On Thu, Aug 04, 2022 at 05:41:39PM -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. > It'd be good to link out to the respective KVM fix, either by commit or lore link if this patch lands before the kernel patches: Link: http://lore.kernel.org/r/20220805135813.2102034-1-maz@xxxxxxxxxx -- Thanks, Oliver > Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx> > 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 12e7d84e..0a7e12f8 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"); > + "expected overflows and values 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)); > } > @@ -731,8 +732,9 @@ static void test_chain_promotion(void) > report_info("MEM_ACCESS counter #0 has value 0x%lx", > read_regn_el0(pmevcntr, 0)); > > - report((read_regn_el0(pmevcntr, 1) == 1) && !read_sysreg(pmovsclr_el0), > - "CHAIN counter enabled: CHAIN counter was incremented and no overflow"); > + report((read_regn_el0(pmevcntr, 1) == 1) && > + (read_sysreg(pmovsclr_el0) == 0x1), > + "CHAIN counter enabled: CHAIN counter was incremented and overflow"); > > report_info("CHAIN counter #1 = 0x%lx, overflow=0x%lx", > read_regn_el0(pmevcntr, 1), read_sysreg(pmovsclr_el0)); > @@ -759,8 +761,9 @@ static void test_chain_promotion(void) > report_info("MEM_ACCESS counter #0 has value 0x%lx", > read_regn_el0(pmevcntr, 0)); > > - report((read_regn_el0(pmevcntr, 1) == 1) && !read_sysreg(pmovsclr_el0), > - "32b->64b: CHAIN counter incremented and no overflow"); > + report((read_regn_el0(pmevcntr, 1) == 1) && > + (read_sysreg(pmovsclr_el0) == 0x1), > + "32b->64b: CHAIN counter incremented and overflow"); > > report_info("CHAIN counter #1 = 0x%lx, overflow=0x%lx", > read_regn_el0(pmevcntr, 1), read_sysreg(pmovsclr_el0)); > @@ -868,8 +871,8 @@ static void test_overflow_interrupt(void) > write_regn_el0(pmevcntr, 0, PRE_OVERFLOW); > isb(); > mem_access_loop(addr, 200, pmu.pmcr_ro | PMU_PMCR_E); > - report(expect_interrupts(0), > - "no overflow interrupt expected on 32b boundary"); > + report(expect_interrupts(0x1), > + "expect overflow interrupt on 32b boundary"); > > /* overflow on odd counter */ > pmu_reset_stats(); > @@ -877,8 +880,8 @@ static void test_overflow_interrupt(void) > write_regn_el0(pmevcntr, 1, ALL_SET); > isb(); > mem_access_loop(addr, 400, pmu.pmcr_ro | PMU_PMCR_E); > - report(expect_interrupts(0x2), > - "expect overflow interrupt on odd counter"); > + report(expect_interrupts(0x3), > + "expect overflow interrupt on even and odd counter"); > } > #endif > > -- > 2.37.1.559.g78731f0fdb-goog > _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
