[PATCH v9 09/12] perf/x86: Add INTEL_TD_METRIC_FIELD_{BITS,MASK} constants

[Zide Chen]

Replace the hard coded field width (8) and the equivalent 0xff mask
used for PERF_METRICS MSR field access with named constants
INTEL_TD_METRIC_FIELD_{BITS,MASK}.

INTEL_TD_METRIC_FIELD_BITS will be used by a subsequent KVM patch to
validat reserved bits in the PERF_METRICS MSR.

No functional change intended.

Signed-off-by: Zide Chen <zide.chen@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
v9: new patch.
---
 arch/x86/events/intel/core.c      | 8 +++++---
 arch/x86/include/asm/perf_event.h | 4 ++++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index cc13164d948f..cbc9a179f2e5 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3159,6 +3159,7 @@ DEFINE_STATIC_CALL(intel_pmu_set_topdown_event_period, x86_perf_event_set_period
 
 static inline u64 icl_get_metrics_event_value(u64 metric, u64 slots, int idx)
 {
+	int shift = (idx - INTEL_PMC_IDX_METRIC_BASE) * INTEL_TD_METRIC_FIELD_BITS;
 	u32 val;
 
 	/*
@@ -3166,8 +3167,8 @@ static inline u64 icl_get_metrics_event_value(u64 metric, u64 slots, int idx)
 	 * summing up to 0xff.
 	 * slots-in-metric = (Metric / 0xff) * slots
 	 */
-	val = (metric >> ((idx - INTEL_PMC_IDX_METRIC_BASE) * 8)) & 0xff;
-	return  mul_u64_u32_div(slots, val, 0xff);
+	val = (metric >> shift) & INTEL_TD_METRIC_FIELD_MASK;
+	return mul_u64_u32_div(slots, val, INTEL_TD_METRIC_FIELD_MASK);
 }
 
 static u64 icl_get_topdown_value(struct perf_event *event,
@@ -4742,7 +4743,8 @@ static int core_pmu_hw_config(struct perf_event *event)
 }
 
 #define INTEL_TD_METRIC_AVAILABLE_MAX	(INTEL_TD_METRIC_RETIRING + \
-					 ((x86_pmu.num_topdown_events - 1) << 8))
+					 ((x86_pmu.num_topdown_events - 1) << \
+					  INTEL_TD_METRIC_FIELD_BITS))
 
 static bool is_available_metric_event(struct perf_event *event)
 {
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 1eb13673e889..ceb6188e5217 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -418,6 +418,10 @@ static inline bool use_fixed_pseudo_encoding(u64 code)
 #define INTEL_TD_METRIC_MAX			INTEL_TD_METRIC_MEM_BOUND
 #define INTEL_TD_METRIC_NUM			8
 
+/* Width, in bits, of each metric's field within the PERF_METRICS MSR. */
+#define INTEL_TD_METRIC_FIELD_BITS		8
+#define INTEL_TD_METRIC_FIELD_MASK		GENMASK_ULL(INTEL_TD_METRIC_FIELD_BITS - 1, 0)
+
 #define INTEL_TD_CFG_METRIC_CLEAR_BIT		0
 #define INTEL_TD_CFG_METRIC_CLEAR		BIT_ULL(INTEL_TD_CFG_METRIC_CLEAR_BIT)
 
-- 
2.55.0