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/cpus.h"
  20 #include "sysemu/sysemu.h"
  21 #include "qemu/error-report.h"
  22
  23 /* Current version of the replay mechanism.
  24    Increase it when file format changes. */
  25 #define REPLAY_VERSION              0xe02006
  26 /* Size of replay log header */
  27 #define HEADER_SIZE                 (sizeof(uint32_t) + sizeof(uint64_t))
  28
  29 ReplayMode replay_mode = REPLAY_MODE_NONE;
  30 char *replay_snapshot;
  31
  32 /* Name of replay file  */
  33 static char *replay_filename;
  34 ReplayState replay_state;
  35 static GSList *replay_blockers;
  36
  37 bool replay_next_event_is(int event)
  38 {
  39     bool res = false;
  40
  41     /* nothing to skip - not all instructions used */
  42     if (replay_state.instructions_count != 0) {
  43         assert(replay_state.data_kind == EVENT_INSTRUCTION);
  44         return event == EVENT_INSTRUCTION;
  45     }
  46
  47     while (true) {
  48         if (event == replay_state.data_kind) {
  49             res = true;
  50         }
  51         switch (replay_state.data_kind) {
  52         case EVENT_SHUTDOWN ... EVENT_SHUTDOWN_LAST:
  53             replay_finish_event();
  54             qemu_system_shutdown_request(replay_state.data_kind -
  55                                          EVENT_SHUTDOWN);
  56             break;
  57         default:
  58             /* clock, time_t, checkpoint and other events */
  59             return res;
  60         }
  61     }
  62     return res;
  63 }
  64
  65 uint64_t replay_get_current_step(void)
  66 {
  67     return cpu_get_icount_raw();
  68 }
  69
  70 int replay_get_instructions(void)
  71 {
  72     int res = 0;
  73     replay_mutex_lock();
  74     if (replay_next_event_is(EVENT_INSTRUCTION)) {
  75         res = replay_state.instructions_count;
  76     }
  77     replay_mutex_unlock();
  78     return res;
  79 }
  80
  81 void replay_account_executed_instructions(void)
  82 {
  83     if (replay_mode == REPLAY_MODE_PLAY) {
  84         replay_mutex_lock();
  85         if (replay_state.instructions_count > 0) {
  86             int count = (int)(replay_get_current_step()
  87                               - replay_state.current_step);
  88
  89             /* Time can only go forward */
  90             assert(count >= 0);
  91
  92             replay_state.instructions_count -= count;
  93             replay_state.current_step += count;
  94             if (replay_state.instructions_count == 0) {
  95                 assert(replay_state.data_kind == EVENT_INSTRUCTION);
  96                 replay_finish_event();
  97                 /* Wake up iothread. This is required because
  98                    timers will not expire until clock counters
  99                    will be read from the log. */
 100                 qemu_notify_event();
 101             }
 102         }
 103         replay_mutex_unlock();
 104     }
 105 }
 106
 107 bool replay_exception(void)
 108 {
 109     if (replay_mode == REPLAY_MODE_RECORD) {
 110         replay_save_instructions();
 111         replay_mutex_lock();
 112         replay_put_event(EVENT_EXCEPTION);
 113         replay_mutex_unlock();
 114         return true;
 115     } else if (replay_mode == REPLAY_MODE_PLAY) {
 116         bool res = replay_has_exception();
 117         if (res) {
 118             replay_mutex_lock();
 119             replay_finish_event();
 120             replay_mutex_unlock();
 121         }
 122         return res;
 123     }
 124
 125     return true;
 126 }
 127
 128 bool replay_has_exception(void)
 129 {
 130     bool res = false;
 131     if (replay_mode == REPLAY_MODE_PLAY) {
 132         replay_account_executed_instructions();
 133         replay_mutex_lock();
 134         res = replay_next_event_is(EVENT_EXCEPTION);
 135         replay_mutex_unlock();
 136     }
 137
 138     return res;
 139 }
 140
 141 bool replay_interrupt(void)
 142 {
 143     if (replay_mode == REPLAY_MODE_RECORD) {
 144         replay_save_instructions();
 145         replay_mutex_lock();
 146         replay_put_event(EVENT_INTERRUPT);
 147         replay_mutex_unlock();
 148         return true;
 149     } else if (replay_mode == REPLAY_MODE_PLAY) {
 150         bool res = replay_has_interrupt();
 151         if (res) {
 152             replay_mutex_lock();
 153             replay_finish_event();
 154             replay_mutex_unlock();
 155         }
 156         return res;
 157     }
 158
 159     return true;
 160 }
 161
 162 bool replay_has_interrupt(void)
 163 {
 164     bool res = false;
 165     if (replay_mode == REPLAY_MODE_PLAY) {
 166         replay_account_executed_instructions();
 167         replay_mutex_lock();
 168         res = replay_next_event_is(EVENT_INTERRUPT);
 169         replay_mutex_unlock();
 170     }
 171     return res;
 172 }
 173
 174 void replay_shutdown_request(ShutdownCause cause)
 175 {
 176     if (replay_mode == REPLAY_MODE_RECORD) {
 177         replay_mutex_lock();
 178         replay_put_event(EVENT_SHUTDOWN + cause);
 179         replay_mutex_unlock();
 180     }
 181 }
 182
 183 bool replay_checkpoint(ReplayCheckpoint checkpoint)
 184 {
 185     bool res = false;
 186     assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);
 187     replay_save_instructions();
 188
 189     if (!replay_file) {
 190         return true;
 191     }
 192
 193     replay_mutex_lock();
 194
 195     if (replay_mode == REPLAY_MODE_PLAY) {
 196         if (replay_next_event_is(EVENT_CHECKPOINT + checkpoint)) {
 197             replay_finish_event();
 198         } else if (replay_state.data_kind != EVENT_ASYNC) {
 199             res = false;
 200             goto out;
 201         }
 202         replay_read_events(checkpoint);
 203         /* replay_read_events may leave some unread events.
 204            Return false if not all of the events associated with
 205            checkpoint were processed */
 206         res = replay_state.data_kind != EVENT_ASYNC;
 207     } else if (replay_mode == REPLAY_MODE_RECORD) {
 208         replay_put_event(EVENT_CHECKPOINT + checkpoint);
 209         replay_save_events(checkpoint);
 210         res = true;
 211     }
 212 out:
 213     replay_mutex_unlock();
 214     return res;
 215 }
 216
 217 static void replay_enable(const char *fname, int mode)
 218 {
 219     const char *fmode = NULL;
 220     assert(!replay_file);
 221
 222     switch (mode) {
 223     case REPLAY_MODE_RECORD:
 224         fmode = "wb";
 225         break;
 226     case REPLAY_MODE_PLAY:
 227         fmode = "rb";
 228         break;
 229     default:
 230         fprintf(stderr, "Replay: internal error: invalid replay mode\n");
 231         exit(1);
 232     }
 233
 234     atexit(replay_finish);
 235
 236     replay_mutex_init();
 237
 238     replay_file = fopen(fname, fmode);
 239     if (replay_file == NULL) {
 240         fprintf(stderr, "Replay: open %s: %s\n", fname, strerror(errno));
 241         exit(1);
 242     }
 243
 244     replay_filename = g_strdup(fname);
 245
 246     replay_mode = mode;
 247     replay_state.data_kind = -1;
 248     replay_state.instructions_count = 0;
 249     replay_state.current_step = 0;
 250     replay_state.has_unread_data = 0;
 251
 252     /* skip file header for RECORD and check it for PLAY */
 253     if (replay_mode == REPLAY_MODE_RECORD) {
 254         fseek(replay_file, HEADER_SIZE, SEEK_SET);
 255     } else if (replay_mode == REPLAY_MODE_PLAY) {
 256         unsigned int version = replay_get_dword();
 257         if (version != REPLAY_VERSION) {
 258             fprintf(stderr, "Replay: invalid input log file version\n");
 259             exit(1);
 260         }
 261         /* go to the beginning */
 262         fseek(replay_file, HEADER_SIZE, SEEK_SET);
 263         replay_fetch_data_kind();
 264     }
 265
 266     replay_init_events();
 267 }
 268
 269 void replay_configure(QemuOpts *opts)
 270 {
 271     const char *fname;
 272     const char *rr;
 273     ReplayMode mode = REPLAY_MODE_NONE;
 274     Location loc;
 275
 276     if (!opts) {
 277         return;
 278     }
 279
 280     loc_push_none(&loc);
 281     qemu_opts_loc_restore(opts);
 282
 283     rr = qemu_opt_get(opts, "rr");
 284     if (!rr) {
 285         /* Just enabling icount */
 286         goto out;
 287     } else if (!strcmp(rr, "record")) {
 288         mode = REPLAY_MODE_RECORD;
 289     } else if (!strcmp(rr, "replay")) {
 290         mode = REPLAY_MODE_PLAY;
 291     } else {
 292         error_report("Invalid icount rr option: %s", rr);
 293         exit(1);
 294     }
 295
 296     fname = qemu_opt_get(opts, "rrfile");
 297     if (!fname) {
 298         error_report("File name not specified for replay");
 299         exit(1);
 300     }
 301
 302     replay_snapshot = g_strdup(qemu_opt_get(opts, "rrsnapshot"));
 303     replay_vmstate_register();
 304     replay_enable(fname, mode);
 305
 306 out:
 307     loc_pop(&loc);
 308 }
 309
 310 void replay_start(void)
 311 {
 312     if (replay_mode == REPLAY_MODE_NONE) {
 313         return;
 314     }
 315
 316     if (replay_blockers) {
 317         error_reportf_err(replay_blockers->data, "Record/replay: ");
 318         exit(1);
 319     }
 320     if (!use_icount) {
 321         error_report("Please enable icount to use record/replay");
 322         exit(1);
 323     }
 324
 325     /* Timer for snapshotting will be set up here. */
 326
 327     replay_enable_events();
 328 }
 329
 330 void replay_finish(void)
 331 {
 332     if (replay_mode == REPLAY_MODE_NONE) {
 333         return;
 334     }
 335
 336     replay_save_instructions();
 337
 338     /* finalize the file */
 339     if (replay_file) {
 340         if (replay_mode == REPLAY_MODE_RECORD) {
 341             /* write end event */
 342             replay_put_event(EVENT_END);
 343
 344             /* write header */
 345             fseek(replay_file, 0, SEEK_SET);
 346             replay_put_dword(REPLAY_VERSION);
 347         }
 348
 349         fclose(replay_file);
 350         replay_file = NULL;
 351     }
 352     if (replay_filename) {
 353         g_free(replay_filename);
 354         replay_filename = NULL;
 355     }
 356
 357     g_free(replay_snapshot);
 358     replay_snapshot = NULL;
 359
 360     replay_finish_events();
 361     replay_mutex_destroy();
 362 }
 363
 364 void replay_add_blocker(Error *reason)
 365 {
 366     replay_blockers = g_slist_prepend(replay_blockers, reason);
 367 }