[PATCH v9 20/21] virt: geniezone: Add tracing support for hyp call and vcpu exit_reason

[Yi-De Wu]

Add tracepoints for hypervisor calls and VCPU exit reasons in GenieZone
driver. It aids performance debugging by providing more information
about hypervisor operations and VCPU behavior.

Command Usage:
echo geniezone:* >> /sys/kernel/tracing/set_event
echo 1 > /sys/kernel/tracing/tracing_on
echo 0 > /sys/kernel/tracing/tracing_on
cat /sys/kernel/tracing/trace

For example:
crosvm_vcpu0-4838 [004] ..... 76053.536034: mtk_hypcall_enter: id=0xbb001005
crosvm_vcpu0-4838 [004] ..... 76053.540039: mtk_hypcall_leave: id=0xbb001005 invalid=0
crosvm_vcpu0-4838 [004] ..... 76053.540040: mtk_vcpu_exit: vcpu exit_reason=0x92920003

This example tracks a hypervisor function call by an ID (`0xbb001005`)
from initiation to termination, which is supported (invalid=0). A vCPU
exit is triggered by an Interrupt Request (IRQ) (exit reason: 0x92920003).

/* VM exit reason */
enum {
	GZVM_EXIT_UNKNOWN = 0x92920000,
	GZVM_EXIT_MMIO = 0x92920001,
	GZVM_EXIT_HYPERCALL = 0x92920002,
	GZVM_EXIT_IRQ = 0x92920003,
	GZVM_EXIT_EXCEPTION = 0x92920004,
	GZVM_EXIT_DEBUG = 0x92920005,
	GZVM_EXIT_FAIL_ENTRY = 0x92920006,
	GZVM_EXIT_INTERNAL_ERROR = 0x92920007,
	GZVM_EXIT_SYSTEM_EVENT = 0x92920008,
	GZVM_EXIT_SHUTDOWN = 0x92920009,
	GZVM_EXIT_GZ = 0x9292000a,
};

Signed-off-by: Liju-clr Chen <liju-clr.chen@xxxxxxxxxxxx>
Signed-off-by: Yi-De Wu <yi-de.wu@xxxxxxxxxxxx>
---
 arch/arm64/geniezone/vm.c          |  5 +++
 drivers/virt/geniezone/gzvm_vcpu.c |  3 ++
 include/trace/events/geniezone.h   | 54 ++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+)
 create mode 100644 include/trace/events/geniezone.h

diff --git a/arch/arm64/geniezone/vm.c b/arch/arm64/geniezone/vm.c
index 571326e70d98..8bec85bf9879 100644
--- a/arch/arm64/geniezone/vm.c
+++ b/arch/arm64/geniezone/vm.c
@@ -7,6 +7,8 @@
 #include <linux/err.h>
 #include <linux/uaccess.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/geniezone.h>
 #include <linux/gzvm.h>
 #include <linux/gzvm_drv.h>
 #include "gzvm_arch_common.h"
@@ -33,7 +35,10 @@ int gzvm_hypcall_wrapper(unsigned long a0, unsigned long a1,
 			 unsigned long a6, unsigned long a7,
 			 struct arm_smccc_res *res)
 {
+	trace_mtk_hypcall_enter(a0);
 	arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res);
+	trace_mtk_hypcall_leave(a0, (res->a0 != ERR_NOT_SUPPORTED) ? 0 : 1);
+
 	return gzvm_err_to_errno(res->a0);
 }
 
diff --git a/drivers/virt/geniezone/gzvm_vcpu.c b/drivers/virt/geniezone/gzvm_vcpu.c
index 86c690749277..138ec064596b 100644
--- a/drivers/virt/geniezone/gzvm_vcpu.c
+++ b/drivers/virt/geniezone/gzvm_vcpu.c
@@ -10,6 +10,8 @@
 #include <linux/mm.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+
+#include <trace/events/geniezone.h>
 #include <linux/gzvm_drv.h>
 
 /* maximum size needed for holding an integer */
@@ -103,6 +105,7 @@ static long gzvm_vcpu_run(struct gzvm_vcpu *vcpu, void __user *argp)
 
 	while (!need_userspace && !signal_pending(current)) {
 		gzvm_arch_vcpu_run(vcpu, &exit_reason);
+		trace_mtk_vcpu_exit(exit_reason);
 
 		switch (exit_reason) {
 		case GZVM_EXIT_MMIO:
diff --git a/include/trace/events/geniezone.h b/include/trace/events/geniezone.h
new file mode 100644
index 000000000000..1fa44f9c4b3c
--- /dev/null
+++ b/include/trace/events/geniezone.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM geniezone
+
+#define _TRACE_GENIEZONE_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(mtk_hypcall_enter,
+	    TP_PROTO(unsigned long id),
+
+	    TP_ARGS(id),
+
+	    TP_STRUCT__entry(__field(unsigned long, id)),
+
+	    TP_fast_assign(__entry->id = id;),
+
+	    TP_printk("id=0x%lx", __entry->id)
+);
+
+TRACE_EVENT(mtk_hypcall_leave,
+	    TP_PROTO(unsigned long id, unsigned long invalid),
+
+	    TP_ARGS(id, invalid),
+
+	    TP_STRUCT__entry(__field(unsigned long, id)
+			     __field(unsigned long, invalid)
+	    ),
+
+	    TP_fast_assign(__entry->id = id;
+			   __entry->invalid = invalid;
+	    ),
+
+	    TP_printk("id=0x%lx invalid=%lu", __entry->id, __entry->invalid)
+);
+
+TRACE_EVENT(mtk_vcpu_exit,
+	    TP_PROTO(unsigned long exit_reason),
+
+	    TP_ARGS(exit_reason),
+
+	    TP_STRUCT__entry(__field(unsigned long, exit_reason)),
+
+	    TP_fast_assign(__entry->exit_reason = exit_reason;),
+
+	    TP_printk("vcpu exit_reason=0x%lx", __entry->exit_reason)
+);
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.18.0