s390x/pci: Rework memory access in zpci instruction
[qemu.git] / cpu-exec.c
blob67381176da8cdce50e2b1a5884215321ec22d996
1 /*
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 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/>.
19 #include "config.h"
20 #include "cpu.h"
21 #include "trace.h"
22 #include "disas/disas.h"
23 #include "tcg.h"
24 #include "qemu/atomic.h"
25 #include "sysemu/qtest.h"
26 #include "qemu/timer.h"
28 /* -icount align implementation. */
30 typedef struct SyncClocks {
31 int64_t diff_clk;
32 int64_t last_cpu_icount;
33 int64_t realtime_clock;
34 } SyncClocks;
36 #if !defined(CONFIG_USER_ONLY)
37 /* Allow the guest to have a max 3ms advance.
38 * The difference between the 2 clocks could therefore
39 * oscillate around 0.
41 #define VM_CLOCK_ADVANCE 3000000
42 #define THRESHOLD_REDUCE 1.5
43 #define MAX_DELAY_PRINT_RATE 2000000000LL
44 #define MAX_NB_PRINTS 100
46 static void align_clocks(SyncClocks *sc, const CPUState *cpu)
48 int64_t cpu_icount;
50 if (!icount_align_option) {
51 return;
54 cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
55 sc->diff_clk += cpu_icount_to_ns(sc->last_cpu_icount - cpu_icount);
56 sc->last_cpu_icount = cpu_icount;
58 if (sc->diff_clk > VM_CLOCK_ADVANCE) {
59 #ifndef _WIN32
60 struct timespec sleep_delay, rem_delay;
61 sleep_delay.tv_sec = sc->diff_clk / 1000000000LL;
62 sleep_delay.tv_nsec = sc->diff_clk % 1000000000LL;
63 if (nanosleep(&sleep_delay, &rem_delay) < 0) {
64 sc->diff_clk = rem_delay.tv_sec * 1000000000LL + rem_delay.tv_nsec;
65 } else {
66 sc->diff_clk = 0;
68 #else
69 Sleep(sc->diff_clk / SCALE_MS);
70 sc->diff_clk = 0;
71 #endif
75 static void print_delay(const SyncClocks *sc)
77 static float threshold_delay;
78 static int64_t last_realtime_clock;
79 static int nb_prints;
81 if (icount_align_option &&
82 sc->realtime_clock - last_realtime_clock >= MAX_DELAY_PRINT_RATE &&
83 nb_prints < MAX_NB_PRINTS) {
84 if ((-sc->diff_clk / (float)1000000000LL > threshold_delay) ||
85 (-sc->diff_clk / (float)1000000000LL <
86 (threshold_delay - THRESHOLD_REDUCE))) {
87 threshold_delay = (-sc->diff_clk / 1000000000LL) + 1;
88 printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
89 threshold_delay - 1,
90 threshold_delay);
91 nb_prints++;
92 last_realtime_clock = sc->realtime_clock;
97 static void init_delay_params(SyncClocks *sc,
98 const CPUState *cpu)
100 if (!icount_align_option) {
101 return;
103 sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
104 sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - sc->realtime_clock;
105 sc->last_cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
106 if (sc->diff_clk < max_delay) {
107 max_delay = sc->diff_clk;
109 if (sc->diff_clk > max_advance) {
110 max_advance = sc->diff_clk;
113 /* Print every 2s max if the guest is late. We limit the number
114 of printed messages to NB_PRINT_MAX(currently 100) */
115 print_delay(sc);
117 #else
118 static void align_clocks(SyncClocks *sc, const CPUState *cpu)
122 static void init_delay_params(SyncClocks *sc, const CPUState *cpu)
125 #endif /* CONFIG USER ONLY */
127 void cpu_loop_exit(CPUState *cpu)
129 cpu->current_tb = NULL;
130 siglongjmp(cpu->jmp_env, 1);
133 /* exit the current TB from a signal handler. The host registers are
134 restored in a state compatible with the CPU emulator
136 #if defined(CONFIG_SOFTMMU)
137 void cpu_resume_from_signal(CPUState *cpu, void *puc)
139 /* XXX: restore cpu registers saved in host registers */
141 cpu->exception_index = -1;
142 siglongjmp(cpu->jmp_env, 1);
144 #endif
146 /* Execute a TB, and fix up the CPU state afterwards if necessary */
147 static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr)
149 CPUArchState *env = cpu->env_ptr;
150 uintptr_t next_tb;
152 #if defined(DEBUG_DISAS)
153 if (qemu_loglevel_mask(CPU_LOG_TB_CPU)) {
154 #if defined(TARGET_I386)
155 log_cpu_state(cpu, CPU_DUMP_CCOP);
156 #elif defined(TARGET_M68K)
157 /* ??? Should not modify env state for dumping. */
158 cpu_m68k_flush_flags(env, env->cc_op);
159 env->cc_op = CC_OP_FLAGS;
160 env->sr = (env->sr & 0xffe0) | env->cc_dest | (env->cc_x << 4);
161 log_cpu_state(cpu, 0);
162 #else
163 log_cpu_state(cpu, 0);
164 #endif
166 #endif /* DEBUG_DISAS */
168 cpu->can_do_io = 0;
169 next_tb = tcg_qemu_tb_exec(env, tb_ptr);
170 cpu->can_do_io = 1;
171 trace_exec_tb_exit((void *) (next_tb & ~TB_EXIT_MASK),
172 next_tb & TB_EXIT_MASK);
174 if ((next_tb & TB_EXIT_MASK) > TB_EXIT_IDX1) {
175 /* We didn't start executing this TB (eg because the instruction
176 * counter hit zero); we must restore the guest PC to the address
177 * of the start of the TB.
179 CPUClass *cc = CPU_GET_CLASS(cpu);
180 TranslationBlock *tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK);
181 if (cc->synchronize_from_tb) {
182 cc->synchronize_from_tb(cpu, tb);
183 } else {
184 assert(cc->set_pc);
185 cc->set_pc(cpu, tb->pc);
188 if ((next_tb & TB_EXIT_MASK) == TB_EXIT_REQUESTED) {
189 /* We were asked to stop executing TBs (probably a pending
190 * interrupt. We've now stopped, so clear the flag.
192 cpu->tcg_exit_req = 0;
194 return next_tb;
197 /* Execute the code without caching the generated code. An interpreter
198 could be used if available. */
199 static void cpu_exec_nocache(CPUArchState *env, int max_cycles,
200 TranslationBlock *orig_tb)
202 CPUState *cpu = ENV_GET_CPU(env);
203 TranslationBlock *tb;
204 target_ulong pc = orig_tb->pc;
205 target_ulong cs_base = orig_tb->cs_base;
206 uint64_t flags = orig_tb->flags;
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;
213 /* tb_gen_code can flush our orig_tb, invalidate it now */
214 tb_phys_invalidate(orig_tb, -1);
215 tb = tb_gen_code(cpu, pc, cs_base, flags,
216 max_cycles | CF_NOCACHE);
217 cpu->current_tb = tb;
218 /* execute the generated code */
219 trace_exec_tb_nocache(tb, tb->pc);
220 cpu_tb_exec(cpu, tb->tc_ptr);
221 cpu->current_tb = NULL;
222 tb_phys_invalidate(tb, -1);
223 tb_free(tb);
226 static TranslationBlock *tb_find_slow(CPUArchState *env,
227 target_ulong pc,
228 target_ulong cs_base,
229 uint64_t flags)
231 CPUState *cpu = ENV_GET_CPU(env);
232 TranslationBlock *tb, **ptb1;
233 unsigned int h;
234 tb_page_addr_t phys_pc, phys_page1;
235 target_ulong virt_page2;
237 tcg_ctx.tb_ctx.tb_invalidated_flag = 0;
239 /* find translated block using physical mappings */
240 phys_pc = get_page_addr_code(env, pc);
241 phys_page1 = phys_pc & TARGET_PAGE_MASK;
242 h = tb_phys_hash_func(phys_pc);
243 ptb1 = &tcg_ctx.tb_ctx.tb_phys_hash[h];
244 for(;;) {
245 tb = *ptb1;
246 if (!tb)
247 goto not_found;
248 if (tb->pc == pc &&
249 tb->page_addr[0] == phys_page1 &&
250 tb->cs_base == cs_base &&
251 tb->flags == flags) {
252 /* check next page if needed */
253 if (tb->page_addr[1] != -1) {
254 tb_page_addr_t phys_page2;
256 virt_page2 = (pc & TARGET_PAGE_MASK) +
257 TARGET_PAGE_SIZE;
258 phys_page2 = get_page_addr_code(env, virt_page2);
259 if (tb->page_addr[1] == phys_page2)
260 goto found;
261 } else {
262 goto found;
265 ptb1 = &tb->phys_hash_next;
267 not_found:
268 /* if no translated code available, then translate it now */
269 tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
271 found:
272 /* Move the last found TB to the head of the list */
273 if (likely(*ptb1)) {
274 *ptb1 = tb->phys_hash_next;
275 tb->phys_hash_next = tcg_ctx.tb_ctx.tb_phys_hash[h];
276 tcg_ctx.tb_ctx.tb_phys_hash[h] = tb;
278 /* we add the TB in the virtual pc hash table */
279 cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)] = tb;
280 return tb;
283 static inline TranslationBlock *tb_find_fast(CPUArchState *env)
285 CPUState *cpu = ENV_GET_CPU(env);
286 TranslationBlock *tb;
287 target_ulong cs_base, pc;
288 int flags;
290 /* we record a subset of the CPU state. It will
291 always be the same before a given translated block
292 is executed. */
293 cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
294 tb = cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)];
295 if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
296 tb->flags != flags)) {
297 tb = tb_find_slow(env, pc, cs_base, flags);
299 return tb;
302 static void cpu_handle_debug_exception(CPUArchState *env)
304 CPUState *cpu = ENV_GET_CPU(env);
305 CPUClass *cc = CPU_GET_CLASS(cpu);
306 CPUWatchpoint *wp;
308 if (!cpu->watchpoint_hit) {
309 QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
310 wp->flags &= ~BP_WATCHPOINT_HIT;
314 cc->debug_excp_handler(cpu);
317 /* main execution loop */
319 volatile sig_atomic_t exit_request;
321 int cpu_exec(CPUArchState *env)
323 CPUState *cpu = ENV_GET_CPU(env);
324 CPUClass *cc = CPU_GET_CLASS(cpu);
325 #ifdef TARGET_I386
326 X86CPU *x86_cpu = X86_CPU(cpu);
327 #endif
328 int ret, interrupt_request;
329 TranslationBlock *tb;
330 uint8_t *tc_ptr;
331 uintptr_t next_tb;
332 SyncClocks sc;
334 /* This must be volatile so it is not trashed by longjmp() */
335 volatile bool have_tb_lock = false;
337 if (cpu->halted) {
338 if (!cpu_has_work(cpu)) {
339 return EXCP_HALTED;
342 cpu->halted = 0;
345 current_cpu = cpu;
347 /* As long as current_cpu is null, up to the assignment just above,
348 * requests by other threads to exit the execution loop are expected to
349 * be issued using the exit_request global. We must make sure that our
350 * evaluation of the global value is performed past the current_cpu
351 * value transition point, which requires a memory barrier as well as
352 * an instruction scheduling constraint on modern architectures. */
353 smp_mb();
355 if (unlikely(exit_request)) {
356 cpu->exit_request = 1;
359 cc->cpu_exec_enter(cpu);
361 /* Calculate difference between guest clock and host clock.
362 * This delay includes the delay of the last cycle, so
363 * what we have to do is sleep until it is 0. As for the
364 * advance/delay we gain here, we try to fix it next time.
366 init_delay_params(&sc, cpu);
368 /* prepare setjmp context for exception handling */
369 for(;;) {
370 if (sigsetjmp(cpu->jmp_env, 0) == 0) {
371 /* if an exception is pending, we execute it here */
372 if (cpu->exception_index >= 0) {
373 if (cpu->exception_index >= EXCP_INTERRUPT) {
374 /* exit request from the cpu execution loop */
375 ret = cpu->exception_index;
376 if (ret == EXCP_DEBUG) {
377 cpu_handle_debug_exception(env);
379 cpu->exception_index = -1;
380 break;
381 } else {
382 #if defined(CONFIG_USER_ONLY)
383 /* if user mode only, we simulate a fake exception
384 which will be handled outside the cpu execution
385 loop */
386 #if defined(TARGET_I386)
387 cc->do_interrupt(cpu);
388 #endif
389 ret = cpu->exception_index;
390 cpu->exception_index = -1;
391 break;
392 #else
393 cc->do_interrupt(cpu);
394 cpu->exception_index = -1;
395 #endif
399 next_tb = 0; /* force lookup of first TB */
400 for(;;) {
401 interrupt_request = cpu->interrupt_request;
402 if (unlikely(interrupt_request)) {
403 if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
404 /* Mask out external interrupts for this step. */
405 interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK;
407 if (interrupt_request & CPU_INTERRUPT_DEBUG) {
408 cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG;
409 cpu->exception_index = EXCP_DEBUG;
410 cpu_loop_exit(cpu);
412 if (interrupt_request & CPU_INTERRUPT_HALT) {
413 cpu->interrupt_request &= ~CPU_INTERRUPT_HALT;
414 cpu->halted = 1;
415 cpu->exception_index = EXCP_HLT;
416 cpu_loop_exit(cpu);
418 #if defined(TARGET_I386)
419 if (interrupt_request & CPU_INTERRUPT_INIT) {
420 cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0);
421 do_cpu_init(x86_cpu);
422 cpu->exception_index = EXCP_HALTED;
423 cpu_loop_exit(cpu);
425 #else
426 if (interrupt_request & CPU_INTERRUPT_RESET) {
427 cpu_reset(cpu);
429 #endif
430 /* The target hook has 3 exit conditions:
431 False when the interrupt isn't processed,
432 True when it is, and we should restart on a new TB,
433 and via longjmp via cpu_loop_exit. */
434 if (cc->cpu_exec_interrupt(cpu, interrupt_request)) {
435 next_tb = 0;
437 /* Don't use the cached interrupt_request value,
438 do_interrupt may have updated the EXITTB flag. */
439 if (cpu->interrupt_request & CPU_INTERRUPT_EXITTB) {
440 cpu->interrupt_request &= ~CPU_INTERRUPT_EXITTB;
441 /* ensure that no TB jump will be modified as
442 the program flow was changed */
443 next_tb = 0;
446 if (unlikely(cpu->exit_request)) {
447 cpu->exit_request = 0;
448 cpu->exception_index = EXCP_INTERRUPT;
449 cpu_loop_exit(cpu);
451 spin_lock(&tcg_ctx.tb_ctx.tb_lock);
452 have_tb_lock = true;
453 tb = tb_find_fast(env);
454 /* Note: we do it here to avoid a gcc bug on Mac OS X when
455 doing it in tb_find_slow */
456 if (tcg_ctx.tb_ctx.tb_invalidated_flag) {
457 /* as some TB could have been invalidated because
458 of memory exceptions while generating the code, we
459 must recompute the hash index here */
460 next_tb = 0;
461 tcg_ctx.tb_ctx.tb_invalidated_flag = 0;
463 if (qemu_loglevel_mask(CPU_LOG_EXEC)) {
464 qemu_log("Trace %p [" TARGET_FMT_lx "] %s\n",
465 tb->tc_ptr, tb->pc, lookup_symbol(tb->pc));
467 /* see if we can patch the calling TB. When the TB
468 spans two pages, we cannot safely do a direct
469 jump. */
470 if (next_tb != 0 && tb->page_addr[1] == -1) {
471 tb_add_jump((TranslationBlock *)(next_tb & ~TB_EXIT_MASK),
472 next_tb & TB_EXIT_MASK, tb);
474 have_tb_lock = false;
475 spin_unlock(&tcg_ctx.tb_ctx.tb_lock);
477 /* cpu_interrupt might be called while translating the
478 TB, but before it is linked into a potentially
479 infinite loop and becomes env->current_tb. Avoid
480 starting execution if there is a pending interrupt. */
481 cpu->current_tb = tb;
482 barrier();
483 if (likely(!cpu->exit_request)) {
484 trace_exec_tb(tb, tb->pc);
485 tc_ptr = tb->tc_ptr;
486 /* execute the generated code */
487 next_tb = cpu_tb_exec(cpu, tc_ptr);
488 switch (next_tb & TB_EXIT_MASK) {
489 case TB_EXIT_REQUESTED:
490 /* Something asked us to stop executing
491 * chained TBs; just continue round the main
492 * loop. Whatever requested the exit will also
493 * have set something else (eg exit_request or
494 * interrupt_request) which we will handle
495 * next time around the loop.
497 next_tb = 0;
498 break;
499 case TB_EXIT_ICOUNT_EXPIRED:
501 /* Instruction counter expired. */
502 int insns_left = cpu->icount_decr.u32;
503 if (cpu->icount_extra && insns_left >= 0) {
504 /* Refill decrementer and continue execution. */
505 cpu->icount_extra += insns_left;
506 insns_left = MIN(0xffff, cpu->icount_extra);
507 cpu->icount_extra -= insns_left;
508 cpu->icount_decr.u16.low = insns_left;
509 } else {
510 if (insns_left > 0) {
511 /* Execute remaining instructions. */
512 tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK);
513 cpu_exec_nocache(env, insns_left, tb);
514 align_clocks(&sc, cpu);
516 cpu->exception_index = EXCP_INTERRUPT;
517 next_tb = 0;
518 cpu_loop_exit(cpu);
520 break;
522 default:
523 break;
526 cpu->current_tb = NULL;
527 /* Try to align the host and virtual clocks
528 if the guest is in advance */
529 align_clocks(&sc, cpu);
530 /* reset soft MMU for next block (it can currently
531 only be set by a memory fault) */
532 } /* for(;;) */
533 } else {
534 /* Reload env after longjmp - the compiler may have smashed all
535 * local variables as longjmp is marked 'noreturn'. */
536 cpu = current_cpu;
537 env = cpu->env_ptr;
538 cc = CPU_GET_CLASS(cpu);
539 cpu->can_do_io = 1;
540 #ifdef TARGET_I386
541 x86_cpu = X86_CPU(cpu);
542 #endif
543 if (have_tb_lock) {
544 spin_unlock(&tcg_ctx.tb_ctx.tb_lock);
545 have_tb_lock = false;
548 } /* for(;;) */
550 cc->cpu_exec_exit(cpu);
552 /* fail safe : never use current_cpu outside cpu_exec() */
553 current_cpu = NULL;
554 return ret;