ppc/pnv: add a PnvICPState object
[qemu.git] / cpu-exec.c
1 /*
2 * emulator main execution loop
3 *
4 * Copyright (c) 2003-2005 Fabrice Bellard
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 */
19 #include "qemu/osdep.h"
20 #include "cpu.h"
21 #include "trace-root.h"
22 #include "disas/disas.h"
23 #include "exec/exec-all.h"
24 #include "tcg.h"
25 #include "qemu/atomic.h"
26 #include "sysemu/qtest.h"
27 #include "qemu/timer.h"
28 #include "exec/address-spaces.h"
29 #include "qemu/rcu.h"
30 #include "exec/tb-hash.h"
31 #include "exec/log.h"
32 #include "qemu/main-loop.h"
33 #if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
34 #include "hw/i386/apic.h"
35 #endif
36 #include "sysemu/cpus.h"
37 #include "sysemu/replay.h"
38
39 /* -icount align implementation. */
40
41 typedef struct SyncClocks {
42 int64_t diff_clk;
43 int64_t last_cpu_icount;
44 int64_t realtime_clock;
45 } SyncClocks;
46
47 #if !defined(CONFIG_USER_ONLY)
48 /* Allow the guest to have a max 3ms advance.
49 * The difference between the 2 clocks could therefore
50 * oscillate around 0.
51 */
52 #define VM_CLOCK_ADVANCE 3000000
53 #define THRESHOLD_REDUCE 1.5
54 #define MAX_DELAY_PRINT_RATE 2000000000LL
55 #define MAX_NB_PRINTS 100
56
57 static void align_clocks(SyncClocks *sc, const CPUState *cpu)
58 {
59 int64_t cpu_icount;
60
61 if (!icount_align_option) {
62 return;
63 }
64
65 cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
66 sc->diff_clk += cpu_icount_to_ns(sc->last_cpu_icount - cpu_icount);
67 sc->last_cpu_icount = cpu_icount;
68
69 if (sc->diff_clk > VM_CLOCK_ADVANCE) {
70 #ifndef _WIN32
71 struct timespec sleep_delay, rem_delay;
72 sleep_delay.tv_sec = sc->diff_clk / 1000000000LL;
73 sleep_delay.tv_nsec = sc->diff_clk % 1000000000LL;
74 if (nanosleep(&sleep_delay, &rem_delay) < 0) {
75 sc->diff_clk = rem_delay.tv_sec * 1000000000LL + rem_delay.tv_nsec;
76 } else {
77 sc->diff_clk = 0;
78 }
79 #else
80 Sleep(sc->diff_clk / SCALE_MS);
81 sc->diff_clk = 0;
82 #endif
83 }
84 }
85
86 static void print_delay(const SyncClocks *sc)
87 {
88 static float threshold_delay;
89 static int64_t last_realtime_clock;
90 static int nb_prints;
91
92 if (icount_align_option &&
93 sc->realtime_clock - last_realtime_clock >= MAX_DELAY_PRINT_RATE &&
94 nb_prints < MAX_NB_PRINTS) {
95 if ((-sc->diff_clk / (float)1000000000LL > threshold_delay) ||
96 (-sc->diff_clk / (float)1000000000LL <
97 (threshold_delay - THRESHOLD_REDUCE))) {
98 threshold_delay = (-sc->diff_clk / 1000000000LL) + 1;
99 printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
100 threshold_delay - 1,
101 threshold_delay);
102 nb_prints++;
103 last_realtime_clock = sc->realtime_clock;
104 }
105 }
106 }
107
108 static void init_delay_params(SyncClocks *sc,
109 const CPUState *cpu)
110 {
111 if (!icount_align_option) {
112 return;
113 }
114 sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
115 sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - sc->realtime_clock;
116 sc->last_cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
117 if (sc->diff_clk < max_delay) {
118 max_delay = sc->diff_clk;
119 }
120 if (sc->diff_clk > max_advance) {
121 max_advance = sc->diff_clk;
122 }
123
124 /* Print every 2s max if the guest is late. We limit the number
125 of printed messages to NB_PRINT_MAX(currently 100) */
126 print_delay(sc);
127 }
128 #else
129 static void align_clocks(SyncClocks *sc, const CPUState *cpu)
130 {
131 }
132
133 static void init_delay_params(SyncClocks *sc, const CPUState *cpu)
134 {
135 }
136 #endif /* CONFIG USER ONLY */
137
138 /* Execute a TB, and fix up the CPU state afterwards if necessary */
139 static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, TranslationBlock *itb)
140 {
141 CPUArchState *env = cpu->env_ptr;
142 uintptr_t ret;
143 TranslationBlock *last_tb;
144 int tb_exit;
145 uint8_t *tb_ptr = itb->tc_ptr;
146
147 qemu_log_mask_and_addr(CPU_LOG_EXEC, itb->pc,
148 "Trace %p [%d: " TARGET_FMT_lx "] %s\n",
149 itb->tc_ptr, cpu->cpu_index, itb->pc,
150 lookup_symbol(itb->pc));
151
152 #if defined(DEBUG_DISAS)
153 if (qemu_loglevel_mask(CPU_LOG_TB_CPU)
154 && qemu_log_in_addr_range(itb->pc)) {
155 qemu_log_lock();
156 #if defined(TARGET_I386)
157 log_cpu_state(cpu, CPU_DUMP_CCOP);
158 #else
159 log_cpu_state(cpu, 0);
160 #endif
161 qemu_log_unlock();
162 }
163 #endif /* DEBUG_DISAS */
164
165 cpu->can_do_io = !use_icount;
166 ret = tcg_qemu_tb_exec(env, tb_ptr);
167 cpu->can_do_io = 1;
168 last_tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK);
169 tb_exit = ret & TB_EXIT_MASK;
170 trace_exec_tb_exit(last_tb, tb_exit);
171
172 if (tb_exit > TB_EXIT_IDX1) {
173 /* We didn't start executing this TB (eg because the instruction
174 * counter hit zero); we must restore the guest PC to the address
175 * of the start of the TB.
176 */
177 CPUClass *cc = CPU_GET_CLASS(cpu);
178 qemu_log_mask_and_addr(CPU_LOG_EXEC, last_tb->pc,
179 "Stopped execution of TB chain before %p ["
180 TARGET_FMT_lx "] %s\n",
181 last_tb->tc_ptr, last_tb->pc,
182 lookup_symbol(last_tb->pc));
183 if (cc->synchronize_from_tb) {
184 cc->synchronize_from_tb(cpu, last_tb);
185 } else {
186 assert(cc->set_pc);
187 cc->set_pc(cpu, last_tb->pc);
188 }
189 }
190 return ret;
191 }
192
193 #ifndef CONFIG_USER_ONLY
194 /* Execute the code without caching the generated code. An interpreter
195 could be used if available. */
196 static void cpu_exec_nocache(CPUState *cpu, int max_cycles,
197 TranslationBlock *orig_tb, bool ignore_icount)
198 {
199 TranslationBlock *tb;
200
201 /* Should never happen.
202 We only end up here when an existing TB is too long. */
203 if (max_cycles > CF_COUNT_MASK)
204 max_cycles = CF_COUNT_MASK;
205
206 tb_lock();
207 tb = tb_gen_code(cpu, orig_tb->pc, orig_tb->cs_base, orig_tb->flags,
208 max_cycles | CF_NOCACHE
209 | (ignore_icount ? CF_IGNORE_ICOUNT : 0));
210 tb->orig_tb = orig_tb;
211 tb_unlock();
212
213 /* execute the generated code */
214 trace_exec_tb_nocache(tb, tb->pc);
215 cpu_tb_exec(cpu, tb);
216
217 tb_lock();
218 tb_phys_invalidate(tb, -1);
219 tb_free(tb);
220 tb_unlock();
221 }
222 #endif
223
224 static void cpu_exec_step(CPUState *cpu)
225 {
226 CPUClass *cc = CPU_GET_CLASS(cpu);
227 CPUArchState *env = (CPUArchState *)cpu->env_ptr;
228 TranslationBlock *tb;
229 target_ulong cs_base, pc;
230 uint32_t flags;
231
232 cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
233 if (sigsetjmp(cpu->jmp_env, 0) == 0) {
234 mmap_lock();
235 tb_lock();
236 tb = tb_gen_code(cpu, pc, cs_base, flags,
237 1 | CF_NOCACHE | CF_IGNORE_ICOUNT);
238 tb->orig_tb = NULL;
239 tb_unlock();
240 mmap_unlock();
241
242 cc->cpu_exec_enter(cpu);
243 /* execute the generated code */
244 trace_exec_tb_nocache(tb, pc);
245 cpu_tb_exec(cpu, tb);
246 cc->cpu_exec_exit(cpu);
247
248 tb_lock();
249 tb_phys_invalidate(tb, -1);
250 tb_free(tb);
251 tb_unlock();
252 } else {
253 /* We may have exited due to another problem here, so we need
254 * to reset any tb_locks we may have taken but didn't release.
255 * The mmap_lock is dropped by tb_gen_code if it runs out of
256 * memory.
257 */
258 #ifndef CONFIG_SOFTMMU
259 tcg_debug_assert(!have_mmap_lock());
260 #endif
261 tb_lock_reset();
262 }
263 }
264
265 void cpu_exec_step_atomic(CPUState *cpu)
266 {
267 start_exclusive();
268
269 /* Since we got here, we know that parallel_cpus must be true. */
270 parallel_cpus = false;
271 cpu_exec_step(cpu);
272 parallel_cpus = true;
273
274 end_exclusive();
275 }
276
277 struct tb_desc {
278 target_ulong pc;
279 target_ulong cs_base;
280 CPUArchState *env;
281 tb_page_addr_t phys_page1;
282 uint32_t flags;
283 };
284
285 static bool tb_cmp(const void *p, const void *d)
286 {
287 const TranslationBlock *tb = p;
288 const struct tb_desc *desc = d;
289
290 if (tb->pc == desc->pc &&
291 tb->page_addr[0] == desc->phys_page1 &&
292 tb->cs_base == desc->cs_base &&
293 tb->flags == desc->flags &&
294 !atomic_read(&tb->invalid)) {
295 /* check next page if needed */
296 if (tb->page_addr[1] == -1) {
297 return true;
298 } else {
299 tb_page_addr_t phys_page2;
300 target_ulong virt_page2;
301
302 virt_page2 = (desc->pc & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
303 phys_page2 = get_page_addr_code(desc->env, virt_page2);
304 if (tb->page_addr[1] == phys_page2) {
305 return true;
306 }
307 }
308 }
309 return false;
310 }
311
312 static TranslationBlock *tb_htable_lookup(CPUState *cpu,
313 target_ulong pc,
314 target_ulong cs_base,
315 uint32_t flags)
316 {
317 tb_page_addr_t phys_pc;
318 struct tb_desc desc;
319 uint32_t h;
320
321 desc.env = (CPUArchState *)cpu->env_ptr;
322 desc.cs_base = cs_base;
323 desc.flags = flags;
324 desc.pc = pc;
325 phys_pc = get_page_addr_code(desc.env, pc);
326 desc.phys_page1 = phys_pc & TARGET_PAGE_MASK;
327 h = tb_hash_func(phys_pc, pc, flags);
328 return qht_lookup(&tcg_ctx.tb_ctx.htable, tb_cmp, &desc, h);
329 }
330
331 static inline TranslationBlock *tb_find(CPUState *cpu,
332 TranslationBlock *last_tb,
333 int tb_exit)
334 {
335 CPUArchState *env = (CPUArchState *)cpu->env_ptr;
336 TranslationBlock *tb;
337 target_ulong cs_base, pc;
338 uint32_t flags;
339 bool have_tb_lock = false;
340
341 /* we record a subset of the CPU state. It will
342 always be the same before a given translated block
343 is executed. */
344 cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
345 tb = atomic_rcu_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)]);
346 if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
347 tb->flags != flags)) {
348 tb = tb_htable_lookup(cpu, pc, cs_base, flags);
349 if (!tb) {
350
351 /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
352 * taken outside tb_lock. As system emulation is currently
353 * single threaded the locks are NOPs.
354 */
355 mmap_lock();
356 tb_lock();
357 have_tb_lock = true;
358
359 /* There's a chance that our desired tb has been translated while
360 * taking the locks so we check again inside the lock.
361 */
362 tb = tb_htable_lookup(cpu, pc, cs_base, flags);
363 if (!tb) {
364 /* if no translated code available, then translate it now */
365 tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
366 }
367
368 mmap_unlock();
369 }
370
371 /* We add the TB in the virtual pc hash table for the fast lookup */
372 atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
373 }
374 #ifndef CONFIG_USER_ONLY
375 /* We don't take care of direct jumps when address mapping changes in
376 * system emulation. So it's not safe to make a direct jump to a TB
377 * spanning two pages because the mapping for the second page can change.
378 */
379 if (tb->page_addr[1] != -1) {
380 last_tb = NULL;
381 }
382 #endif
383 /* See if we can patch the calling TB. */
384 if (last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
385 if (!have_tb_lock) {
386 tb_lock();
387 have_tb_lock = true;
388 }
389 if (!tb->invalid) {
390 tb_add_jump(last_tb, tb_exit, tb);
391 }
392 }
393 if (have_tb_lock) {
394 tb_unlock();
395 }
396 return tb;
397 }
398
399 static inline bool cpu_handle_halt(CPUState *cpu)
400 {
401 if (cpu->halted) {
402 #if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
403 if ((cpu->interrupt_request & CPU_INTERRUPT_POLL)
404 && replay_interrupt()) {
405 X86CPU *x86_cpu = X86_CPU(cpu);
406 qemu_mutex_lock_iothread();
407 apic_poll_irq(x86_cpu->apic_state);
408 cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
409 qemu_mutex_unlock_iothread();
410 }
411 #endif
412 if (!cpu_has_work(cpu)) {
413 return true;
414 }
415
416 cpu->halted = 0;
417 }
418
419 return false;
420 }
421
422 static inline void cpu_handle_debug_exception(CPUState *cpu)
423 {
424 CPUClass *cc = CPU_GET_CLASS(cpu);
425 CPUWatchpoint *wp;
426
427 if (!cpu->watchpoint_hit) {
428 QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
429 wp->flags &= ~BP_WATCHPOINT_HIT;
430 }
431 }
432
433 cc->debug_excp_handler(cpu);
434 }
435
436 static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
437 {
438 if (cpu->exception_index >= 0) {
439 if (cpu->exception_index >= EXCP_INTERRUPT) {
440 /* exit request from the cpu execution loop */
441 *ret = cpu->exception_index;
442 if (*ret == EXCP_DEBUG) {
443 cpu_handle_debug_exception(cpu);
444 }
445 cpu->exception_index = -1;
446 return true;
447 } else {
448 #if defined(CONFIG_USER_ONLY)
449 /* if user mode only, we simulate a fake exception
450 which will be handled outside the cpu execution
451 loop */
452 #if defined(TARGET_I386)
453 CPUClass *cc = CPU_GET_CLASS(cpu);
454 cc->do_interrupt(cpu);
455 #endif
456 *ret = cpu->exception_index;
457 cpu->exception_index = -1;
458 return true;
459 #else
460 if (replay_exception()) {
461 CPUClass *cc = CPU_GET_CLASS(cpu);
462 qemu_mutex_lock_iothread();
463 cc->do_interrupt(cpu);
464 qemu_mutex_unlock_iothread();
465 cpu->exception_index = -1;
466 } else if (!replay_has_interrupt()) {
467 /* give a chance to iothread in replay mode */
468 *ret = EXCP_INTERRUPT;
469 return true;
470 }
471 #endif
472 }
473 #ifndef CONFIG_USER_ONLY
474 } else if (replay_has_exception()
475 && cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
476 /* try to cause an exception pending in the log */
477 cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0), true);
478 *ret = -1;
479 return true;
480 #endif
481 }
482
483 return false;
484 }
485
486 static inline bool cpu_handle_interrupt(CPUState *cpu,
487 TranslationBlock **last_tb)
488 {
489 CPUClass *cc = CPU_GET_CLASS(cpu);
490
491 if (unlikely(atomic_read(&cpu->interrupt_request))) {
492 int interrupt_request;
493 qemu_mutex_lock_iothread();
494 interrupt_request = cpu->interrupt_request;
495 if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
496 /* Mask out external interrupts for this step. */
497 interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK;
498 }
499 if (interrupt_request & CPU_INTERRUPT_DEBUG) {
500 cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG;
501 cpu->exception_index = EXCP_DEBUG;
502 qemu_mutex_unlock_iothread();
503 return true;
504 }
505 if (replay_mode == REPLAY_MODE_PLAY && !replay_has_interrupt()) {
506 /* Do nothing */
507 } else if (interrupt_request & CPU_INTERRUPT_HALT) {
508 replay_interrupt();
509 cpu->interrupt_request &= ~CPU_INTERRUPT_HALT;
510 cpu->halted = 1;
511 cpu->exception_index = EXCP_HLT;
512 qemu_mutex_unlock_iothread();
513 return true;
514 }
515 #if defined(TARGET_I386)
516 else if (interrupt_request & CPU_INTERRUPT_INIT) {
517 X86CPU *x86_cpu = X86_CPU(cpu);
518 CPUArchState *env = &x86_cpu->env;
519 replay_interrupt();
520 cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0, 0);
521 do_cpu_init(x86_cpu);
522 cpu->exception_index = EXCP_HALTED;
523 qemu_mutex_unlock_iothread();
524 return true;
525 }
526 #else
527 else if (interrupt_request & CPU_INTERRUPT_RESET) {
528 replay_interrupt();
529 cpu_reset(cpu);
530 qemu_mutex_unlock_iothread();
531 return true;
532 }
533 #endif
534 /* The target hook has 3 exit conditions:
535 False when the interrupt isn't processed,
536 True when it is, and we should restart on a new TB,
537 and via longjmp via cpu_loop_exit. */
538 else {
539 if (cc->cpu_exec_interrupt(cpu, interrupt_request)) {
540 replay_interrupt();
541 *last_tb = NULL;
542 }
543 /* The target hook may have updated the 'cpu->interrupt_request';
544 * reload the 'interrupt_request' value */
545 interrupt_request = cpu->interrupt_request;
546 }
547 if (interrupt_request & CPU_INTERRUPT_EXITTB) {
548 cpu->interrupt_request &= ~CPU_INTERRUPT_EXITTB;
549 /* ensure that no TB jump will be modified as
550 the program flow was changed */
551 *last_tb = NULL;
552 }
553
554 /* If we exit via cpu_loop_exit/longjmp it is reset in cpu_exec */
555 qemu_mutex_unlock_iothread();
556 }
557
558 /* Finally, check if we need to exit to the main loop. */
559 if (unlikely(atomic_read(&cpu->exit_request)
560 || (use_icount && cpu->icount_decr.u16.low + cpu->icount_extra == 0))) {
561 atomic_set(&cpu->exit_request, 0);
562 cpu->exception_index = EXCP_INTERRUPT;
563 return true;
564 }
565
566 return false;
567 }
568
569 static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
570 TranslationBlock **last_tb, int *tb_exit)
571 {
572 uintptr_t ret;
573 int32_t insns_left;
574
575 trace_exec_tb(tb, tb->pc);
576 ret = cpu_tb_exec(cpu, tb);
577 tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK);
578 *tb_exit = ret & TB_EXIT_MASK;
579 if (*tb_exit != TB_EXIT_REQUESTED) {
580 *last_tb = tb;
581 return;
582 }
583
584 *last_tb = NULL;
585 insns_left = atomic_read(&cpu->icount_decr.u32);
586 atomic_set(&cpu->icount_decr.u16.high, 0);
587 if (insns_left < 0) {
588 /* Something asked us to stop executing chained TBs; just
589 * continue round the main loop. Whatever requested the exit
590 * will also have set something else (eg exit_request or
591 * interrupt_request) which we will handle next time around
592 * the loop. But we need to ensure the zeroing of icount_decr
593 * comes before the next read of cpu->exit_request
594 * or cpu->interrupt_request.
595 */
596 smp_mb();
597 return;
598 }
599
600 /* Instruction counter expired. */
601 assert(use_icount);
602 #ifndef CONFIG_USER_ONLY
603 /* Ensure global icount has gone forward */
604 cpu_update_icount(cpu);
605 /* Refill decrementer and continue execution. */
606 insns_left = MIN(0xffff, cpu->icount_budget);
607 cpu->icount_decr.u16.low = insns_left;
608 cpu->icount_extra = cpu->icount_budget - insns_left;
609 if (!cpu->icount_extra) {
610 /* Execute any remaining instructions, then let the main loop
611 * handle the next event.
612 */
613 if (insns_left > 0) {
614 cpu_exec_nocache(cpu, insns_left, tb, false);
615 }
616 }
617 #endif
618 }
619
620 /* main execution loop */
621
622 int cpu_exec(CPUState *cpu)
623 {
624 CPUClass *cc = CPU_GET_CLASS(cpu);
625 int ret;
626 SyncClocks sc = { 0 };
627
628 /* replay_interrupt may need current_cpu */
629 current_cpu = cpu;
630
631 if (cpu_handle_halt(cpu)) {
632 return EXCP_HALTED;
633 }
634
635 rcu_read_lock();
636
637 cc->cpu_exec_enter(cpu);
638
639 /* Calculate difference between guest clock and host clock.
640 * This delay includes the delay of the last cycle, so
641 * what we have to do is sleep until it is 0. As for the
642 * advance/delay we gain here, we try to fix it next time.
643 */
644 init_delay_params(&sc, cpu);
645
646 /* prepare setjmp context for exception handling */
647 if (sigsetjmp(cpu->jmp_env, 0) != 0) {
648 #if defined(__clang__) || !QEMU_GNUC_PREREQ(4, 6)
649 /* Some compilers wrongly smash all local variables after
650 * siglongjmp. There were bug reports for gcc 4.5.0 and clang.
651 * Reload essential local variables here for those compilers.
652 * Newer versions of gcc would complain about this code (-Wclobbered). */
653 cpu = current_cpu;
654 cc = CPU_GET_CLASS(cpu);
655 #else /* buggy compiler */
656 /* Assert that the compiler does not smash local variables. */
657 g_assert(cpu == current_cpu);
658 g_assert(cc == CPU_GET_CLASS(cpu));
659 #endif /* buggy compiler */
660 cpu->can_do_io = 1;
661 tb_lock_reset();
662 if (qemu_mutex_iothread_locked()) {
663 qemu_mutex_unlock_iothread();
664 }
665 }
666
667 /* if an exception is pending, we execute it here */
668 while (!cpu_handle_exception(cpu, &ret)) {
669 TranslationBlock *last_tb = NULL;
670 int tb_exit = 0;
671
672 while (!cpu_handle_interrupt(cpu, &last_tb)) {
673 TranslationBlock *tb = tb_find(cpu, last_tb, tb_exit);
674 cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit);
675 /* Try to align the host and virtual clocks
676 if the guest is in advance */
677 align_clocks(&sc, cpu);
678 }
679 }
680
681 cc->cpu_exec_exit(cpu);
682 rcu_read_unlock();
683
684 return ret;
685 }