perf/x86/intel: Avoid disable PMU if !cpuc->enabled in sample read

The WARN_ON(this_cpu_read(cpu_hw_events.enabled)) in the
intel_pmu_save_and_restart_reload() is triggered, when sampling read
topdown events.

In a NMI handler, the cpu_hw_events.enabled is set and used to indicate
the status of core PMU. The generic pmu->pmu_disable_count, updated in
the perf_pmu_disable/enable pair, is not touched.
However, the perf_pmu_disable/enable pair is invoked when sampling read
in a NMI handler. The cpuc->enabled is mistakenly set by the
perf_pmu_enable().

Avoid disabling PMU if the core PMU is already disabled.
Merge the logic together.

Fixes: 7b2c05a15d29 ("perf/x86/intel: Generic support for hardware TopDown metrics")
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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/20250121152303.3128733-2-kan.liang@linux.intel.com

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 2acea83526c635421a7c59505178c6d714e99b45..1ccc961f818210bfe13720fb5f876e5c9078e642 100644 (file)
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2785,28 +2785,33 @@ static u64 icl_update_topdown_event(struct perf_event *event)
 
 DEFINE_STATIC_CALL(intel_pmu_update_topdown_event, x86_perf_event_update);
 
-static void intel_pmu_read_topdown_event(struct perf_event *event)
+static void intel_pmu_read_event(struct perf_event *event)
 {
-       struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+       if (event->hw.flags & (PERF_X86_EVENT_AUTO_RELOAD | PERF_X86_EVENT_TOPDOWN)) {
+               struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+               bool pmu_enabled = cpuc->enabled;
 
-       /* Only need to call update_topdown_event() once for group read. */
-       if ((cpuc->txn_flags & PERF_PMU_TXN_READ) &&
-           !is_slots_event(event))
-               return;
+               /* Only need to call update_topdown_event() once for group read. */
+               if (is_metric_event(event) && (cpuc->txn_flags & PERF_PMU_TXN_READ))
+                       return;
 
-       perf_pmu_disable(event->pmu);
-       static_call(intel_pmu_update_topdown_event)(event);
-       perf_pmu_enable(event->pmu);
-}
+               cpuc->enabled = 0;
+               if (pmu_enabled)
+                       intel_pmu_disable_all();
 
-static void intel_pmu_read_event(struct perf_event *event)
-{
-       if (event->hw.flags & PERF_X86_EVENT_AUTO_RELOAD)
-               intel_pmu_auto_reload_read(event);
-       else if (is_topdown_count(event))
-               intel_pmu_read_topdown_event(event);
-       else
-               x86_perf_event_update(event);
+               if (is_topdown_event(event))
+                       static_call(intel_pmu_update_topdown_event)(event);
+               else
+                       intel_pmu_drain_pebs_buffer();
+
+               cpuc->enabled = pmu_enabled;
+               if (pmu_enabled)
+                       intel_pmu_enable_all(0);
+
+               return;
+       }
+
+       x86_perf_event_update(event);
 }
 
 static void intel_pmu_enable_fixed(struct perf_event *event)

diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 322963b02a91262b5dc65f2f28442ca0b0e4ae4f..eb14b46423e58fe21566ae86f1f3458deb63a39f 100644 (file)
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -953,7 +953,7 @@ unlock:
        return 1;
 }
 
-static inline void intel_pmu_drain_pebs_buffer(void)
+void intel_pmu_drain_pebs_buffer(void)
 {
        struct perf_sample_data data;
 
@@ -2094,15 +2094,6 @@ get_next_pebs_record_by_bit(void *base, void *top, int bit)
        return NULL;
 }
 
-void intel_pmu_auto_reload_read(struct perf_event *event)
-{
-       WARN_ON(!(event->hw.flags & PERF_X86_EVENT_AUTO_RELOAD));
-
-       perf_pmu_disable(event->pmu);
-       intel_pmu_drain_pebs_buffer();
-       perf_pmu_enable(event->pmu);
-}
-
 /*
  * Special variant of intel_pmu_save_and_restart() for auto-reload.
  */

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 084e9196b45828abf8ab11c89361bbbc397df14a..536a112f6353edda048b8d57adebc7ce5d4422f6 100644 (file)
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -1644,7 +1644,7 @@ void intel_pmu_pebs_disable_all(void);
 
 void intel_pmu_pebs_sched_task(struct perf_event_pmu_context *pmu_ctx, bool sched_in);
 
-void intel_pmu_auto_reload_read(struct perf_event *event);
+void intel_pmu_drain_pebs_buffer(void);
 
 void intel_pmu_store_pebs_lbrs(struct lbr_entry *lbr);