From: Dapeng Mi <dapeng1.mi@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>,
Eranian Stephane <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Dapeng Mi <dapeng1.mi@intel.com>, Zide Chen <zide.chen@intel.com>,
Falcon Thomas <thomas.falcon@intel.com>,
Xudong Hao <xudong.hao@intel.com>,
Dapeng Mi <dapeng1.mi@linux.intel.com>,
stable@vger.kernel.org
Subject: [PATCH 1/8] perf/x86/intel: Remove anythread_deprecated bit from perf_capabilities
Date: Fri, 5 Jun 2026 09:11:29 +0800 [thread overview]
Message-ID: <20260605011136.2043393-2-dapeng1.mi@linux.intel.com> (raw)
In-Reply-To: <20260605011136.2043393-1-dapeng1.mi@linux.intel.com>
AnyThread mode deprecation is enumerated by CPUID.0AH:EDX[15] instead of
PERF_CAPABILITIES MSR. It's not a good practice to define a bit to
represent "anythread deprecation" in perf_capabilities. It leads to the
anythread_deprecated bit could be overwritten by the real value of
PERF_CAPABILITIES MSR, just like the below code in update_pmu_cap() does.
```
if (!intel_pmu_broken_perf_cap()) {
/* Perf Metric (Bit 15) and PEBS via PT (Bit 16) are hybrid enumeration */
rdmsrq(MSR_IA32_PERF_CAPABILITIES, hybrid(pmu, intel_cap).capabilities);
}
```
It leads to the anythread_deprecated bit is cleared to 0 and the "any"
attribute is incorrectly shown in the /sys/devices/cpu/format/ folder on
these support Perfmon v6 platforms, like Clearwater Forest.
```
$grep . /sys/devices/cpu/format/*
/sys/devices/cpu/format/acr_mask:config2:0-63
/sys/devices/cpu/format/any:config:21
/sys/devices/cpu/format/cmask:config:24-31
```
So remove the anythread_deprecated bit from perf_capabilities structure
and directly depends on CPUID.0AH:EDX[15] to judge if anythread is
deprecated.
Cc: stable@vger.kernel.org
Reported-by: Namhyung Kim <namhyung@kernel.org>
Fixes: cadbaa039b99 ("perf/x86/intel: Make anythread filter support conditional")
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Reviewed-by: Zide Chen <zide.chen@intel.com>
---
Original patch link:
https://lore.kernel.org/all/20260423053306.3033331-1-dapeng1.mi@linux.intel.com/
arch/x86/events/intel/core.c | 10 +++-------
arch/x86/events/perf_event.h | 2 +-
2 files changed, 4 insertions(+), 8 deletions(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 0217e701aeeb..ea3ab3050a3b 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -7946,12 +7946,6 @@ __init int intel_pmu_init(void)
x86_add_quirk(intel_arch_events_quirk); /* Install first, so it runs last */
- if (version >= 5) {
- x86_pmu.intel_cap.anythread_deprecated = edx.split.anythread_deprecated;
- if (x86_pmu.intel_cap.anythread_deprecated)
- pr_cont(" AnyThread deprecated, ");
- }
-
/* The perf side of core PMU is ready to support the mediated vPMU. */
x86_get_pmu(smp_processor_id())->capabilities |= PERF_PMU_CAP_MEDIATED_VPMU;
@@ -8828,8 +8822,10 @@ __init int intel_pmu_init(void)
&x86_pmu.intel_ctrl);
/* AnyThread may be deprecated on arch perfmon v5 or later */
- if (x86_pmu.intel_cap.anythread_deprecated)
+ if (version >= 5 && edx.split.anythread_deprecated) {
x86_pmu.format_attrs = intel_arch_formats_attr;
+ pr_cont("AnyThread deprecated, ");
+ }
intel_pmu_check_event_constraints_all(NULL);
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index eae24bb35dc1..5902a297daa1 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -668,7 +668,7 @@ union perf_capabilities {
u64 perf_metrics:1;
u64 pebs_output_pt_available:1;
u64 pebs_timing_info:1;
- u64 anythread_deprecated:1;
+ u64 __reserved:1;
u64 rdpmc_metrics_clear:1;
};
u64 capabilities;
--
2.34.1
next prev parent reply other threads:[~2026-06-05 1:16 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-05 1:11 [PATCH 0/8] perf/x86: Miscellaneous PMU bug fixes Dapeng Mi
2026-06-05 1:11 ` Dapeng Mi [this message]
2026-06-05 1:11 ` [PATCH 2/8] perf/x86: Introduce is_x86_pmu() helper Dapeng Mi
2026-06-05 1:11 ` [PATCH 3/8] perf/x86: Update cap_user_rdpmc base on rdpmc user disable state Dapeng Mi
2026-06-05 1:11 ` [PATCH 4/8] perf/x86/intel: Fix redundant branch type check in intel_pmu_lbr_filter() Dapeng Mi
2026-06-05 1:11 ` [PATCH 5/8] perf/x86/intel: Fix kernel address leakages in LBR stack Dapeng Mi
2026-06-05 1:33 ` sashiko-bot
2026-06-05 3:20 ` Mi, Dapeng
2026-06-05 1:11 ` [PATCH 6/8] perf/x86/intel: Validate return value of intel_pmu_init_hybrid() Dapeng Mi
2026-06-05 1:36 ` sashiko-bot
2026-06-05 3:29 ` Mi, Dapeng
2026-06-05 1:11 ` [PATCH 7/8] perf/x86/intel: Drop fixed-counter PEBS constraints for baseline PEBS Dapeng Mi
2026-06-05 1:11 ` [PATCH 8/8] perf/core: Fix kernel register info leak via hardware skid Dapeng Mi
2026-06-05 1:38 ` sashiko-bot
2026-06-05 3:42 ` Mi, Dapeng
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