Pavel Dovgalyuk | e3b09ad | 2020-10-03 20:13:20 +0300 | [diff] [blame] | 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" |
Pavel Dovgalyuk | e751067 | 2020-10-03 20:13:26 +0300 | [diff] [blame] | 15 | #include "sysemu/runstate.h" |
Pavel Dovgalyuk | e3b09ad | 2020-10-03 20:13:20 +0300 | [diff] [blame] | 16 | #include "replay-internal.h" |
| 17 | #include "monitor/hmp.h" |
| 18 | #include "monitor/monitor.h" |
| 19 | #include "qapi/qapi-commands-replay.h" |
Pavel Dovgalyuk | e751067 | 2020-10-03 20:13:26 +0300 | [diff] [blame] | 20 | #include "qapi/qmp/qdict.h" |
| 21 | #include "qemu/timer.h" |
Pavel Dovgalyuk | f6baed3 | 2020-10-03 20:13:31 +0300 | [diff] [blame] | 22 | #include "block/snapshot.h" |
| 23 | #include "migration/snapshot.h" |
Pavel Dovgalyuk | e3b09ad | 2020-10-03 20:13:20 +0300 | [diff] [blame] | 24 | |
Pavel Dovgalyuk | fda8458 | 2020-10-03 20:13:43 +0300 | [diff] [blame] | 25 | static bool replay_is_debugging; |
Pavel Dovgalyuk | cda3825 | 2020-10-03 20:13:49 +0300 | [diff] [blame] | 26 | static int64_t replay_last_breakpoint; |
| 27 | static int64_t replay_last_snapshot; |
Pavel Dovgalyuk | fda8458 | 2020-10-03 20:13:43 +0300 | [diff] [blame] | 28 | |
| 29 | bool replay_running_debug(void) |
| 30 | { |
| 31 | return replay_is_debugging; |
| 32 | } |
| 33 | |
Pavel Dovgalyuk | e3b09ad | 2020-10-03 20:13:20 +0300 | [diff] [blame] | 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 | } |
Pavel Dovgalyuk | e751067 | 2020-10-03 20:13:26 +0300 | [diff] [blame] | 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) { |
Pavel Dovgalyuk | e751067 | 2020-10-03 20:13:26 +0300 | [diff] [blame] | 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 | } |
Pavel Dovgalyuk | f6baed3 | 2020-10-03 20:13:31 +0300 | [diff] [blame] | 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; |
Daniel P. Berrangé | 3d3e9b1 | 2021-02-04 12:48:28 +0000 | [diff] [blame] | 146 | int rv; |
Pavel Dovgalyuk | f6baed3 | 2020-10-03 20:13:31 +0300 | [diff] [blame] | 147 | int nb_sns, i; |
| 148 | AioContext *aio_context; |
| 149 | |
| 150 | *snapshot_icount = -1; |
| 151 | |
Daniel P. Berrangé | c22d644 | 2021-02-04 12:48:27 +0000 | [diff] [blame] | 152 | bs = bdrv_all_find_vmstate_bs(NULL, false, NULL, NULL); |
Pavel Dovgalyuk | f6baed3 | 2020-10-03 20:13:31 +0300 | [diff] [blame] | 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++) { |
Daniel P. Berrangé | 3d3e9b1 | 2021-02-04 12:48:28 +0000 | [diff] [blame] | 163 | rv = bdrv_all_has_snapshot(sn_tab[i].name, false, NULL, NULL); |
| 164 | if (rv < 0) |
| 165 | goto fail; |
| 166 | if (rv == 1) { |
Pavel Dovgalyuk | f6baed3 | 2020-10-03 20:13:31 +0300 | [diff] [blame] | 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); |
Daniel P. Berrangé | f1a9fcd | 2021-02-04 12:48:30 +0000 | [diff] [blame] | 199 | load_snapshot(snapshot, NULL, false, NULL, errp); |
Pavel Dovgalyuk | f6baed3 | 2020-10-03 20:13:31 +0300 | [diff] [blame] | 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 | } |
Pavel Dovgalyuk | fda8458 | 2020-10-03 20:13:43 +0300 | [diff] [blame] | 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 | } |
Pavel Dovgalyuk | cda3825 | 2020-10-03 20:13:49 +0300 | [diff] [blame] | 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(); |
Pavel Dovgalyuk | cda3825 | 2020-10-03 20:13:49 +0300 | [diff] [blame] | 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 | } |
Pavel Dovgalyuk | cda3825 | 2020-10-03 20:13:49 +0300 | [diff] [blame] | 291 | } |
Pavel Dovgalyuk | cda3825 | 2020-10-03 20:13:49 +0300 | [diff] [blame] | 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 | } |
Pavel Dovgalyuk | 56357d8 | 2020-10-03 20:14:01 +0300 | [diff] [blame] | 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) { |
Daniel P. Berrangé | f1a9fcd | 2021-02-04 12:48:30 +0000 | [diff] [blame] | 330 | if (!save_snapshot("start_debugging", true, NULL, false, NULL, NULL)) { |
Pavel Dovgalyuk | 56357d8 | 2020-10-03 20:14:01 +0300 | [diff] [blame] | 331 | /* Can't create the snapshot. Continue conventional debugging. */ |
| 332 | } |
| 333 | } |
| 334 | } |