replay/replay.c

   1 /*
   2  * replay.c
   3  *
   4  * Copyright (c) 2010-2015 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 "qemu-common.h"
  15 #include "sysemu/replay.h"
  16 #include "replay-internal.h"
  17 #include "qemu/timer.h"
  18 #include "qemu/main-loop.h"
  19 #include "sysemu/sysemu.h"
  20 #include "qemu/error-report.h"
  21
  22 /* Current version of the replay mechanism.
  23    Increase it when file format changes. */
  24 #define REPLAY_VERSION              0xe02004
  25 /* Size of replay log header */
  26 #define HEADER_SIZE                 (sizeof(uint32_t) + sizeof(uint64_t))
  27
  28 ReplayMode replay_mode = REPLAY_MODE_NONE;
  29
  30 /* Name of replay file  */
  31 static char *replay_filename;
  32 ReplayState replay_state;
  33 static GSList *replay_blockers;
  34
  35 bool replay_next_event_is(int event)
  36 {
  37     bool res = false;
  38
  39     /* nothing to skip - not all instructions used */
  40     if (replay_state.instructions_count != 0) {
  41         assert(replay_data_kind == EVENT_INSTRUCTION);
  42         return event == EVENT_INSTRUCTION;
  43     }
  44
  45     while (true) {
  46         if (event == replay_data_kind) {
  47             res = true;
  48         }
  49         switch (replay_data_kind) {
  50         case EVENT_SHUTDOWN:
  51             replay_finish_event();
  52             qemu_system_shutdown_request();
  53             break;
  54         default:
  55             /* clock, time_t, checkpoint and other events */
  56             return res;
  57         }
  58     }
  59     return res;
  60 }
  61
  62 uint64_t replay_get_current_step(void)
  63 {
  64     return cpu_get_icount_raw();
  65 }
  66
  67 int replay_get_instructions(void)
  68 {
  69     int res = 0;
  70     replay_mutex_lock();
  71     if (replay_next_event_is(EVENT_INSTRUCTION)) {
  72         res = replay_state.instructions_count;
  73     }
  74     replay_mutex_unlock();
  75     return res;
  76 }
  77
  78 void replay_account_executed_instructions(void)
  79 {
  80     if (replay_mode == REPLAY_MODE_PLAY) {
  81         replay_mutex_lock();
  82         if (replay_state.instructions_count > 0) {
  83             int count = (int)(replay_get_current_step()
  84                               - replay_state.current_step);
  85             replay_state.instructions_count -= count;
  86             replay_state.current_step += count;
  87             if (replay_state.instructions_count == 0) {
  88                 assert(replay_data_kind == EVENT_INSTRUCTION);
  89                 replay_finish_event();
  90                 /* Wake up iothread. This is required because
  91                    timers will not expire until clock counters
  92                    will be read from the log. */
  93                 qemu_notify_event();
  94             }
  95         }
  96         replay_mutex_unlock();
  97     }
  98 }
  99
 100 bool replay_exception(void)
 101 {
 102     if (replay_mode == REPLAY_MODE_RECORD) {
 103         replay_save_instructions();
 104         replay_mutex_lock();
 105         replay_put_event(EVENT_EXCEPTION);
 106         replay_mutex_unlock();
 107         return true;
 108     } else if (replay_mode == REPLAY_MODE_PLAY) {
 109         bool res = replay_has_exception();
 110         if (res) {
 111             replay_mutex_lock();
 112             replay_finish_event();
 113             replay_mutex_unlock();
 114         }
 115         return res;
 116     }
 117
 118     return true;
 119 }
 120
 121 bool replay_has_exception(void)
 122 {
 123     bool res = false;
 124     if (replay_mode == REPLAY_MODE_PLAY) {
 125         replay_account_executed_instructions();
 126         replay_mutex_lock();
 127         res = replay_next_event_is(EVENT_EXCEPTION);
 128         replay_mutex_unlock();
 129     }
 130
 131     return res;
 132 }
 133
 134 bool replay_interrupt(void)
 135 {
 136     if (replay_mode == REPLAY_MODE_RECORD) {
 137         replay_save_instructions();
 138         replay_mutex_lock();
 139         replay_put_event(EVENT_INTERRUPT);
 140         replay_mutex_unlock();
 141         return true;
 142     } else if (replay_mode == REPLAY_MODE_PLAY) {
 143         bool res = replay_has_interrupt();
 144         if (res) {
 145             replay_mutex_lock();
 146             replay_finish_event();
 147             replay_mutex_unlock();
 148         }
 149         return res;
 150     }
 151
 152     return true;
 153 }
 154
 155 bool replay_has_interrupt(void)
 156 {
 157     bool res = false;
 158     if (replay_mode == REPLAY_MODE_PLAY) {
 159         replay_account_executed_instructions();
 160         replay_mutex_lock();
 161         res = replay_next_event_is(EVENT_INTERRUPT);
 162         replay_mutex_unlock();
 163     }
 164     return res;
 165 }
 166
 167 void replay_shutdown_request(void)
 168 {
 169     if (replay_mode == REPLAY_MODE_RECORD) {
 170         replay_mutex_lock();
 171         replay_put_event(EVENT_SHUTDOWN);
 172         replay_mutex_unlock();
 173     }
 174 }
 175
 176 bool replay_checkpoint(ReplayCheckpoint checkpoint)
 177 {
 178     bool res = false;
 179     assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);
 180     replay_save_instructions();
 181
 182     if (!replay_file) {
 183         return true;
 184     }
 185
 186     replay_mutex_lock();
 187
 188     if (replay_mode == REPLAY_MODE_PLAY) {
 189         if (replay_next_event_is(EVENT_CHECKPOINT + checkpoint)) {
 190             replay_finish_event();
 191         } else if (replay_data_kind != EVENT_ASYNC) {
 192             res = false;
 193             goto out;
 194         }
 195         replay_read_events(checkpoint);
 196         /* replay_read_events may leave some unread events.
 197            Return false if not all of the events associated with
 198            checkpoint were processed */
 199         res = replay_data_kind != EVENT_ASYNC;
 200     } else if (replay_mode == REPLAY_MODE_RECORD) {
 201         replay_put_event(EVENT_CHECKPOINT + checkpoint);
 202         replay_save_events(checkpoint);
 203         res = true;
 204     }
 205 out:
 206     replay_mutex_unlock();
 207     return res;
 208 }
 209
 210 static void replay_enable(const char *fname, int mode)
 211 {
 212     const char *fmode = NULL;
 213     assert(!replay_file);
 214
 215     switch (mode) {
 216     case REPLAY_MODE_RECORD:
 217         fmode = "wb";
 218         break;
 219     case REPLAY_MODE_PLAY:
 220         fmode = "rb";
 221         break;
 222     default:
 223         fprintf(stderr, "Replay: internal error: invalid replay mode\n");
 224         exit(1);
 225     }
 226
 227     atexit(replay_finish);
 228
 229     replay_mutex_init();
 230
 231     replay_file = fopen(fname, fmode);
 232     if (replay_file == NULL) {
 233         fprintf(stderr, "Replay: open %s: %s\n", fname, strerror(errno));
 234         exit(1);
 235     }
 236
 237     replay_filename = g_strdup(fname);
 238
 239     replay_mode = mode;
 240     replay_data_kind = -1;
 241     replay_state.instructions_count = 0;
 242     replay_state.current_step = 0;
 243
 244     /* skip file header for RECORD and check it for PLAY */
 245     if (replay_mode == REPLAY_MODE_RECORD) {
 246         fseek(replay_file, HEADER_SIZE, SEEK_SET);
 247     } else if (replay_mode == REPLAY_MODE_PLAY) {
 248         unsigned int version = replay_get_dword();
 249         if (version != REPLAY_VERSION) {
 250             fprintf(stderr, "Replay: invalid input log file version\n");
 251             exit(1);
 252         }
 253         /* go to the beginning */
 254         fseek(replay_file, HEADER_SIZE, SEEK_SET);
 255         replay_fetch_data_kind();
 256     }
 257
 258     replay_init_events();
 259 }
 260
 261 void replay_configure(QemuOpts *opts)
 262 {
 263     const char *fname;
 264     const char *rr;
 265     ReplayMode mode = REPLAY_MODE_NONE;
 266     Location loc;
 267
 268     if (!opts) {
 269         return;
 270     }
 271
 272     loc_push_none(&loc);
 273     qemu_opts_loc_restore(opts);
 274
 275     rr = qemu_opt_get(opts, "rr");
 276     if (!rr) {
 277         /* Just enabling icount */
 278         goto out;
 279     } else if (!strcmp(rr, "record")) {
 280         mode = REPLAY_MODE_RECORD;
 281     } else if (!strcmp(rr, "replay")) {
 282         mode = REPLAY_MODE_PLAY;
 283     } else {
 284         error_report("Invalid icount rr option: %s", rr);
 285         exit(1);
 286     }
 287
 288     fname = qemu_opt_get(opts, "rrfile");
 289     if (!fname) {
 290         error_report("File name not specified for replay");
 291         exit(1);
 292     }
 293
 294     replay_enable(fname, mode);
 295
 296 out:
 297     loc_pop(&loc);
 298 }
 299
 300 void replay_start(void)
 301 {
 302     if (replay_mode == REPLAY_MODE_NONE) {
 303         return;
 304     }
 305
 306     if (replay_blockers) {
 307         error_reportf_err(replay_blockers->data, "Record/replay: ");
 308         exit(1);
 309     }
 310     if (!use_icount) {
 311         error_report("Please enable icount to use record/replay");
 312         exit(1);
 313     }
 314
 315     /* Timer for snapshotting will be set up here. */
 316
 317     replay_enable_events();
 318 }
 319
 320 void replay_finish(void)
 321 {
 322     if (replay_mode == REPLAY_MODE_NONE) {
 323         return;
 324     }
 325
 326     replay_save_instructions();
 327
 328     /* finalize the file */
 329     if (replay_file) {
 330         if (replay_mode == REPLAY_MODE_RECORD) {
 331             /* write end event */
 332             replay_put_event(EVENT_END);
 333
 334             /* write header */
 335             fseek(replay_file, 0, SEEK_SET);
 336             replay_put_dword(REPLAY_VERSION);
 337         }
 338
 339         fclose(replay_file);
 340         replay_file = NULL;
 341     }
 342     if (replay_filename) {
 343         g_free(replay_filename);
 344         replay_filename = NULL;
 345     }
 346
 347     replay_finish_events();
 348     replay_mutex_destroy();
 349 }
 350
 351 void replay_add_blocker(Error *reason)
 352 {
 353     replay_blockers = g_slist_prepend(replay_blockers, reason);
 354 }