diff options
Diffstat (limited to 'replay/replay-debugging.c')
| -rw-r--r-- | replay/replay-debugging.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c new file mode 100644 index 0000000000..ee9e86daa9 --- /dev/null +++ b/replay/replay-debugging.c @@ -0,0 +1,334 @@ +/* + * replay-debugging.c + * + * Copyright (c) 2010-2020 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 "sysemu/runstate.h" +#include "replay-internal.h" +#include "monitor/hmp.h" +#include "monitor/monitor.h" +#include "qapi/qapi-commands-replay.h" +#include "qapi/qmp/qdict.h" +#include "qemu/timer.h" +#include "block/snapshot.h" +#include "migration/snapshot.h" + +static bool replay_is_debugging; +static int64_t replay_last_breakpoint; +static int64_t replay_last_snapshot; + +bool replay_running_debug(void) +{ + return replay_is_debugging; +} + +void hmp_info_replay(Monitor *mon, const QDict *qdict) +{ + if (replay_mode == REPLAY_MODE_NONE) { + monitor_printf(mon, "Record/replay is not active\n"); + } else { + monitor_printf(mon, + "%s execution '%s': instruction count = %"PRId64"\n", + replay_mode == REPLAY_MODE_RECORD ? "Recording" : "Replaying", + replay_get_filename(), replay_get_current_icount()); + } +} + +ReplayInfo *qmp_query_replay(Error **errp) +{ + ReplayInfo *retval = g_new0(ReplayInfo, 1); + + retval->mode = replay_mode; + if (replay_get_filename()) { + retval->filename = g_strdup(replay_get_filename()); + retval->has_filename = true; + } + retval->icount = replay_get_current_icount(); + return retval; +} + +static void replay_break(uint64_t icount, QEMUTimerCB callback, void *opaque) +{ + assert(replay_mode == REPLAY_MODE_PLAY); + assert(replay_mutex_locked()); + assert(replay_break_icount >= replay_get_current_icount()); + assert(callback); + + replay_break_icount = icount; + + if (replay_break_timer) { + timer_del(replay_break_timer); + } + replay_break_timer = timer_new_ns(QEMU_CLOCK_REALTIME, + callback, opaque); +} + +static void replay_delete_break(void) +{ + assert(replay_mode == REPLAY_MODE_PLAY); + assert(replay_mutex_locked()); + + if (replay_break_timer) { + timer_del(replay_break_timer); + timer_free(replay_break_timer); + replay_break_timer = NULL; + } + replay_break_icount = -1ULL; +} + +static void replay_stop_vm(void *opaque) +{ + vm_stop(RUN_STATE_PAUSED); + replay_delete_break(); +} + +void qmp_replay_break(int64_t icount, Error **errp) +{ + if (replay_mode == REPLAY_MODE_PLAY) { + if (icount >= replay_get_current_icount()) { + replay_break(icount, replay_stop_vm, NULL); + } else { + error_setg(errp, + "cannot set breakpoint at the instruction in the past"); + } + } else { + error_setg(errp, "setting the breakpoint is allowed only in play mode"); + } +} + +void hmp_replay_break(Monitor *mon, const QDict *qdict) +{ + int64_t icount = qdict_get_try_int(qdict, "icount", -1LL); + Error *err = NULL; + + qmp_replay_break(icount, &err); + if (err) { + error_report_err(err); + return; + } +} + +void qmp_replay_delete_break(Error **errp) +{ + if (replay_mode == REPLAY_MODE_PLAY) { + replay_delete_break(); + } else { + error_setg(errp, "replay breakpoints are allowed only in play mode"); + } +} + +void hmp_replay_delete_break(Monitor *mon, const QDict *qdict) +{ + Error *err = NULL; + + qmp_replay_delete_break(&err); + if (err) { + error_report_err(err); + return; + } +} + +static char *replay_find_nearest_snapshot(int64_t icount, + int64_t *snapshot_icount) +{ + BlockDriverState *bs; + QEMUSnapshotInfo *sn_tab; + QEMUSnapshotInfo *nearest = NULL; + char *ret = NULL; + int nb_sns, i; + AioContext *aio_context; + + *snapshot_icount = -1; + + bs = bdrv_all_find_vmstate_bs(); + if (!bs) { + goto fail; + } + aio_context = bdrv_get_aio_context(bs); + + aio_context_acquire(aio_context); + nb_sns = bdrv_snapshot_list(bs, &sn_tab); + aio_context_release(aio_context); + + for (i = 0; i < nb_sns; i++) { + if (bdrv_all_find_snapshot(sn_tab[i].name, &bs) == 0) { + if (sn_tab[i].icount != -1ULL + && sn_tab[i].icount <= icount + && (!nearest || nearest->icount < sn_tab[i].icount)) { + nearest = &sn_tab[i]; + } + } + } + if (nearest) { + ret = g_strdup(nearest->name); + *snapshot_icount = nearest->icount; + } + g_free(sn_tab); + +fail: + return ret; +} + +static void replay_seek(int64_t icount, QEMUTimerCB callback, Error **errp) +{ + char *snapshot = NULL; + int64_t snapshot_icount; + + if (replay_mode != REPLAY_MODE_PLAY) { + error_setg(errp, "replay must be enabled to seek"); + return; + } + + snapshot = replay_find_nearest_snapshot(icount, &snapshot_icount); + if (snapshot) { + if (icount < replay_get_current_icount() + || replay_get_current_icount() < snapshot_icount) { + vm_stop(RUN_STATE_RESTORE_VM); + load_snapshot(snapshot, errp); + } + g_free(snapshot); + } + if (replay_get_current_icount() <= icount) { + replay_break(icount, callback, NULL); + vm_start(); + } else { + error_setg(errp, "cannot seek to the specified instruction count"); + } +} + +void qmp_replay_seek(int64_t icount, Error **errp) +{ + replay_seek(icount, replay_stop_vm, errp); +} + +void hmp_replay_seek(Monitor *mon, const QDict *qdict) +{ + int64_t icount = qdict_get_try_int(qdict, "icount", -1LL); + Error *err = NULL; + + qmp_replay_seek(icount, &err); + if (err) { + error_report_err(err); + return; + } +} + +static void replay_stop_vm_debug(void *opaque) +{ + replay_is_debugging = false; + vm_stop(RUN_STATE_DEBUG); + replay_delete_break(); +} + +bool replay_reverse_step(void) +{ + Error *err = NULL; + + assert(replay_mode == REPLAY_MODE_PLAY); + + if (replay_get_current_icount() != 0) { + replay_seek(replay_get_current_icount() - 1, + replay_stop_vm_debug, &err); + if (err) { + error_free(err); + return false; + } + replay_is_debugging = true; + return true; + } + + return false; +} + +static void replay_continue_end(void) +{ + replay_is_debugging = false; + vm_stop(RUN_STATE_DEBUG); + replay_delete_break(); +} + +static void replay_continue_stop(void *opaque) +{ + Error *err = NULL; + if (replay_last_breakpoint != -1LL) { + replay_seek(replay_last_breakpoint, replay_stop_vm_debug, &err); + if (err) { + error_free(err); + replay_continue_end(); + } + return; + } + /* + * No breakpoints since the last snapshot. + * Find previous snapshot and try again. + */ + if (replay_last_snapshot != 0) { + replay_seek(replay_last_snapshot - 1, replay_continue_stop, &err); + if (err) { + error_free(err); + replay_continue_end(); + } + replay_last_snapshot = replay_get_current_icount(); + return; + } else { + /* Seek to the very first step */ + replay_seek(0, replay_stop_vm_debug, &err); + if (err) { + error_free(err); + replay_continue_end(); + } + return; + } + replay_continue_end(); +} + +bool replay_reverse_continue(void) +{ + Error *err = NULL; + + assert(replay_mode == REPLAY_MODE_PLAY); + + if (replay_get_current_icount() != 0) { + replay_seek(replay_get_current_icount() - 1, + replay_continue_stop, &err); + if (err) { + error_free(err); + return false; + } + replay_last_breakpoint = -1LL; + replay_is_debugging = true; + replay_last_snapshot = replay_get_current_icount(); + return true; + } + + return false; +} + +void replay_breakpoint(void) +{ + assert(replay_mode == REPLAY_MODE_PLAY); + replay_last_breakpoint = replay_get_current_icount(); +} + +void replay_gdb_attached(void) +{ + /* + * Create VM snapshot on temporary overlay to allow reverse + * debugging even if snapshots were not enabled. + */ + if (replay_mode == REPLAY_MODE_PLAY + && !replay_snapshot) { + if (save_snapshot("start_debugging", NULL) != 0) { + /* Can't create the snapshot. Continue conventional debugging. */ + } + } +} |