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 "qemu-common.h"
  14 #include "sysemu/replay.h"
  15 #include "replay-internal.h"
  16 #include "qemu/timer.h"
  17 #include "qemu/main-loop.h"
  18 #include "sysemu/sysemu.h"
  19 #include "qemu/error-report.h"
  20
  21 /* Current version of the replay mechanism.
  22    Increase it when file format changes. */
  23 #define REPLAY_VERSION              0xe02002
  24 /* Size of replay log header */
  25 #define HEADER_SIZE                 (sizeof(uint32_t) + sizeof(uint64_t))
  26
  27 ReplayMode replay_mode = REPLAY_MODE_NONE;
  28
  29 /* Name of replay file  */
  30 static char *replay_filename;
  31 ReplayState replay_state;
  32 static GSList *replay_blockers;
  33
  34 bool replay_next_event_is(int event)
  35 {
  36     bool res = false;
  37
  38     /* nothing to skip - not all instructions used */
  39     if (replay_state.instructions_count != 0) {
  40         assert(replay_data_kind == EVENT_INSTRUCTION);
  41         return event == EVENT_INSTRUCTION;
  42     }
  43
  44     while (true) {
  45         if (event == replay_data_kind) {
  46             res = true;
  47         }
  48         switch (replay_data_kind) {
  49         case EVENT_SHUTDOWN:
  50             replay_finish_event();
  51             qemu_system_shutdown_request();
  52             break;
  53         default:
  54             /* clock, time_t, checkpoint and other events */
  55             return res;
  56         }
  57     }
  58     return res;
  59 }
  60
  61 uint64_t replay_get_current_step(void)
  62 {
  63     return cpu_get_icount_raw();
  64 }
  65
  66 int replay_get_instructions(void)
  67 {
  68     int res = 0;
  69     replay_mutex_lock();
  70     if (replay_next_event_is(EVENT_INSTRUCTION)) {
  71         res = replay_state.instructions_count;
  72     }
  73     replay_mutex_unlock();
  74     return res;
  75 }
  76
  77 void replay_account_executed_instructions(void)
  78 {
  79     if (replay_mode == REPLAY_MODE_PLAY) {
  80         replay_mutex_lock();
  81         if (replay_state.instructions_count > 0) {
  82             int count = (int)(replay_get_current_step()
  83                               - replay_state.current_step);
  84             replay_state.instructions_count -= count;
  85             replay_state.current_step += count;
  86             if (replay_state.instructions_count == 0) {
  87                 assert(replay_data_kind == EVENT_INSTRUCTION);
  88                 replay_finish_event();
  89                 /* Wake up iothread. This is required because
  90                    timers will not expire until clock counters
  91                    will be read from the log. */
  92                 qemu_notify_event();
  93             }
  94         }
  95         replay_mutex_unlock();
  96     }
  97 }
  98
  99 bool replay_exception(void)
 100 {
 101     if (replay_mode == REPLAY_MODE_RECORD) {
 102         replay_save_instructions();
 103         replay_mutex_lock();
 104         replay_put_event(EVENT_EXCEPTION);
 105         replay_mutex_unlock();
 106         return true;
 107     } else if (replay_mode == REPLAY_MODE_PLAY) {
 108         bool res = replay_has_exception();
 109         if (res) {
 110             replay_mutex_lock();
 111             replay_finish_event();
 112             replay_mutex_unlock();
 113         }
 114         return res;
 115     }
 116
 117     return true;
 118 }
 119
 120 bool replay_has_exception(void)
 121 {
 122     bool res = false;
 123     if (replay_mode == REPLAY_MODE_PLAY) {
 124         replay_account_executed_instructions();
 125         replay_mutex_lock();
 126         res = replay_next_event_is(EVENT_EXCEPTION);
 127         replay_mutex_unlock();
 128     }
 129
 130     return res;
 131 }
 132
 133 bool replay_interrupt(void)
 134 {
 135     if (replay_mode == REPLAY_MODE_RECORD) {
 136         replay_save_instructions();
 137         replay_mutex_lock();
 138         replay_put_event(EVENT_INTERRUPT);
 139         replay_mutex_unlock();
 140         return true;
 141     } else if (replay_mode == REPLAY_MODE_PLAY) {
 142         bool res = replay_has_interrupt();
 143         if (res) {
 144             replay_mutex_lock();
 145             replay_finish_event();
 146             replay_mutex_unlock();
 147         }
 148         return res;
 149     }
 150
 151     return true;
 152 }
 153
 154 bool replay_has_interrupt(void)
 155 {
 156     bool res = false;
 157     if (replay_mode == REPLAY_MODE_PLAY) {
 158         replay_account_executed_instructions();
 159         replay_mutex_lock();
 160         res = replay_next_event_is(EVENT_INTERRUPT);
 161         replay_mutex_unlock();
 162     }
 163     return res;
 164 }
 165
 166 void replay_shutdown_request(void)
 167 {
 168     if (replay_mode == REPLAY_MODE_RECORD) {
 169         replay_mutex_lock();
 170         replay_put_event(EVENT_SHUTDOWN);
 171         replay_mutex_unlock();
 172     }
 173 }
 174
 175 bool replay_checkpoint(ReplayCheckpoint checkpoint)
 176 {
 177     bool res = false;
 178     assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);
 179     replay_save_instructions();
 180
 181     if (!replay_file) {
 182         return true;
 183     }
 184
 185     replay_mutex_lock();
 186
 187     if (replay_mode == REPLAY_MODE_PLAY) {
 188         if (replay_next_event_is(EVENT_CHECKPOINT + checkpoint)) {
 189             replay_finish_event();
 190         } else if (replay_data_kind != EVENT_ASYNC) {
 191             res = false;
 192             goto out;
 193         }
 194         replay_read_events(checkpoint);
 195         /* replay_read_events may leave some unread events.
 196            Return false if not all of the events associated with
 197            checkpoint were processed */
 198         res = replay_data_kind != EVENT_ASYNC;
 199     } else if (replay_mode == REPLAY_MODE_RECORD) {
 200         replay_put_event(EVENT_CHECKPOINT + checkpoint);
 201         replay_save_events(checkpoint);
 202         res = true;
 203     }
 204 out:
 205     replay_mutex_unlock();
 206     return res;
 207 }
 208
 209 static void replay_enable(const char *fname, int mode)
 210 {
 211     const char *fmode = NULL;
 212     assert(!replay_file);
 213
 214     switch (mode) {
 215     case REPLAY_MODE_RECORD:
 216         fmode = "wb";
 217         break;
 218     case REPLAY_MODE_PLAY:
 219         fmode = "rb";
 220         break;
 221     default:
 222         fprintf(stderr, "Replay: internal error: invalid replay mode\n");
 223         exit(1);
 224     }
 225
 226     atexit(replay_finish);
 227
 228     replay_mutex_init();
 229
 230     replay_file = fopen(fname, fmode);
 231     if (replay_file == NULL) {
 232         fprintf(stderr, "Replay: open %s: %s\n", fname, strerror(errno));
 233         exit(1);
 234     }
 235
 236     replay_filename = g_strdup(fname);
 237
 238     replay_mode = mode;
 239     replay_data_kind = -1;
 240     replay_state.instructions_count = 0;
 241     replay_state.current_step = 0;
 242
 243     /* skip file header for RECORD and check it for PLAY */
 244     if (replay_mode == REPLAY_MODE_RECORD) {
 245         fseek(replay_file, HEADER_SIZE, SEEK_SET);
 246     } else if (replay_mode == REPLAY_MODE_PLAY) {
 247         unsigned int version = replay_get_dword();
 248         if (version != REPLAY_VERSION) {
 249             fprintf(stderr, "Replay: invalid input log file version\n");
 250             exit(1);
 251         }
 252         /* go to the beginning */
 253         fseek(replay_file, HEADER_SIZE, SEEK_SET);
 254         replay_fetch_data_kind();
 255     }
 256
 257     replay_init_events();
 258 }
 259
 260 void replay_configure(QemuOpts *opts)
 261 {
 262     const char *fname;
 263     const char *rr;
 264     ReplayMode mode = REPLAY_MODE_NONE;
 265
 266     rr = qemu_opt_get(opts, "rr");
 267     if (!rr) {
 268         /* Just enabling icount */
 269         return;
 270     } else if (!strcmp(rr, "record")) {
 271         mode = REPLAY_MODE_RECORD;
 272     } else if (!strcmp(rr, "replay")) {
 273         mode = REPLAY_MODE_PLAY;
 274     } else {
 275         error_report("Invalid icount rr option: %s", rr);
 276         exit(1);
 277     }
 278
 279     fname = qemu_opt_get(opts, "rrfile");
 280     if (!fname) {
 281         error_report("File name not specified for replay");
 282         exit(1);
 283     }
 284
 285     replay_enable(fname, mode);
 286 }
 287
 288 void replay_start(void)
 289 {
 290     if (replay_mode == REPLAY_MODE_NONE) {
 291         return;
 292     }
 293
 294     if (replay_blockers) {
 295         error_reportf_err(replay_blockers->data, "Record/replay: ");
 296         exit(1);
 297     }
 298     if (!use_icount) {
 299         error_report("Please enable icount to use record/replay");
 300         exit(1);
 301     }
 302
 303     /* Timer for snapshotting will be set up here. */
 304
 305     replay_enable_events();
 306 }
 307
 308 void replay_finish(void)
 309 {
 310     if (replay_mode == REPLAY_MODE_NONE) {
 311         return;
 312     }
 313
 314     replay_save_instructions();
 315
 316     /* finalize the file */
 317     if (replay_file) {
 318         if (replay_mode == REPLAY_MODE_RECORD) {
 319             /* write end event */
 320             replay_put_event(EVENT_END);
 321
 322             /* write header */
 323             fseek(replay_file, 0, SEEK_SET);
 324             replay_put_dword(REPLAY_VERSION);
 325         }
 326
 327         fclose(replay_file);
 328         replay_file = NULL;
 329     }
 330     if (replay_filename) {
 331         g_free(replay_filename);
 332         replay_filename = NULL;
 333     }
 334
 335     replay_finish_events();
 336     replay_mutex_destroy();
 337 }
 338
 339 void replay_add_blocker(Error *reason)
 340 {
 341     replay_blockers = g_slist_prepend(replay_blockers, reason);
 342 }