From f6baed3d1485817e812ac8b275b5b4158384c59e Mon Sep 17 00:00:00 2001 From: Pavel Dovgalyuk Date: Sat, 3 Oct 2020 20:13:31 +0300 Subject: [PATCH] replay: implement replay-seek command This patch adds hmp/qmp commands replay_seek/replay-seek that proceed the execution to the specified instruction count. The command automatically loads nearest snapshot and replays the execution to find the desired instruction count. Signed-off-by: Pavel Dovgalyuk Acked-by: Markus Armbruster -- v4 changes: - fixed HMP command description indent - removed useless error_free call Message-Id: <160174521180.12451.14033112911009278753.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini --- hmp-commands.hx | 18 ++++++++ include/monitor/hmp.h | 1 + qapi/replay.json | 20 +++++++++ replay/replay-debugging.c | 87 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 126 insertions(+) diff --git a/hmp-commands.hx b/hmp-commands.hx index 7680d0b380..e43ce600b8 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -1836,6 +1836,24 @@ SRST The command is ignored when there are no replay breakpoints. ERST + { + .name = "replay_seek", + .args_type = "icount:i", + .params = "icount", + .help = "replay execution to the specified instruction count", + .cmd = hmp_replay_seek, + }, + +SRST +``replay_seek`` *icount* + Automatically proceed to the instruction count *icount*, when + replaying the execution. The command automatically loads nearest + snapshot and replays the execution to find the desired instruction. + When there is no preceding snapshot or the execution is not replayed, + then the command fails. + *icount* for the reference may be observed with ``info replay`` command. +ERST + { .name = "info", .args_type = "item:s?", diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h index 809ad638bb..ed2913fd18 100644 --- a/include/monitor/hmp.h +++ b/include/monitor/hmp.h @@ -132,5 +132,6 @@ void hmp_info_sev(Monitor *mon, const QDict *qdict); void hmp_info_replay(Monitor *mon, const QDict *qdict); void hmp_replay_break(Monitor *mon, const QDict *qdict); void hmp_replay_delete_break(Monitor *mon, const QDict *qdict); +void hmp_replay_seek(Monitor *mon, const QDict *qdict); #endif diff --git a/qapi/replay.json b/qapi/replay.json index 173ba76107..bfd83d7591 100644 --- a/qapi/replay.json +++ b/qapi/replay.json @@ -99,3 +99,23 @@ # ## { 'command': 'replay-delete-break' } + +## +# @replay-seek: +# +# Automatically proceed to the instruction count @icount, when +# replaying the execution. The command automatically loads nearest +# snapshot and replays the execution to find the desired instruction. +# When there is no preceding snapshot or the execution is not replayed, +# then the command fails. +# icount for the reference may be obtained with @query-replay command. +# +# @icount: target instruction count +# +# Since: 5.2 +# +# Example: +# +# -> { "execute": "replay-seek", "data": { "icount": 220414 } } +## +{ 'command': 'replay-seek', 'data': { 'icount': 'int' } } diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c index 3dc23b84fc..e1fe6b8661 100644 --- a/replay/replay-debugging.c +++ b/replay/replay-debugging.c @@ -19,6 +19,8 @@ #include "qapi/qapi-commands-replay.h" #include "qapi/qmp/qdict.h" #include "qemu/timer.h" +#include "block/snapshot.h" +#include "migration/snapshot.h" void hmp_info_replay(Monitor *mon, const QDict *qdict) { @@ -125,3 +127,88 @@ void hmp_replay_delete_break(Monitor *mon, const QDict *qdict) 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; + } +}