[PATCH 6.6.y] perf/x86/intel: Fix ARCH_PERFMON_NUM_COUNTER_LEAF

[Kan Liang <kan.liang@xxxxxxxxxxxxxxx>]

The EAX of the CPUID Leaf 023H enumerates the mask of valid sub-leaves.
To tell the availability of the sub-leaf 1 (enumerate the counter mask),
perf should check the bit 1 (0x2) of EAS, rather than bit 0 (0x1).

The error is not user-visible on bare metal. Because the sub-leaf 0 and
the sub-leaf 1 are always available. However, it may bring issues in a
virtualization environment when a VMM only enumerates the sub-leaf 0.

Introduce the cpuid35_e?x to replace the macros, which makes the
implementation style consistent.

Fixes: eb467aaac21e ("perf/x86/intel: Support Architectural PerfMon Extension leaf")
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20250129154820.3755948-3-kan.liang@xxxxxxxxxxxxxxx
---
 arch/x86/events/intel/core.c      | 17 ++++++++++-------
 arch/x86/include/asm/perf_event.h | 26 +++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 37c8badd2701..52f2ca214617 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -4643,16 +4643,19 @@ static void intel_pmu_check_num_counters(int *num_counters,
 
 static void update_pmu_cap(struct x86_hybrid_pmu *pmu)
 {
-	unsigned int sub_bitmaps = cpuid_eax(ARCH_PERFMON_EXT_LEAF);
-	unsigned int eax, ebx, ecx, edx;
+	unsigned int cntr, fixed_cntr, ecx, edx;
+	union cpuid35_eax eax;
+	union cpuid35_ebx ebx;
 
-	if (sub_bitmaps & ARCH_PERFMON_NUM_COUNTER_LEAF_BIT) {
+	cpuid(ARCH_PERFMON_EXT_LEAF, &eax.full, &ebx.full, &ecx, &edx);
+
+	if (eax.split.cntr_subleaf) {
 		cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_NUM_COUNTER_LEAF,
-			    &eax, &ebx, &ecx, &edx);
-		pmu->num_counters = fls(eax);
-		pmu->num_counters_fixed = fls(ebx);
+			    &cntr, &fixed_cntr, &ecx, &edx);
+		pmu->num_counters = fls(cntr);
+		pmu->num_counters_fixed = fls(fixed_cntr);
 		intel_pmu_check_num_counters(&pmu->num_counters, &pmu->num_counters_fixed,
-					     &pmu->intel_ctrl, ebx);
+					     &pmu->intel_ctrl, fixed_cntr);
 	}
 }
 
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 85a9fd5a3ec3..384e8a7db482 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -177,9 +177,33 @@ union cpuid10_edx {
  * detection/enumeration details:
  */
 #define ARCH_PERFMON_EXT_LEAF			0x00000023
-#define ARCH_PERFMON_NUM_COUNTER_LEAF_BIT	0x1
 #define ARCH_PERFMON_NUM_COUNTER_LEAF		0x1
 
+union cpuid35_eax {
+	struct {
+		unsigned int	leaf0:1;
+		/* Counters Sub-Leaf */
+		unsigned int    cntr_subleaf:1;
+		/* Auto Counter Reload Sub-Leaf */
+		unsigned int    acr_subleaf:1;
+		/* Events Sub-Leaf */
+		unsigned int    events_subleaf:1;
+		unsigned int	reserved:28;
+	} split;
+	unsigned int            full;
+};
+
+union cpuid35_ebx {
+	struct {
+		/* UnitMask2 Supported */
+		unsigned int    umask2:1;
+		/* EQ-bit Supported */
+		unsigned int    eq:1;
+		unsigned int	reserved:30;
+	} split;
+	unsigned int            full;
+};
+
 /*
  * Intel Architectural LBR CPUID detection/enumeration details:
  */
-- 
2.38.1