[PATCH] iommu/arm-smmu-v3: Add tracepoint for EVTQ events

[PATCH] iommu/arm-smmu-v3: Add tracepoint for EVTQ events

[Chen Jun]

Events reported by the SMMU can severely impact accelerator
performance. Currently, only events that the SMMU fails to handle are
printed to the kernel log, leaving most events invisible to users.
To analyze and optimize accelerator performance, complete visibility
into all SMMU-reported events is required.

Add a tracepoint in the EVTQ interrupt handler to capture every
event record reported by the SMMU. This allows users to collect all
event information via ftrace/perf for further analysis, complementing
the existing event decoder and error dump which only cover a subset
of events.

Signed-off-by: Chen Jun <chenjun102@huawei.com>
---
 drivers/iommu/arm/arm-smmu-v3/Makefile      |  2 +-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c |  3 ++
 drivers/iommu/arm/arm-smmu-v3/trace.c       |  9 ++++
 drivers/iommu/arm/arm-smmu-v3/trace.h       | 53 +++++++++++++++++++++
 4 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 drivers/iommu/arm/arm-smmu-v3/trace.c
 create mode 100644 drivers/iommu/arm/arm-smmu-v3/trace.h

diff --git a/drivers/iommu/arm/arm-smmu-v3/Makefile b/drivers/iommu/arm/arm-smmu-v3/Makefile
index 493a659cc66b..63a8d71bfc93 100644
--- a/drivers/iommu/arm/arm-smmu-v3/Makefile
+++ b/drivers/iommu/arm/arm-smmu-v3/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_ARM_SMMU_V3) += arm_smmu_v3.o
-arm_smmu_v3-y := arm-smmu-v3.o
+arm_smmu_v3-y := arm-smmu-v3.o trace.o
 arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_IOMMUFD) += arm-smmu-v3-iommufd.o
 arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_SVA) += arm-smmu-v3-sva.o
 arm_smmu_v3-$(CONFIG_TEGRA241_CMDQV) += tegra241-cmdqv.o
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index e8d7dbe495f0..85e6c25b73ed 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -34,6 +34,8 @@
 #include "arm-smmu-v3.h"
 #include "../../dma-iommu.h"
 
+#include "trace.h"
+
 static bool disable_msipolling;
 module_param(disable_msipolling, bool, 0444);
 MODULE_PARM_DESC(disable_msipolling,
@@ -2271,6 +2273,7 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
 
 	do {
 		while (!queue_remove_raw(q, evt)) {
+			trace_smmu_evtq_event(smmu, evt);
 			arm_smmu_decode_event(smmu, evt, &event);
 			if (arm_smmu_handle_event(smmu, evt, &event))
 				arm_smmu_dump_event(smmu, evt, &event, &rs);
diff --git a/drivers/iommu/arm/arm-smmu-v3/trace.c b/drivers/iommu/arm/arm-smmu-v3/trace.c
new file mode 100644
index 000000000000..77378698b1a3
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/trace.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ARM SMMUv3 trace support
+ *
+ * Copyright (c) 2026 OpenCloudOS / openEuler
+ */
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
diff --git a/drivers/iommu/arm/arm-smmu-v3/trace.h b/drivers/iommu/arm/arm-smmu-v3/trace.h
new file mode 100644
index 000000000000..7cec8d41745e
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/trace.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * ARM SMMUv3 trace support
+ *
+ * Copyright (c) 2026 OpenCloudOS / openEuler
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM arm_smmu_v3
+
+#if !defined(_TRACE_ARM_SMMU_V3_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_ARM_SMMU_V3_H
+
+#include <linux/tracepoint.h>
+
+#include "arm-smmu-v3.h"
+
+TRACE_EVENT(smmu_evtq_event,
+
+	TP_PROTO(struct arm_smmu_device *smmu, u64 *evt),
+
+	TP_ARGS(smmu, evt),
+
+	TP_STRUCT__entry(
+		__string(iommu, dev_name(smmu->dev))
+		__field(u64, evt0)
+		__field(u64, evt1)
+		__field(u64, evt2)
+		__field(u64, evt3)
+	),
+
+	TP_fast_assign(
+		__assign_str(iommu);
+		__entry->evt0 = evt[0];
+		__entry->evt1 = evt[1];
+		__entry->evt2 = evt[2];
+		__entry->evt3 = evt[3];
+	),
+
+	TP_printk("%s evt: 0x%016llx 0x%016llx 0x%016llx 0x%016llx",
+		__get_str(iommu),
+		__entry->evt0, __entry->evt1,
+		__entry->evt2, __entry->evt3)
+);
+
+#endif /* _TRACE_ARM_SMMU_V3_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_PATH ../../drivers/iommu/arm/arm-smmu-v3/
+#define TRACE_INCLUDE_FILE trace
+#include <trace/define_trace.h>
-- 
2.22.0