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bellard7d132992003-03-06 23:23:54 +00001/*
陳韋任e965fc32012-02-06 14:02:55 +08002 * emulator main execution loop
ths5fafdf22007-09-16 21:08:06 +00003 *
bellard66321a12005-04-06 20:47:48 +00004 * Copyright (c) 2003-2005 Fabrice Bellard
bellard7d132992003-03-06 23:23:54 +00005 *
bellard3ef693a2003-03-23 20:17:16 +00006 * 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.
bellard7d132992003-03-06 23:23:54 +000010 *
bellard3ef693a2003-03-23 20:17:16 +000011 * 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.
bellard7d132992003-03-06 23:23:54 +000015 *
bellard3ef693a2003-03-23 20:17:16 +000016 * You should have received a copy of the GNU Lesser General Public
Blue Swirl8167ee82009-07-16 20:47:01 +000017 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
bellard7d132992003-03-06 23:23:54 +000018 */
Peter Maydell7b31bbc2016-01-26 18:16:56 +000019#include "qemu/osdep.h"
Blue Swirlcea5f9a2011-05-15 16:03:25 +000020#include "cpu.h"
Alex Bennée6db8b532014-08-01 17:08:57 +010021#include "trace.h"
Paolo Bonzini76cad712012-10-24 11:12:21 +020022#include "disas/disas.h"
Paolo Bonzini63c91552016-03-15 13:18:37 +010023#include "exec/exec-all.h"
bellard7cb69ca2008-05-10 10:55:51 +000024#include "tcg.h"
Paolo Bonzini1de7afc2012-12-17 18:20:00 +010025#include "qemu/atomic.h"
Paolo Bonzini9c17d612012-12-17 18:20:04 +010026#include "sysemu/qtest.h"
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +020027#include "qemu/timer.h"
Paolo Bonzini9d82b5a2013-08-16 08:26:30 +020028#include "exec/address-spaces.h"
Paolo Bonzini79e2b9a2015-01-21 12:09:14 +010029#include "qemu/rcu.h"
Peter Crosthwaitee1b89322015-05-30 23:11:45 -070030#include "exec/tb-hash.h"
Paolo Bonzini508127e2016-01-07 16:55:28 +030031#include "exec/log.h"
Pavel Dovgalyuk6220e902015-09-17 19:23:31 +030032#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
33#include "hw/i386/apic.h"
34#endif
Pavel Dovgalyuk6f060962015-09-17 19:24:16 +030035#include "sysemu/replay.h"
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +020036
37/* -icount align implementation. */
38
39typedef struct SyncClocks {
40 int64_t diff_clk;
41 int64_t last_cpu_icount;
Sebastian Tanase7f7bc142014-07-25 11:56:32 +020042 int64_t realtime_clock;
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +020043} SyncClocks;
44
45#if !defined(CONFIG_USER_ONLY)
46/* Allow the guest to have a max 3ms advance.
47 * The difference between the 2 clocks could therefore
48 * oscillate around 0.
49 */
50#define VM_CLOCK_ADVANCE 3000000
Sebastian Tanase7f7bc142014-07-25 11:56:32 +020051#define THRESHOLD_REDUCE 1.5
52#define MAX_DELAY_PRINT_RATE 2000000000LL
53#define MAX_NB_PRINTS 100
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +020054
55static void align_clocks(SyncClocks *sc, const CPUState *cpu)
56{
57 int64_t cpu_icount;
58
59 if (!icount_align_option) {
60 return;
61 }
62
63 cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
64 sc->diff_clk += cpu_icount_to_ns(sc->last_cpu_icount - cpu_icount);
65 sc->last_cpu_icount = cpu_icount;
66
67 if (sc->diff_clk > VM_CLOCK_ADVANCE) {
68#ifndef _WIN32
69 struct timespec sleep_delay, rem_delay;
70 sleep_delay.tv_sec = sc->diff_clk / 1000000000LL;
71 sleep_delay.tv_nsec = sc->diff_clk % 1000000000LL;
72 if (nanosleep(&sleep_delay, &rem_delay) < 0) {
Paolo Bonzinia498d0e2015-01-28 10:09:55 +010073 sc->diff_clk = rem_delay.tv_sec * 1000000000LL + rem_delay.tv_nsec;
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +020074 } else {
75 sc->diff_clk = 0;
76 }
77#else
78 Sleep(sc->diff_clk / SCALE_MS);
79 sc->diff_clk = 0;
80#endif
81 }
82}
83
Sebastian Tanase7f7bc142014-07-25 11:56:32 +020084static void print_delay(const SyncClocks *sc)
85{
86 static float threshold_delay;
87 static int64_t last_realtime_clock;
88 static int nb_prints;
89
90 if (icount_align_option &&
91 sc->realtime_clock - last_realtime_clock >= MAX_DELAY_PRINT_RATE &&
92 nb_prints < MAX_NB_PRINTS) {
93 if ((-sc->diff_clk / (float)1000000000LL > threshold_delay) ||
94 (-sc->diff_clk / (float)1000000000LL <
95 (threshold_delay - THRESHOLD_REDUCE))) {
96 threshold_delay = (-sc->diff_clk / 1000000000LL) + 1;
97 printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
98 threshold_delay - 1,
99 threshold_delay);
100 nb_prints++;
101 last_realtime_clock = sc->realtime_clock;
102 }
103 }
104}
105
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +0200106static void init_delay_params(SyncClocks *sc,
107 const CPUState *cpu)
108{
109 if (!icount_align_option) {
110 return;
111 }
Paolo Bonzini2e91cc62015-01-28 10:16:37 +0100112 sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
113 sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - sc->realtime_clock;
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +0200114 sc->last_cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
Sebastian Tanase27498be2014-07-25 11:56:33 +0200115 if (sc->diff_clk < max_delay) {
116 max_delay = sc->diff_clk;
117 }
118 if (sc->diff_clk > max_advance) {
119 max_advance = sc->diff_clk;
120 }
Sebastian Tanase7f7bc142014-07-25 11:56:32 +0200121
122 /* Print every 2s max if the guest is late. We limit the number
123 of printed messages to NB_PRINT_MAX(currently 100) */
124 print_delay(sc);
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +0200125}
126#else
127static void align_clocks(SyncClocks *sc, const CPUState *cpu)
128{
129}
130
131static void init_delay_params(SyncClocks *sc, const CPUState *cpu)
132{
133}
134#endif /* CONFIG USER ONLY */
bellard7d132992003-03-06 23:23:54 +0000135
Peter Maydell77211372013-02-22 18:10:02 +0000136/* Execute a TB, and fix up the CPU state afterwards if necessary */
Peter Maydell1a830632016-03-15 14:30:19 +0000137static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, TranslationBlock *itb)
Peter Maydell77211372013-02-22 18:10:02 +0000138{
139 CPUArchState *env = cpu->env_ptr;
Sergey Fedorov819af242016-04-21 15:58:23 +0300140 uintptr_t ret;
141 TranslationBlock *last_tb;
142 int tb_exit;
Peter Maydell1a830632016-03-15 14:30:19 +0000143 uint8_t *tb_ptr = itb->tc_ptr;
144
Alex Bennéed977e1c2016-03-15 14:30:21 +0000145 qemu_log_mask_and_addr(CPU_LOG_EXEC, itb->pc,
146 "Trace %p [" TARGET_FMT_lx "] %s\n",
147 itb->tc_ptr, itb->pc, lookup_symbol(itb->pc));
Richard Henderson03afa5f2013-11-06 17:29:39 +1000148
149#if defined(DEBUG_DISAS)
150 if (qemu_loglevel_mask(CPU_LOG_TB_CPU)) {
151#if defined(TARGET_I386)
152 log_cpu_state(cpu, CPU_DUMP_CCOP);
153#elif defined(TARGET_M68K)
154 /* ??? Should not modify env state for dumping. */
155 cpu_m68k_flush_flags(env, env->cc_op);
156 env->cc_op = CC_OP_FLAGS;
157 env->sr = (env->sr & 0xffe0) | env->cc_dest | (env->cc_x << 4);
158 log_cpu_state(cpu, 0);
159#else
160 log_cpu_state(cpu, 0);
161#endif
162 }
163#endif /* DEBUG_DISAS */
164
Paolo Bonzini414b15c2015-06-24 14:16:26 +0200165 cpu->can_do_io = !use_icount;
Sergey Fedorov819af242016-04-21 15:58:23 +0300166 ret = tcg_qemu_tb_exec(env, tb_ptr);
Pavel Dovgalyuk626cf8f2014-12-08 10:53:17 +0300167 cpu->can_do_io = 1;
Sergey Fedorov819af242016-04-21 15:58:23 +0300168 last_tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK);
169 tb_exit = ret & TB_EXIT_MASK;
170 trace_exec_tb_exit(last_tb, tb_exit);
Alex Bennée6db8b532014-08-01 17:08:57 +0100171
Sergey Fedorov819af242016-04-21 15:58:23 +0300172 if (tb_exit > TB_EXIT_IDX1) {
Peter Maydell77211372013-02-22 18:10:02 +0000173 /* 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 */
Andreas Färberbdf7ae52013-06-28 19:31:32 +0200177 CPUClass *cc = CPU_GET_CLASS(cpu);
Sergey Fedorov819af242016-04-21 15:58:23 +0300178 qemu_log_mask_and_addr(CPU_LOG_EXEC, last_tb->pc,
Alex Bennéed977e1c2016-03-15 14:30:21 +0000179 "Stopped execution of TB chain before %p ["
180 TARGET_FMT_lx "] %s\n",
Sergey Fedorov819af242016-04-21 15:58:23 +0300181 last_tb->tc_ptr, last_tb->pc,
182 lookup_symbol(last_tb->pc));
Andreas Färberbdf7ae52013-06-28 19:31:32 +0200183 if (cc->synchronize_from_tb) {
Sergey Fedorov819af242016-04-21 15:58:23 +0300184 cc->synchronize_from_tb(cpu, last_tb);
Andreas Färberbdf7ae52013-06-28 19:31:32 +0200185 } else {
186 assert(cc->set_pc);
Sergey Fedorov819af242016-04-21 15:58:23 +0300187 cc->set_pc(cpu, last_tb->pc);
Andreas Färberbdf7ae52013-06-28 19:31:32 +0200188 }
Peter Maydell77211372013-02-22 18:10:02 +0000189 }
Sergey Fedorov819af242016-04-21 15:58:23 +0300190 if (tb_exit == TB_EXIT_REQUESTED) {
Peter Maydell378df4b2013-02-22 18:10:03 +0000191 /* We were asked to stop executing TBs (probably a pending
192 * interrupt. We've now stopped, so clear the flag.
193 */
194 cpu->tcg_exit_req = 0;
195 }
Sergey Fedorov819af242016-04-21 15:58:23 +0300196 return ret;
Peter Maydell77211372013-02-22 18:10:02 +0000197}
198
Paolo Bonzini7687bf52015-08-11 11:05:12 +0200199#ifndef CONFIG_USER_ONLY
pbrook2e70f6e2008-06-29 01:03:05 +0000200/* Execute the code without caching the generated code. An interpreter
201 could be used if available. */
Peter Crosthwaiteea3e9842015-06-18 10:24:55 -0700202static void cpu_exec_nocache(CPUState *cpu, int max_cycles,
Pavel Dovgalyuk56c02692015-09-17 19:23:59 +0300203 TranslationBlock *orig_tb, bool ignore_icount)
pbrook2e70f6e2008-06-29 01:03:05 +0000204{
pbrook2e70f6e2008-06-29 01:03:05 +0000205 TranslationBlock *tb;
Sergey Fedorov6f789be2016-04-13 22:40:18 +0300206 bool old_tb_flushed;
pbrook2e70f6e2008-06-29 01:03:05 +0000207
208 /* Should never happen.
209 We only end up here when an existing TB is too long. */
210 if (max_cycles > CF_COUNT_MASK)
211 max_cycles = CF_COUNT_MASK;
212
Sergey Fedorov6f789be2016-04-13 22:40:18 +0300213 old_tb_flushed = cpu->tb_flushed;
214 cpu->tb_flushed = false;
Sergey Fedorov02d57ea2015-06-30 12:35:09 +0300215 tb = tb_gen_code(cpu, orig_tb->pc, orig_tb->cs_base, orig_tb->flags,
Pavel Dovgalyuk56c02692015-09-17 19:23:59 +0300216 max_cycles | CF_NOCACHE
217 | (ignore_icount ? CF_IGNORE_ICOUNT : 0));
Sergey Fedorov6f789be2016-04-13 22:40:18 +0300218 tb->orig_tb = cpu->tb_flushed ? NULL : orig_tb;
219 cpu->tb_flushed |= old_tb_flushed;
pbrook2e70f6e2008-06-29 01:03:05 +0000220 /* execute the generated code */
Alex Bennée6db8b532014-08-01 17:08:57 +0100221 trace_exec_tb_nocache(tb, tb->pc);
Peter Maydell1a830632016-03-15 14:30:19 +0000222 cpu_tb_exec(cpu, tb);
pbrook2e70f6e2008-06-29 01:03:05 +0000223 tb_phys_invalidate(tb, -1);
224 tb_free(tb);
225}
Paolo Bonzini7687bf52015-08-11 11:05:12 +0200226#endif
pbrook2e70f6e2008-06-29 01:03:05 +0000227
Emilio G. Cota909eaac2016-06-08 14:55:32 -0400228struct tb_desc {
229 target_ulong pc;
230 target_ulong cs_base;
231 CPUArchState *env;
232 tb_page_addr_t phys_page1;
233 uint32_t flags;
234};
235
236static bool tb_cmp(const void *p, const void *d)
237{
238 const TranslationBlock *tb = p;
239 const struct tb_desc *desc = d;
240
241 if (tb->pc == desc->pc &&
242 tb->page_addr[0] == desc->phys_page1 &&
243 tb->cs_base == desc->cs_base &&
Paolo Bonzini6d21e422016-07-19 08:36:18 +0200244 tb->flags == desc->flags &&
245 !atomic_read(&tb->invalid)) {
Emilio G. Cota909eaac2016-06-08 14:55:32 -0400246 /* check next page if needed */
247 if (tb->page_addr[1] == -1) {
248 return true;
249 } else {
250 tb_page_addr_t phys_page2;
251 target_ulong virt_page2;
252
253 virt_page2 = (desc->pc & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
254 phys_page2 = get_page_addr_code(desc->env, virt_page2);
255 if (tb->page_addr[1] == phys_page2) {
256 return true;
257 }
258 }
259 }
260 return false;
261}
262
Paolo Bonzini9fd1a942015-08-11 11:33:24 +0200263static TranslationBlock *tb_find_physical(CPUState *cpu,
264 target_ulong pc,
265 target_ulong cs_base,
Emilio G. Cota89fee742016-04-07 13:19:22 -0400266 uint32_t flags)
bellard8a40a182005-11-20 10:35:40 +0000267{
Emilio G. Cota909eaac2016-06-08 14:55:32 -0400268 tb_page_addr_t phys_pc;
269 struct tb_desc desc;
Emilio G. Cota42bd3222016-06-08 14:55:25 -0400270 uint32_t h;
ths3b46e622007-09-17 08:09:54 +0000271
Emilio G. Cota909eaac2016-06-08 14:55:32 -0400272 desc.env = (CPUArchState *)cpu->env_ptr;
273 desc.cs_base = cs_base;
274 desc.flags = flags;
275 desc.pc = pc;
276 phys_pc = get_page_addr_code(desc.env, pc);
277 desc.phys_page1 = phys_pc & TARGET_PAGE_MASK;
Emilio G. Cota42bd3222016-06-08 14:55:25 -0400278 h = tb_hash_func(phys_pc, pc, flags);
Emilio G. Cota909eaac2016-06-08 14:55:32 -0400279 return qht_lookup(&tcg_ctx.tb_ctx.htable, tb_cmp, &desc, h);
Paolo Bonzini9fd1a942015-08-11 11:33:24 +0200280}
281
282static TranslationBlock *tb_find_slow(CPUState *cpu,
283 target_ulong pc,
284 target_ulong cs_base,
Emilio G. Cota89fee742016-04-07 13:19:22 -0400285 uint32_t flags)
Paolo Bonzini9fd1a942015-08-11 11:33:24 +0200286{
287 TranslationBlock *tb;
288
289 tb = tb_find_physical(cpu, pc, cs_base, flags);
Alex Bennée518615c2016-07-15 20:58:49 +0300290 if (!tb) {
Paolo Bonzini9fd1a942015-08-11 11:33:24 +0200291
Alex Bennée518615c2016-07-15 20:58:49 +0300292 /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
293 * taken outside tb_lock. As system emulation is currently
294 * single threaded the locks are NOPs.
295 */
296 mmap_lock();
297 tb_lock();
298
299 /* There's a chance that our desired tb has been translated while
300 * taking the locks so we check again inside the lock.
301 */
302 tb = tb_find_physical(cpu, pc, cs_base, flags);
303 if (!tb) {
304 /* if no translated code available, then translate it now */
305 tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
306 }
307
308 tb_unlock();
Paolo Bonzini9fd1a942015-08-11 11:33:24 +0200309 mmap_unlock();
Paolo Bonzini9fd1a942015-08-11 11:33:24 +0200310 }
Paolo Bonzini9fd1a942015-08-11 11:33:24 +0200311
Alex Bennée518615c2016-07-15 20:58:49 +0300312 /* We add the TB in the virtual pc hash table for the fast lookup */
Sergey Fedorov89a16b12016-07-15 20:58:43 +0300313 atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
bellard8a40a182005-11-20 10:35:40 +0000314 return tb;
315}
316
Sergey Fedorova0522c72016-04-25 18:17:30 +0300317static inline TranslationBlock *tb_find_fast(CPUState *cpu,
Sergey Fedorov4b7e6952016-07-15 20:58:42 +0300318 TranslationBlock *last_tb,
Sergey Fedorova0522c72016-04-25 18:17:30 +0300319 int tb_exit)
bellard8a40a182005-11-20 10:35:40 +0000320{
Peter Crosthwaiteea3e9842015-06-18 10:24:55 -0700321 CPUArchState *env = (CPUArchState *)cpu->env_ptr;
bellard8a40a182005-11-20 10:35:40 +0000322 TranslationBlock *tb;
323 target_ulong cs_base, pc;
Emilio G. Cota89fee742016-04-07 13:19:22 -0400324 uint32_t flags;
bellard8a40a182005-11-20 10:35:40 +0000325
326 /* we record a subset of the CPU state. It will
327 always be the same before a given translated block
328 is executed. */
aliguori6b917542008-11-18 19:46:41 +0000329 cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
Sergey Fedorov89a16b12016-07-15 20:58:43 +0300330 tb = atomic_rcu_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)]);
ths551bd272008-07-03 17:57:36 +0000331 if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
332 tb->flags != flags)) {
Peter Crosthwaiteea3e9842015-06-18 10:24:55 -0700333 tb = tb_find_slow(cpu, pc, cs_base, flags);
bellard8a40a182005-11-20 10:35:40 +0000334 }
Sergey Fedorovc88c67e2016-05-16 16:13:00 +0300335#ifndef CONFIG_USER_ONLY
336 /* We don't take care of direct jumps when address mapping changes in
337 * system emulation. So it's not safe to make a direct jump to a TB
338 * spanning two pages because the mapping for the second page can change.
339 */
340 if (tb->page_addr[1] != -1) {
Sergey Fedorov4b7e6952016-07-15 20:58:42 +0300341 last_tb = NULL;
Sergey Fedorovc88c67e2016-05-16 16:13:00 +0300342 }
343#endif
Sergey Fedorova0522c72016-04-25 18:17:30 +0300344 /* See if we can patch the calling TB. */
Sergey Fedorov4b7e6952016-07-15 20:58:42 +0300345 if (last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
Alex Bennée518615c2016-07-15 20:58:49 +0300346 tb_lock();
Sergey Fedorov118b0732016-07-15 20:58:44 +0300347 /* Check if translation buffer has been flushed */
348 if (cpu->tb_flushed) {
349 cpu->tb_flushed = false;
Paolo Bonzini6d21e422016-07-19 08:36:18 +0200350 } else if (!tb->invalid) {
Sergey Fedorov118b0732016-07-15 20:58:44 +0300351 tb_add_jump(last_tb, tb_exit, tb);
352 }
Alex Bennée518615c2016-07-15 20:58:49 +0300353 tb_unlock();
Sergey Fedorova0522c72016-04-25 18:17:30 +0300354 }
bellard8a40a182005-11-20 10:35:40 +0000355 return tb;
356}
357
Sergey Fedorov8b2d34e2016-05-11 13:21:47 +0300358static inline bool cpu_handle_halt(CPUState *cpu)
359{
360 if (cpu->halted) {
361#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
362 if ((cpu->interrupt_request & CPU_INTERRUPT_POLL)
363 && replay_interrupt()) {
364 X86CPU *x86_cpu = X86_CPU(cpu);
365 apic_poll_irq(x86_cpu->apic_state);
366 cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
367 }
368#endif
369 if (!cpu_has_work(cpu)) {
370 current_cpu = NULL;
371 return true;
372 }
373
374 cpu->halted = 0;
375 }
376
377 return false;
378}
379
Sergey Fedorovea284762016-05-11 13:21:48 +0300380static inline void cpu_handle_debug_exception(CPUState *cpu)
Jan Kiszka1009d2e2011-03-15 12:26:13 +0100381{
Peter Maydell86025ee2014-09-12 14:06:48 +0100382 CPUClass *cc = CPU_GET_CLASS(cpu);
Jan Kiszka1009d2e2011-03-15 12:26:13 +0100383 CPUWatchpoint *wp;
384
Andreas Färberff4700b2013-08-26 18:23:18 +0200385 if (!cpu->watchpoint_hit) {
386 QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
Jan Kiszka1009d2e2011-03-15 12:26:13 +0100387 wp->flags &= ~BP_WATCHPOINT_HIT;
388 }
389 }
Peter Maydell86025ee2014-09-12 14:06:48 +0100390
391 cc->debug_excp_handler(cpu);
Jan Kiszka1009d2e2011-03-15 12:26:13 +0100392}
393
Sergey Fedorovea284762016-05-11 13:21:48 +0300394static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
395{
396 if (cpu->exception_index >= 0) {
397 if (cpu->exception_index >= EXCP_INTERRUPT) {
398 /* exit request from the cpu execution loop */
399 *ret = cpu->exception_index;
400 if (*ret == EXCP_DEBUG) {
401 cpu_handle_debug_exception(cpu);
402 }
403 cpu->exception_index = -1;
404 return true;
405 } else {
406#if defined(CONFIG_USER_ONLY)
407 /* if user mode only, we simulate a fake exception
408 which will be handled outside the cpu execution
409 loop */
410#if defined(TARGET_I386)
411 CPUClass *cc = CPU_GET_CLASS(cpu);
412 cc->do_interrupt(cpu);
413#endif
414 *ret = cpu->exception_index;
415 cpu->exception_index = -1;
416 return true;
417#else
418 if (replay_exception()) {
419 CPUClass *cc = CPU_GET_CLASS(cpu);
420 cc->do_interrupt(cpu);
421 cpu->exception_index = -1;
422 } else if (!replay_has_interrupt()) {
423 /* give a chance to iothread in replay mode */
424 *ret = EXCP_INTERRUPT;
425 return true;
426 }
427#endif
428 }
429#ifndef CONFIG_USER_ONLY
430 } else if (replay_has_exception()
431 && cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
432 /* try to cause an exception pending in the log */
Sergey Fedorov4b7e6952016-07-15 20:58:42 +0300433 cpu_exec_nocache(cpu, 1, tb_find_fast(cpu, NULL, 0), true);
Sergey Fedorovea284762016-05-11 13:21:48 +0300434 *ret = -1;
435 return true;
436#endif
437 }
438
439 return false;
440}
441
Sergey Fedorovc385e6e2016-05-11 13:21:49 +0300442static inline void cpu_handle_interrupt(CPUState *cpu,
443 TranslationBlock **last_tb)
444{
445 CPUClass *cc = CPU_GET_CLASS(cpu);
446 int interrupt_request = cpu->interrupt_request;
447
448 if (unlikely(interrupt_request)) {
449 if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
450 /* Mask out external interrupts for this step. */
451 interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK;
452 }
453 if (interrupt_request & CPU_INTERRUPT_DEBUG) {
454 cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG;
455 cpu->exception_index = EXCP_DEBUG;
456 cpu_loop_exit(cpu);
457 }
458 if (replay_mode == REPLAY_MODE_PLAY && !replay_has_interrupt()) {
459 /* Do nothing */
460 } else if (interrupt_request & CPU_INTERRUPT_HALT) {
461 replay_interrupt();
462 cpu->interrupt_request &= ~CPU_INTERRUPT_HALT;
463 cpu->halted = 1;
464 cpu->exception_index = EXCP_HLT;
465 cpu_loop_exit(cpu);
466 }
467#if defined(TARGET_I386)
468 else if (interrupt_request & CPU_INTERRUPT_INIT) {
469 X86CPU *x86_cpu = X86_CPU(cpu);
470 CPUArchState *env = &x86_cpu->env;
471 replay_interrupt();
472 cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0);
473 do_cpu_init(x86_cpu);
474 cpu->exception_index = EXCP_HALTED;
475 cpu_loop_exit(cpu);
476 }
477#else
478 else if (interrupt_request & CPU_INTERRUPT_RESET) {
479 replay_interrupt();
480 cpu_reset(cpu);
481 cpu_loop_exit(cpu);
482 }
483#endif
484 /* The target hook has 3 exit conditions:
485 False when the interrupt isn't processed,
486 True when it is, and we should restart on a new TB,
487 and via longjmp via cpu_loop_exit. */
488 else {
489 replay_interrupt();
490 if (cc->cpu_exec_interrupt(cpu, interrupt_request)) {
491 *last_tb = NULL;
492 }
Sergey Fedorov8b1fe3f2016-05-12 19:52:17 +0300493 /* The target hook may have updated the 'cpu->interrupt_request';
494 * reload the 'interrupt_request' value */
495 interrupt_request = cpu->interrupt_request;
Sergey Fedorovc385e6e2016-05-11 13:21:49 +0300496 }
Sergey Fedorov8b1fe3f2016-05-12 19:52:17 +0300497 if (interrupt_request & CPU_INTERRUPT_EXITTB) {
Sergey Fedorovc385e6e2016-05-11 13:21:49 +0300498 cpu->interrupt_request &= ~CPU_INTERRUPT_EXITTB;
499 /* ensure that no TB jump will be modified as
500 the program flow was changed */
501 *last_tb = NULL;
502 }
503 }
504 if (unlikely(cpu->exit_request || replay_has_interrupt())) {
505 cpu->exit_request = 0;
506 cpu->exception_index = EXCP_INTERRUPT;
507 cpu_loop_exit(cpu);
508 }
509}
510
Sergey Fedorov928de9e2016-05-11 13:21:50 +0300511static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
512 TranslationBlock **last_tb, int *tb_exit,
513 SyncClocks *sc)
514{
515 uintptr_t ret;
516
517 if (unlikely(cpu->exit_request)) {
518 return;
519 }
520
521 trace_exec_tb(tb, tb->pc);
522 ret = cpu_tb_exec(cpu, tb);
523 *last_tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK);
524 *tb_exit = ret & TB_EXIT_MASK;
525 switch (*tb_exit) {
526 case TB_EXIT_REQUESTED:
527 /* Something asked us to stop executing
528 * chained TBs; just continue round the main
529 * loop. Whatever requested the exit will also
530 * have set something else (eg exit_request or
531 * interrupt_request) which we will handle
532 * next time around the loop. But we need to
533 * ensure the tcg_exit_req read in generated code
534 * comes before the next read of cpu->exit_request
535 * or cpu->interrupt_request.
536 */
537 smp_rmb();
538 *last_tb = NULL;
539 break;
540 case TB_EXIT_ICOUNT_EXPIRED:
541 {
542 /* Instruction counter expired. */
543#ifdef CONFIG_USER_ONLY
544 abort();
545#else
546 int insns_left = cpu->icount_decr.u32;
547 if (cpu->icount_extra && insns_left >= 0) {
548 /* Refill decrementer and continue execution. */
549 cpu->icount_extra += insns_left;
550 insns_left = MIN(0xffff, cpu->icount_extra);
551 cpu->icount_extra -= insns_left;
552 cpu->icount_decr.u16.low = insns_left;
553 } else {
554 if (insns_left > 0) {
555 /* Execute remaining instructions. */
556 cpu_exec_nocache(cpu, insns_left, *last_tb, false);
557 align_clocks(sc, cpu);
558 }
559 cpu->exception_index = EXCP_INTERRUPT;
560 *last_tb = NULL;
561 cpu_loop_exit(cpu);
562 }
563 break;
564#endif
565 }
566 default:
567 break;
568 }
569}
570
bellard7d132992003-03-06 23:23:54 +0000571/* main execution loop */
572
Peter Crosthwaiteea3e9842015-06-18 10:24:55 -0700573int cpu_exec(CPUState *cpu)
bellard7d132992003-03-06 23:23:54 +0000574{
Andreas Färber97a8ea52013-02-02 10:57:51 +0100575 CPUClass *cc = CPU_GET_CLASS(cpu);
Sergey Fedorovc385e6e2016-05-11 13:21:49 +0300576 int ret;
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +0200577 SyncClocks sc;
578
Pavel Dovgalyuk6f060962015-09-17 19:24:16 +0300579 /* replay_interrupt may need current_cpu */
580 current_cpu = cpu;
581
Sergey Fedorov8b2d34e2016-05-11 13:21:47 +0300582 if (cpu_handle_halt(cpu)) {
583 return EXCP_HALTED;
Paolo Bonzinieda48c32011-03-12 17:43:56 +0100584 }
bellard5a1e3cf2005-11-23 21:02:53 +0000585
Paolo Bonzini9373e632015-08-18 06:24:34 -0700586 atomic_mb_set(&tcg_current_cpu, cpu);
Paolo Bonzini79e2b9a2015-01-21 12:09:14 +0100587 rcu_read_lock();
588
Paolo Bonziniaed807c2015-08-18 06:43:15 -0700589 if (unlikely(atomic_mb_read(&exit_request))) {
Andreas Färberfcd7d002012-12-17 08:02:44 +0100590 cpu->exit_request = 1;
Marcelo Tosatti1a28cac2010-05-04 09:45:20 -0300591 }
592
Richard Hendersoncffe7b32014-09-13 09:45:12 -0700593 cc->cpu_exec_enter(cpu);
bellard9d27abd2003-05-10 13:13:54 +0000594
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +0200595 /* Calculate difference between guest clock and host clock.
596 * This delay includes the delay of the last cycle, so
597 * what we have to do is sleep until it is 0. As for the
598 * advance/delay we gain here, we try to fix it next time.
599 */
600 init_delay_params(&sc, cpu);
601
bellard3fb2ded2003-06-24 13:22:59 +0000602 for(;;) {
Sergey Fedorovea284762016-05-11 13:21:48 +0300603 /* prepare setjmp context for exception handling */
Andreas Färber6f03bef2013-08-26 06:22:03 +0200604 if (sigsetjmp(cpu->jmp_env, 0) == 0) {
Sergey Fedorovca7d8e12016-07-15 22:31:23 +0300605 TranslationBlock *tb, *last_tb = NULL;
606 int tb_exit = 0;
607
bellard3fb2ded2003-06-24 13:22:59 +0000608 /* if an exception is pending, we execute it here */
Sergey Fedorovea284762016-05-11 13:21:48 +0300609 if (cpu_handle_exception(cpu, &ret)) {
Pavel Dovgalyuk6f060962015-09-17 19:24:16 +0300610 break;
ths5fafdf22007-09-16 21:08:06 +0000611 }
bellard9df217a2005-02-10 22:05:51 +0000612
Sergey Fedorov118b0732016-07-15 20:58:44 +0300613 atomic_mb_set(&cpu->tb_flushed, false); /* reset before first TB lookup */
bellard3fb2ded2003-06-24 13:22:59 +0000614 for(;;) {
Sergey Fedorovc385e6e2016-05-11 13:21:49 +0300615 cpu_handle_interrupt(cpu, &last_tb);
Sergey Fedorov4b7e6952016-07-15 20:58:42 +0300616 tb = tb_find_fast(cpu, last_tb, tb_exit);
Sergey Fedorov928de9e2016-05-11 13:21:50 +0300617 cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
Sebastian Tanasec2aa5f82014-07-25 11:56:31 +0200618 /* Try to align the host and virtual clocks
619 if the guest is in advance */
620 align_clocks(&sc, cpu);
ths50a518e2007-06-03 18:52:15 +0000621 } /* for(;;) */
Jan Kiszka0d101932011-07-02 09:50:51 +0200622 } else {
Stefan Weil0448f5f2015-09-26 13:23:26 +0200623#if defined(__clang__) || !QEMU_GNUC_PREREQ(4, 6)
624 /* Some compilers wrongly smash all local variables after
625 * siglongjmp. There were bug reports for gcc 4.5.0 and clang.
626 * Reload essential local variables here for those compilers.
627 * Newer versions of gcc would complain about this code (-Wclobbered). */
Andreas Färber4917cf42013-05-27 05:17:50 +0200628 cpu = current_cpu;
Juergen Lock6c78f292013-10-03 16:09:37 +0200629 cc = CPU_GET_CLASS(cpu);
Stefan Weil0448f5f2015-09-26 13:23:26 +0200630#else /* buggy compiler */
631 /* Assert that the compiler does not smash local variables. */
632 g_assert(cpu == current_cpu);
633 g_assert(cc == CPU_GET_CLASS(cpu));
Stefan Weil0448f5f2015-09-26 13:23:26 +0200634#endif /* buggy compiler */
635 cpu->can_do_io = 1;
KONRAD Frederic677ef622015-08-10 17:27:02 +0200636 tb_lock_reset();
bellard7d132992003-03-06 23:23:54 +0000637 }
bellard3fb2ded2003-06-24 13:22:59 +0000638 } /* for(;;) */
639
Richard Hendersoncffe7b32014-09-13 09:45:12 -0700640 cc->cpu_exec_exit(cpu);
Paolo Bonzini79e2b9a2015-01-21 12:09:14 +0100641 rcu_read_unlock();
pbrook1057eaa2007-02-04 13:37:44 +0000642
Andreas Färber4917cf42013-05-27 05:17:50 +0200643 /* fail safe : never use current_cpu outside cpu_exec() */
644 current_cpu = NULL;
Paolo Bonzini9373e632015-08-18 06:24:34 -0700645
646 /* Does not need atomic_mb_set because a spurious wakeup is okay. */
647 atomic_set(&tcg_current_cpu, NULL);
bellard7d132992003-03-06 23:23:54 +0000648 return ret;
649}