[PATCH v7 13/19] KVM: selftests: Add functional test for Intel's fixed PMU counters

[Sean Christopherson <seanjc@google.com>]

From: Jinrong Liang <cloudliang@tencent.com>

Extend the fixed counters test to verify that supported counters can
actually be enabled in the control MSRs, that unsupported counters cannot,
and that enabled counters actually count.

Co-developed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
[sean: fold into the rd/wr access test, massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 31 ++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index 8c934e261f2d..b9c073d3ade9 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -324,7 +324,6 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters
 		vector = wrmsr_safe(msr, 0);
 		GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector);
 	}
-	GUEST_DONE();
 }
 
 static void guest_test_gp_counters(void)
@@ -342,6 +341,7 @@ static void guest_test_gp_counters(void)
 		base_msr = MSR_IA32_PERFCTR0;
 
 	guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters, 0);
+	GUEST_DONE();
 }
 
 static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities,
@@ -365,6 +365,7 @@ static void guest_test_fixed_counters(void)
 {
 	uint64_t supported_bitmask = 0;
 	uint8_t nr_fixed_counters = 0;
+	uint8_t i;
 
 	/* Fixed counters require Architectural vPMU Version 2+. */
 	if (guest_get_pmu_version() >= 2)
@@ -379,6 +380,34 @@ static void guest_test_fixed_counters(void)
 
 	guest_rd_wr_counters(MSR_CORE_PERF_FIXED_CTR0, MAX_NR_FIXED_COUNTERS,
 			     nr_fixed_counters, supported_bitmask);
+
+	for (i = 0; i < MAX_NR_FIXED_COUNTERS; i++) {
+		uint8_t vector;
+		uint64_t val;
+
+		if (i >= nr_fixed_counters && !(supported_bitmask & BIT_ULL(i))) {
+			vector = wrmsr_safe(MSR_CORE_PERF_FIXED_CTR_CTRL,
+					    FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
+			__GUEST_ASSERT(vector == GP_VECTOR,
+				       "Expected #GP for counter %u in FIXED_CTR_CTRL", i);
+
+			vector = wrmsr_safe(MSR_CORE_PERF_GLOBAL_CTRL,
+					    FIXED_PMC_GLOBAL_CTRL_ENABLE(i));
+			__GUEST_ASSERT(vector == GP_VECTOR,
+				       "Expected #GP for counter %u in PERF_GLOBAL_CTRL", i);
+			continue;
+		}
+
+		wrmsr(MSR_CORE_PERF_FIXED_CTR0 + i, 0);
+		wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, FIXED_PMC_GLOBAL_CTRL_ENABLE(i));
+		__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
+		val = rdmsr(MSR_CORE_PERF_FIXED_CTR0 + i);
+
+		GUEST_ASSERT_NE(val, 0);
+	}
+	GUEST_DONE();
 }
 
 static void test_fixed_counters(uint8_t pmu_version, uint64_t perf_capabilities,
-- 
2.42.0.869.gea05f2083d-goog