The Linux Kernel Mailing List
 help / color / mirror / Atom feed
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>
Subject: [PATCH 6/7] perf/x86/intel: Fix intel_cap handling on hybrid PMUs
Date: Fri, 10 Jul 2026 14:51:27 +0800	[thread overview]
Message-ID: <20260710065128.1799838-7-dapeng1.mi@linux.intel.com> (raw)
In-Reply-To: <20260710065128.1799838-1-dapeng1.mi@linux.intel.com>

intel_cap (IA32_PERF_CAPABILITIES) updates are currently tied to
X86_FEATURE_ARCH_PERFMON_EXT, but these are independent feature paths.
As a result, hybrid PMU capability state can be updated under the wrong
condition.

Also, intel_pmu_broken_perf_cap() is too narrow. Per RPL018, the missing
PERF_METRICS_AVAILABLE bit affects both Raptor Lake and Meteor Lake
parts, not only the currently covered subset.

Move intel_cap updates out of the ARCH_PERFMON_EXT-gated path, extend
intel_pmu_broken_perf_cap() coverage to both RPL and MTL families, and
introduce intel_update_pmu_caps() to centralize PMU capability updates.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
 arch/x86/events/intel/core.c | 41 ++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 83c60ad00085..36de21484ada 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -6147,8 +6147,15 @@ static void intel_pmu_check_extra_regs(struct extra_reg *extra_regs);
 
 static inline bool intel_pmu_broken_perf_cap(void)
 {
-	/* The Perf Metric (Bit 15) is always cleared */
-	if (boot_cpu_data.x86_vfm == INTEL_METEORLAKE ||
+	/*
+	 * The Perf Metric (Bit 15) is always cleared on P-core of
+	 * PRL and MTL. Details can be found in RPL018 Errata Details.
+	 * https://edc.intel.com/content/www/us/en/design/products/platforms/details/raptor-lake-s/13th-generation-core-processor-specification-update/errata-details/
+	 */
+	if (boot_cpu_data.x86_vfm == INTEL_RAPTORLAKE ||
+	    boot_cpu_data.x86_vfm == INTEL_RAPTORLAKE_P ||
+	    boot_cpu_data.x86_vfm == INTEL_RAPTORLAKE_S ||
+	    boot_cpu_data.x86_vfm == INTEL_METEORLAKE ||
 	    boot_cpu_data.x86_vfm == INTEL_METEORLAKE_L)
 		return true;
 
@@ -6183,7 +6190,7 @@ static inline void __intel_update_large_pebs_flags(struct pmu *pmu)
 
 #define counter_mask(_gp, _fixed) ((_gp) | ((u64)(_fixed) << INTEL_PMC_IDX_FIXED))
 
-static void update_pmu_cap(struct pmu *pmu)
+static void update_pmu_cap_from_perfmonext(struct pmu *pmu)
 {
 	unsigned int eax, ebx, ecx, edx;
 	union cpuid35_eax eax_0;
@@ -6241,10 +6248,24 @@ static void update_pmu_cap(struct pmu *pmu)
 		WARN_ON(x86_pmu.arch_pebs == 1);
 		x86_pmu.arch_pebs = 0;
 	}
+}
+
+static void intel_update_pmu_caps(struct pmu *pmu)
+{
+	if (this_cpu_has(X86_FEATURE_ARCH_PERFMON_EXT))
+		update_pmu_cap_from_perfmonext(pmu);
 
-	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);
+	if (is_hybrid() && this_cpu_has(X86_FEATURE_PDCM)) {
+		rdmsrq(MSR_IA32_PERF_CAPABILITIES,
+		       hybrid(pmu, intel_cap).capabilities);
+
+		/*
+		 * Restore perf_metrics on platforms with broken
+		 * perf_capablities.
+		 */
+		if (intel_pmu_broken_perf_cap() &&
+		    hybrid_pmu(pmu)->pmu_type == hybrid_big)
+			hybrid(pmu, intel_cap).perf_metrics = 1;
 	}
 }
 
@@ -6329,9 +6350,7 @@ static bool init_hybrid_pmu(int cpu)
 	if (!cpumask_empty(&pmu->supported_cpus))
 		goto end;
 
-	if (this_cpu_has(X86_FEATURE_ARCH_PERFMON_EXT))
-		update_pmu_cap(&pmu->pmu);
-
+	intel_update_pmu_caps(&pmu->pmu);
 	intel_pmu_check_hybrid_pmus(pmu);
 
 	if (!check_hw_exists(pmu->cntr_mask, pmu->fixed_cntr_mask)) {
@@ -8827,8 +8846,8 @@ __init int intel_pmu_init(void)
 	 * from the leaf 0xa. The core specific update will be done later
 	 * when a new type is online.
 	 */
-	if (!is_hybrid() && boot_cpu_has(X86_FEATURE_ARCH_PERFMON_EXT))
-		update_pmu_cap(NULL);
+	if (!is_hybrid())
+		intel_update_pmu_caps(NULL);
 
 	if (x86_pmu.arch_pebs) {
 		static_call_update(intel_pmu_disable_event_ext,
-- 
2.34.1


  parent reply	other threads:[~2026-07-10  6:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-10  6:51 [PATCH 0/7] perf/x86: Miscellaneous PMU bug fixes and optimizations Dapeng Mi
2026-07-10  6:51 ` [PATCH 1/7] perf/x86: Unregister PMI handler on PMU init failure Dapeng Mi
2026-07-10  6:51 ` [PATCH 2/7] perf/x86: Free hybrid state " Dapeng Mi
2026-07-10  6:51 ` [PATCH 3/7] perf/x86/intel: Clear cpuc->pmu on hybrid " Dapeng Mi
2026-07-10  8:20   ` Mi, Dapeng
2026-07-10  6:51 ` [PATCH 4/7] perf/x86/intel: Unwind cpuc state if PEBS buffer setup fails Dapeng Mi
2026-07-10  6:51 ` [PATCH 5/7] perf/x86: Remove stale fixed counter helper and fix hybrid PMU access Dapeng Mi
2026-07-10  6:51 ` Dapeng Mi [this message]
2026-07-10  6:51 ` [PATCH 7/7] perf/x86: Optimize ACR handling in match_prev_assignment() Dapeng Mi

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260710065128.1799838-7-dapeng1.mi@linux.intel.com \
    --to=dapeng1.mi@linux.intel.com \
    --cc=acme@kernel.org \
    --cc=adrian.hunter@intel.com \
    --cc=ak@linux.intel.com \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=dapeng1.mi@intel.com \
    --cc=eranian@google.com \
    --cc=irogers@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-perf-users@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=namhyung@kernel.org \
    --cc=peterz@infradead.org \
    --cc=thomas.falcon@intel.com \
    --cc=xudong.hao@intel.com \
    --cc=zide.chen@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox