Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
[qemu.git] / replay / replay-debugging.c
1 /*
2 * replay-debugging.c
3 *
4 * Copyright (c) 2010-2020 Institute for System Programming
5 * of the Russian Academy of Sciences.
6 *
7 * This work is licensed under the terms of the GNU GPL, version 2 or later.
8 * See the COPYING file in the top-level directory.
9 *
10 */
11
12 #include "qemu/osdep.h"
13 #include "qapi/error.h"
14 #include "sysemu/replay.h"
15 #include "sysemu/runstate.h"
16 #include "replay-internal.h"
17 #include "monitor/hmp.h"
18 #include "monitor/monitor.h"
19 #include "qapi/qapi-commands-replay.h"
20 #include "qapi/qmp/qdict.h"
21 #include "qemu/timer.h"
22 #include "block/snapshot.h"
23 #include "migration/snapshot.h"
24
25 static bool replay_is_debugging;
26 static int64_t replay_last_breakpoint;
27 static int64_t replay_last_snapshot;
28
29 bool replay_running_debug(void)
30 {
31 return replay_is_debugging;
32 }
33
34 void hmp_info_replay(Monitor *mon, const QDict *qdict)
35 {
36 if (replay_mode == REPLAY_MODE_NONE) {
37 monitor_printf(mon, "Record/replay is not active\n");
38 } else {
39 monitor_printf(mon,
40 "%s execution '%s': instruction count = %"PRId64"\n",
41 replay_mode == REPLAY_MODE_RECORD ? "Recording" : "Replaying",
42 replay_get_filename(), replay_get_current_icount());
43 }
44 }
45
46 ReplayInfo *qmp_query_replay(Error **errp)
47 {
48 ReplayInfo *retval = g_new0(ReplayInfo, 1);
49
50 retval->mode = replay_mode;
51 if (replay_get_filename()) {
52 retval->filename = g_strdup(replay_get_filename());
53 retval->has_filename = true;
54 }
55 retval->icount = replay_get_current_icount();
56 return retval;
57 }
58
59 static void replay_break(uint64_t icount, QEMUTimerCB callback, void *opaque)
60 {
61 assert(replay_mode == REPLAY_MODE_PLAY);
62 assert(replay_mutex_locked());
63 assert(replay_break_icount >= replay_get_current_icount());
64 assert(callback);
65
66 replay_break_icount = icount;
67
68 if (replay_break_timer) {
69 timer_del(replay_break_timer);
70 }
71 replay_break_timer = timer_new_ns(QEMU_CLOCK_REALTIME,
72 callback, opaque);
73 }
74
75 static void replay_delete_break(void)
76 {
77 assert(replay_mode == REPLAY_MODE_PLAY);
78 assert(replay_mutex_locked());
79
80 if (replay_break_timer) {
81 timer_free(replay_break_timer);
82 replay_break_timer = NULL;
83 }
84 replay_break_icount = -1ULL;
85 }
86
87 static void replay_stop_vm(void *opaque)
88 {
89 vm_stop(RUN_STATE_PAUSED);
90 replay_delete_break();
91 }
92
93 void qmp_replay_break(int64_t icount, Error **errp)
94 {
95 if (replay_mode == REPLAY_MODE_PLAY) {
96 if (icount >= replay_get_current_icount()) {
97 replay_break(icount, replay_stop_vm, NULL);
98 } else {
99 error_setg(errp,
100 "cannot set breakpoint at the instruction in the past");
101 }
102 } else {
103 error_setg(errp, "setting the breakpoint is allowed only in play mode");
104 }
105 }
106
107 void hmp_replay_break(Monitor *mon, const QDict *qdict)
108 {
109 int64_t icount = qdict_get_try_int(qdict, "icount", -1LL);
110 Error *err = NULL;
111
112 qmp_replay_break(icount, &err);
113 if (err) {
114 error_report_err(err);
115 return;
116 }
117 }
118
119 void qmp_replay_delete_break(Error **errp)
120 {
121 if (replay_mode == REPLAY_MODE_PLAY) {
122 replay_delete_break();
123 } else {
124 error_setg(errp, "replay breakpoints are allowed only in play mode");
125 }
126 }
127
128 void hmp_replay_delete_break(Monitor *mon, const QDict *qdict)
129 {
130 Error *err = NULL;
131
132 qmp_replay_delete_break(&err);
133 if (err) {
134 error_report_err(err);
135 return;
136 }
137 }
138
139 static char *replay_find_nearest_snapshot(int64_t icount,
140 int64_t *snapshot_icount)
141 {
142 BlockDriverState *bs;
143 QEMUSnapshotInfo *sn_tab;
144 QEMUSnapshotInfo *nearest = NULL;
145 char *ret = NULL;
146 int rv;
147 int nb_sns, i;
148 AioContext *aio_context;
149
150 *snapshot_icount = -1;
151
152 bs = bdrv_all_find_vmstate_bs(NULL, false, NULL, NULL);
153 if (!bs) {
154 goto fail;
155 }
156 aio_context = bdrv_get_aio_context(bs);
157
158 aio_context_acquire(aio_context);
159 nb_sns = bdrv_snapshot_list(bs, &sn_tab);
160 aio_context_release(aio_context);
161
162 for (i = 0; i < nb_sns; i++) {
163 rv = bdrv_all_has_snapshot(sn_tab[i].name, false, NULL, NULL);
164 if (rv < 0)
165 goto fail;
166 if (rv == 1) {
167 if (sn_tab[i].icount != -1ULL
168 && sn_tab[i].icount <= icount
169 && (!nearest || nearest->icount < sn_tab[i].icount)) {
170 nearest = &sn_tab[i];
171 }
172 }
173 }
174 if (nearest) {
175 ret = g_strdup(nearest->name);
176 *snapshot_icount = nearest->icount;
177 }
178 g_free(sn_tab);
179
180 fail:
181 return ret;
182 }
183
184 static void replay_seek(int64_t icount, QEMUTimerCB callback, Error **errp)
185 {
186 char *snapshot = NULL;
187 int64_t snapshot_icount;
188
189 if (replay_mode != REPLAY_MODE_PLAY) {
190 error_setg(errp, "replay must be enabled to seek");
191 return;
192 }
193
194 snapshot = replay_find_nearest_snapshot(icount, &snapshot_icount);
195 if (snapshot) {
196 if (icount < replay_get_current_icount()
197 || replay_get_current_icount() < snapshot_icount) {
198 vm_stop(RUN_STATE_RESTORE_VM);
199 load_snapshot(snapshot, NULL, false, NULL, errp);
200 }
201 g_free(snapshot);
202 }
203 if (replay_get_current_icount() <= icount) {
204 replay_break(icount, callback, NULL);
205 vm_start();
206 } else {
207 error_setg(errp, "cannot seek to the specified instruction count");
208 }
209 }
210
211 void qmp_replay_seek(int64_t icount, Error **errp)
212 {
213 replay_seek(icount, replay_stop_vm, errp);
214 }
215
216 void hmp_replay_seek(Monitor *mon, const QDict *qdict)
217 {
218 int64_t icount = qdict_get_try_int(qdict, "icount", -1LL);
219 Error *err = NULL;
220
221 qmp_replay_seek(icount, &err);
222 if (err) {
223 error_report_err(err);
224 return;
225 }
226 }
227
228 static void replay_stop_vm_debug(void *opaque)
229 {
230 replay_is_debugging = false;
231 vm_stop(RUN_STATE_DEBUG);
232 replay_delete_break();
233 }
234
235 bool replay_reverse_step(void)
236 {
237 Error *err = NULL;
238
239 assert(replay_mode == REPLAY_MODE_PLAY);
240
241 if (replay_get_current_icount() != 0) {
242 replay_seek(replay_get_current_icount() - 1,
243 replay_stop_vm_debug, &err);
244 if (err) {
245 error_free(err);
246 return false;
247 }
248 replay_is_debugging = true;
249 return true;
250 }
251
252 return false;
253 }
254
255 static void replay_continue_end(void)
256 {
257 replay_is_debugging = false;
258 vm_stop(RUN_STATE_DEBUG);
259 replay_delete_break();
260 }
261
262 static void replay_continue_stop(void *opaque)
263 {
264 Error *err = NULL;
265 if (replay_last_breakpoint != -1LL) {
266 replay_seek(replay_last_breakpoint, replay_stop_vm_debug, &err);
267 if (err) {
268 error_free(err);
269 replay_continue_end();
270 }
271 return;
272 }
273 /*
274 * No breakpoints since the last snapshot.
275 * Find previous snapshot and try again.
276 */
277 if (replay_last_snapshot != 0) {
278 replay_seek(replay_last_snapshot - 1, replay_continue_stop, &err);
279 if (err) {
280 error_free(err);
281 replay_continue_end();
282 }
283 replay_last_snapshot = replay_get_current_icount();
284 } else {
285 /* Seek to the very first step */
286 replay_seek(0, replay_stop_vm_debug, &err);
287 if (err) {
288 error_free(err);
289 replay_continue_end();
290 }
291 }
292 }
293
294 bool replay_reverse_continue(void)
295 {
296 Error *err = NULL;
297
298 assert(replay_mode == REPLAY_MODE_PLAY);
299
300 if (replay_get_current_icount() != 0) {
301 replay_seek(replay_get_current_icount() - 1,
302 replay_continue_stop, &err);
303 if (err) {
304 error_free(err);
305 return false;
306 }
307 replay_last_breakpoint = -1LL;
308 replay_is_debugging = true;
309 replay_last_snapshot = replay_get_current_icount();
310 return true;
311 }
312
313 return false;
314 }
315
316 void replay_breakpoint(void)
317 {
318 assert(replay_mode == REPLAY_MODE_PLAY);
319 replay_last_breakpoint = replay_get_current_icount();
320 }
321
322 void replay_gdb_attached(void)
323 {
324 /*
325 * Create VM snapshot on temporary overlay to allow reverse
326 * debugging even if snapshots were not enabled.
327 */
328 if (replay_mode == REPLAY_MODE_PLAY
329 && !replay_snapshot) {
330 if (!save_snapshot("start_debugging", true, NULL, false, NULL, NULL)) {
331 /* Can't create the snapshot. Continue conventional debugging. */
332 }
333 }
334 }