@@ -96,6 +96,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___tracing_update_clock,
 	__KVM_HOST_SMCCC_FUNC___tracing_reset,
 	__KVM_HOST_SMCCC_FUNC___tracing_enable_event,
+	__KVM_HOST_SMCCC_FUNC___tracing_write_event,
 };
 
 #define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]

@@ -46,4 +46,15 @@ HYP_EVENT(hyp_exit,
 	),
 	HE_PRINTK("reason=%s vcpu=%d", __hyp_enter_exit_reason_str(__entry->reason), __entry->vcpu)
 );
+
+HYP_EVENT(selftest,
+	HE_PROTO(u64 id),
+	HE_STRUCT(
+		he_field(u64, id)
+	),
+	HE_ASSIGN(
+		__entry->id = id;
+	),
+	RE_PRINTK("id=%llu", __entry->id)
+);
 #endif

@@ -643,6 +643,13 @@ static void handle___tracing_enable_event(struct kvm_cpu_context *host_ctxt)
 	cpu_reg(host_ctxt, 1) = __tracing_enable_event(id, enable);
 }
 
+static void handle___tracing_write_event(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(u64, id, host_ctxt, 1);
+
+	trace_selftest(id);
+}
+
 typedef void (*hcall_t)(struct kvm_cpu_context *);
 
 #define HANDLE_FUNC(x)	[__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x

@@ -691,6 +698,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__tracing_update_clock),
 	HANDLE_FUNC(__tracing_reset),
 	HANDLE_FUNC(__tracing_enable_event),
+	HANDLE_FUNC(__tracing_write_event),
 };
 
 static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)

@@ -348,8 +348,30 @@ static int hyp_trace_clock_show(struct seq_file *m, void *v)
 }
 DEFINE_SHOW_ATTRIBUTE(hyp_trace_clock);
 
+static ssize_t hyp_trace_write_event_write(struct file *f, const char __user *ubuf,
+					   size_t cnt, loff_t *pos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	kvm_call_hyp_nvhe(__tracing_write_event, val);
+
+	return cnt;
+}
+
+static const struct file_operations hyp_trace_write_event_fops = {
+	.write	= hyp_trace_write_event_write,
+};
+
 static int hyp_trace_init_tracefs(struct dentry *d, void *priv)
 {
+	if (!tracefs_create_file("write_event", 0200, d, NULL, &hyp_trace_write_event_fops))
+		return -ENOMEM;
+
 	return tracefs_create_file("trace_clock", 0440, d, NULL, &hyp_trace_clock_fops) ?
 		0 : -ENOMEM;
 }