[PATCH v4 6/6] KVM: selftests: Test the PMU event "Instructions retired"

[Sean Christopherson]

From: Aaron Lewis <aaronlewis@xxxxxxxxxx>

Add testing for the event "Instructions retired" (0xc0) in the PMU
event filter on both Intel and AMD to ensure that the event doesn't
count when it is disallowed.  Unlike most of the other events, the
event "Instructions retired" will be incremented by KVM when an
instruction is emulated.  Test that this case is being properly handled
and that KVM doesn't increment the counter when that event is
disallowed.

Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230307141400.1486314-6-aaronlewis@xxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 .../kvm/x86_64/pmu_event_filter_test.c        | 34 +++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
index 5112aece3f95..40507ed9fe8a 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
@@ -54,6 +54,21 @@
 
 #define AMD_ZEN_BR_RETIRED EVENT(0xc2, 0)
 
+
+/*
+ * "Retired instructions", from Processor Programming Reference
+ * (PPR) for AMD Family 17h Model 01h, Revision B1 Processors,
+ * Preliminary Processor Programming Reference (PPR) for AMD Family
+ * 17h Model 31h, Revision B0 Processors, and Preliminary Processor
+ * Programming Reference (PPR) for AMD Family 19h Model 01h, Revision
+ * B1 Processors Volume 1 of 2.
+ *                      --- and ---
+ * "Instructions retired", from the Intel SDM, volume 3,
+ * "Pre-defined Architectural Performance Events."
+ */
+
+#define INST_RETIRED EVENT(0xc0, 0)
+
 /*
  * This event list comprises Intel's eight architectural events plus
  * AMD's "retired branch instructions" for Zen[123] (and possibly
@@ -61,7 +76,7 @@
  */
 static const uint64_t event_list[] = {
 	EVENT(0x3c, 0),
-	EVENT(0xc0, 0),
+	INST_RETIRED,
 	EVENT(0x3c, 1),
 	EVENT(0x2e, 0x4f),
 	EVENT(0x2e, 0x41),
@@ -76,6 +91,7 @@ struct {
 	uint64_t stores;
 	uint64_t loads_stores;
 	uint64_t branches_retired;
+	uint64_t instructions_retired;
 } pmc_results;
 
 /*
@@ -110,10 +126,12 @@ static void check_msr(uint32_t msr, uint64_t bits_to_flip)
 static void run_and_measure_loop(uint32_t msr_base)
 {
 	const uint64_t branches_retired = rdmsr(msr_base + 0);
+	const uint64_t insn_retired = rdmsr(msr_base + 1);
 
 	__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
 
 	pmc_results.branches_retired = rdmsr(msr_base + 0) - branches_retired;
+	pmc_results.instructions_retired = rdmsr(msr_base + 1) - insn_retired;
 }
 
 static void intel_guest_code(void)
@@ -127,7 +145,9 @@ static void intel_guest_code(void)
 		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
 		wrmsr(MSR_P6_EVNTSEL0, ARCH_PERFMON_EVENTSEL_ENABLE |
 		      ARCH_PERFMON_EVENTSEL_OS | INTEL_BR_RETIRED);
-		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0x1);
+		wrmsr(MSR_P6_EVNTSEL1, ARCH_PERFMON_EVENTSEL_ENABLE |
+		      ARCH_PERFMON_EVENTSEL_OS | INST_RETIRED);
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0x3);
 
 		run_and_measure_loop(MSR_IA32_PMC0);
 		GUEST_SYNC(0);
@@ -149,6 +169,8 @@ static void amd_guest_code(void)
 		wrmsr(MSR_K7_EVNTSEL0, 0);
 		wrmsr(MSR_K7_EVNTSEL0, ARCH_PERFMON_EVENTSEL_ENABLE |
 		      ARCH_PERFMON_EVENTSEL_OS | AMD_ZEN_BR_RETIRED);
+		wrmsr(MSR_K7_EVNTSEL1, ARCH_PERFMON_EVENTSEL_ENABLE |
+		      ARCH_PERFMON_EVENTSEL_OS | INST_RETIRED);
 
 		run_and_measure_loop(MSR_K7_PERFCTR0);
 		GUEST_SYNC(0);
@@ -263,20 +285,26 @@ static struct kvm_pmu_event_filter *remove_event(struct kvm_pmu_event_filter *f,
 #define ASSERT_PMC_COUNTING_INSTRUCTIONS()						\
 do {											\
 	uint64_t br = pmc_results.branches_retired;					\
+	uint64_t ir = pmc_results.instructions_retired;					\
 											\
 	if (br && br != NUM_BRANCHES)							\
 		pr_info("%s: Branch instructions retired = %lu (expected %u)\n",	\
 			__func__, br, NUM_BRANCHES);					\
 	TEST_ASSERT(br, "%s: Branch instructions retired = %lu (expected > 0)",		\
 		    __func__, br);							\
+	TEST_ASSERT(ir,	"%s: Instructions retired = %lu (expected > 0)",		\
+		    __func__, ir);							\
 } while (0)
 
 #define ASSERT_PMC_NOT_COUNTING_INSTRUCTIONS()						\
 do {											\
 	uint64_t br = pmc_results.branches_retired;					\
+	uint64_t ir = pmc_results.instructions_retired;					\
 											\
 	TEST_ASSERT(!br, "%s: Branch instructions retired = %lu (expected 0)",		\
 		    __func__, br);							\
+	TEST_ASSERT(!ir, "%s: Instructions retired = %lu (expected 0)",			\
+		    __func__, ir);							\
 } while (0)
 
 static void test_without_filter(struct kvm_vcpu *vcpu)
@@ -329,6 +357,7 @@ static void test_not_member_deny_list(struct kvm_vcpu *vcpu)
 {
 	struct kvm_pmu_event_filter *f = event_filter(KVM_PMU_EVENT_DENY);
 
+	remove_event(f, INST_RETIRED);
 	remove_event(f, INTEL_BR_RETIRED);
 	remove_event(f, AMD_ZEN_BR_RETIRED);
 	test_with_filter(vcpu, f);
@@ -341,6 +370,7 @@ static void test_not_member_allow_list(struct kvm_vcpu *vcpu)
 {
 	struct kvm_pmu_event_filter *f = event_filter(KVM_PMU_EVENT_ALLOW);
 
+	remove_event(f, INST_RETIRED);
 	remove_event(f, INTEL_BR_RETIRED);
 	remove_event(f, AMD_ZEN_BR_RETIRED);
 	test_with_filter(vcpu, f);
-- 
2.40.0.577.gac1e443424-goog