4 * Copyright (c) 2010-2015 Institute for System Programming
5 * of the Russian Academy of Sciences.
7 * This work is licensed under the terms of the GNU GPL, version 2 or later.
8 * See the COPYING file in the top-level directory.
12 #include "qemu/osdep.h"
13 #include "sysemu/replay.h"
14 #include "sysemu/runstate.h"
15 #include "replay-internal.h"
16 #include "qemu/error-report.h"
17 #include "qemu/main-loop.h"
19 /* Mutex to protect reading and writing events to the log.
20 data_kind and has_unread_data are also protected
22 It also protects replay events queue which stores events to be
23 written or read to the log. */
24 static QemuMutex lock;
25 /* Condition and queue for fair ordering of mutex lock requests. */
26 static QemuCond mutex_cond;
27 static unsigned long mutex_head, mutex_tail;
29 /* File for replay writing */
30 static bool write_error;
33 static void replay_write_error(void)
36 error_report("replay write error");
41 static void replay_read_error(void)
43 error_report("error reading the replay data");
47 void replay_put_byte(uint8_t byte)
50 if (putc(byte, replay_file) == EOF) {
56 void replay_put_event(uint8_t event)
58 assert(event < EVENT_COUNT);
59 replay_put_byte(event);
63 void replay_put_word(uint16_t word)
65 replay_put_byte(word >> 8);
66 replay_put_byte(word);
69 void replay_put_dword(uint32_t dword)
71 replay_put_word(dword >> 16);
72 replay_put_word(dword);
75 void replay_put_qword(int64_t qword)
77 replay_put_dword(qword >> 32);
78 replay_put_dword(qword);
81 void replay_put_array(const uint8_t *buf, size_t size)
84 replay_put_dword(size);
85 if (fwrite(buf, 1, size, replay_file) != size) {
91 uint8_t replay_get_byte(void)
95 int r = getc(replay_file);
104 uint16_t replay_get_word(void)
108 word = replay_get_byte();
109 word = (word << 8) + replay_get_byte();
115 uint32_t replay_get_dword(void)
119 dword = replay_get_word();
120 dword = (dword << 16) + replay_get_word();
126 int64_t replay_get_qword(void)
130 qword = replay_get_dword();
131 qword = (qword << 32) + replay_get_dword();
137 void replay_get_array(uint8_t *buf, size_t *size)
140 *size = replay_get_dword();
141 if (fread(buf, 1, *size, replay_file) != *size) {
147 void replay_get_array_alloc(uint8_t **buf, size_t *size)
150 *size = replay_get_dword();
151 *buf = g_malloc(*size);
152 if (fread(*buf, 1, *size, replay_file) != *size) {
158 void replay_check_error(void)
161 if (feof(replay_file)) {
162 error_report("replay file is over");
163 qemu_system_vmstop_request_prepare();
164 qemu_system_vmstop_request(RUN_STATE_PAUSED);
165 } else if (ferror(replay_file)) {
166 error_report("replay file is over or something goes wrong");
167 qemu_system_vmstop_request_prepare();
168 qemu_system_vmstop_request(RUN_STATE_INTERNAL_ERROR);
173 void replay_fetch_data_kind(void)
176 if (!replay_state.has_unread_data) {
177 replay_state.data_kind = replay_get_byte();
178 if (replay_state.data_kind == EVENT_INSTRUCTION) {
179 replay_state.instruction_count = replay_get_dword();
181 replay_check_error();
182 replay_state.has_unread_data = 1;
183 if (replay_state.data_kind >= EVENT_COUNT) {
184 error_report("Replay: unknown event kind %d",
185 replay_state.data_kind);
192 void replay_finish_event(void)
194 replay_state.has_unread_data = 0;
195 replay_fetch_data_kind();
198 static __thread bool replay_locked;
200 void replay_mutex_init(void)
202 qemu_mutex_init(&lock);
203 qemu_cond_init(&mutex_cond);
204 /* Hold the mutex while we start-up */
205 replay_locked = true;
209 bool replay_mutex_locked(void)
211 return replay_locked;
214 /* Ordering constraints, replay_lock must be taken before BQL */
215 void replay_mutex_lock(void)
217 if (replay_mode != REPLAY_MODE_NONE) {
219 g_assert(!qemu_mutex_iothread_locked());
220 g_assert(!replay_mutex_locked());
221 qemu_mutex_lock(&lock);
223 while (id != mutex_head) {
224 qemu_cond_wait(&mutex_cond, &lock);
226 replay_locked = true;
227 qemu_mutex_unlock(&lock);
231 void replay_mutex_unlock(void)
233 if (replay_mode != REPLAY_MODE_NONE) {
234 g_assert(replay_mutex_locked());
235 qemu_mutex_lock(&lock);
237 replay_locked = false;
238 qemu_cond_broadcast(&mutex_cond);
239 qemu_mutex_unlock(&lock);
243 void replay_advance_current_icount(uint64_t current_icount)
245 int diff = (int)(current_icount - replay_state.current_icount);
247 /* Time can only go forward */
250 if (replay_mode == REPLAY_MODE_RECORD) {
252 replay_put_event(EVENT_INSTRUCTION);
253 replay_put_dword(diff);
254 replay_state.current_icount += diff;
256 } else if (replay_mode == REPLAY_MODE_PLAY) {
258 replay_state.instruction_count -= diff;
259 replay_state.current_icount += diff;
260 if (replay_state.instruction_count == 0) {
261 assert(replay_state.data_kind == EVENT_INSTRUCTION);
262 replay_finish_event();
263 /* Wake up iothread. This is required because
264 timers will not expire until clock counters
265 will be read from the log. */
269 /* Execution reached the break step */
270 if (replay_break_icount == replay_state.current_icount) {
271 /* Cannot make callback directly from the vCPU thread */
272 timer_mod_ns(replay_break_timer,
273 qemu_clock_get_ns(QEMU_CLOCK_REALTIME));
278 /*! Saves cached instructions. */
279 void replay_save_instructions(void)
281 if (replay_file && replay_mode == REPLAY_MODE_RECORD) {
282 g_assert(replay_mutex_locked());
283 replay_advance_current_icount(replay_get_current_icount());