From: Kan Liang kan.liang@linux.intel.com
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@linux.intel.com Cc: stable@vger.kernel.org --- arch/x86/events/intel/core.c | 18 ++++++++++-------- arch/x86/include/asm/perf_event.h | 28 +++++++++++++++++++++++++--- 2 files changed, 35 insertions(+), 11 deletions(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 0a1030eb6db8..120df9620951 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -4945,20 +4945,22 @@ static inline bool intel_pmu_broken_perf_cap(void)
static void update_pmu_cap(struct x86_hybrid_pmu *pmu) { - unsigned int sub_bitmaps, eax, ebx, ecx, edx; + unsigned int cntr, fixed_cntr, ecx, edx; + union cpuid35_eax eax; + union cpuid35_ebx ebx;
- cpuid(ARCH_PERFMON_EXT_LEAF, &sub_bitmaps, &ebx, &ecx, &edx); + cpuid(ARCH_PERFMON_EXT_LEAF, &eax.full, &ebx.full, &ecx, &edx);
- if (ebx & ARCH_PERFMON_EXT_UMASK2) + if (ebx.split.umask2) pmu->config_mask |= ARCH_PERFMON_EVENTSEL_UMASK2; - if (ebx & ARCH_PERFMON_EXT_EQ) + if (ebx.split.eq) pmu->config_mask |= ARCH_PERFMON_EVENTSEL_EQ;
- if (sub_bitmaps & ARCH_PERFMON_NUM_COUNTER_LEAF_BIT) { + if (eax.split.cntr_subleaf) { cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_NUM_COUNTER_LEAF, - &eax, &ebx, &ecx, &edx); - pmu->cntr_mask64 = eax; - pmu->fixed_cntr_mask64 = ebx; + &cntr, &fixed_cntr, &ecx, &edx); + pmu->cntr_mask64 = cntr; + pmu->fixed_cntr_mask64 = fixed_cntr; }
if (!intel_pmu_broken_perf_cap()) { diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index adaeb8ca3a8a..9aef5d044706 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -194,11 +194,33 @@ union cpuid10_edx { * detection/enumeration details: */ #define ARCH_PERFMON_EXT_LEAF 0x00000023 -#define ARCH_PERFMON_EXT_UMASK2 0x1 -#define ARCH_PERFMON_EXT_EQ 0x2 -#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: */
The following commit has been merged into the perf/urgent branch of tip:
Commit-ID: 47a973fd75639fe80d59f9e1860113bb2a0b112b Gitweb: https://git.kernel.org/tip/47a973fd75639fe80d59f9e1860113bb2a0b112b Author: Kan Liang kan.liang@linux.intel.com AuthorDate: Wed, 29 Jan 2025 07:48:19 -08:00 Committer: Peter Zijlstra peterz@infradead.org CommitterDate: Sat, 08 Feb 2025 15:47:25 +01:00
perf/x86/intel: Fix ARCH_PERFMON_NUM_COUNTER_LEAF
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@linux.intel.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20250129154820.3755948-3-kan.liang@linux.intel.com --- arch/x86/events/intel/core.c | 18 ++++++++++-------- arch/x86/include/asm/perf_event.h | 28 +++++++++++++++++++++++++--- 2 files changed, 35 insertions(+), 11 deletions(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 966f783..f3d5b71 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -4905,20 +4905,22 @@ static inline bool intel_pmu_broken_perf_cap(void)
static void update_pmu_cap(struct x86_hybrid_pmu *pmu) { - unsigned int sub_bitmaps, eax, ebx, ecx, edx; + unsigned int cntr, fixed_cntr, ecx, edx; + union cpuid35_eax eax; + union cpuid35_ebx ebx;
- cpuid(ARCH_PERFMON_EXT_LEAF, &sub_bitmaps, &ebx, &ecx, &edx); + cpuid(ARCH_PERFMON_EXT_LEAF, &eax.full, &ebx.full, &ecx, &edx);
- if (ebx & ARCH_PERFMON_EXT_UMASK2) + if (ebx.split.umask2) pmu->config_mask |= ARCH_PERFMON_EVENTSEL_UMASK2; - if (ebx & ARCH_PERFMON_EXT_EQ) + if (ebx.split.eq) pmu->config_mask |= ARCH_PERFMON_EVENTSEL_EQ;
- if (sub_bitmaps & ARCH_PERFMON_NUM_COUNTER_LEAF_BIT) { + if (eax.split.cntr_subleaf) { cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_NUM_COUNTER_LEAF, - &eax, &ebx, &ecx, &edx); - pmu->cntr_mask64 = eax; - pmu->fixed_cntr_mask64 = ebx; + &cntr, &fixed_cntr, &ecx, &edx); + pmu->cntr_mask64 = cntr; + pmu->fixed_cntr_mask64 = fixed_cntr; }
if (!intel_pmu_broken_perf_cap()) { diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index 1ac79f3..0ba8d20 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -188,11 +188,33 @@ union cpuid10_edx { * detection/enumeration details: */ #define ARCH_PERFMON_EXT_LEAF 0x00000023 -#define ARCH_PERFMON_EXT_UMASK2 0x1 -#define ARCH_PERFMON_EXT_EQ 0x2 -#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: */
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