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

[Kan Liang <kan.liang@xxxxxxxxxxxxxxx>]

[ Upstream commit 47a973fd75639fe80d59f9e1860113bb2a0b112b ]

(The patch is not exactly the same as the upstream patch. Because in the
6.6 stable kernel, the umask2/eq enumeration is not supported. The
number of counters is used rather than the counter mask. But the change
is straightforward, which utilizes the structured union to replace the
macros when parsing the CPUID enumeration. It also fixed a wrong
macros.)

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
---
 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