jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
1/*
2 * Interface for configuring and controlling the state of tracing events.
3 *
4 * Copyright (C) 2011-2016 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 "trace/control.h"
12#include "qemu/help_option.h"
13#include "qemu/option.h"
14#ifdef CONFIG_TRACE_SIMPLE
15#include "trace/simple.h"
16#endif
17#ifdef CONFIG_TRACE_FTRACE
18#include "trace/ftrace.h"
19#endif
20#ifdef CONFIG_TRACE_LOG
21#include "qemu/log.h"
22#endif
23#ifdef CONFIG_TRACE_SYSLOG
24#include <syslog.h>
25#endif
26#include "qapi/error.h"
27#include "qemu/error-report.h"
28#include "qemu/config-file.h"
29#include "monitor/monitor.h"
30#include "trace-root.h"
31
32int trace_events_enabled_count;
33
34typedef struct TraceEventGroup {
35 TraceEvent **events;
36} TraceEventGroup;
37
38static TraceEventGroup *event_groups;
39static size_t nevent_groups;
40static uint32_t next_id;
41static uint32_t next_vcpu_id;
42
43QemuOptsList qemu_trace_opts = {
44 .name = "trace",
45 .implied_opt_name = "enable",
46 .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
47 .desc = {
48 {
49 .name = "enable",
50 .type = QEMU_OPT_STRING,
51 },
52 {
53 .name = "events",
54 .type = QEMU_OPT_STRING,
55 },{
56 .name = "file",
57 .type = QEMU_OPT_STRING,
58 },
59 { /* end of list */ }
60 },
61};
62
63
64void trace_event_register_group(TraceEvent **events)
65{
66 size_t i;
67 for (i = 0; events[i] != NULL; i++) {
68 events[i]->id = next_id++;
69 if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
70 continue;
71 }
72
73 if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
74 events[i]->vcpu_id = next_vcpu_id++;
75 } else {
76 warn_report("too many vcpu trace events; dropping '%s'",
77 events[i]->name);
78 }
79 }
80 event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
81 event_groups[nevent_groups].events = events;
82 nevent_groups++;
83}
84
85
86TraceEvent *trace_event_name(const char *name)
87{
88 assert(name != NULL);
89
90 TraceEventIter iter;
91 TraceEvent *ev;
92 trace_event_iter_init(&iter, NULL);
93 while ((ev = trace_event_iter_next(&iter)) != NULL) {
94 if (strcmp(trace_event_get_name(ev), name) == 0) {
95 return ev;
96 }
97 }
98 return NULL;
99}
100
101void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
102{
103 iter->event = 0;
104 iter->group = 0;
105 iter->pattern = pattern;
106}
107
108TraceEvent *trace_event_iter_next(TraceEventIter *iter)
109{
110 while (iter->group < nevent_groups &&
111 event_groups[iter->group].events[iter->event] != NULL) {
112 TraceEvent *ev = event_groups[iter->group].events[iter->event];
113 iter->event++;
114 if (event_groups[iter->group].events[iter->event] == NULL) {
115 iter->event = 0;
116 iter->group++;
117 }
118 if (!iter->pattern ||
119 g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) {
120 return ev;
121 }
122 }
123
124 return NULL;
125}
126
127void trace_list_events(void)
128{
129 TraceEventIter iter;
130 TraceEvent *ev;
131 trace_event_iter_init(&iter, NULL);
132 while ((ev = trace_event_iter_next(&iter)) != NULL) {
133 fprintf(stderr, "%s\n", trace_event_get_name(ev));
134 }
135#ifdef CONFIG_TRACE_DTRACE
136 fprintf(stderr, "This list of names of trace points may be incomplete "
137 "when using the DTrace/SystemTap backends.\n"
138 "Run 'qemu-trace-stap list %s' to print the full list.\n",
139 error_get_progname());
140#endif
141}
142
143static void do_trace_enable_events(const char *line_buf)
144{
145 const bool enable = ('-' != line_buf[0]);
146 const char *line_ptr = enable ? line_buf : line_buf + 1;
147 TraceEventIter iter;
148 TraceEvent *ev;
149 bool is_pattern = trace_event_is_pattern(line_ptr);
150
151 trace_event_iter_init(&iter, line_ptr);
152 while ((ev = trace_event_iter_next(&iter)) != NULL) {
153 if (!trace_event_get_state_static(ev)) {
154 if (!is_pattern) {
155 warn_report("trace event '%s' is not traceable",
156 line_ptr);
157 return;
158 }
159 continue;
160 }
161
162 /* start tracing */
163 trace_event_set_state_dynamic(ev, enable);
164 if (!is_pattern) {
165 return;
166 }
167 }
168
169 if (!is_pattern) {
170 warn_report("trace event '%s' does not exist",
171 line_ptr);
172 }
173}
174
175void trace_enable_events(const char *line_buf)
176{
177 if (is_help_option(line_buf)) {
178 trace_list_events();
179 if (cur_mon == NULL) {
180 exit(0);
181 }
182 } else {
183 do_trace_enable_events(line_buf);
184 }
185}
186
187static void trace_init_events(const char *fname)
188{
189 Location loc;
190 FILE *fp;
191 char line_buf[1024];
192 size_t line_idx = 0;
193
194 if (fname == NULL) {
195 return;
196 }
197
198 loc_push_none(&loc);
199 loc_set_file(fname, 0);
200 fp = fopen(fname, "r");
201 if (!fp) {
202 error_report("%s", strerror(errno));
203 exit(1);
204 }
205 while (fgets(line_buf, sizeof(line_buf), fp)) {
206 loc_set_file(fname, ++line_idx);
207 size_t len = strlen(line_buf);
208 if (len > 1) { /* skip empty lines */
209 line_buf[len - 1] = '\0';
210 if ('#' == line_buf[0]) { /* skip commented lines */
211 continue;
212 }
213 trace_enable_events(line_buf);
214 }
215 }
216 if (fclose(fp) != 0) {
217 loc_set_file(fname, 0);
218 error_report("%s", strerror(errno));
219 exit(1);
220 }
221 loc_pop(&loc);
222}
223
224void trace_init_file(const char *file)
225{
226#ifdef CONFIG_TRACE_SIMPLE
227 st_set_trace_file(file);
228#elif defined CONFIG_TRACE_LOG
229 /*
230 * If both the simple and the log backends are enabled, "--trace file"
231 * only applies to the simple backend; use "-D" for the log
232 * backend. However we should only override -D if we actually have
233 * something to override it with.
234 */
235 if (file) {
236 qemu_set_log_filename(file, &error_fatal);
237 }
238#else
239 if (file) {
240 fprintf(stderr, "error: --trace file=...: "
241 "option not supported by the selected tracing backends\n");
242 exit(1);
243 }
244#endif
245}
246
247void trace_fini_vcpu(CPUState *vcpu)
248{
249 TraceEventIter iter;
250 TraceEvent *ev;
251
252 trace_guest_cpu_exit(vcpu);
253
254 trace_event_iter_init(&iter, NULL);
255 while ((ev = trace_event_iter_next(&iter)) != NULL) {
256 if (trace_event_is_vcpu(ev) &&
257 trace_event_get_state_static(ev) &&
258 trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
259 /* must disable to affect the global counter */
260 trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
261 }
262 }
263}
264
265bool trace_init_backends(void)
266{
267#ifdef CONFIG_TRACE_SIMPLE
268 if (!st_init()) {
269 fprintf(stderr, "failed to initialize simple tracing backend.\n");
270 return false;
271 }
272#endif
273
274#ifdef CONFIG_TRACE_FTRACE
275 if (!ftrace_init()) {
276 fprintf(stderr, "failed to initialize ftrace backend.\n");
277 return false;
278 }
279#endif
280
281#ifdef CONFIG_TRACE_SYSLOG
282 openlog(NULL, LOG_PID, LOG_DAEMON);
283#endif
284
285 return true;
286}
287
288char *trace_opt_parse(const char *optarg)
289{
290 char *trace_file;
291 QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
292 optarg, true);
293 if (!opts) {
294 exit(1);
295 }
296 if (qemu_opt_get(opts, "enable")) {
297 trace_enable_events(qemu_opt_get(opts, "enable"));
298 }
299 trace_init_events(qemu_opt_get(opts, "events"));
300 trace_file = g_strdup(qemu_opt_get(opts, "file"));
301 qemu_opts_del(opts);
302
303 return trace_file;
304}
305
306uint32_t trace_get_vcpu_event_count(void)
307{
308 return next_vcpu_id;
309}