[kvm-unit-tests PATCH v4 3/4] arm: pmu: Reset the pmu registers before starting some tests

[Ricardo Koller <ricarkol@google.com>]

Some registers like the PMOVS reset to an architecturally UNKNOWN value.
Most tests expect them to be reset (mostly zeroed) using pmu_reset().
Add a pmu_reset() on all the tests that need one.

As a bonus, fix a couple of comments related to the register state
before a sub-test.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 arm/pmu.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arm/pmu.c b/arm/pmu.c
index a5260178..756e0d26 100644
--- a/arm/pmu.c
+++ b/arm/pmu.c
@@ -842,7 +842,7 @@ static void test_overflow_interrupt(void)
 	write_regn_el0(pmevcntr, 1, PRE_OVERFLOW);
 	isb();
 
-	/* interrupts are disabled */
+	/* interrupts are disabled (PMINTENSET_EL1 == 0) */
 
 	mem_access_loop(addr, 200, pmu.pmcr_ro | PMU_PMCR_E);
 	report(expect_interrupts(0), "no overflow interrupt after preset");
@@ -858,7 +858,7 @@ static void test_overflow_interrupt(void)
 	isb();
 	report(expect_interrupts(0), "no overflow interrupt after counting");
 
-	/* enable interrupts */
+	/* enable interrupts (PMINTENSET_EL1 <= ALL_SET) */
 
 	pmu_reset_stats();
 
@@ -906,6 +906,7 @@ static bool check_cycles_increase(void)
 	bool success = true;
 
 	/* init before event access, this test only cares about cycle count */
+	pmu_reset();
 	set_pmcntenset(1 << PMU_CYCLE_IDX);
 	set_pmccfiltr(0); /* count cycles in EL0, EL1, but not EL2 */
 
@@ -960,6 +961,7 @@ static bool check_cpi(int cpi)
 	uint32_t pmcr = get_pmcr() | PMU_PMCR_LC | PMU_PMCR_C | PMU_PMCR_E;
 
 	/* init before event access, this test only cares about cycle count */
+	pmu_reset();
 	set_pmcntenset(1 << PMU_CYCLE_IDX);
 	set_pmccfiltr(0); /* count cycles in EL0, EL1, but not EL2 */
 
-- 
2.37.1.559.g78731f0fdb-goog