[PATCH v10 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_vcpu0-4874    [007] .....    94.757349: mtk_hypcall_enter: id=0xfb001005
crosvm_vcpu0-4874    [007] .....    94.760902: mtk_hypcall_leave: id=0xfb001005 invalid=0
crosvm_vcpu0-4874    [007] .....    94.760902: mtk_vcpu_exit: vcpu exit_reason=IRQ(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          |  4 ++
 drivers/virt/geniezone/gzvm_vcpu.c |  5 +-
 include/trace/events/geniezone.h   | 84 ++++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+), 2 deletions(-)
 create mode 100644 include/trace/events/geniezone.h

diff --git a/arch/arm64/geniezone/vm.c b/arch/arm64/geniezone/vm.c
index a477546c5a1a..c00142f2e942 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/soc/mediatek/gzvm_drv.h>
 #include "gzvm_arch_common.h"
@@ -44,11 +46,13 @@ int gzvm_hypcall_wrapper(unsigned long a0, unsigned long a1,
 		.a6 = a6,
 		.a7 = a7,
 	};
+	trace_mtk_hypcall_enter(a0);
 	arm_smccc_1_2_hvc(&args, &res_1_2);
 	res->a0 = res_1_2.a0;
 	res->a1 = res_1_2.a1;
 	res->a2 = res_1_2.a2;
 	res->a3 = res_1_2.a3;
+	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 e135d9388090..28bd690e4b7c 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/soc/mediatek/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:
@@ -141,11 +144,9 @@ static long gzvm_vcpu_run(struct gzvm_vcpu *vcpu, void __user *argp)
 		default:
 			pr_err("vcpu unknown exit\n");
 			need_userspace = true;
-			goto out;
 		}
 	}
 
-out:
 	if (copy_to_user(argp, vcpu->run, sizeof(struct gzvm_vcpu_run)))
 		return -EFAULT;
 	if (signal_pending(current)) {
diff --git a/include/trace/events/geniezone.h b/include/trace/events/geniezone.h
new file mode 100644
index 000000000000..4fffd826ba67
--- /dev/null
+++ b/include/trace/events/geniezone.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM geniezone
+
+#define _TRACE_GENIEZONE_H
+
+#include <linux/gzvm.h>
+#include <linux/tracepoint.h>
+
+#define GZVM_EXIT_REASONS \
+EM(UNKNOWN)\
+EM(MMIO)\
+EM(HYPERCALL)\
+EM(IRQ)\
+EM(EXCEPTION)\
+EM(DEBUG)\
+EM(FAIL_ENTRY)\
+EM(INTERNAL_ERROR)\
+EM(SYSTEM_EVENT)\
+EM(SHUTDOWN)\
+EMe(GZ)
+
+#undef EM
+#undef EMe
+#define EM(a) TRACE_DEFINE_ENUM(GZVM_EXIT_##a);
+#define EMe(a) TRACE_DEFINE_ENUM(GZVM_EXIT_##a);
+
+GZVM_EXIT_REASONS
+
+#undef EM
+#undef EMe
+
+#define EM(a)       { GZVM_EXIT_##a, #a },
+#define EMe(a)      { GZVM_EXIT_##a, #a }
+
+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=%s(0x%lx)",
+		      __print_symbolic(__entry->exit_reason, GZVM_EXIT_REASONS),
+		      __entry->exit_reason)
+
+);
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.18.0