summaryrefslogtreecommitdiffstats
path: root/replay/replay.c
blob: 822826140118eaf0575bbfa8050efeb9d4b390d3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
/*
 * replay.c
 *
 * Copyright (c) 2010-2015 Institute for System Programming
 *                         of the Russian Academy of Sciences.
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#include "qemu/osdep.h"
#include "qapi/error.h"
#include "sysemu/replay.h"
#include "replay-internal.h"
#include "qemu/timer.h"
#include "qemu/main-loop.h"
#include "qemu/option.h"
#include "sysemu/cpus.h"
#include "sysemu/sysemu.h"
#include "qemu/error-report.h"

/* Current version of the replay mechanism.
   Increase it when file format changes. */
#define REPLAY_VERSION              0xe02007
/* Size of replay log header */
#define HEADER_SIZE                 (sizeof(uint32_t) + sizeof(uint64_t))

ReplayMode replay_mode = REPLAY_MODE_NONE;
char *replay_snapshot;

/* Name of replay file  */
static char *replay_filename;
ReplayState replay_state;
static GSList *replay_blockers;

bool replay_next_event_is(int event)
{
    bool res = false;

    /* nothing to skip - not all instructions used */
    if (replay_state.instructions_count != 0) {
        assert(replay_state.data_kind == EVENT_INSTRUCTION);
        return event == EVENT_INSTRUCTION;
    }

    while (true) {
        if (event == replay_state.data_kind) {
            res = true;
        }
        switch (replay_state.data_kind) {
        case EVENT_SHUTDOWN ... EVENT_SHUTDOWN_LAST:
            replay_finish_event();
            qemu_system_shutdown_request(replay_state.data_kind -
                                         EVENT_SHUTDOWN);
            break;
        default:
            /* clock, time_t, checkpoint and other events */
            return res;
        }
    }
    return res;
}

uint64_t replay_get_current_step(void)
{
    return cpu_get_icount_raw();
}

int replay_get_instructions(void)
{
    int res = 0;
    replay_mutex_lock();
    if (replay_next_event_is(EVENT_INSTRUCTION)) {
        res = replay_state.instructions_count;
    }
    replay_mutex_unlock();
    return res;
}

void replay_account_executed_instructions(void)
{
    if (replay_mode == REPLAY_MODE_PLAY) {
        g_assert(replay_mutex_locked());
        if (replay_state.instructions_count > 0) {
            int count = (int)(replay_get_current_step()
                              - replay_state.current_step);

            /* Time can only go forward */
            assert(count >= 0);

            replay_state.instructions_count -= count;
            replay_state.current_step += count;
            if (replay_state.instructions_count == 0) {
                assert(replay_state.data_kind == EVENT_INSTRUCTION);
                replay_finish_event();
                /* Wake up iothread. This is required because
                   timers will not expire until clock counters
                   will be read from the log. */
                qemu_notify_event();
            }
        }
    }
}

bool replay_exception(void)
{

    if (replay_mode == REPLAY_MODE_RECORD) {
        g_assert(replay_mutex_locked());
        replay_save_instructions();
        replay_put_event(EVENT_EXCEPTION);
        return true;
    } else if (replay_mode == REPLAY_MODE_PLAY) {
        g_assert(replay_mutex_locked());
        bool res = replay_has_exception();
        if (res) {
            replay_finish_event();
        }
        return res;
    }

    return true;
}

bool replay_has_exception(void)
{
    bool res = false;
    if (replay_mode == REPLAY_MODE_PLAY) {
        g_assert(replay_mutex_locked());
        replay_account_executed_instructions();
        res = replay_next_event_is(EVENT_EXCEPTION);
    }

    return res;
}

bool replay_interrupt(void)
{
    if (replay_mode == REPLAY_MODE_RECORD) {
        g_assert(replay_mutex_locked());
        replay_save_instructions();
        replay_put_event(EVENT_INTERRUPT);
        return true;
    } else if (replay_mode == REPLAY_MODE_PLAY) {
        g_assert(replay_mutex_locked());
        bool res = replay_has_interrupt();
        if (res) {
            replay_finish_event();
        }
        return res;
    }

    return true;
}

bool replay_has_interrupt(void)
{
    bool res = false;
    if (replay_mode == REPLAY_MODE_PLAY) {
        g_assert(replay_mutex_locked());
        replay_account_executed_instructions();
        res = replay_next_event_is(EVENT_INTERRUPT);
    }
    return res;
}

void replay_shutdown_request(ShutdownCause cause)
{
    if (replay_mode == REPLAY_MODE_RECORD) {
        g_assert(replay_mutex_locked());
        replay_put_event(EVENT_SHUTDOWN + cause);
    }
}

bool replay_checkpoint(ReplayCheckpoint checkpoint)
{
    bool res = false;
    static bool in_checkpoint;
    assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);

    if (!replay_file) {
        return true;
    }

    if (in_checkpoint) {
        /* If we are already in checkpoint, then there is no need
           for additional synchronization.
           Recursion occurs when HW event modifies timers.
           Timer modification may invoke the checkpoint and
           proceed to recursion. */
        return true;
    }
    in_checkpoint = true;

    replay_save_instructions();

    if (replay_mode == REPLAY_MODE_PLAY) {
        g_assert(replay_mutex_locked());
        if (replay_next_event_is(EVENT_CHECKPOINT + checkpoint)) {
            replay_finish_event();
        } else if (replay_state.data_kind != EVENT_ASYNC) {
            res = false;
            goto out;
        }
        replay_read_events(checkpoint);
        /* replay_read_events may leave some unread events.
           Return false if not all of the events associated with
           checkpoint were processed */
        res = replay_state.data_kind != EVENT_ASYNC;
    } else if (replay_mode == REPLAY_MODE_RECORD) {
        g_assert(replay_mutex_locked());
        replay_put_event(EVENT_CHECKPOINT + checkpoint);
        /* This checkpoint belongs to several threads.
           Processing events from different threads is
           non-deterministic */
        if (checkpoint != CHECKPOINT_CLOCK_WARP_START) {
            replay_save_events(checkpoint);
        }
        res = true;
    }
out:
    in_checkpoint = false;
    return res;
}

static void replay_enable(const char *fname, int mode)
{
    const char *fmode = NULL;
    assert(!replay_file);

    switch (mode) {
    case REPLAY_MODE_RECORD:
        fmode = "wb";
        break;
    case REPLAY_MODE_PLAY:
        fmode = "rb";
        break;
    default:
        fprintf(stderr, "Replay: internal error: invalid replay mode\n");
        exit(1);
    }

    atexit(replay_finish);

    replay_file = fopen(fname, fmode);
    if (replay_file == NULL) {
        fprintf(stderr, "Replay: open %s: %s\n", fname, strerror(errno));
        exit(1);
    }

    replay_filename = g_strdup(fname);
    replay_mode = mode;
    replay_mutex_init();

    replay_state.data_kind = -1;
    replay_state.instructions_count = 0;
    replay_state.current_step = 0;
    replay_state.has_unread_data = 0;

    /* skip file header for RECORD and check it for PLAY */
    if (replay_mode == REPLAY_MODE_RECORD) {
        fseek(replay_file, HEADER_SIZE, SEEK_SET);
    } else if (replay_mode == REPLAY_MODE_PLAY) {
        unsigned int version = replay_get_dword();
        if (version != REPLAY_VERSION) {
            fprintf(stderr, "Replay: invalid input log file version\n");
            exit(1);
        }
        /* go to the beginning */
        fseek(replay_file, HEADER_SIZE, SEEK_SET);
        replay_fetch_data_kind();
    }

    replay_init_events();
}

void replay_configure(QemuOpts *opts)
{
    const char *fname;
    const char *rr;
    ReplayMode mode = REPLAY_MODE_NONE;
    Location loc;

    if (!opts) {
        return;
    }

    loc_push_none(&loc);
    qemu_opts_loc_restore(opts);

    rr = qemu_opt_get(opts, "rr");
    if (!rr) {
        /* Just enabling icount */
        goto out;
    } else if (!strcmp(rr, "record")) {
        mode = REPLAY_MODE_RECORD;
    } else if (!strcmp(rr, "replay")) {
        mode = REPLAY_MODE_PLAY;
    } else {
        error_report("Invalid icount rr option: %s", rr);
        exit(1);
    }

    fname = qemu_opt_get(opts, "rrfile");
    if (!fname) {
        error_report("File name not specified for replay");
        exit(1);
    }

    replay_snapshot = g_strdup(qemu_opt_get(opts, "rrsnapshot"));
    replay_vmstate_register();
    replay_enable(fname, mode);

out:
    loc_pop(&loc);
}

void replay_start(void)
{
    if (replay_mode == REPLAY_MODE_NONE) {
        return;
    }

    if (replay_blockers) {
        error_reportf_err(replay_blockers->data, "Record/replay: ");
        exit(1);
    }
    if (!use_icount) {
        error_report("Please enable icount to use record/replay");
        exit(1);
    }

    /* Timer for snapshotting will be set up here. */

    replay_enable_events();
}

void replay_finish(void)
{
    if (replay_mode == REPLAY_MODE_NONE) {
        return;
    }

    replay_save_instructions();

    /* finalize the file */
    if (replay_file) {
        if (replay_mode == REPLAY_MODE_RECORD) {
            /* write end event */
            replay_put_event(EVENT_END);

            /* write header */
            fseek(replay_file, 0, SEEK_SET);
            replay_put_dword(REPLAY_VERSION);
        }

        fclose(replay_file);
        replay_file = NULL;
    }
    if (replay_filename) {
        g_free(replay_filename);
        replay_filename = NULL;
    }

    g_free(replay_snapshot);
    replay_snapshot = NULL;

    replay_finish_events();
}

void replay_add_blocker(Error *reason)
{
    replay_blockers = g_slist_prepend(replay_blockers, reason);
}