,8 @@ static int test_device_sid;
>   static struct senseid *senseid;
>   struct ccw1 *ccw;
>   
> +char alignment_test_page[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
> +
>   static void test_enumerate(void)
>   {
>   	test_device_sid = css_enumerate();
> @@ -331,6 +333,61 @@ static void test_schm_fmt1(void)
>   	free_io_mem(mb1, sizeof(struct measurement_block_format1));
>   }
>   
> +static void test_msch(void)
> +{
> +	int invalid_pmcw_flags[] = {0, 1, 6, 7};
> +	struct schib test_schib;
> +	uint16_t old_pmcw_flags;
> +	const int align_to = 4;
> +	int invalid_flag;
> +	int cc;
> +
> +	if (!test_device_sid) {
> +		report_skip("No device");
> +		return;
> +	}
> +
> +	cc = stsch(test_device_sid, &schib);
> +	if (cc) {
> +		report_fail("stsch: sch %08x failed with cc=%d", test_device_sid, cc);
> +		return;
> +	}
> +
> +	report_prefix_push("Unaligned");
> +	for (int i = 1; i < align_to; i *= 2) {
> +		report_prefix_pushf("%d", i);
> +
> +		expect_pgm_int();
> +		msch(test_device_sid, (struct schib *)(alignment_test_page + i));
> +		check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
> +
> +		report_prefix_pop();
> +	}
> +	report_prefix_pop();
> +
> +	report_prefix_push("Invalid SCHIB");
> +	old_pmcw_flags = schib.pmcw.flags;
> +	for (int i = 0; i < ARRAY_SIZE(invalid_pmcw_flags); i++) {
> +		invalid_flag = invalid_pmcw_flags[i];
> +
> +		report_prefix_pushf("PMCW flag bit %d set", invalid_flag);
> +
> +		schib.pmcw.flags = old_pmcw_flags | BIT(15 - invalid_flag);
> +		expect_pgm_int();
> +		msch(test_device_sid, &schib);
> +		check_pgm_int_code(PGM_INT_CODE_OPERAND);
> +
> +		cc = stsch(test_device_sid, &test_schib);
> +		report(!cc, "STSCH succeeded");
> +		report(!(test_schib.pmcw.flags & BIT(15 - invalid_flag)), "Clear on STSCH");
> +
> +		report_prefix_pop();
> +	}
> +	report_prefix_pop();
> +
> +	schib.pmcw.flags = old_pmcw_flags;
> +}
> +
>   static struct {
>   	const char *name;
>   	void (*func)(void);
> @@ -343,6 +400,7 @@ static struct {
>   	{ "measurement block (schm)", test_schm },
>   	{ "measurement block format0", test_schm_fmt0 },
>   	{ "measurement block format1", test_schm_fmt1 },
> +	{ "msch", test_msch },
>   	{ NULL, NULL }
>   };
>   
> 

-- 
Pierre Morel
IBM Lab Boeblingen