On Sat, Jul 30, 2022 at 01:52:38PM +0100, Marc Zyngier wrote: > Crumbs... With Drew's new email this time. > > On Sat, 30 Jul 2022 13:47:14 +0100, > Marc Zyngier <maz@xxxxxxxxxx> wrote: > > > > Hi Ricardo, > > > > On Mon, 18 Jul 2022 16:49:10 +0100, > > Ricardo Koller <ricarkol@xxxxxxxxxx> 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 removing the > > > checks. > > > > > > Signed-off-by: Ricardo Koller <ricarkol@xxxxxxxxxx> > > > --- > > > arm/pmu.c | 21 ++++++++++----------- > > > 1 file changed, 10 insertions(+), 11 deletions(-) > > > > > > diff --git a/arm/pmu.c b/arm/pmu.c > > > index a7899c3c..4f2c5096 100644 > > > --- a/arm/pmu.c > > > +++ b/arm/pmu.c > > > @@ -581,7 +581,6 @@ 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"); > > > > > > /* test 64b overflow */ > > > > > > @@ -593,7 +592,7 @@ 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) & 0x2) == 0, "no overflow recorded for chained incr #2"); > > > > > > write_regn_el0(pmevcntr, 0, PRE_OVERFLOW); > > > write_regn_el0(pmevcntr, 1, ALL_SET); > > > @@ -601,7 +600,7 @@ 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) & 0x2, "overflow on chain counter"); > > > } > > > > > > static void test_chained_sw_incr(void) > > > @@ -626,10 +625,10 @@ static void test_chained_sw_incr(void) > > > for (i = 0; i < 100; i++) > > > write_sysreg(0x1, pmswinc_el0); > > > > > > - report(!read_sysreg(pmovsclr_el0) && (read_regn_el0(pmevcntr, 1) == 1), > > > - "no overflow and chain counter incremented after 100 SW_INCR/CHAIN"); > > > + report(read_regn_el0(pmevcntr, 1) == 1, > > > + "no 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)); > > > + read_regn_el0(pmevcntr, 0), read_regn_el0(pmevcntr, 1)); > > > > > > /* 64b SW_INCR and overflow on CHAIN counter*/ > > > pmu_reset(); > > > @@ -644,7 +643,7 @@ static void test_chained_sw_incr(void) > > > for (i = 0; i < 100; i++) > > > write_sysreg(0x1, pmswinc_el0); > > > > > > - report((read_sysreg(pmovsclr_el0) == 0x2) && > > > + report((read_sysreg(pmovsclr_el0) & 0x2) && > > > (read_regn_el0(pmevcntr, 1) == 0) && > > > (read_regn_el0(pmevcntr, 0) == 84), > > > "overflow on chain counter and expected values after 100 SW_INCR/CHAIN"); > > > @@ -727,8 +726,8 @@ 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), > > > + "CHAIN counter enabled: CHAIN counter was incremented"); > > > > > > report_info("CHAIN counter #1 = 0x%lx, overflow=0x%lx", > > > read_regn_el0(pmevcntr, 1), read_sysreg(pmovsclr_el0)); > > > @@ -755,8 +754,8 @@ 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), > > > + "32b->64b: CHAIN counter incremented"); > > > > > > report_info("CHAIN counter #1 = 0x%lx, overflow=0x%lx", > > > read_regn_el0(pmevcntr, 1), read_sysreg(pmovsclr_el0)); > > > > I'm looking at fixing KVM to match this (see the binch of hacks at > > [1]), and still getting a couple of failures in the PMU overflow tests > > despite my best effort to fix the code: > > > > $ ./arm-run arm/pmu.flat --append pmu-overflow-interrupt > > /usr/bin/qemu-system-aarch64 -nodefaults -machine virt,gic-version=host -accel kvm -cpu host -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd -device pci-testdev -display none -serial stdio -kernel arm/pmu.flat --append pmu-overflow-interrupt # -initrd /tmp/tmp.RQ6FmkvXay > > INFO: PMU version: 0x1 > > INFO: PMU implementer/ID code: 0x41("A")/0x3 > > INFO: Implements 6 event counters > > PASS: pmu: pmu-overflow-interrupt: no overflow interrupt after preset > > PASS: pmu: pmu-overflow-interrupt: no overflow interrupt after counting > > INFO: pmu: pmu-overflow-interrupt: overflow=0x0 > > PASS: pmu: pmu-overflow-interrupt: overflow interrupts expected on #0 and #1 > > FAIL: pmu: pmu-overflow-interrupt: no overflow interrupt expected on 32b boundary > > FAIL: pmu: pmu-overflow-interrupt: expect overflow interrupt on odd counter > > SUMMARY: 5 tests, 2 unexpected failures > > > > Looking at the kut code, I'm wondering whether you're still missing a > > couple of extra fixes such as: > > > > diff --git a/arm/pmu.c b/arm/pmu.c > > index 4f2c5096..e0b9f71a 100644 > > --- a/arm/pmu.c > > +++ b/arm/pmu.c > > @@ -861,8 +861,8 @@ 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(1), > > + "expect overflow interrupt on 32b counter"); > > > > /* overflow on odd counter */ > > pmu_reset_stats(); > > @@ -870,8 +870,8 @@ 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+odd counters"); > > } > > #endif > > > > With that, all PMU tests pass. Am I missing something? Did you notice > > these failing on HW? > > Actually, yes. But, I wasn't 100% sure. I tried a PMU passthrough prototype on both real HW and the fast-model, and with test_overflow_interrupt() I see an interrupt overflow hitting EL2. I wasn't sure whether I should be forwarding it to the guest. Thanks, Ricardo > > Thanks, > > > > M. > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/pmu-chained > > > > -- > > Without deviation from the norm, progress is not possible. > > -- > Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm