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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 v2 1/9] perf/x86/intel: Remove anythread_deprecated bit from perf_capabilities
Date: Tue,  9 Jun 2026 13:02:14 +0800	[thread overview]
Message-ID: <20260609050222.2458129-2-dapeng1.mi@linux.intel.com> (raw)
In-Reply-To: <20260609050222.2458129-1-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>
Reviewed-by: Thomas Falcon <thomas.falcon@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


  reply	other threads:[~2026-06-09  5:07 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-09  5:02 [Patch v2 0/9] perf/x86: Miscellaneous PMU bug fixes Dapeng Mi
2026-06-09  5:02 ` Dapeng Mi [this message]
2026-06-09  5:02 ` [Patch v2 2/9] perf/x86: Introduce is_x86_pmu() helper Dapeng Mi
2026-06-09  5:02 ` [Patch v2 3/9] perf/x86: Update cap_user_rdpmc base on rdpmc user disable state Dapeng Mi
2026-06-09 14:48   ` Peter Zijlstra
2026-06-10  1:47     ` Mi, Dapeng
2026-06-09  5:02 ` [Patch v2 4/9] perf/x86/intel: Fallback to sw branch type decoding if no hw decoding Dapeng Mi
2026-06-09  5:24   ` sashiko-bot
2026-06-09 10:04     ` Mi, Dapeng
2026-06-09 14:49   ` Peter Zijlstra
2026-06-10  1:53     ` Mi, Dapeng
2026-06-09  5:02 ` [Patch v2 5/9] perf/x86/intel: Drop LBR entries whose privilege level mismatches br_sel Dapeng Mi
2026-06-09  5:21   ` sashiko-bot
2026-06-09  9:40     ` Mi, Dapeng
2026-06-09 14:52   ` Peter Zijlstra
2026-06-10  1:57     ` Mi, Dapeng
2026-06-09  5:02 ` [Patch v2 6/9] perf/x86/intel: Validate return value of intel_pmu_init_hybrid() Dapeng Mi
2026-06-09  5:25   ` sashiko-bot
2026-06-09  9:44     ` Mi, Dapeng
2026-06-10  8:16   ` Peter Zijlstra
2026-06-10  8:34     ` Mi, Dapeng
2026-06-09  5:02 ` [Patch v2 7/9] perf/x86/intel: Drop fixed-counter PEBS constraints for baseline PEBS Dapeng Mi
2026-06-10  8:20   ` Peter Zijlstra
2026-06-10  8:23     ` Peter Zijlstra
2026-06-10  8:50     ` Mi, Dapeng
2026-06-10 11:21       ` Peter Zijlstra
2026-06-10 11:42         ` Mi, Dapeng
2026-06-10 22:22           ` Peter Zijlstra
2026-06-09  5:02 ` [Patch v2 8/9] perf/core: Fix kernel register info leak via hardware skid Dapeng Mi
2026-06-10  9:16   ` Peter Zijlstra
2026-06-09  5:02 ` [Patch v2 9/9] perf/core: Check kernel access when kernel callchains are requested Dapeng Mi
2026-06-09  5:24   ` sashiko-bot
2026-06-09  9:49     ` Mi, Dapeng

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