On Wed, Aug 03, 2022 at 11:23:28AM -0700, Ricardo Koller wrote:
> A chained event overflowing on the low counter can set the overflow flag
> in PMOVS. KVM does not set it, but real HW and the fast-model seem to.
> Moreover, the AArch64.IncrementEventCounter() pseudocode in the ARM ARM
> (DDI 0487H.a, J1.1.1 "aarch64/debug") also sets the PMOVS bit on
> overflow.
>
> The pmu chain tests fail on bare metal when checking the overflow flag
> of the low counter _not_ being set on overflow. Fix by checking for
> overflow. Note that this test fails in KVM without the respective fix.
>
> Signed-off-by: Ricardo Koller <ricarkol@xxxxxxxxxx>
> ---
> arm/pmu.c | 33 ++++++++++++++++++---------------
> 1 file changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/arm/pmu.c b/arm/pmu.c
> index 7c5bc259..258780f4 100644
> --- a/arm/pmu.c
> +++ b/arm/pmu.c
> @@ -583,7 +583,7 @@ static void test_chained_counters(void)
> precise_instrs_loop(22, pmu.pmcr_ro | PMU_PMCR_E);
>
> report(read_regn_el0(pmevcntr, 1) == 1, "CHAIN counter #1 incremented");
> - report(!read_sysreg(pmovsclr_el0), "no overflow recorded for chained incr #1");
> + report(read_sysreg(pmovsclr_el0) == 0x1, "overflow recorded for chained incr #1");
>
> /* test 64b overflow */
>
> @@ -595,7 +595,7 @@ static void test_chained_counters(void)
> precise_instrs_loop(22, pmu.pmcr_ro | PMU_PMCR_E);
> report_info("overflow reg = 0x%lx", read_sysreg(pmovsclr_el0));
> report(read_regn_el0(pmevcntr, 1) == 2, "CHAIN counter #1 set to 2");
> - report(!read_sysreg(pmovsclr_el0), "no overflow recorded for chained incr #2");
> + report(read_sysreg(pmovsclr_el0) == 0x1, "overflow recorded for chained incr #2");
>
> write_regn_el0(pmevcntr, 0, PRE_OVERFLOW);
> write_regn_el0(pmevcntr, 1, ALL_SET);
> @@ -603,7 +603,7 @@ static void test_chained_counters(void)
> precise_instrs_loop(22, pmu.pmcr_ro | PMU_PMCR_E);
> report_info("overflow reg = 0x%lx", read_sysreg(pmovsclr_el0));
> report(!read_regn_el0(pmevcntr, 1), "CHAIN counter #1 wrapped");
> - report(read_sysreg(pmovsclr_el0) == 0x2, "overflow on chain counter");
> + report(read_sysreg(pmovsclr_el0) == 0x3, "overflow on even and odd counters");
> }
>
> static void test_chained_sw_incr(void)
> @@ -629,8 +629,9 @@ static void test_chained_sw_incr(void)
> write_sysreg(0x1, pmswinc_el0);
>
> isb();
> - report(!read_sysreg(pmovsclr_el0) && (read_regn_el0(pmevcntr, 1) == 1),
> - "no overflow and chain counter incremented after 100 SW_INCR/CHAIN");
> + report((read_sysreg(pmovsclr_el0) == 0x1) &&
> + (read_regn_el0(pmevcntr, 1) == 1),
> + "overflow and chain counter incremented after 100 SW_INCR/CHAIN");
> report_info("overflow=0x%lx, #0=%ld #1=%ld", read_sysreg(pmovsclr_el0),
> read_regn_el0(pmevcntr, 0), read_regn_el0(pmevcntr, 1));
>
> @@ -648,10 +649,10 @@ static void test_chained_sw_incr(void)
> write_sysreg(0x1, pmswinc_el0);
>
> isb();
> - report((read_sysreg(pmovsclr_el0) == 0x2) &&
> + report((read_sysreg(pmovsclr_el0) == 0x3) &&
> (read_regn_el0(pmevcntr, 1) == 0) &&
> (read_regn_el0(pmevcntr, 0) == 84),
> - "overflow on chain counter and expected values after 100 SW_INCR/CHAIN");
> + "overflow on even and odd counters, and expected values after 100 SW_INCR/CHAIN");
Besides the extra space, this doesn't read well (to me).
Thanks,
drew
