1/*
2 * Interface for configuring and controlling the state of tracing events.
3 *
4 * Copyright (C) 2014-2017 Lluís Vilanova <vilanova@ac.upc.edu>
5 *
6 * This work is licensed under the terms of the GNU GPL, version 2 or later.
7 * See the COPYING file in the top-level directory.
8 */
9
10#include "qemu/osdep.h"
11#include "cpu.h"
12#include "trace-root.h"
13#include "trace/control.h"
14
15
16void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
17{
18 bool state_pre;
19 assert(trace_event_get_state_static(ev));
20 /*
21 * We ignore the "vcpu" property here, since no vCPUs have been created
22 * yet. Then dstate can only be 1 or 0.
23 */
24 state_pre = *ev->dstate;
25 if (state_pre != state) {
26 if (state) {
27 trace_events_enabled_count++;
28 *ev->dstate = 1;
29 } else {
30 trace_events_enabled_count--;
31 *ev->dstate = 0;
32 }
33 }
34}
35
36void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
37{
38 CPUState *vcpu;
39 assert(trace_event_get_state_static(ev));
40 if (trace_event_is_vcpu(ev) && likely(first_cpu != NULL)) {
41 CPU_FOREACH(vcpu) {
42 trace_event_set_vcpu_state_dynamic(vcpu, ev, state);
43 }
44 } else {
45 /*
46 * Without the "vcpu" property, dstate can only be 1 or 0. With it, we
47 * haven't instantiated any vCPU yet, so we will set a global state
48 * instead, and trace_init_vcpu will reconcile it afterwards.
49 */
50 bool state_pre = *ev->dstate;
51 if (state_pre != state) {
52 if (state) {
53 trace_events_enabled_count++;
54 *ev->dstate = 1;
55 } else {
56 trace_events_enabled_count--;
57 *ev->dstate = 0;
58 }
59 }
60 }
61}
62
63static void trace_event_synchronize_vcpu_state_dynamic(
64 CPUState *vcpu, run_on_cpu_data ignored)
65{
66 bitmap_copy(vcpu->trace_dstate, vcpu->trace_dstate_delayed,
67 CPU_TRACE_DSTATE_MAX_EVENTS);
68 cpu_tb_jmp_cache_clear(vcpu);
69}
70
71void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
72 TraceEvent *ev, bool state)
73{
74 uint32_t vcpu_id;
75 bool state_pre;
76 assert(trace_event_get_state_static(ev));
77 assert(trace_event_is_vcpu(ev));
78 vcpu_id = trace_event_get_vcpu_id(ev);
79 state_pre = test_bit(vcpu_id, vcpu->trace_dstate);
80 if (state_pre != state) {
81 if (state) {
82 trace_events_enabled_count++;
83 set_bit(vcpu_id, vcpu->trace_dstate_delayed);
84 (*ev->dstate)++;
85 } else {
86 trace_events_enabled_count--;
87 clear_bit(vcpu_id, vcpu->trace_dstate_delayed);
88 (*ev->dstate)--;
89 }
90 if (vcpu->created) {
91 /*
92 * Delay changes until next TB; we want all TBs to be built from a
93 * single set of dstate values to ensure consistency of generated
94 * tracing code.
95 */
96 async_run_on_cpu(vcpu, trace_event_synchronize_vcpu_state_dynamic,
97 RUN_ON_CPU_NULL);
98 } else {
99 trace_event_synchronize_vcpu_state_dynamic(vcpu, RUN_ON_CPU_NULL);
100 }
101 }
102}
103
104static bool adding_first_cpu1(void)
105{
106 CPUState *cpu;
107 size_t count = 0;
108 CPU_FOREACH(cpu) {
109 count++;
110 if (count > 1) {
111 return false;
112 }
113 }
114 return true;
115}
116
117static bool adding_first_cpu(void)
118{
119 bool res;
120 cpu_list_lock();
121 res = adding_first_cpu1();
122 cpu_list_unlock();
123 return res;
124}
125
126void trace_init_vcpu(CPUState *vcpu)
127{
128 TraceEventIter iter;
129 TraceEvent *ev;
130 trace_event_iter_init(&iter, NULL);
131 while ((ev = trace_event_iter_next(&iter)) != NULL) {
132 if (trace_event_is_vcpu(ev) &&
133 trace_event_get_state_static(ev) &&
134 trace_event_get_state_dynamic(ev)) {
135 if (adding_first_cpu()) {
136 /* check preconditions */
137 assert(*ev->dstate == 1);
138 /* disable early-init state ... */
139 *ev->dstate = 0;
140 trace_events_enabled_count--;
141 /* ... and properly re-enable */
142 trace_event_set_vcpu_state_dynamic(vcpu, ev, true);
143 } else {
144 trace_event_set_vcpu_state_dynamic(vcpu, ev, true);
145 }
146 }
147 }
148 trace_guest_cpu_enter(vcpu);
149}
150