replay/replay-debugging.c

   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"
  15 #include "sysemu/runstate.h"
  16 #include "replay-internal.h"
  17 #include "monitor/hmp.h"
  18 #include "monitor/monitor.h"
  19 #include "qapi/qapi-commands-replay.h"
  20 #include "qapi/qmp/qdict.h"
  21 #include "qemu/timer.h"
  22 #include "block/snapshot.h"
  23 #include "migration/snapshot.h"
  24
  25 static bool replay_is_debugging;
  26
  27 bool replay_running_debug(void)
  28 {
  29     return replay_is_debugging;
  30 }
  31
  32 void hmp_info_replay(Monitor *mon, const QDict *qdict)
  33 {
  34     if (replay_mode == REPLAY_MODE_NONE) {
  35         monitor_printf(mon, "Record/replay is not active\n");
  36     } else {
  37         monitor_printf(mon,
  38             "%s execution '%s': instruction count = %"PRId64"\n",
  39             replay_mode == REPLAY_MODE_RECORD ? "Recording" : "Replaying",
  40             replay_get_filename(), replay_get_current_icount());
  41     }
  42 }
  43
  44 ReplayInfo *qmp_query_replay(Error **errp)
  45 {
  46     ReplayInfo *retval = g_new0(ReplayInfo, 1);
  47
  48     retval->mode = replay_mode;
  49     if (replay_get_filename()) {
  50         retval->filename = g_strdup(replay_get_filename());
  51         retval->has_filename = true;
  52     }
  53     retval->icount = replay_get_current_icount();
  54     return retval;
  55 }
  56
  57 static void replay_break(uint64_t icount, QEMUTimerCB callback, void *opaque)
  58 {
  59     assert(replay_mode == REPLAY_MODE_PLAY);
  60     assert(replay_mutex_locked());
  61     assert(replay_break_icount >= replay_get_current_icount());
  62     assert(callback);
  63
  64     replay_break_icount = icount;
  65
  66     if (replay_break_timer) {
  67         timer_del(replay_break_timer);
  68     }
  69     replay_break_timer = timer_new_ns(QEMU_CLOCK_REALTIME,
  70                                       callback, opaque);
  71 }
  72
  73 static void replay_delete_break(void)
  74 {
  75     assert(replay_mode == REPLAY_MODE_PLAY);
  76     assert(replay_mutex_locked());
  77
  78     if (replay_break_timer) {
  79         timer_del(replay_break_timer);
  80         timer_free(replay_break_timer);
  81         replay_break_timer = NULL;
  82     }
  83     replay_break_icount = -1ULL;
  84 }
  85
  86 static void replay_stop_vm(void *opaque)
  87 {
  88     vm_stop(RUN_STATE_PAUSED);
  89     replay_delete_break();
  90 }
  91
  92 void qmp_replay_break(int64_t icount, Error **errp)
  93 {
  94     if (replay_mode == REPLAY_MODE_PLAY) {
  95         if (icount >= replay_get_current_icount()) {
  96             replay_break(icount, replay_stop_vm, NULL);
  97         } else {
  98             error_setg(errp,
  99                 "cannot set breakpoint at the instruction in the past");
 100         }
 101     } else {
 102         error_setg(errp, "setting the breakpoint is allowed only in play mode");
 103     }
 104 }
 105
 106 void hmp_replay_break(Monitor *mon, const QDict *qdict)
 107 {
 108     int64_t icount = qdict_get_try_int(qdict, "icount", -1LL);
 109     Error *err = NULL;
 110
 111     qmp_replay_break(icount, &err);
 112     if (err) {
 113         error_report_err(err);
 114         return;
 115     }
 116 }
 117
 118 void qmp_replay_delete_break(Error **errp)
 119 {
 120     if (replay_mode == REPLAY_MODE_PLAY) {
 121         replay_delete_break();
 122     } else {
 123         error_setg(errp, "replay breakpoints are allowed only in play mode");
 124     }
 125 }
 126
 127 void hmp_replay_delete_break(Monitor *mon, const QDict *qdict)
 128 {
 129     Error *err = NULL;
 130
 131     qmp_replay_delete_break(&err);
 132     if (err) {
 133         error_report_err(err);
 134         return;
 135     }
 136 }
 137
 138 static char *replay_find_nearest_snapshot(int64_t icount,
 139                                           int64_t *snapshot_icount)
 140 {
 141     BlockDriverState *bs;
 142     QEMUSnapshotInfo *sn_tab;
 143     QEMUSnapshotInfo *nearest = NULL;
 144     char *ret = NULL;
 145     int nb_sns, i;
 146     AioContext *aio_context;
 147
 148     *snapshot_icount = -1;
 149
 150     bs = bdrv_all_find_vmstate_bs();
 151     if (!bs) {
 152         goto fail;
 153     }
 154     aio_context = bdrv_get_aio_context(bs);
 155
 156     aio_context_acquire(aio_context);
 157     nb_sns = bdrv_snapshot_list(bs, &sn_tab);
 158     aio_context_release(aio_context);
 159
 160     for (i = 0; i < nb_sns; i++) {
 161         if (bdrv_all_find_snapshot(sn_tab[i].name, &bs) == 0) {
 162             if (sn_tab[i].icount != -1ULL
 163                 && sn_tab[i].icount <= icount
 164                 && (!nearest || nearest->icount < sn_tab[i].icount)) {
 165                 nearest = &sn_tab[i];
 166             }
 167         }
 168     }
 169     if (nearest) {
 170         ret = g_strdup(nearest->name);
 171         *snapshot_icount = nearest->icount;
 172     }
 173     g_free(sn_tab);
 174
 175 fail:
 176     return ret;
 177 }
 178
 179 static void replay_seek(int64_t icount, QEMUTimerCB callback, Error **errp)
 180 {
 181     char *snapshot = NULL;
 182     int64_t snapshot_icount;
 183
 184     if (replay_mode != REPLAY_MODE_PLAY) {
 185         error_setg(errp, "replay must be enabled to seek");
 186         return;
 187     }
 188
 189     snapshot = replay_find_nearest_snapshot(icount, &snapshot_icount);
 190     if (snapshot) {
 191         if (icount < replay_get_current_icount()
 192             || replay_get_current_icount() < snapshot_icount) {
 193             vm_stop(RUN_STATE_RESTORE_VM);
 194             load_snapshot(snapshot, errp);
 195         }
 196         g_free(snapshot);
 197     }
 198     if (replay_get_current_icount() <= icount) {
 199         replay_break(icount, callback, NULL);
 200         vm_start();
 201     } else {
 202         error_setg(errp, "cannot seek to the specified instruction count");
 203     }
 204 }
 205
 206 void qmp_replay_seek(int64_t icount, Error **errp)
 207 {
 208     replay_seek(icount, replay_stop_vm, errp);
 209 }
 210
 211 void hmp_replay_seek(Monitor *mon, const QDict *qdict)
 212 {
 213     int64_t icount = qdict_get_try_int(qdict, "icount", -1LL);
 214     Error *err = NULL;
 215
 216     qmp_replay_seek(icount, &err);
 217     if (err) {
 218         error_report_err(err);
 219         return;
 220     }
 221 }
 222
 223 static void replay_stop_vm_debug(void *opaque)
 224 {
 225     replay_is_debugging = false;
 226     vm_stop(RUN_STATE_DEBUG);
 227     replay_delete_break();
 228 }
 229
 230 bool replay_reverse_step(void)
 231 {
 232     Error *err = NULL;
 233
 234     assert(replay_mode == REPLAY_MODE_PLAY);
 235
 236     if (replay_get_current_icount() != 0) {
 237         replay_seek(replay_get_current_icount() - 1,
 238                     replay_stop_vm_debug, &err);
 239         if (err) {
 240             error_free(err);
 241             return false;
 242         }
 243         replay_is_debugging = true;
 244         return true;
 245     }
 246
 247     return false;
 248 }