[PATCH RFC v4 3/4] RISC-V: paravirt: pvqspinlock: Add trace point for pv_kick/wait

[GUO Ren (XuanTie)]

Add tracepoints for pv_kick and pv_wait to observe the paravirt
qspinlock behavior:

  # cd /sys/kernel/debug/tracing
  # echo 1 > events/paravirt/enable
  # cat trace
  TASK-PID   CPU#  |||||  TIMESTAMP  FUNCTION
     | |       |   |||||     |         |
    sh-100   [001] d..2.  28.312294: pv_wait: cpu 1 out of wfi
  <idle>-0   [000] d.h4.  28.322030: pv_kick: cpu 0 kick target cpu 1

Reviewed-by: Leonardo Bras <leobras at redhat.com>
Signed-off-by: GUO Ren (XuanTie) <guoren at kernel.org>
---
 arch/riscv/kernel/qspinlock_paravirt.c           |  7 +++
 arch/riscv/kernel/trace_events_filter_paravirt.h | 58 ++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/arch/riscv/kernel/qspinlock_paravirt.c b/arch/riscv/kernel/qspinlock_paravirt.c
index c534447437fe..04b13994e971 100644
--- a/arch/riscv/kernel/qspinlock_paravirt.c
+++ b/arch/riscv/kernel/qspinlock_paravirt.c
@@ -7,8 +7,13 @@
 #include <asm/qspinlock_paravirt.h>
 #include <asm/sbi.h>
 
+#define CREATE_TRACE_POINTS
+#include "trace_events_filter_paravirt.h"
+
 void pv_kick(int cpu)
 {
+	trace_pv_kick(smp_processor_id(), cpu);
+
 	sbi_ecall(SBI_EXT_PVLOCK, SBI_EXT_PVLOCK_KICK_CPU,
 		  cpuid_to_hartid_map(cpu), 0, 0, 0, 0, 0);
 }
@@ -25,6 +30,8 @@ void pv_wait(u8 *ptr, u8 val)
 		goto out;
 
 	wait_for_interrupt();
+
+	trace_pv_wait(smp_processor_id());
 out:
 	local_irq_restore(flags);
 }
diff --git a/arch/riscv/kernel/trace_events_filter_paravirt.h b/arch/riscv/kernel/trace_events_filter_paravirt.h
new file mode 100644
index 000000000000..8d57efda2c17
--- /dev/null
+++ b/arch/riscv/kernel/trace_events_filter_paravirt.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2026 GUO Ren (XuanTie) <guoren at kernel.org>
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM paravirt
+
+#if !defined(_TRACE_PARAVIRT_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PARAVIRT_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(pv_kick,
+	TP_PROTO(int cpu, int target),
+	TP_ARGS(cpu, target),
+
+	TP_STRUCT__entry(
+		__field(int, cpu)
+		__field(int, target)
+	),
+
+	TP_fast_assign(
+		__entry->cpu = cpu;
+		__entry->target = target;
+	),
+
+	TP_printk("cpu %d pv_kick target cpu %d",
+		__entry->cpu,
+		__entry->target
+	)
+);
+
+TRACE_EVENT(pv_wait,
+	TP_PROTO(int cpu),
+	TP_ARGS(cpu),
+
+	TP_STRUCT__entry(
+		__field(int, cpu)
+	),
+
+	TP_fast_assign(
+		__entry->cpu = cpu;
+	),
+
+	TP_printk("cpu %d out of wfi",
+		__entry->cpu
+	)
+);
+
+#endif /* _TRACE_PARAVIRT_H || TRACE_HEADER_MULTI_READ */
+
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_PATH ../../../arch/riscv/kernel/
+#define TRACE_INCLUDE_FILE trace_events_filter_paravirt
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

-- 
2.43.0