[kvm-unit-tests PATCH v3 07/12] arm: pmu: Basic event counter Tests

[Eric Auger]

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>
Reviewed-by: Andre Przywara <address@hidden>

---

v2 -> v3:
- used BIT() for PMEVTYPER_EXCLUDE_EL1/0
- print the event id in hexa (Peter)
- added prefix pop
- s/write_regn/write_regn_el0
- s/read_regn/read_regn_el0
- remove print_pmevtyper
- moved write/read_regn_el0 into lib/arm64/asm/sysreg.h
- added pmu prefix to the test names
- Kept Andre's R-b as functional code has not changed

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              | 248 +++++++++++++++++++++++++++++++++++++++++
 arm/unittests.cfg      |  18 +++
 lib/arm64/asm/sysreg.h |   6 +
 3 files changed, 272 insertions(+)

diff --git a/arm/pmu.c b/arm/pmu.c
index 8c49e50..45dccf7 100644
--- a/arm/pmu.c
+++ b/arm/pmu.c
@@ -19,9 +19,14 @@
 #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
@@ -38,6 +43,7 @@
 #define SW_INCR                        0x0
 #define INST_RETIRED           0x8
 #define CPU_CYCLES             0x11
+#define MEM_ACCESS             0x13
 #define INST_PREC              0x1B
 #define STALL_FRONTEND         0x23
 #define STALL_BACKEND          0x24
@@ -47,6 +53,10 @@
 #define EXT_COMMON_EVENTS_LOW  0x4000
 #define EXT_COMMON_EVENTS_HIGH 0x403F
 
+#define ALL_SET                        0xFFFFFFFF
+#define ALL_CLEAR              0x0
+#define PRE_OVERFLOW           0xFFFFFFF0
+
 struct pmu {
        unsigned int version;
        unsigned int nb_implemented_counters;
@@ -127,6 +137,9 @@ 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
@@ -175,6 +188,11 @@ 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 BIT(31)
+#define PMEVTYPER_EXCLUDE_EL0 BIT(30)
 
 static bool is_event_supported(uint32_t n, bool warn)
 {
@@ -228,6 +246,224 @@ 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(ALL_SET, PMCNTENCLR_EL0);
+       /* clear overflow reg */
+       write_sysreg(ALL_SET, pmovsclr_el0);
+       /* disable overflow interrupts on all counters */
+       write_sysreg(ALL_SET, pmintenclr_el1);
+       isb();
+}
+
+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_el0(pmevtyper, 1) & 0xFFF) == 0xEA,
+               "PMESELR/PMXEVTYPER/PMEVTYPERn");
+       report((read_regn_el0(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 0x%x 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[] = {CPU_CYCLES, 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_el0(pmevtyper, 0, CPU_CYCLES | PMEVTYPER_EXCLUDE_EL0);
+       write_regn_el0(pmevtyper, 1, INST_RETIRED | PMEVTYPER_EXCLUDE_EL0);
+
+       /* disable all counters */
+       write_sysreg_s(ALL_SET, 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 pre overflow value to trigger an overflow */
+       write_regn_el0(pmevcntr, 0, PRE_OVERFLOW);
+       report(read_regn_el0(pmevcntr, 0) == PRE_OVERFLOW,
+               "counter #0 preset to pre-overflow value");
+       report(!read_regn_el0(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(ALL_SET, pmovsclr_el0);
+       report(!read_sysreg(pmovsclr_el0), "check overflow reg is 0");
+
+       /* disable overflow interrupts on all counters*/
+       write_sysreg(ALL_SET, 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_el0(pmevcntr, 0));
+       report_info("counter #1 is 0x%lx (INST_RETIRED)",
+                   read_regn_el0(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[] = {MEM_ACCESS, MEM_ACCESS};
+
+       if (!satisfy_prerequisites(events, ARRAY_SIZE(events)))
+               return;
+
+       pmu_reset();
+
+       write_regn_el0(pmevtyper, 0, MEM_ACCESS | PMEVTYPER_EXCLUDE_EL0);
+       write_regn_el0(pmevtyper, 1, MEM_ACCESS | 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_el0(pmevcntr, 
0));
+       report_info("counter #1 is %ld (MEM_ACCESS)", read_regn_el0(pmevcntr, 
1));
+       /* We may measure more than 20 mem access depending on the core */
+       report((read_regn_el0(pmevcntr, 0) == read_regn_el0(pmevcntr, 1)) &&
+              (read_regn_el0(pmevcntr, 0) >= 20) && !read_sysreg(pmovsclr_el0),
+              "Ran 20 mem accesses");
+
+       pmu_reset();
+
+       write_regn_el0(pmevcntr, 0, PRE_OVERFLOW);
+       write_regn_el0(pmevcntr, 1, PRE_OVERFLOW);
+       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_el0(pmevcntr, 0), read_regn_el0(pmevcntr, 1),
+                       read_sysreg(pmovsclr_el0));
+}
+
 #endif
 
 /*
@@ -402,6 +638,18 @@ int main(int argc, char *argv[])
                report_prefix_push(argv[1]);
                test_event_introspection();
                report_prefix_pop();
+       } else if (strcmp(argv[1], "pmu-event-counter-config") == 0) {
+               report_prefix_push(argv[1]);
+               test_event_counter_config();
+               report_prefix_pop();
+       } else if (strcmp(argv[1], "pmu-basic-event-count") == 0) {
+               report_prefix_push(argv[1]);
+               test_basic_event_count();
+               report_prefix_pop();
+       } else if (strcmp(argv[1], "pmu-mem-access") == 0) {
+               report_prefix_push(argv[1]);
+               test_mem_access();
+               report_prefix_pop();
        } else {
                report_abort("Unknown sub-test '%s'", argv[1]);
        }
diff --git a/arm/unittests.cfg b/arm/unittests.cfg
index f993548..32ab8c6 100644
--- a/arm/unittests.cfg
+++ b/arm/unittests.cfg
@@ -72,6 +72,24 @@ groups = pmu
 arch = arm64
 extra_params = -append 'pmu-event-introspection'
 
+[pmu-event-counter-config]
+file = pmu.flat
+groups = pmu
+arch = arm64
+extra_params = -append 'pmu-event-counter-config'
+
+[pmu-basic-event-count]
+file = pmu.flat
+groups = pmu
+arch = arm64
+extra_params = -append 'pmu-basic-event-count'
+
+[pmu-mem-access]
+file = pmu.flat
+groups = pmu
+arch = arm64
+extra_params = -append 'pmu-mem-access'
+
 # Test PMU support (TCG) with -icount IPC=1
 #[pmu-tcg-icount-1]
 #file = pmu.flat
diff --git a/lib/arm64/asm/sysreg.h b/lib/arm64/asm/sysreg.h
index a45eebd..378bf7e 100644
--- a/lib/arm64/asm/sysreg.h
+++ b/lib/arm64/asm/sysreg.h
@@ -49,6 +49,12 @@
        asm volatile("msr_s " xstr(r) ", %x0" : : "rZ" (__val));\
 } while (0)
 
+#define write_regn_el0(__reg, __n, __val) \
+       write_sysreg((__val), __reg ## __n ## _el0)
+
+#define read_regn_el0(__reg, __n) \
+       read_sysreg(__reg ## __n ## _el0)
+
 asm(
 "      .irp    
num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n"
 "      .equ    .L__reg_num_x\\num, \\num\n"
-- 
2.20.1