[kvm-unit-tests RFC 10/10] pmu: Test overflow interrupts

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

Test overflows for MEM_ACESS and SW_INCR events. Also tests
overflows with 64-bit events.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 arm/pmu.c         | 133 +++++++++++++++++++++++++++++++++++++++++++++-
 arm/unittests.cfg |   6 +++
 2 files changed, 138 insertions(+), 1 deletion(-)

diff --git a/arm/pmu.c b/arm/pmu.c
index 47d46a2..a63b93e 100644
--- a/arm/pmu.c
+++ b/arm/pmu.c
@@ -45,8 +45,12 @@ struct pmu {
 	uint32_t pmcr_ro;
 };
 
-static struct pmu pmu;
+struct pmu_stats {
+	unsigned long bitmap;
+	uint32_t interrupts[32];
+};
 
+static struct pmu pmu;
 
 #if defined(__arm__)
 #define ID_DFR0_PERFMON_SHIFT 24
@@ -117,6 +121,7 @@ static void test_mem_access(void) {}
 static void test_chained_counters(void) {}
 static void test_chained_sw_incr(void) {}
 static void test_chain_promotion(void) {}
+static void test_overflow_interrupt(void) {}
 
 #elif defined(__aarch64__)
 #define ID_AA64DFR0_PERFMON_SHIFT 8
@@ -263,6 +268,43 @@ asm volatile(
 	: );
 }
 
+static struct pmu_stats pmu_stats;
+
+static void irq_handler(struct pt_regs *regs)
+{
+        uint32_t irqstat, irqnr;
+
+        irqstat = gic_read_iar();
+        irqnr = gic_iar_irqnr(irqstat);
+        gic_write_eoir(irqstat);
+
+        if (irqnr == 23) {
+                unsigned long overflows = read_sysreg(pmovsclr_el0);
+		int i;
+
+                report_info("--> PMU overflow interrupt %d (counter bitmask 0x%lx)", irqnr, overflows);
+		for (i = 0; i < 32; i++) {
+			if (test_and_clear_bit(i, &overflows)) {
+				pmu_stats.interrupts[i]++;
+				pmu_stats.bitmap |= 1 << i;
+			}
+		}
+                write_sysreg(0xFFFFFFFF, pmovsclr_el0);
+        } else {
+                report_info("Unexpected interrupt: %d\n", irqnr);
+        }
+}
+
+static void pmu_reset_stats(void)
+{
+	int i;
+
+	for (i = 0; i < 32; i++) {
+		pmu_stats.interrupts[i] = 0;
+	}
+	pmu_stats.bitmap = 0;
+}
+
 static void pmu_reset(void)
 {
 	/* reset all counters, counting disabled at PMCR level*/
@@ -273,6 +315,7 @@ static void pmu_reset(void)
 	write_sysreg(0xFFFFFFFF, pmovsclr_el0);
 	/* disable overflow interrupts on all counters */
 	write_sysreg(0xFFFFFFFF, pmintenclr_el1);
+	pmu_reset_stats();
 	isb();
 }
 
@@ -691,8 +734,93 @@ static void test_chain_promotion(void)
 			read_sysreg(pmovsclr_el0));
 }
 
+static bool expect_interrupts(uint32_t bitmap)
+{
+	int i;
+
+	if (pmu_stats.bitmap ^ bitmap)
+		return false;
+
+	for (i = 0; i < 32; i++) {
+		if (test_and_clear_bit(i, &pmu_stats.bitmap))
+			if (pmu_stats.interrupts[i] != 1)
+				return false;
+	}
+	return true;
+}
+
+static void test_overflow_interrupt(void)
+{
+	uint32_t events[] = { 0x13 /* MEM_ACCESS */, 0x00 /* SW_INCR */};
+	void *addr = malloc(PAGE_SIZE);
+	int i;
+
+	if (!satisfy_prerequisites(events, ARRAY_SIZE(events)))
+		return;
+
+	setup_irq(irq_handler);
+	gic_enable_irq(23);
+
+	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);
+	write_regn(pmevcntr, 0, 0xFFFFFFF0);
+	write_regn(pmevcntr, 1, 0xFFFFFFF0);
+	isb();
+
+	/* interrupts are disabled */
+
+	mem_access_loop(addr, 200, pmu.pmcr_ro | PMU_PMCR_E);
+	report("no overflow interrupt received", expect_interrupts(0));
+
+	set_pmcr(pmu.pmcr_ro | PMU_PMCR_E);
+	for (i = 0; i < 100; i++) {
+		write_sysreg(0x2, pmswinc_el0);
+	}
+	set_pmcr(pmu.pmcr_ro);
+	report("no overflow interrupt received", expect_interrupts(0));
+
+	/* enable interrupts */
+
+	pmu_reset_stats();
+
+	write_regn(pmevcntr, 0, 0xFFFFFFF0);
+	write_regn(pmevcntr, 1, 0xFFFFFFF0);
+	write_sysreg(0xFFFFFFFF, pmintenset_el1);
+	isb();
+
+	mem_access_loop(addr, 200, pmu.pmcr_ro | PMU_PMCR_E);
+	for (i = 0; i < 100; i++) {
+		write_sysreg(0x3, pmswinc_el0);
+	}
+	mem_access_loop(addr, 200, pmu.pmcr_ro);
+	report_info("overflow=0x%lx", read_sysreg(pmovsclr_el0));
+	report("overflow interrupts expected on #0 and #1", expect_interrupts(0x3));
+
+	/* promote to 64-b */
+
+	pmu_reset_stats();
+
+	events[1] = 0x1E /* CHAIN */;
+        write_regn(pmevtyper, 1, events[1] | PMEVTYPER_EXCLUDE_EL0);
+	write_regn(pmevcntr, 0, 0xFFFFFFF0);
+	isb();
+	mem_access_loop(addr, 200, pmu.pmcr_ro | PMU_PMCR_E);
+	report("no overflow interrupt expected on 32b boundary", expect_interrupts(0));
+
+	/* overflow on odd counter */
+	pmu_reset_stats();
+	write_regn(pmevcntr, 0, 0xFFFFFFF0);
+	write_regn(pmevcntr, 1, 0xFFFFFFFF);
+	isb();
+	mem_access_loop(addr, 200, pmu.pmcr_ro | PMU_PMCR_E);
+	report("expect overflow interrupt on odd counter", expect_interrupts(0x2));
+}
 #endif
 
+
 /*
  * As a simple sanity check on the PMCR_EL0, ensure the implementer field isn't
  * null. Also print out a couple other interesting fields for diagnostic
@@ -896,6 +1024,9 @@ int main(int argc, char *argv[])
 	} else if (strcmp(argv[1], "chain-promotion") == 0) {
 		report_prefix_push(argv[1]);
 		test_chain_promotion();
+	} else if (strcmp(argv[1], "overflow-interrupt") == 0) {
+		report_prefix_push(argv[1]);
+		test_overflow_interrupt();
 	} else {
 		report_abort("Unknown subtest '%s'", argv[1]);
 	}
diff --git a/arm/unittests.cfg b/arm/unittests.cfg
index eb6e87e..31b4c7a 100644
--- a/arm/unittests.cfg
+++ b/arm/unittests.cfg
@@ -108,6 +108,12 @@ groups = pmu
 arch = arm64
 extra_params = -append 'chain-promotion'
 
+[pmu-chain-promotion]
+file = pmu.flat
+groups = pmu
+arch = arm64
+extra_params = -append 'overflow-interrupt'
+
 # Test PMU support (TCG) with -icount IPC=1
 #[pmu-tcg-icount-1]
 #file = pmu.flat
-- 
2.20.1