replay/replay-debugging.c - qemu - Git at Google

 /*
  * 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_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();
     } else {
         /* Seek to the very first step */
         replay_seek(0, replay_stop_vm_debug, &err);
         if (err) {
             error_free(err);
             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. */
         }
     }
 }
	/*
	* 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_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();
	} else {
	/* Seek to the very first step */
	replay_seek(0, replay_stop_vm_debug, &err);
	if (err) {
	error_free(err);
	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. */
	}
	}
	}