linux-kernel - [PATCH 4/6] KVM: x86: selftests: Test read/write core counters

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Message-ID: <20240813164244.751597-5-coltonlewis@google.com>
Date: Tue, 13 Aug 2024 16:42:42 +0000
From: Colton Lewis <coltonlewis@...gle.com>
To: kvm@...r.kernel.org
Cc: Mingwei Zhang <mizhang@...gle.com>, Jinrong Liang <ljr.kernel@...il.com>, 
	Jim Mattson <jmattson@...gle.com>, Aaron Lewis <aaronlewis@...gle.com>, 
	Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, Shuah Khan <shuah@...nel.org>, 
	linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Colton Lewis <coltonlewis@...gle.com>
Subject: [PATCH 4/6] KVM: x86: selftests: Test read/write core counters

Run a basic test to ensure we can write an arbitrary value to the core
counters and read it back.

Signed-off-by: Colton Lewis <coltonlewis@...gle.com>
---
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)

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 a11df073331a..9620fc33d26e 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -324,6 +324,7 @@ static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities,
  */
 #define MAX_NR_GP_COUNTERS	8
 #define MAX_NR_FIXED_COUNTERS	3
+#define MAX_NR_CORE_COUNTERS	6
 
 #define GUEST_ASSERT_PMC_MSR_ACCESS(insn, msr, expect_gp, vector)		\
 __GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector,			\
@@ -644,8 +645,48 @@ static uint8_t nr_core_counters(void)
 	return amd_nr_core_counters;
 }
 
+static void guest_test_rdwr_core_counters(void)
+{
+	bool core_ext = this_cpu_has(X86_FEATURE_PERF_CTR_EXT_CORE);
+	uint8_t nr_counters = this_cpu_property(X86_PROPERTY_NUM_PERF_CTR_CORE);
+	uint8_t i;
+	uint32_t esel_msr_base = core_ext ? MSR_F15H_PERF_CTL : MSR_K7_EVNTSEL0;
+	uint32_t cnt_msr_base = core_ext ? MSR_F15H_PERF_CTR : MSR_K7_PERFCTR0;
+	uint32_t msr_step = core_ext ? 2 : 1;
+
+	for (i = 0; i < MAX_NR_CORE_COUNTERS; i++) {
+		uint64_t test_val = 0xffff;
+		uint32_t esel_msr = esel_msr_base + msr_step * i;
+		uint32_t cnt_msr = cnt_msr_base + msr_step * i;
+		bool expect_gp = !(i < nr_counters);
+		uint8_t vector;
+		uint64_t val;
+
+		/* Test event selection register. */
+		vector = wrmsr_safe(esel_msr, test_val);
+		GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, esel_msr, expect_gp, vector);
+
+		vector = rdmsr_safe(esel_msr, &val);
+		GUEST_ASSERT_PMC_MSR_ACCESS(RDMSR, esel_msr, expect_gp, vector);
+
+		if (!expect_gp)
+			GUEST_ASSERT_PMC_VALUE(RDMSR, esel_msr, val, test_val);
+
+		/* Test counter register. */
+		vector = wrmsr_safe(cnt_msr, test_val);
+		GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, cnt_msr, expect_gp, vector);
+
+		vector = rdmsr_safe(cnt_msr, &val);
+		GUEST_ASSERT_PMC_MSR_ACCESS(RDMSR, cnt_msr, expect_gp, vector);
+
+		if (!expect_gp)
+			GUEST_ASSERT_PMC_VALUE(RDMSR, cnt_msr, val, test_val);
+	}
+}
+
 static void guest_test_core_counters(void)
 {
+	guest_test_rdwr_core_counters();
 	GUEST_DONE();
 }
 
-- 
2.46.0.76.ge559c4bf1a-goog