xemu/replay/replay-char.c
Alex Bennée d759c951f3 replay: push replay_mutex_lock up the call tree
Now instead of using the replay_lock to guard the output of the log we
now use it to protect the whole execution section. This replaces what
the BQL used to do when it was held during TCG execution.

We also introduce some rules for locking order - mainly that you
cannot take the replay_mutex while holding the BQL. This leads to some
slight sophistry during start-up and extending the
replay_mutex_destroy function to unlock the mutex without checking
for the BQL condition so it can be cleanly dropped in the non-replay
case.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Tested-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20180227095248.1060.40374.stgit@pasha-VirtualBox>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
2018-03-12 17:10:36 +01:00

160 lines
3.8 KiB
C
Executable File

/*
* replay-char.c
*
* Copyright (c) 2010-2016 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 "qemu/error-report.h"
#include "sysemu/replay.h"
#include "replay-internal.h"
#include "sysemu/sysemu.h"
#include "chardev/char.h"
/* Char drivers that generate qemu_chr_be_write events
that should be saved into the log. */
static Chardev **char_drivers;
static int drivers_count;
/* Char event attributes. */
typedef struct CharEvent {
int id;
uint8_t *buf;
size_t len;
} CharEvent;
static int find_char_driver(Chardev *chr)
{
int i = 0;
for ( ; i < drivers_count ; ++i) {
if (char_drivers[i] == chr) {
return i;
}
}
return -1;
}
void replay_register_char_driver(Chardev *chr)
{
if (replay_mode == REPLAY_MODE_NONE) {
return;
}
char_drivers = g_realloc(char_drivers,
sizeof(*char_drivers) * (drivers_count + 1));
char_drivers[drivers_count++] = chr;
}
void replay_chr_be_write(Chardev *s, uint8_t *buf, int len)
{
CharEvent *event = g_malloc0(sizeof(CharEvent));
event->id = find_char_driver(s);
if (event->id < 0) {
fprintf(stderr, "Replay: cannot find char driver\n");
exit(1);
}
event->buf = g_malloc(len);
memcpy(event->buf, buf, len);
event->len = len;
replay_add_event(REPLAY_ASYNC_EVENT_CHAR_READ, event, NULL, 0);
}
void replay_event_char_read_run(void *opaque)
{
CharEvent *event = (CharEvent *)opaque;
qemu_chr_be_write_impl(char_drivers[event->id], event->buf,
(int)event->len);
g_free(event->buf);
g_free(event);
}
void replay_event_char_read_save(void *opaque)
{
CharEvent *event = (CharEvent *)opaque;
replay_put_byte(event->id);
replay_put_array(event->buf, event->len);
}
void *replay_event_char_read_load(void)
{
CharEvent *event = g_malloc0(sizeof(CharEvent));
event->id = replay_get_byte();
replay_get_array_alloc(&event->buf, &event->len);
return event;
}
void replay_char_write_event_save(int res, int offset)
{
g_assert(replay_mutex_locked());
replay_save_instructions();
replay_put_event(EVENT_CHAR_WRITE);
replay_put_dword(res);
replay_put_dword(offset);
}
void replay_char_write_event_load(int *res, int *offset)
{
g_assert(replay_mutex_locked());
replay_account_executed_instructions();
if (replay_next_event_is(EVENT_CHAR_WRITE)) {
*res = replay_get_dword();
*offset = replay_get_dword();
replay_finish_event();
} else {
error_report("Missing character write event in the replay log");
exit(1);
}
}
int replay_char_read_all_load(uint8_t *buf)
{
g_assert(replay_mutex_locked());
if (replay_next_event_is(EVENT_CHAR_READ_ALL)) {
size_t size;
int res;
replay_get_array(buf, &size);
replay_finish_event();
res = (int)size;
assert(res >= 0);
return res;
} else if (replay_next_event_is(EVENT_CHAR_READ_ALL_ERROR)) {
int res = replay_get_dword();
replay_finish_event();
return res;
} else {
error_report("Missing character read all event in the replay log");
exit(1);
}
}
void replay_char_read_all_save_error(int res)
{
g_assert(replay_mutex_locked());
assert(res < 0);
replay_save_instructions();
replay_put_event(EVENT_CHAR_READ_ALL_ERROR);
replay_put_dword(res);
}
void replay_char_read_all_save_buf(uint8_t *buf, int offset)
{
g_assert(replay_mutex_locked());
replay_save_instructions();
replay_put_event(EVENT_CHAR_READ_ALL);
replay_put_array(buf, offset);
}