Re: [kvm-unit-tests PATCH v4 6/8] s390x: Add more tests for STSCH

Pierre Morel
2022-02-24T18:34:56Z

On 2/24/22 16:43, Nico Boehr wrote:
> css_lib extensively uses STSCH, but two more cases deserve their own
> tests:
>
> - unaligned address for SCHIB. We check for misalignment by 1 and 2
> bytes.
> - channel not operational
> - bit 47 in SID not set
> - bit 5 of PMCW flags.
> As per the principles of operation, bit 5 of the PMCW flags shall be
> ignored by msch and always stored as zero by stsch.
>
> 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").
>
> 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: Claudio Imbrenda <imbrenda@linux.ibm.com>

I thought I already gave my R-B for some time.
You can do the checks for the MSS and so on in a future patch.

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

> ---
> s390x/css.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 82 insertions(+)
>
> diff --git a/s390x/css.c b/s390x/css.c
> index 7fe5283c41d0..dd84e670ce99 100644
> --- a/s390x/css.c
> +++ b/s390x/css.c
> @@ -501,6 +501,86 @@ static void test_ssch(void)
> report_prefix_pop();
> }
>
> +static void test_stsch(void)
> +{
> + const int align_to = 4;
> + struct schib schib;
> + int cc;
> +
> + if (!test_device_sid) {
> + report_skip("No device");
> + return;
> + }
> +
> + report_prefix_push("Unaligned");
> + for (int i = 1; i < align_to; i *= 2) {
> + report_prefix_pushf("%d", i);
> +
> + expect_pgm_int();
> + stsch(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 subchannel number");
> + cc = stsch(0x0001ffff, &schib);
> + report(cc == 3, "Channel not operational");
> + report_prefix_pop();
> +
> + /*
> + * No matter if multiple-subchannel-set facility is installed, bit 47
> + * always needs to be 1.
> + */
> + report_prefix_push("Bit 47 in SID is zero");
> + expect_pgm_int();
> + stsch(0x0000ffff, &schib);
> + check_pgm_int_code(PGM_INT_CODE_OPERAND);
> + report_prefix_pop();
> +}
> +
> +/*
> + * According to architecture MSCH does ignore bit 5 of the second word
> + * but STSCH will store bit 5 as zero.
> + */
> +static void test_pmcw_bit5(void)
> +{
> + int cc;
> + uint16_t old_pmcw_flags;
> +
> + cc = stsch(test_device_sid, &schib);
> + if (cc) {
> + report_fail("stsch: sch %08x failed with cc=%d", test_device_sid, cc);
> + return;
> + }
> + old_pmcw_flags = schib.pmcw.flags;
> +
> + report_prefix_push("Bit 5 set");
> +
> + schib.pmcw.flags = old_pmcw_flags | BIT(15 - 5);
> + cc = msch(test_device_sid, &schib);
> + report(!cc, "MSCH cc == 0");
> +
> + cc = stsch(test_device_sid, &schib);
> + report(!cc, "STSCH cc == 0");
> + report(!(schib.pmcw.flags & BIT(15 - 5)), "STSCH PMCW Bit 5 is clear");
> +
> + report_prefix_pop();
> +
> + report_prefix_push("Bit 5 clear");
> +
> + schib.pmcw.flags = old_pmcw_flags & ~BIT(15 - 5);
> + cc = msch(test_device_sid, &schib);
> + report(!cc, "MSCH cc == 0");
> +
> + cc = stsch(test_device_sid, &schib);
> + report(!cc, "STSCH cc == 0");
> + report(!(schib.pmcw.flags & BIT(15 - 5)), "STSCH PMCW Bit 5 is clear");
> +
> + report_prefix_pop();
> +}
> +
> static struct {
> const char *name;
> void (*func)(void);
> @@ -516,6 +596,8 @@ static struct {
> { "msch", test_msch },
> { "stcrw", test_stcrw },
> { "ssch", test_ssch },
> + { "stsch", test_stsch },
> + { "pmcw bit 5 ignored", test_pmcw_bit5 },
> { NULL, NULL }
> };
>
>

--
Pierre Morel
IBM Lab Boeblingen