2 * emulator main execution loop
4 * Copyright (c) 2003-2005 Fabrice Bellard
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 2.1 of the License, or (at your option) any later version.
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.
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/>.
20 #include "qemu/osdep.h"
21 #include "qemu-common.h"
22 #include "qemu/qemu-print.h"
25 #include "disas/disas.h"
26 #include "exec/exec-all.h"
28 #include "qemu/atomic.h"
29 #include "qemu/compiler.h"
30 #include "sysemu/qtest.h"
31 #include "qemu/timer.h"
33 #include "exec/tb-hash.h"
34 #include "exec/tb-lookup.h"
36 #include "qemu/main-loop.h"
37 #if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
38 #include "hw/i386/apic.h"
40 #include "sysemu/cpus.h"
41 #include "exec/cpu-all.h"
42 #include "sysemu/cpu-timers.h"
43 #include "sysemu/replay.h"
46 /* -icount align implementation. */
48 typedef struct SyncClocks
{
50 int64_t last_cpu_icount
;
51 int64_t realtime_clock
;
54 #if !defined(CONFIG_USER_ONLY)
55 /* Allow the guest to have a max 3ms advance.
56 * The difference between the 2 clocks could therefore
59 #define VM_CLOCK_ADVANCE 3000000
60 #define THRESHOLD_REDUCE 1.5
61 #define MAX_DELAY_PRINT_RATE 2000000000LL
62 #define MAX_NB_PRINTS 100
64 static int64_t max_delay
;
65 static int64_t max_advance
;
67 static void align_clocks(SyncClocks
*sc
, CPUState
*cpu
)
71 if (!icount_align_option
) {
75 cpu_icount
= cpu
->icount_extra
+ cpu_neg(cpu
)->icount_decr
.u16
.low
;
76 sc
->diff_clk
+= icount_to_ns(sc
->last_cpu_icount
- cpu_icount
);
77 sc
->last_cpu_icount
= cpu_icount
;
79 if (sc
->diff_clk
> VM_CLOCK_ADVANCE
) {
81 struct timespec sleep_delay
, rem_delay
;
82 sleep_delay
.tv_sec
= sc
->diff_clk
/ 1000000000LL;
83 sleep_delay
.tv_nsec
= sc
->diff_clk
% 1000000000LL;
84 if (nanosleep(&sleep_delay
, &rem_delay
) < 0) {
85 sc
->diff_clk
= rem_delay
.tv_sec
* 1000000000LL + rem_delay
.tv_nsec
;
90 Sleep(sc
->diff_clk
/ SCALE_MS
);
96 static void print_delay(const SyncClocks
*sc
)
98 static float threshold_delay
;
99 static int64_t last_realtime_clock
;
100 static int nb_prints
;
102 if (icount_align_option
&&
103 sc
->realtime_clock
- last_realtime_clock
>= MAX_DELAY_PRINT_RATE
&&
104 nb_prints
< MAX_NB_PRINTS
) {
105 if ((-sc
->diff_clk
/ (float)1000000000LL > threshold_delay
) ||
106 (-sc
->diff_clk
/ (float)1000000000LL <
107 (threshold_delay
- THRESHOLD_REDUCE
))) {
108 threshold_delay
= (-sc
->diff_clk
/ 1000000000LL) + 1;
109 qemu_printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
113 last_realtime_clock
= sc
->realtime_clock
;
118 static void init_delay_params(SyncClocks
*sc
, CPUState
*cpu
)
120 if (!icount_align_option
) {
123 sc
->realtime_clock
= qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT
);
124 sc
->diff_clk
= qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL
) - sc
->realtime_clock
;
126 = cpu
->icount_extra
+ cpu_neg(cpu
)->icount_decr
.u16
.low
;
127 if (sc
->diff_clk
< max_delay
) {
128 max_delay
= sc
->diff_clk
;
130 if (sc
->diff_clk
> max_advance
) {
131 max_advance
= sc
->diff_clk
;
134 /* Print every 2s max if the guest is late. We limit the number
135 of printed messages to NB_PRINT_MAX(currently 100) */
139 static void align_clocks(SyncClocks
*sc
, const CPUState
*cpu
)
143 static void init_delay_params(SyncClocks
*sc
, const CPUState
*cpu
)
146 #endif /* CONFIG USER ONLY */
148 /* Execute a TB, and fix up the CPU state afterwards if necessary */
150 * Disable CFI checks.
151 * TCG creates binary blobs at runtime, with the transformed code.
152 * A TB is a blob of binary code, created at runtime and called with an
153 * indirect function call. Since such function did not exist at compile time,
154 * the CFI runtime has no way to verify its signature and would fail.
155 * TCG is not considered a security-sensitive part of QEMU so this does not
156 * affect the impact of CFI in environment with high security requirements
158 static inline TranslationBlock
* QEMU_DISABLE_CFI
159 cpu_tb_exec(CPUState
*cpu
, TranslationBlock
*itb
, int *tb_exit
)
161 CPUArchState
*env
= cpu
->env_ptr
;
163 TranslationBlock
*last_tb
;
164 const void *tb_ptr
= itb
->tc
.ptr
;
166 qemu_log_mask_and_addr(CPU_LOG_EXEC
, itb
->pc
,
168 TARGET_FMT_lx
"/" TARGET_FMT_lx
"/%#x] %s\n",
169 cpu
->cpu_index
, itb
->tc
.ptr
,
170 itb
->cs_base
, itb
->pc
, itb
->flags
,
171 lookup_symbol(itb
->pc
));
173 #if defined(DEBUG_DISAS)
174 if (qemu_loglevel_mask(CPU_LOG_TB_CPU
)
175 && qemu_log_in_addr_range(itb
->pc
)) {
176 FILE *logfile
= qemu_log_lock();
178 if (qemu_loglevel_mask(CPU_LOG_TB_FPU
)) {
179 flags
|= CPU_DUMP_FPU
;
181 #if defined(TARGET_I386)
182 flags
|= CPU_DUMP_CCOP
;
184 log_cpu_state(cpu
, flags
);
185 qemu_log_unlock(logfile
);
187 #endif /* DEBUG_DISAS */
189 ret
= tcg_qemu_tb_exec(env
, tb_ptr
);
192 * TODO: Delay swapping back to the read-write region of the TB
193 * until we actually need to modify the TB. The read-only copy,
194 * coming from the rx region, shares the same host TLB entry as
195 * the code that executed the exit_tb opcode that arrived here.
196 * If we insist on touching both the RX and the RW pages, we
197 * double the host TLB pressure.
199 last_tb
= tcg_splitwx_to_rw((void *)(ret
& ~TB_EXIT_MASK
));
200 *tb_exit
= ret
& TB_EXIT_MASK
;
202 trace_exec_tb_exit(last_tb
, *tb_exit
);
204 if (*tb_exit
> TB_EXIT_IDX1
) {
205 /* We didn't start executing this TB (eg because the instruction
206 * counter hit zero); we must restore the guest PC to the address
207 * of the start of the TB.
209 CPUClass
*cc
= CPU_GET_CLASS(cpu
);
210 qemu_log_mask_and_addr(CPU_LOG_EXEC
, last_tb
->pc
,
211 "Stopped execution of TB chain before %p ["
212 TARGET_FMT_lx
"] %s\n",
213 last_tb
->tc
.ptr
, last_tb
->pc
,
214 lookup_symbol(last_tb
->pc
));
215 if (cc
->synchronize_from_tb
) {
216 cc
->synchronize_from_tb(cpu
, last_tb
);
219 cc
->set_pc(cpu
, last_tb
->pc
);
225 #ifndef CONFIG_USER_ONLY
226 /* Execute the code without caching the generated code. An interpreter
227 could be used if available. */
228 static void cpu_exec_nocache(CPUState
*cpu
, int max_cycles
,
229 TranslationBlock
*orig_tb
, bool ignore_icount
)
231 TranslationBlock
*tb
;
232 uint32_t cflags
= curr_cflags() | CF_NOCACHE
;
236 cflags
&= ~CF_USE_ICOUNT
;
239 /* Should never happen.
240 We only end up here when an existing TB is too long. */
241 cflags
|= MIN(max_cycles
, CF_COUNT_MASK
);
244 tb
= tb_gen_code(cpu
, orig_tb
->pc
, orig_tb
->cs_base
,
245 orig_tb
->flags
, cflags
);
246 tb
->orig_tb
= orig_tb
;
249 /* execute the generated code */
250 trace_exec_tb_nocache(tb
, tb
->pc
);
251 cpu_tb_exec(cpu
, tb
, &tb_exit
);
254 tb_phys_invalidate(tb
, -1);
260 static void cpu_exec_enter(CPUState
*cpu
)
262 CPUClass
*cc
= CPU_GET_CLASS(cpu
);
264 if (cc
->cpu_exec_enter
) {
265 cc
->cpu_exec_enter(cpu
);
269 static void cpu_exec_exit(CPUState
*cpu
)
271 CPUClass
*cc
= CPU_GET_CLASS(cpu
);
273 if (cc
->cpu_exec_exit
) {
274 cc
->cpu_exec_exit(cpu
);
278 void cpu_exec_step_atomic(CPUState
*cpu
)
280 TranslationBlock
*tb
;
281 target_ulong cs_base
, pc
;
284 uint32_t cf_mask
= cflags
& CF_HASH_MASK
;
287 if (sigsetjmp(cpu
->jmp_env
, 0) == 0) {
289 g_assert(cpu
== current_cpu
);
290 g_assert(!cpu
->running
);
293 tb
= tb_lookup__cpu_state(cpu
, &pc
, &cs_base
, &flags
, cf_mask
);
296 tb
= tb_gen_code(cpu
, pc
, cs_base
, flags
, cflags
);
300 /* Since we got here, we know that parallel_cpus must be true. */
301 parallel_cpus
= false;
303 /* execute the generated code */
304 trace_exec_tb(tb
, pc
);
305 cpu_tb_exec(cpu
, tb
, &tb_exit
);
309 * The mmap_lock is dropped by tb_gen_code if it runs out of
312 #ifndef CONFIG_SOFTMMU
313 tcg_debug_assert(!have_mmap_lock());
315 if (qemu_mutex_iothread_locked()) {
316 qemu_mutex_unlock_iothread();
318 assert_no_pages_locked();
319 qemu_plugin_disable_mem_helpers(cpu
);
324 * As we start the exclusive region before codegen we must still
325 * be in the region if we longjump out of either the codegen or
328 g_assert(cpu_in_exclusive_context(cpu
));
329 parallel_cpus
= true;
330 cpu
->running
= false;
336 target_ulong cs_base
;
338 tb_page_addr_t phys_page1
;
341 uint32_t trace_vcpu_dstate
;
344 static bool tb_lookup_cmp(const void *p
, const void *d
)
346 const TranslationBlock
*tb
= p
;
347 const struct tb_desc
*desc
= d
;
349 if (tb
->pc
== desc
->pc
&&
350 tb
->page_addr
[0] == desc
->phys_page1
&&
351 tb
->cs_base
== desc
->cs_base
&&
352 tb
->flags
== desc
->flags
&&
353 tb
->trace_vcpu_dstate
== desc
->trace_vcpu_dstate
&&
354 (tb_cflags(tb
) & (CF_HASH_MASK
| CF_INVALID
)) == desc
->cf_mask
) {
355 /* check next page if needed */
356 if (tb
->page_addr
[1] == -1) {
359 tb_page_addr_t phys_page2
;
360 target_ulong virt_page2
;
362 virt_page2
= (desc
->pc
& TARGET_PAGE_MASK
) + TARGET_PAGE_SIZE
;
363 phys_page2
= get_page_addr_code(desc
->env
, virt_page2
);
364 if (tb
->page_addr
[1] == phys_page2
) {
372 TranslationBlock
*tb_htable_lookup(CPUState
*cpu
, target_ulong pc
,
373 target_ulong cs_base
, uint32_t flags
,
376 tb_page_addr_t phys_pc
;
380 desc
.env
= (CPUArchState
*)cpu
->env_ptr
;
381 desc
.cs_base
= cs_base
;
383 desc
.cf_mask
= cf_mask
;
384 desc
.trace_vcpu_dstate
= *cpu
->trace_dstate
;
386 phys_pc
= get_page_addr_code(desc
.env
, pc
);
390 desc
.phys_page1
= phys_pc
& TARGET_PAGE_MASK
;
391 h
= tb_hash_func(phys_pc
, pc
, flags
, cf_mask
, *cpu
->trace_dstate
);
392 return qht_lookup_custom(&tb_ctx
.htable
, &desc
, h
, tb_lookup_cmp
);
395 void tb_set_jmp_target(TranslationBlock
*tb
, int n
, uintptr_t addr
)
397 if (TCG_TARGET_HAS_direct_jump
) {
398 uintptr_t offset
= tb
->jmp_target_arg
[n
];
399 uintptr_t tc_ptr
= (uintptr_t)tb
->tc
.ptr
;
400 uintptr_t jmp_rx
= tc_ptr
+ offset
;
401 uintptr_t jmp_rw
= jmp_rx
- tcg_splitwx_diff
;
402 tb_target_set_jmp_target(tc_ptr
, jmp_rx
, jmp_rw
, addr
);
404 tb
->jmp_target_arg
[n
] = addr
;
408 static inline void tb_add_jump(TranslationBlock
*tb
, int n
,
409 TranslationBlock
*tb_next
)
413 assert(n
< ARRAY_SIZE(tb
->jmp_list_next
));
414 qemu_spin_lock(&tb_next
->jmp_lock
);
416 /* make sure the destination TB is valid */
417 if (tb_next
->cflags
& CF_INVALID
) {
418 goto out_unlock_next
;
420 /* Atomically claim the jump destination slot only if it was NULL */
421 old
= qatomic_cmpxchg(&tb
->jmp_dest
[n
], (uintptr_t)NULL
,
424 goto out_unlock_next
;
427 /* patch the native jump address */
428 tb_set_jmp_target(tb
, n
, (uintptr_t)tb_next
->tc
.ptr
);
430 /* add in TB jmp list */
431 tb
->jmp_list_next
[n
] = tb_next
->jmp_list_head
;
432 tb_next
->jmp_list_head
= (uintptr_t)tb
| n
;
434 qemu_spin_unlock(&tb_next
->jmp_lock
);
436 qemu_log_mask_and_addr(CPU_LOG_EXEC
, tb
->pc
,
437 "Linking TBs %p [" TARGET_FMT_lx
438 "] index %d -> %p [" TARGET_FMT_lx
"]\n",
439 tb
->tc
.ptr
, tb
->pc
, n
,
440 tb_next
->tc
.ptr
, tb_next
->pc
);
444 qemu_spin_unlock(&tb_next
->jmp_lock
);
448 static inline TranslationBlock
*tb_find(CPUState
*cpu
,
449 TranslationBlock
*last_tb
,
450 int tb_exit
, uint32_t cf_mask
)
452 TranslationBlock
*tb
;
453 target_ulong cs_base
, pc
;
456 tb
= tb_lookup__cpu_state(cpu
, &pc
, &cs_base
, &flags
, cf_mask
);
459 tb
= tb_gen_code(cpu
, pc
, cs_base
, flags
, cf_mask
);
461 /* We add the TB in the virtual pc hash table for the fast lookup */
462 qatomic_set(&cpu
->tb_jmp_cache
[tb_jmp_cache_hash_func(pc
)], tb
);
464 #ifndef CONFIG_USER_ONLY
465 /* We don't take care of direct jumps when address mapping changes in
466 * system emulation. So it's not safe to make a direct jump to a TB
467 * spanning two pages because the mapping for the second page can change.
469 if (tb
->page_addr
[1] != -1) {
473 /* See if we can patch the calling TB. */
475 tb_add_jump(last_tb
, tb_exit
, tb
);
480 static inline bool cpu_handle_halt(CPUState
*cpu
)
483 #if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
484 if (cpu
->interrupt_request
& CPU_INTERRUPT_POLL
) {
485 X86CPU
*x86_cpu
= X86_CPU(cpu
);
486 qemu_mutex_lock_iothread();
487 apic_poll_irq(x86_cpu
->apic_state
);
488 cpu_reset_interrupt(cpu
, CPU_INTERRUPT_POLL
);
489 qemu_mutex_unlock_iothread();
492 if (!cpu_has_work(cpu
)) {
502 static inline void cpu_handle_debug_exception(CPUState
*cpu
)
504 CPUClass
*cc
= CPU_GET_CLASS(cpu
);
507 if (!cpu
->watchpoint_hit
) {
508 QTAILQ_FOREACH(wp
, &cpu
->watchpoints
, entry
) {
509 wp
->flags
&= ~BP_WATCHPOINT_HIT
;
513 if (cc
->debug_excp_handler
) {
514 cc
->debug_excp_handler(cpu
);
518 static inline bool cpu_handle_exception(CPUState
*cpu
, int *ret
)
520 if (cpu
->exception_index
< 0) {
521 #ifndef CONFIG_USER_ONLY
522 if (replay_has_exception()
523 && cpu_neg(cpu
)->icount_decr
.u16
.low
+ cpu
->icount_extra
== 0) {
524 /* try to cause an exception pending in the log */
525 cpu_exec_nocache(cpu
, 1, tb_find(cpu
, NULL
, 0, curr_cflags()), true);
528 if (cpu
->exception_index
< 0) {
533 if (cpu
->exception_index
>= EXCP_INTERRUPT
) {
534 /* exit request from the cpu execution loop */
535 *ret
= cpu
->exception_index
;
536 if (*ret
== EXCP_DEBUG
) {
537 cpu_handle_debug_exception(cpu
);
539 cpu
->exception_index
= -1;
542 #if defined(CONFIG_USER_ONLY)
543 /* if user mode only, we simulate a fake exception
544 which will be handled outside the cpu execution
546 #if defined(TARGET_I386)
547 CPUClass
*cc
= CPU_GET_CLASS(cpu
);
548 cc
->do_interrupt(cpu
);
550 *ret
= cpu
->exception_index
;
551 cpu
->exception_index
= -1;
554 if (replay_exception()) {
555 CPUClass
*cc
= CPU_GET_CLASS(cpu
);
556 qemu_mutex_lock_iothread();
557 cc
->do_interrupt(cpu
);
558 qemu_mutex_unlock_iothread();
559 cpu
->exception_index
= -1;
561 if (unlikely(cpu
->singlestep_enabled
)) {
563 * After processing the exception, ensure an EXCP_DEBUG is
564 * raised when single-stepping so that GDB doesn't miss the
568 cpu_handle_debug_exception(cpu
);
571 } else if (!replay_has_interrupt()) {
572 /* give a chance to iothread in replay mode */
573 *ret
= EXCP_INTERRUPT
;
583 * CPU_INTERRUPT_POLL is a virtual event which gets converted into a
584 * "real" interrupt event later. It does not need to be recorded for
587 static inline bool need_replay_interrupt(int interrupt_request
)
589 #if defined(TARGET_I386)
590 return !(interrupt_request
& CPU_INTERRUPT_POLL
);
596 static inline bool cpu_handle_interrupt(CPUState
*cpu
,
597 TranslationBlock
**last_tb
)
599 CPUClass
*cc
= CPU_GET_CLASS(cpu
);
601 /* Clear the interrupt flag now since we're processing
602 * cpu->interrupt_request and cpu->exit_request.
603 * Ensure zeroing happens before reading cpu->exit_request or
604 * cpu->interrupt_request (see also smp_wmb in cpu_exit())
606 qatomic_mb_set(&cpu_neg(cpu
)->icount_decr
.u16
.high
, 0);
608 if (unlikely(qatomic_read(&cpu
->interrupt_request
))) {
609 int interrupt_request
;
610 qemu_mutex_lock_iothread();
611 interrupt_request
= cpu
->interrupt_request
;
612 if (unlikely(cpu
->singlestep_enabled
& SSTEP_NOIRQ
)) {
613 /* Mask out external interrupts for this step. */
614 interrupt_request
&= ~CPU_INTERRUPT_SSTEP_MASK
;
616 if (interrupt_request
& CPU_INTERRUPT_DEBUG
) {
617 cpu
->interrupt_request
&= ~CPU_INTERRUPT_DEBUG
;
618 cpu
->exception_index
= EXCP_DEBUG
;
619 qemu_mutex_unlock_iothread();
622 if (replay_mode
== REPLAY_MODE_PLAY
&& !replay_has_interrupt()) {
624 } else if (interrupt_request
& CPU_INTERRUPT_HALT
) {
626 cpu
->interrupt_request
&= ~CPU_INTERRUPT_HALT
;
628 cpu
->exception_index
= EXCP_HLT
;
629 qemu_mutex_unlock_iothread();
632 #if defined(TARGET_I386)
633 else if (interrupt_request
& CPU_INTERRUPT_INIT
) {
634 X86CPU
*x86_cpu
= X86_CPU(cpu
);
635 CPUArchState
*env
= &x86_cpu
->env
;
637 cpu_svm_check_intercept_param(env
, SVM_EXIT_INIT
, 0, 0);
638 do_cpu_init(x86_cpu
);
639 cpu
->exception_index
= EXCP_HALTED
;
640 qemu_mutex_unlock_iothread();
644 else if (interrupt_request
& CPU_INTERRUPT_RESET
) {
647 qemu_mutex_unlock_iothread();
651 /* The target hook has 3 exit conditions:
652 False when the interrupt isn't processed,
653 True when it is, and we should restart on a new TB,
654 and via longjmp via cpu_loop_exit. */
656 if (cc
->cpu_exec_interrupt
&&
657 cc
->cpu_exec_interrupt(cpu
, interrupt_request
)) {
658 if (need_replay_interrupt(interrupt_request
)) {
662 * After processing the interrupt, ensure an EXCP_DEBUG is
663 * raised when single-stepping so that GDB doesn't miss the
666 cpu
->exception_index
=
667 (cpu
->singlestep_enabled
? EXCP_DEBUG
: -1);
670 /* The target hook may have updated the 'cpu->interrupt_request';
671 * reload the 'interrupt_request' value */
672 interrupt_request
= cpu
->interrupt_request
;
674 if (interrupt_request
& CPU_INTERRUPT_EXITTB
) {
675 cpu
->interrupt_request
&= ~CPU_INTERRUPT_EXITTB
;
676 /* ensure that no TB jump will be modified as
677 the program flow was changed */
681 /* If we exit via cpu_loop_exit/longjmp it is reset in cpu_exec */
682 qemu_mutex_unlock_iothread();
685 /* Finally, check if we need to exit to the main loop. */
686 if (unlikely(qatomic_read(&cpu
->exit_request
))
688 && cpu_neg(cpu
)->icount_decr
.u16
.low
+ cpu
->icount_extra
== 0)) {
689 qatomic_set(&cpu
->exit_request
, 0);
690 if (cpu
->exception_index
== -1) {
691 cpu
->exception_index
= EXCP_INTERRUPT
;
699 static inline void cpu_loop_exec_tb(CPUState
*cpu
, TranslationBlock
*tb
,
700 TranslationBlock
**last_tb
, int *tb_exit
)
704 trace_exec_tb(tb
, tb
->pc
);
705 tb
= cpu_tb_exec(cpu
, tb
, tb_exit
);
706 if (*tb_exit
!= TB_EXIT_REQUESTED
) {
712 insns_left
= qatomic_read(&cpu_neg(cpu
)->icount_decr
.u32
);
713 if (insns_left
< 0) {
714 /* Something asked us to stop executing chained TBs; just
715 * continue round the main loop. Whatever requested the exit
716 * will also have set something else (eg exit_request or
717 * interrupt_request) which will be handled by
718 * cpu_handle_interrupt. cpu_handle_interrupt will also
719 * clear cpu->icount_decr.u16.high.
724 /* Instruction counter expired. */
725 assert(icount_enabled());
726 #ifndef CONFIG_USER_ONLY
727 /* Ensure global icount has gone forward */
729 /* Refill decrementer and continue execution. */
730 insns_left
= MIN(0xffff, cpu
->icount_budget
);
731 cpu_neg(cpu
)->icount_decr
.u16
.low
= insns_left
;
732 cpu
->icount_extra
= cpu
->icount_budget
- insns_left
;
733 if (!cpu
->icount_extra
&& insns_left
< tb
->icount
) {
734 /* Execute any remaining instructions, then let the main loop
735 * handle the next event.
737 if (insns_left
> 0) {
738 cpu_exec_nocache(cpu
, insns_left
, tb
, false);
744 /* main execution loop */
746 int cpu_exec(CPUState
*cpu
)
748 CPUClass
*cc
= CPU_GET_CLASS(cpu
);
750 SyncClocks sc
= { 0 };
752 /* replay_interrupt may need current_cpu */
755 if (cpu_handle_halt(cpu
)) {
763 /* Calculate difference between guest clock and host clock.
764 * This delay includes the delay of the last cycle, so
765 * what we have to do is sleep until it is 0. As for the
766 * advance/delay we gain here, we try to fix it next time.
768 init_delay_params(&sc
, cpu
);
770 /* prepare setjmp context for exception handling */
771 if (sigsetjmp(cpu
->jmp_env
, 0) != 0) {
772 #if defined(__clang__)
773 /* Some compilers wrongly smash all local variables after
774 * siglongjmp. There were bug reports for gcc 4.5.0 and clang.
775 * Reload essential local variables here for those compilers.
776 * Newer versions of gcc would complain about this code (-Wclobbered). */
778 cc
= CPU_GET_CLASS(cpu
);
779 #else /* buggy compiler */
780 /* Assert that the compiler does not smash local variables. */
781 g_assert(cpu
== current_cpu
);
782 g_assert(cc
== CPU_GET_CLASS(cpu
));
783 #endif /* buggy compiler */
784 #ifndef CONFIG_SOFTMMU
785 tcg_debug_assert(!have_mmap_lock());
787 if (qemu_mutex_iothread_locked()) {
788 qemu_mutex_unlock_iothread();
790 qemu_plugin_disable_mem_helpers(cpu
);
792 assert_no_pages_locked();
795 /* if an exception is pending, we execute it here */
796 while (!cpu_handle_exception(cpu
, &ret
)) {
797 TranslationBlock
*last_tb
= NULL
;
800 while (!cpu_handle_interrupt(cpu
, &last_tb
)) {
801 uint32_t cflags
= cpu
->cflags_next_tb
;
802 TranslationBlock
*tb
;
804 /* When requested, use an exact setting for cflags for the next
805 execution. This is used for icount, precise smc, and stop-
806 after-access watchpoints. Since this request should never
807 have CF_INVALID set, -1 is a convenient invalid value that
808 does not require tcg headers for cpu_common_reset. */
810 cflags
= curr_cflags();
812 cpu
->cflags_next_tb
= -1;
815 tb
= tb_find(cpu
, last_tb
, tb_exit
, cflags
);
816 cpu_loop_exec_tb(cpu
, tb
, &last_tb
, &tb_exit
);
817 /* Try to align the host and virtual clocks
818 if the guest is in advance */
819 align_clocks(&sc
, cpu
);
829 #ifndef CONFIG_USER_ONLY
831 void dump_drift_info(void)
833 if (!icount_enabled()) {
837 qemu_printf("Host - Guest clock %"PRIi64
" ms\n",
838 (cpu_get_clock() - icount_get()) / SCALE_MS
);
839 if (icount_align_option
) {
840 qemu_printf("Max guest delay %"PRIi64
" ms\n",
841 -max_delay
/ SCALE_MS
);
842 qemu_printf("Max guest advance %"PRIi64
" ms\n",
843 max_advance
/ SCALE_MS
);
845 qemu_printf("Max guest delay NA\n");
846 qemu_printf("Max guest advance NA\n");
850 #endif /* !CONFIG_USER_ONLY */