gdbstub: add reverse step support in replay mode

[mirror_qemu.git] / include / sysemu / replay.h

#ifndef REPLAY_H
#define REPLAY_H

/*
 * replay.h
 *
 * 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 "qapi/qapi-types-misc.h"
#include "qapi/qapi-types-run-state.h"
#include "qapi/qapi-types-replay.h"
#include "qapi/qapi-types-ui.h"
#include "block/aio.h"

/* replay clock kinds */
enum ReplayClockKind {
    /* host_clock */
    REPLAY_CLOCK_HOST,
    /* virtual_rt_clock */
    REPLAY_CLOCK_VIRTUAL_RT,
    REPLAY_CLOCK_COUNT
};
typedef enum ReplayClockKind ReplayClockKind;

/* IDs of the checkpoints */
enum ReplayCheckpoint {
    CHECKPOINT_CLOCK_WARP_START,
    CHECKPOINT_CLOCK_WARP_ACCOUNT,
    CHECKPOINT_RESET_REQUESTED,
    CHECKPOINT_SUSPEND_REQUESTED,
    CHECKPOINT_CLOCK_VIRTUAL,
    CHECKPOINT_CLOCK_HOST,
    CHECKPOINT_CLOCK_VIRTUAL_RT,
    CHECKPOINT_INIT,
    CHECKPOINT_RESET,
    CHECKPOINT_COUNT
};
typedef enum ReplayCheckpoint ReplayCheckpoint;

typedef struct ReplayNetState ReplayNetState;

extern ReplayMode replay_mode;

/* Name of the initial VM snapshot */
extern char *replay_snapshot;

/* Replay locking
 *
 * The locks are needed to protect the shared structures and log file
 * when doing record/replay. They also are the main sync-point between
 * the main-loop thread and the vCPU thread. This was a role
 * previously filled by the BQL which has been busy trying to reduce
 * its impact across the code. This ensures blocks of events stay
 * sequential and reproducible.
 */

void replay_mutex_lock(void);
void replay_mutex_unlock(void);

/* Replay process control functions */

/*! Enables recording or saving event log with specified parameters */
void replay_configure(struct QemuOpts *opts);
/*! Initializes timers used for snapshotting and enables events recording */
void replay_start(void);
/*! Closes replay log file and frees other resources. */
void replay_finish(void);
/*! Adds replay blocker with the specified error description */
void replay_add_blocker(Error *reason);
/* Returns name of the replay log file */
const char *replay_get_filename(void);
/*
 * Start making one step in backward direction.
 * Used by gdbstub for backwards debugging.
 * Returns true on success.
 */
bool replay_reverse_step(void);
/*
 * Returns true if replay module is processing
 * reverse_continue or reverse_step request
 */
bool replay_running_debug(void);

/* Processing the instructions */

/*! Returns number of executed instructions. */
uint64_t replay_get_current_icount(void);
/*! Returns number of instructions to execute in replay mode. */
int replay_get_instructions(void);
/*! Updates instructions counter in replay mode. */
void replay_account_executed_instructions(void);

/* Interrupts and exceptions */

/*! Called by exception handler to write or read
    exception processing events. */
bool replay_exception(void);
/*! Used to determine that exception is pending.
    Does not proceed to the next event in the log. */
bool replay_has_exception(void);
/*! Called by interrupt handlers to write or read
    interrupt processing events.
    \return true if interrupt should be processed */
bool replay_interrupt(void);
/*! Tries to read interrupt event from the file.
    Returns true, when interrupt request is pending */
bool replay_has_interrupt(void);

/* Processing clocks and other time sources */

/*! Save the specified clock */
int64_t replay_save_clock(ReplayClockKind kind, int64_t clock,
                          int64_t raw_icount);
/*! Read the specified clock from the log or return cached data */
int64_t replay_read_clock(ReplayClockKind kind);
/*! Saves or reads the clock depending on the current replay mode. */
#define REPLAY_CLOCK(clock, value)                                      \
    (replay_mode == REPLAY_MODE_PLAY ? replay_read_clock((clock))       \
        : replay_mode == REPLAY_MODE_RECORD                             \
            ? replay_save_clock((clock), (value), icount_get_raw()) \
        : (value))
#define REPLAY_CLOCK_LOCKED(clock, value)                               \
    (replay_mode == REPLAY_MODE_PLAY ? replay_read_clock((clock))       \
        : replay_mode == REPLAY_MODE_RECORD                             \
            ? replay_save_clock((clock), (value), icount_get_raw_locked()) \
        : (value))

/* Processing data from random generators */

/* Saves the values from the random number generator */
void replay_save_random(int ret, void *buf, size_t len);
/* Loads the saved values for the random number generator */
int replay_read_random(void *buf, size_t len);

/* Events */

/*! Called when qemu shutdown is requested. */
void replay_shutdown_request(ShutdownCause cause);
/*! Should be called at check points in the execution.
    These check points are skipped, if they were not met.
    Saves checkpoint in the SAVE mode and validates in the PLAY mode.
    Returns 0 in PLAY mode if checkpoint was not found.
    Returns 1 in all other cases. */
bool replay_checkpoint(ReplayCheckpoint checkpoint);
/*! Used to determine that checkpoint is pending.
    Does not proceed to the next event in the log. */
bool replay_has_checkpoint(void);

/* Asynchronous events queue */

/*! Disables storing events in the queue */
void replay_disable_events(void);
/*! Enables storing events in the queue */
void replay_enable_events(void);
/*! Returns true when saving events is enabled */
bool replay_events_enabled(void);
/* Flushes events queue */
void replay_flush_events(void);
/*! Adds bottom half event to the queue */
void replay_bh_schedule_event(QEMUBH *bh);
/* Adds oneshot bottom half event to the queue */
void replay_bh_schedule_oneshot_event(AioContext *ctx,
    QEMUBHFunc *cb, void *opaque);
/*! Adds input event to the queue */
void replay_input_event(QemuConsole *src, InputEvent *evt);
/*! Adds input sync event to the queue */
void replay_input_sync_event(void);
/*! Adds block layer event to the queue */
void replay_block_event(QEMUBH *bh, uint64_t id);
/*! Returns ID for the next block event */
uint64_t blkreplay_next_id(void);

/* Character device */

/*! Registers char driver to save it's events */
void replay_register_char_driver(struct Chardev *chr);
/*! Saves write to char device event to the log */
void replay_chr_be_write(struct Chardev *s, uint8_t *buf, int len);
/*! Writes char write return value to the replay log. */
void replay_char_write_event_save(int res, int offset);
/*! Reads char write return value from the replay log. */
void replay_char_write_event_load(int *res, int *offset);
/*! Reads information about read_all character event. */
int replay_char_read_all_load(uint8_t *buf);
/*! Writes character read_all error code into the replay log. */
void replay_char_read_all_save_error(int res);
/*! Writes character read_all execution result into the replay log. */
void replay_char_read_all_save_buf(uint8_t *buf, int offset);

/* Network */

/*! Registers replay network filter attached to some backend. */
ReplayNetState *replay_register_net(NetFilterState *nfs);
/*! Unregisters replay network filter. */
void replay_unregister_net(ReplayNetState *rns);
/*! Called to write network packet to the replay log. */
void replay_net_packet_event(ReplayNetState *rns, unsigned flags,
                             const struct iovec *iov, int iovcnt);

/* Audio */

/*! Saves/restores number of played samples of audio out operation. */
void replay_audio_out(size_t *played);
/*! Saves/restores recorded samples of audio in operation. */
void replay_audio_in(size_t *recorded, void *samples, size_t *wpos, size_t size);

/* VM state operations */

/*! Called at the start of execution.
    Loads or saves initial vmstate depending on execution mode. */
void replay_vmstate_init(void);
/*! Called to ensure that replay state is consistent and VM snapshot
    can be created */
bool replay_can_snapshot(void);

#endif