[kvm-unit-tests PATCH v4 17/24] x86/pmu: Add GP/Fixed counters reset helpers

[Like Xu <like.xu.linux@xxxxxxxxx>]

From: Like Xu <likexu@xxxxxxxxxxx>

In generic pmu testing, it is very common to initialize the test env by
resetting counters registers. Add these helpers to for code reusability.

Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
 lib/x86/pmu.c |  1 +
 lib/x86/pmu.h | 38 ++++++++++++++++++++++++++++++++++++++
 x86/pmu.c     |  2 +-
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/lib/x86/pmu.c b/lib/x86/pmu.c
index c0d100d..0ce1691 100644
--- a/lib/x86/pmu.c
+++ b/lib/x86/pmu.c
@@ -10,4 +10,5 @@ void pmu_init(void)
         pmu.perf_cap = rdmsr(MSR_IA32_PERF_CAPABILITIES);
     pmu.msr_gp_counter_base = MSR_IA32_PERFCTR0;
     pmu.msr_gp_event_select_base = MSR_P6_EVNTSEL0;
+    reset_all_counters();
 }
\ No newline at end of file
diff --git a/lib/x86/pmu.h b/lib/x86/pmu.h
index 7487a30..564b672 100644
--- a/lib/x86/pmu.h
+++ b/lib/x86/pmu.h
@@ -156,4 +156,42 @@ static inline bool pmu_use_full_writes(void)
 	return gp_counter_base() == MSR_IA32_PMC0;
 }
 
+static inline u32 fixed_counter_msr(unsigned int i)
+{
+	return MSR_CORE_PERF_FIXED_CTR0 + i;
+}
+
+static inline void write_fixed_counter_value(unsigned int i, u64 value)
+{
+	wrmsr(fixed_counter_msr(i), value);
+}
+
+static inline void reset_all_gp_counters(void)
+{
+	unsigned int idx;
+
+	for (idx = 0; idx < pmu_nr_gp_counters(); idx++) {
+		write_gp_event_select(idx, 0);
+		write_gp_counter_value(idx, 0);
+	}
+}
+
+static inline void reset_all_fixed_counters(void)
+{
+    unsigned int idx;
+
+	if (!pmu_nr_fixed_counters())
+		return;
+
+	wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, 0);
+	for (idx = 0; idx < pmu_nr_fixed_counters(); idx++)
+		write_fixed_counter_value(idx, 0);
+}
+
+static inline void reset_all_counters(void)
+{
+    reset_all_gp_counters();
+    reset_all_fixed_counters();
+}
+
 #endif /* _X86_PMU_H_ */
diff --git a/x86/pmu.c b/x86/pmu.c
index 589c7cb..7786b49 100644
--- a/x86/pmu.c
+++ b/x86/pmu.c
@@ -397,7 +397,7 @@ static void check_rdpmc(void)
 			.idx = i
 		};
 
-		wrmsr(MSR_CORE_PERF_FIXED_CTR0 + i, x);
+		write_fixed_counter_value(i, x);
 		report(rdpmc(i | (1 << 30)) == x, "fixed cntr-%d", i);
 
 		exc = test_for_exception(GP_VECTOR, do_rdpmc_fast, &cnt);
-- 
2.38.1