qemu/replay/replay.c
Pavel Dovgalyuk 7cebff0d03 replay: fix recursive checkpoints
Record/replay uses checkpoints to synchronize the execution
of the threads and timers. Hardware events such as BH are
processed at the checkpoints too.
Event processing can cause refreshing the virtual timers
and calling the icount-related functions, that also use checkpoints.
This patch prevents recursive processing of such checkpoints,
because they have their own records in the log and should be
processed later.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Message-Id: <161700476500.1140362.10108444973730452257.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-01 09:40:45 +02:00

404 lines
10 KiB
C

/*
* replay.c
*
* 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 "qemu/osdep.h"
#include "qapi/error.h"
#include "sysemu/cpu-timers.h"
#include "sysemu/replay.h"
#include "sysemu/runstate.h"
#include "replay-internal.h"
#include "qemu/main-loop.h"
#include "qemu/option.h"
#include "sysemu/cpus.h"
#include "qemu/error-report.h"
/* Current version of the replay mechanism.
Increase it when file format changes. */
#define REPLAY_VERSION 0xe0200a
/* Size of replay log header */
#define HEADER_SIZE (sizeof(uint32_t) + sizeof(uint64_t))
ReplayMode replay_mode = REPLAY_MODE_NONE;
char *replay_snapshot;
/* Name of replay file */
static char *replay_filename;
ReplayState replay_state;
static GSList *replay_blockers;
/* Replay breakpoints */
uint64_t replay_break_icount = -1ULL;
QEMUTimer *replay_break_timer;
bool replay_next_event_is(int event)
{
bool res = false;
/* nothing to skip - not all instructions used */
if (replay_state.instruction_count != 0) {
assert(replay_state.data_kind == EVENT_INSTRUCTION);
return event == EVENT_INSTRUCTION;
}
while (true) {
unsigned int data_kind = replay_state.data_kind;
if (event == data_kind) {
res = true;
}
switch (data_kind) {
case EVENT_SHUTDOWN ... EVENT_SHUTDOWN_LAST:
replay_finish_event();
qemu_system_shutdown_request(data_kind - EVENT_SHUTDOWN);
break;
default:
/* clock, time_t, checkpoint and other events */
return res;
}
}
return res;
}
uint64_t replay_get_current_icount(void)
{
return icount_get_raw();
}
int replay_get_instructions(void)
{
int res = 0;
replay_mutex_lock();
if (replay_next_event_is(EVENT_INSTRUCTION)) {
res = replay_state.instruction_count;
if (replay_break_icount != -1LL) {
uint64_t current = replay_get_current_icount();
assert(replay_break_icount >= current);
if (current + res > replay_break_icount) {
res = replay_break_icount - current;
}
}
}
replay_mutex_unlock();
return res;
}
void replay_account_executed_instructions(void)
{
if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
if (replay_state.instruction_count > 0) {
replay_advance_current_icount(replay_get_current_icount());
}
}
}
bool replay_exception(void)
{
if (replay_mode == REPLAY_MODE_RECORD) {
g_assert(replay_mutex_locked());
replay_save_instructions();
replay_put_event(EVENT_EXCEPTION);
return true;
} else if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
bool res = replay_has_exception();
if (res) {
replay_finish_event();
}
return res;
}
return true;
}
bool replay_has_exception(void)
{
bool res = false;
if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
replay_account_executed_instructions();
res = replay_next_event_is(EVENT_EXCEPTION);
}
return res;
}
bool replay_interrupt(void)
{
if (replay_mode == REPLAY_MODE_RECORD) {
g_assert(replay_mutex_locked());
replay_save_instructions();
replay_put_event(EVENT_INTERRUPT);
return true;
} else if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
bool res = replay_has_interrupt();
if (res) {
replay_finish_event();
}
return res;
}
return true;
}
bool replay_has_interrupt(void)
{
bool res = false;
if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
replay_account_executed_instructions();
res = replay_next_event_is(EVENT_INTERRUPT);
}
return res;
}
void replay_shutdown_request(ShutdownCause cause)
{
if (replay_mode == REPLAY_MODE_RECORD) {
g_assert(replay_mutex_locked());
replay_put_event(EVENT_SHUTDOWN + cause);
}
}
bool replay_checkpoint(ReplayCheckpoint checkpoint)
{
bool res = false;
static bool in_checkpoint;
assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);
if (!replay_file) {
return true;
}
if (in_checkpoint) {
/*
Recursion occurs when HW event modifies timers.
Prevent performing icount warp in this case and
wait for another invocation of the checkpoint.
*/
g_assert(replay_mode == REPLAY_MODE_PLAY);
return false;
}
in_checkpoint = true;
replay_save_instructions();
if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
if (replay_next_event_is(EVENT_CHECKPOINT + checkpoint)) {
replay_finish_event();
} else if (replay_state.data_kind != EVENT_ASYNC) {
res = false;
goto out;
}
replay_read_events(checkpoint);
/* replay_read_events may leave some unread events.
Return false if not all of the events associated with
checkpoint were processed */
res = replay_state.data_kind != EVENT_ASYNC;
} else if (replay_mode == REPLAY_MODE_RECORD) {
g_assert(replay_mutex_locked());
replay_put_event(EVENT_CHECKPOINT + checkpoint);
/* This checkpoint belongs to several threads.
Processing events from different threads is
non-deterministic */
if (checkpoint != CHECKPOINT_CLOCK_WARP_START
/* FIXME: this is temporary fix, other checkpoints
may also be invoked from the different threads someday.
Asynchronous event processing should be refactored
to create additional replay event kind which is
nailed to the one of the threads and which processes
the event queue. */
&& checkpoint != CHECKPOINT_CLOCK_VIRTUAL) {
replay_save_events(checkpoint);
}
res = true;
}
out:
in_checkpoint = false;
return res;
}
bool replay_has_checkpoint(void)
{
bool res = false;
if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
replay_account_executed_instructions();
res = EVENT_CHECKPOINT <= replay_state.data_kind
&& replay_state.data_kind <= EVENT_CHECKPOINT_LAST;
}
return res;
}
static void replay_enable(const char *fname, int mode)
{
const char *fmode = NULL;
assert(!replay_file);
switch (mode) {
case REPLAY_MODE_RECORD:
fmode = "wb";
break;
case REPLAY_MODE_PLAY:
fmode = "rb";
break;
default:
fprintf(stderr, "Replay: internal error: invalid replay mode\n");
exit(1);
}
atexit(replay_finish);
replay_file = fopen(fname, fmode);
if (replay_file == NULL) {
fprintf(stderr, "Replay: open %s: %s\n", fname, strerror(errno));
exit(1);
}
replay_filename = g_strdup(fname);
replay_mode = mode;
replay_mutex_init();
replay_state.data_kind = -1;
replay_state.instruction_count = 0;
replay_state.current_icount = 0;
replay_state.has_unread_data = 0;
/* skip file header for RECORD and check it for PLAY */
if (replay_mode == REPLAY_MODE_RECORD) {
fseek(replay_file, HEADER_SIZE, SEEK_SET);
} else if (replay_mode == REPLAY_MODE_PLAY) {
unsigned int version = replay_get_dword();
if (version != REPLAY_VERSION) {
fprintf(stderr, "Replay: invalid input log file version\n");
exit(1);
}
/* go to the beginning */
fseek(replay_file, HEADER_SIZE, SEEK_SET);
replay_fetch_data_kind();
}
replay_init_events();
}
void replay_configure(QemuOpts *opts)
{
const char *fname;
const char *rr;
ReplayMode mode = REPLAY_MODE_NONE;
Location loc;
if (!opts) {
return;
}
loc_push_none(&loc);
qemu_opts_loc_restore(opts);
rr = qemu_opt_get(opts, "rr");
if (!rr) {
/* Just enabling icount */
goto out;
} else if (!strcmp(rr, "record")) {
mode = REPLAY_MODE_RECORD;
} else if (!strcmp(rr, "replay")) {
mode = REPLAY_MODE_PLAY;
} else {
error_report("Invalid icount rr option: %s", rr);
exit(1);
}
fname = qemu_opt_get(opts, "rrfile");
if (!fname) {
error_report("File name not specified for replay");
exit(1);
}
replay_snapshot = g_strdup(qemu_opt_get(opts, "rrsnapshot"));
replay_vmstate_register();
replay_enable(fname, mode);
out:
loc_pop(&loc);
}
void replay_start(void)
{
if (replay_mode == REPLAY_MODE_NONE) {
return;
}
if (replay_blockers) {
error_reportf_err(replay_blockers->data, "Record/replay: ");
exit(1);
}
if (!icount_enabled()) {
error_report("Please enable icount to use record/replay");
exit(1);
}
/* Timer for snapshotting will be set up here. */
replay_enable_events();
}
void replay_finish(void)
{
if (replay_mode == REPLAY_MODE_NONE) {
return;
}
replay_save_instructions();
/* finalize the file */
if (replay_file) {
if (replay_mode == REPLAY_MODE_RECORD) {
/*
* Can't do it in the signal handler, therefore
* add shutdown event here for the case of Ctrl-C.
*/
replay_shutdown_request(SHUTDOWN_CAUSE_HOST_SIGNAL);
/* write end event */
replay_put_event(EVENT_END);
/* write header */
fseek(replay_file, 0, SEEK_SET);
replay_put_dword(REPLAY_VERSION);
}
fclose(replay_file);
replay_file = NULL;
}
if (replay_filename) {
g_free(replay_filename);
replay_filename = NULL;
}
g_free(replay_snapshot);
replay_snapshot = NULL;
replay_mode = REPLAY_MODE_NONE;
replay_finish_events();
}
void replay_add_blocker(Error *reason)
{
replay_blockers = g_slist_prepend(replay_blockers, reason);
}
const char *replay_get_filename(void)
{
return replay_filename;
}