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Re: [kvm-unit-tests PATCH v2 5/9] arm: pmu: Basic event counter Tests
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From: |
Andrew Jones |
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Subject: |
Re: [kvm-unit-tests PATCH v2 5/9] arm: pmu: Basic event counter Tests |
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Date: |
Thu, 5 Mar 2020 10:42:17 +0100 |
On Thu, Jan 30, 2020 at 12:25:06PM +0100, Eric Auger wrote:
> Adds the following tests:
> - event-counter-config: test event counter configuration
> - basic-event-count:
> - programs counters #0 and #1 to count 2 required events
> (resp. CPU_CYCLES and INST_RETIRED). Counter #0 is preset
> to a value close enough to the 32b
> overflow limit so that we check the overflow bit is set
> after the execution of the asm loop.
> - mem-access: counts MEM_ACCESS event on counters #0 and #1
> with and without 32-bit overflow.
>
> Signed-off-by: Eric Auger <address@hidden>
>
> ---
>
> v1 -> v2:
> - fix PMCNTENSET_EL0 and PMCNTENCLR_EL0 op0
> - print PMEVTYPER SH
> - properly clobber used regs and add "cc"
> - simplify mem_access_loop
> ---
> arm/pmu.c | 269 ++++++++++++++++++++++++++++++++++++++++++++++
> arm/unittests.cfg | 18 ++++
> 2 files changed, 287 insertions(+)
>
> diff --git a/arm/pmu.c b/arm/pmu.c
> index 4a26a76..1b0101f 100644
> --- a/arm/pmu.c
> +++ b/arm/pmu.c
> @@ -18,9 +18,15 @@
> #include "asm/barrier.h"
> #include "asm/sysreg.h"
> #include "asm/processor.h"
> +#include <bitops.h>
> +#include <asm/gic.h>
>
> #define PMU_PMCR_E (1 << 0)
> +#define PMU_PMCR_P (1 << 1)
> #define PMU_PMCR_C (1 << 2)
> +#define PMU_PMCR_D (1 << 3)
> +#define PMU_PMCR_X (1 << 4)
> +#define PMU_PMCR_DP (1 << 5)
> #define PMU_PMCR_LC (1 << 6)
> #define PMU_PMCR_N_SHIFT 11
> #define PMU_PMCR_N_MASK 0x1f
> @@ -104,6 +110,9 @@ static inline void precise_instrs_loop(int loop, uint32_t
> pmcr)
>
> /* event counter tests only implemented for aarch64 */
> static void test_event_introspection(void) {}
> +static void test_event_counter_config(void) {}
> +static void test_basic_event_count(void) {}
> +static void test_mem_access(void) {}
>
> #elif defined(__aarch64__)
> #define ID_AA64DFR0_PERFMON_SHIFT 8
> @@ -145,6 +154,33 @@ static inline void precise_instrs_loop(int loop,
> uint32_t pmcr)
> }
>
> #define PMCEID1_EL0 sys_reg(3, 3, 9, 12, 7)
> +#define PMCNTENSET_EL0 sys_reg(3, 3, 9, 12, 1)
> +#define PMCNTENCLR_EL0 sys_reg(3, 3, 9, 12, 2)
> +
> +#define PMEVTYPER_EXCLUDE_EL1 (1 << 31)
> +#define PMEVTYPER_EXCLUDE_EL0 (1 << 30)
> +
> +#define regn_el0(__reg, __n) __reg ## __n ## _el0
> +#define write_regn(__reg, __n, __val) \
> + write_sysreg((__val), __reg ## __n ## _el0)
> +
> +#define read_regn(__reg, __n) \
> + read_sysreg(__reg ## __n ## _el0)
> +
> +#define print_pmevtyper(__s, __n) do { \
> + uint32_t val; \
> + val = read_regn(pmevtyper, __n);\
> + report_info("%s pmevtyper%d=0x%x, eventcount=0x%x (p=%ld, u=%ld
> nsk=%ld, nsu=%ld, nsh=%ld m=%ld, mt=%ld, sh=%ld)", \
> + (__s), (__n), val, val & 0xFFFF, \
> + (BIT_MASK(31) & val) >> 31, \
> + (BIT_MASK(30) & val) >> 30, \
> + (BIT_MASK(29) & val) >> 29, \
> + (BIT_MASK(28) & val) >> 28, \
> + (BIT_MASK(27) & val) >> 27, \
> + (BIT_MASK(26) & val) >> 26, \
> + (BIT_MASK(25) & val) >> 25); \
> + (BIT_MASK(24) & val) >> 24); \
> + } while (0)
>
> static bool is_event_supported(uint32_t n, bool warn)
> {
> @@ -198,6 +234,230 @@ static void test_event_introspection(void)
> report(required_events, "Check required events are implemented");
> }
>
> +/*
> + * Extra instructions inserted by the compiler would be difficult to
> compensate
> + * for, so hand assemble everything between, and including, the PMCR accesses
> + * to start and stop counting. isb instructions are inserted to make sure
> + * pmccntr read after this function returns the exact instructions executed
> + * in the controlled block. Loads @loop times the data at @address into x9.
> + */
> +static void mem_access_loop(void *addr, int loop, uint32_t pmcr)
> +{
> +asm volatile(
> + " msr pmcr_el0, %[pmcr]\n"
> + " isb\n"
> + " mov x10, %[loop]\n"
> + "1: sub x10, x10, #1\n"
> + " ldr x9, [%[addr]]\n"
> + " cmp x10, #0x0\n"
> + " b.gt 1b\n"
> + " msr pmcr_el0, xzr\n"
> + " isb\n"
> + :
> + : [addr] "r" (addr), [pmcr] "r" (pmcr), [loop] "r" (loop)
> + : "x9", "x10", "cc");
> +}
> +
> +static void pmu_reset(void)
> +{
> + /* reset all counters, counting disabled at PMCR level*/
> + set_pmcr(pmu.pmcr_ro | PMU_PMCR_LC | PMU_PMCR_C | PMU_PMCR_P);
> + /* Disable all counters */
> + write_sysreg_s(0xFFFFFFFF, PMCNTENCLR_EL0);
> + /* clear overflow reg */
> + write_sysreg(0xFFFFFFFF, pmovsclr_el0);
> + /* disable overflow interrupts on all counters */
> + write_sysreg(0xFFFFFFFF, pmintenclr_el1);
> + isb();
Is there a test we can do here to ensure the PMU was succesfully reset and
assert if not? Reset is a critical part of each test prep, so we should be
sure it has been done.
> +}
> +
> +static void test_event_counter_config(void)
> +{
> + int i;
> +
> + if (!pmu.nb_implemented_counters) {
> + report_skip("No event counter, skip ...");
> + return;
> + }
> +
> + pmu_reset();
> +
> + /*
> + * Test setting through PMESELR/PMXEVTYPER and PMEVTYPERn read,
> + * select counter 0
> + */
> + write_sysreg(1, PMSELR_EL0);
> + /* program this counter to count unsupported event */
> + write_sysreg(0xEA, PMXEVTYPER_EL0);
> + write_sysreg(0xdeadbeef, PMXEVCNTR_EL0);
> + report((read_regn(pmevtyper, 1) & 0xFFF) == 0xEA,
> + "PMESELR/PMXEVTYPER/PMEVTYPERn");
> + report((read_regn(pmevcntr, 1) == 0xdeadbeef),
> + "PMESELR/PMXEVCNTR/PMEVCNTRn");
> +
> + /* try to configure an unsupported event within the range [0x0, 0x3F] */
> + for (i = 0; i <= 0x3F; i++) {
> + if (!is_event_supported(i, false))
> + break;
> + }
> + if (i > 0x3F) {
> + report_skip("pmevtyper: all events within [0x0, 0x3F] are
> supported");
> + return;
> + }
> +
> + /* select counter 0 */
> + write_sysreg(0, PMSELR_EL0);
> + /* program this counter to count unsupported event */
> + write_sysreg(i, PMXEVCNTR_EL0);
> + /* read the counter value */
> + read_sysreg(PMXEVCNTR_EL0);
> + report(read_sysreg(PMXEVCNTR_EL0) == i,
> + "read of a counter programmed with unsupported event");
> +
> +}
> +
> +static bool satisfy_prerequisites(uint32_t *events, unsigned int nb_events)
> +{
> + int i;
> +
> + if (pmu.nb_implemented_counters < nb_events) {
> + report_skip("Skip test as number of counters is too small (%d)",
> + pmu.nb_implemented_counters);
> + return false;
> + }
> +
> + for (i = 0; i < nb_events; i++) {
> + if (!is_event_supported(events[i], false)) {
> + report_skip("Skip test as event %d is not supported",
> + events[i]);
> + return false;
> + }
> + }
> + return true;
> +}
> +
> +static void test_basic_event_count(void)
> +{
> + uint32_t implemented_counter_mask, non_implemented_counter_mask;
> + uint32_t counter_mask;
> + uint32_t events[] = {
> + 0x11, /* CPU_CYCLES */
> + 0x8, /* INST_RETIRED */
> + };
> +
> + if (!satisfy_prerequisites(events, ARRAY_SIZE(events)))
> + return;
> +
> + implemented_counter_mask = BIT(pmu.nb_implemented_counters) - 1;
> + non_implemented_counter_mask = ~(BIT(31) | implemented_counter_mask);
> + counter_mask = implemented_counter_mask | non_implemented_counter_mask;
> +
> + write_regn(pmevtyper, 0, events[0] | PMEVTYPER_EXCLUDE_EL0);
> + write_regn(pmevtyper, 1, events[1] | PMEVTYPER_EXCLUDE_EL0);
> +
> + /* disable all counters */
> + write_sysreg_s(0xFFFFFFFF, PMCNTENCLR_EL0);
> + report(!read_sysreg_s(PMCNTENCLR_EL0) && !read_sysreg_s(PMCNTENSET_EL0),
> + "pmcntenclr: disable all counters");
> +
> + /*
> + * clear cycle and all event counters and allow counter enablement
> + * through PMCNTENSET. LC is RES1.
> + */
> + set_pmcr(pmu.pmcr_ro | PMU_PMCR_LC | PMU_PMCR_C | PMU_PMCR_P);
> + isb();
> + report(get_pmcr() == (pmu.pmcr_ro | PMU_PMCR_LC), "pmcr: reset
> counters");
> +
> + /* Preset counter #0 to 0xFFFFFFF0 to trigger an overflow interrupt */
> + write_regn(pmevcntr, 0, 0xFFFFFFF0);
> + report(read_regn(pmevcntr, 0) == 0xFFFFFFF0,
> + "counter #0 preset to 0xFFFFFFF0");
> + report(!read_regn(pmevcntr, 1), "counter #1 is 0");
> +
> + /*
> + * Enable all implemented counters and also attempt to enable
> + * not supported counters. Counting still is disabled by !PMCR.E
> + */
> + write_sysreg_s(counter_mask, PMCNTENSET_EL0);
> +
> + /* check only those implemented are enabled */
> + report((read_sysreg_s(PMCNTENSET_EL0) == read_sysreg_s(PMCNTENCLR_EL0))
> &&
> + (read_sysreg_s(PMCNTENSET_EL0) == implemented_counter_mask),
> + "pmcntenset: enabled implemented_counters");
> +
> + /* Disable all counters but counters #0 and #1 */
> + write_sysreg_s(~0x3, PMCNTENCLR_EL0);
> + report((read_sysreg_s(PMCNTENSET_EL0) == read_sysreg_s(PMCNTENCLR_EL0))
> &&
> + (read_sysreg_s(PMCNTENSET_EL0) == 0x3),
> + "pmcntenset: just enabled #0 and #1");
> +
> + /* clear overflow register */
> + write_sysreg(0xFFFFFFFF, pmovsclr_el0);
> + report(!read_sysreg(pmovsclr_el0), "check overflow reg is 0");
> +
> + /* disable overflow interrupts on all counters*/
> + write_sysreg(0xFFFFFFFF, pmintenclr_el1);
> + report(!read_sysreg(pmintenclr_el1),
> + "pmintenclr_el1=0, all interrupts disabled");
> +
> + /* enable overflow interrupts on all event counters */
> + write_sysreg(implemented_counter_mask | non_implemented_counter_mask,
> + pmintenset_el1);
> + report(read_sysreg(pmintenset_el1) == implemented_counter_mask,
> + "overflow interrupts enabled on all implemented counters");
> +
> + /* Set PMCR.E, execute asm code and unset PMCR.E */
> + precise_instrs_loop(20, pmu.pmcr_ro | PMU_PMCR_E);
> +
> + report_info("counter #0 is 0x%lx (CPU_CYCLES)",
> + read_regn(pmevcntr, 0));
> + report_info("counter #1 is 0x%lx (INST_RETIRED)",
> + read_regn(pmevcntr, 1));
> +
> + report_info("overflow reg = 0x%lx", read_sysreg(pmovsclr_el0));
> + report(read_sysreg(pmovsclr_el0) & 0x1,
> + "check overflow happened on #0 only");
> +}
> +
> +static void test_mem_access(void)
> +{
> + void *addr = malloc(PAGE_SIZE);
> + uint32_t events[] = {
> + 0x13, /* MEM_ACCESS */
> + 0x13, /* MEM_ACCESS */
> + };
> +
> + if (!satisfy_prerequisites(events, ARRAY_SIZE(events)))
> + return;
> +
> + pmu_reset();
> +
> + write_regn(pmevtyper, 0, events[0] | PMEVTYPER_EXCLUDE_EL0);
> + write_regn(pmevtyper, 1, events[1] | PMEVTYPER_EXCLUDE_EL0);
> + write_sysreg_s(0x3, PMCNTENSET_EL0);
> + isb();
> + mem_access_loop(addr, 20, pmu.pmcr_ro | PMU_PMCR_E);
> + report_info("counter #0 is %ld (MEM_ACCESS)", read_regn(pmevcntr, 0));
> + report_info("counter #1 is %ld (MEM_ACCESS)", read_regn(pmevcntr, 1));
> + /* We may measure more than 20 mem access depending on the core */
> + report((read_regn(pmevcntr, 0) == read_regn(pmevcntr, 1)) &&
> + (read_regn(pmevcntr, 0) >= 20) && !read_sysreg(pmovsclr_el0),
> + "Ran 20 mem accesses");
> +
> + pmu_reset();
> +
> + write_regn(pmevcntr, 0, 0xFFFFFFFA);
> + write_regn(pmevcntr, 1, 0xFFFFFFF0);
> + write_sysreg_s(0x3, PMCNTENSET_EL0);
> + isb();
> + mem_access_loop(addr, 20, pmu.pmcr_ro | PMU_PMCR_E);
> + report(read_sysreg(pmovsclr_el0) == 0x3,
> + "Ran 20 mem accesses with expected overflows on both counters");
> + report_info("cnt#0 = %ld cnt#1=%ld overflow=0x%lx",
> + read_regn(pmevcntr, 0), read_regn(pmevcntr, 1),
> + read_sysreg(pmovsclr_el0));
> +}
> +
> #endif
>
> /*
> @@ -388,6 +648,15 @@ int main(int argc, char *argv[])
> } else if (strcmp(argv[1], "event-introspection") == 0) {
> report_prefix_push(argv[1]);
> test_event_introspection();
> + } else if (strcmp(argv[1], "event-counter-config") == 0) {
> + report_prefix_push(argv[1]);
> + test_event_counter_config();
> + } else if (strcmp(argv[1], "basic-event-count") == 0) {
> + report_prefix_push(argv[1]);
> + test_basic_event_count();
> + } else if (strcmp(argv[1], "mem-access") == 0) {
> + report_prefix_push(argv[1]);
> + test_mem_access();
> } else {
> report_abort("Unknown sub-test '%s'", argv[1]);
> }
> diff --git a/arm/unittests.cfg b/arm/unittests.cfg
> index 4433ef3..7a59403 100644
> --- a/arm/unittests.cfg
> +++ b/arm/unittests.cfg
> @@ -72,6 +72,24 @@ groups = pmu
> arch = arm64
> extra_params = -append 'event-introspection'
>
> +[pmu-event-counter-config]
> +file = pmu.flat
> +groups = pmu
> +arch = arm64
> +extra_params = -append 'event-counter-config'
> +
> +[pmu-basic-event-count]
> +file = pmu.flat
> +groups = pmu
> +arch = arm64
> +extra_params = -append 'basic-event-count'
> +
> +[pmu-mem-access]
> +file = pmu.flat
> +groups = pmu
> +arch = arm64
> +extra_params = -append 'mem-access'
> +
> # Test PMU support (TCG) with -icount IPC=1
> #[pmu-tcg-icount-1]
> #file = pmu.flat
> --
> 2.20.1
>
>