Re: [kvm-unit-tests PATCH v2 5/9] arm: pmu: Basic event counter Tests

[Auger Eric <eric.auger@redhat.com>]

Hi Drew,

On 3/5/20 10:42 AM, Andrew Jones wrote:
> 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 <eric.auger@redhat.com>
>>
>> ---
>>
>> 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.
we can read the regs we have just written (?). In case the reset were to
fail, the subsequent test would fail anyway.

Thanks

Eric
> 
>> +}
>> +
>> +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
>>
>>

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