[kvm-unit-tests PATCH v2 2/3] arm: pmu: Reset the pmu registers before starting some tests

From: Ricardo Koller <ricarkol@google.com>
To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
	andrew.jones@linux.dev
Cc: maz@kernel.org, alexandru.elisei@arm.com, eric.auger@redhat.com,
	oliver.upton@linux.dev, reijiw@google.com,
	Ricardo Koller <ricarkol@google.com>
Subject: [kvm-unit-tests PATCH v2 2/3] arm: pmu: Reset the pmu registers before starting some tests
Date: Wed,  3 Aug 2022 11:23:27 -0700	[thread overview]
Message-ID: <20220803182328.2438598-3-ricarkol@google.com> (raw)
In-Reply-To: <20220803182328.2438598-1-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.

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 76156f78..7c5bc259 100644
--- a/arm/pmu.c
+++ b/arm/pmu.c
@@ -826,7 +826,7 @@ 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");
@@ -841,7 +841,7 @@ 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();
 
@@ -889,6 +889,7 @@ 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 */
 
@@ -943,6 +944,7 @@ 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 */
 
-- 
2.37.1.455.g008518b4e5-goog

