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Diffstat (limited to 'src/cpu-exec.c')
| -rw-r--r-- | src/cpu-exec.c | 616 |
1 files changed, 616 insertions, 0 deletions
diff --git a/src/cpu-exec.c b/src/cpu-exec.c new file mode 100644 index 0000000..5e1f380 --- /dev/null +++ b/src/cpu-exec.c @@ -0,0 +1,616 @@ +/* + * emulator main execution loop + * + * Copyright (c) 2003-2005 Fabrice Bellard + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + */ +#include "config.h" +#include "cpu.h" +#include "trace.h" +#include "disas/disas.h" +#include "tcg.h" +#include "qemu/atomic.h" +#include "sysemu/qtest.h" +#include "qemu/timer.h" +#include "exec/address-spaces.h" +#include "qemu/rcu.h" +#include "exec/tb-hash.h" +#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY) +#include "hw/i386/apic.h" +#endif +#include "sysemu/replay.h" +#include "hqemu.h" + +/* -icount align implementation. */ + +typedef struct SyncClocks { + int64_t diff_clk; + int64_t last_cpu_icount; + int64_t realtime_clock; +} SyncClocks; + +#if !defined(CONFIG_USER_ONLY) +/* Allow the guest to have a max 3ms advance. + * The difference between the 2 clocks could therefore + * oscillate around 0. + */ +#define VM_CLOCK_ADVANCE 3000000 +#define THRESHOLD_REDUCE 1.5 +#define MAX_DELAY_PRINT_RATE 2000000000LL +#define MAX_NB_PRINTS 100 + +static void align_clocks(SyncClocks *sc, const CPUState *cpu) +{ + int64_t cpu_icount; + + if (!icount_align_option) { + return; + } + + cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low; + sc->diff_clk += cpu_icount_to_ns(sc->last_cpu_icount - cpu_icount); + sc->last_cpu_icount = cpu_icount; + + if (sc->diff_clk > VM_CLOCK_ADVANCE) { +#ifndef _WIN32 + struct timespec sleep_delay, rem_delay; + sleep_delay.tv_sec = sc->diff_clk / 1000000000LL; + sleep_delay.tv_nsec = sc->diff_clk % 1000000000LL; + if (nanosleep(&sleep_delay, &rem_delay) < 0) { + sc->diff_clk = rem_delay.tv_sec * 1000000000LL + rem_delay.tv_nsec; + } else { + sc->diff_clk = 0; + } +#else + Sleep(sc->diff_clk / SCALE_MS); + sc->diff_clk = 0; +#endif + } +} + +static void print_delay(const SyncClocks *sc) +{ + static float threshold_delay; + static int64_t last_realtime_clock; + static int nb_prints; + + if (icount_align_option && + sc->realtime_clock - last_realtime_clock >= MAX_DELAY_PRINT_RATE && + nb_prints < MAX_NB_PRINTS) { + if ((-sc->diff_clk / (float)1000000000LL > threshold_delay) || + (-sc->diff_clk / (float)1000000000LL < + (threshold_delay - THRESHOLD_REDUCE))) { + threshold_delay = (-sc->diff_clk / 1000000000LL) + 1; + printf("Warning: The guest is now late by %.1f to %.1f seconds\n", + threshold_delay - 1, + threshold_delay); + nb_prints++; + last_realtime_clock = sc->realtime_clock; + } + } +} + +static void init_delay_params(SyncClocks *sc, + const CPUState *cpu) +{ + memset(sc, 0, sizeof(SyncClocks)); + if (!icount_align_option) { + return; + } + sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT); + sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - sc->realtime_clock; + sc->last_cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low; + if (sc->diff_clk < max_delay) { + max_delay = sc->diff_clk; + } + if (sc->diff_clk > max_advance) { + max_advance = sc->diff_clk; + } + + /* Print every 2s max if the guest is late. We limit the number + of printed messages to NB_PRINT_MAX(currently 100) */ + print_delay(sc); +} +#else +static void align_clocks(SyncClocks *sc, const CPUState *cpu) +{ +} + +static void init_delay_params(SyncClocks *sc, const CPUState *cpu) +{ +} +#endif /* CONFIG USER ONLY */ + +/* Execute a TB, and fix up the CPU state afterwards if necessary */ +static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr) +{ + CPUArchState *env = cpu->env_ptr; + uintptr_t next_tb; + +#if defined(DEBUG_DISAS) + if (qemu_loglevel_mask(CPU_LOG_TB_CPU)) { +#if defined(TARGET_I386) + log_cpu_state(cpu, CPU_DUMP_CCOP); +#elif defined(TARGET_M68K) + /* ??? Should not modify env state for dumping. */ + cpu_m68k_flush_flags(env, env->cc_op); + env->cc_op = CC_OP_FLAGS; + env->sr = (env->sr & 0xffe0) | env->cc_dest | (env->cc_x << 4); + log_cpu_state(cpu, 0); +#else + log_cpu_state(cpu, 0); +#endif + } +#endif /* DEBUG_DISAS */ + + cpu->can_do_io = !use_icount; + next_tb = tcg_qemu_tb_exec(env, tb_ptr); + cpu->can_do_io = 1; + trace_exec_tb_exit((void *) (next_tb & ~TB_EXIT_MASK), + next_tb & TB_EXIT_MASK); + +#if defined(CONFIG_LLVM) + if ((next_tb & TB_EXIT_MASK) == TB_EXIT_LLVM) + return next_tb; +#endif + if ((next_tb & TB_EXIT_MASK) > TB_EXIT_IDX1) { + /* We didn't start executing this TB (eg because the instruction + * counter hit zero); we must restore the guest PC to the address + * of the start of the TB. + */ + CPUClass *cc = CPU_GET_CLASS(cpu); + TranslationBlock *tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK); + if (cc->synchronize_from_tb) { + cc->synchronize_from_tb(cpu, tb); + } else { + assert(cc->set_pc); + cc->set_pc(cpu, tb->pc); + } + } + if ((next_tb & TB_EXIT_MASK) == TB_EXIT_REQUESTED) { + /* We were asked to stop executing TBs (probably a pending + * interrupt. We've now stopped, so clear the flag. + */ + cpu->tcg_exit_req = 0; + } + return next_tb; +} + +/* Execute the code without caching the generated code. An interpreter + could be used if available. */ +static void cpu_exec_nocache(CPUState *cpu, int max_cycles, + TranslationBlock *orig_tb, bool ignore_icount) +{ + TranslationBlock *tb; + + /* Should never happen. + We only end up here when an existing TB is too long. */ + if (max_cycles > CF_COUNT_MASK) + max_cycles = CF_COUNT_MASK; + + tb = tb_gen_code(cpu, orig_tb->pc, orig_tb->cs_base, orig_tb->flags, + max_cycles | CF_NOCACHE + | (ignore_icount ? CF_IGNORE_ICOUNT : 0)); + tb->orig_tb = tcg_ctx.tb_ctx->tb_invalidated_flag ? NULL : orig_tb; + cpu->current_tb = tb; + /* execute the generated code */ + trace_exec_tb_nocache(tb, tb->pc); + cpu_tb_exec(cpu, tb->tc_ptr); + cpu->current_tb = NULL; + tb_phys_invalidate(tb, -1); + tb_free(tb); +} + +static TranslationBlock *tb_find_physical(CPUState *cpu, + target_ulong pc, + target_ulong cs_base, + uint64_t flags) +{ + CPUArchState *env = (CPUArchState *)cpu->env_ptr; + TranslationBlock *tb, **ptb1; + unsigned int h; + tb_page_addr_t phys_pc, phys_page1; + target_ulong virt_page2; + + tcg_ctx.tb_ctx->tb_invalidated_flag = 0; + + /* find translated block using physical mappings */ + phys_pc = get_page_addr_code(env, pc); + phys_page1 = phys_pc & TARGET_PAGE_MASK; + h = tb_phys_hash_func(pc); + ptb1 = &tcg_ctx.tb_ctx->tb_phys_hash[h]; + for(;;) { + tb = *ptb1; + if (!tb) { + return NULL; + } + if (tb->pc == pc && + tb->page_addr[0] == phys_page1 && + tb->cs_base == cs_base && + tb->flags == flags) { + /* check next page if needed */ + if (tb->page_addr[1] != -1) { + tb_page_addr_t phys_page2; + + virt_page2 = (pc & TARGET_PAGE_MASK) + + TARGET_PAGE_SIZE; + phys_page2 = get_page_addr_code(env, virt_page2); + if (tb->page_addr[1] == phys_page2) { + break; + } + } else { + break; + } + } + ptb1 = &tb->phys_hash_next; + } + + /* Move the TB to the head of the list */ + *ptb1 = tb->phys_hash_next; + tb->phys_hash_next = tcg_ctx.tb_ctx->tb_phys_hash[h]; + tcg_ctx.tb_ctx->tb_phys_hash[h] = tb; + return tb; +} + +static TranslationBlock *tb_find_slow(CPUState *cpu, + target_ulong pc, + target_ulong cs_base, + uint64_t flags) +{ + TranslationBlock *tb; + + tb = tb_find_physical(cpu, pc, cs_base, flags); + if (tb) { + goto found; + } + +#ifdef CONFIG_USER_ONLY + /* mmap_lock is needed by tb_gen_code, and mmap_lock must be + * taken outside tb_lock. Since we're momentarily dropping + * tb_lock, there's a chance that our desired tb has been + * translated. + */ + tb_unlock(); + mmap_lock(); + tb_lock(); + tb = tb_find_physical(cpu, pc, cs_base, flags); + if (tb) { + mmap_unlock(); + goto found; + } +#endif + + /* if no translated code available, then translate it now */ + tb = tb_gen_code(cpu, pc, cs_base, flags, 0); + +#ifdef CONFIG_USER_ONLY + mmap_unlock(); +#endif + +found: + /* we add the TB in the virtual pc hash table */ + cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)] = tb; + return tb; +} + +static inline TranslationBlock *tb_find_fast(CPUState *cpu) +{ + CPUArchState *env = (CPUArchState *)cpu->env_ptr; + TranslationBlock *tb; + target_ulong cs_base, pc; + int flags; + + /* we record a subset of the CPU state. It will + always be the same before a given translated block + is executed. */ + cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags); + tb = cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)]; + if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base || + tb->flags != flags)) { + tb = tb_find_slow(cpu, pc, cs_base, flags); + } + + itlb_update_entry(env, tb); + ibtc_update_entry(env, tb); + + return tb; +} + +static void cpu_handle_debug_exception(CPUState *cpu) +{ + CPUClass *cc = CPU_GET_CLASS(cpu); + CPUWatchpoint *wp; + + if (!cpu->watchpoint_hit) { + QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { + wp->flags &= ~BP_WATCHPOINT_HIT; + } + } + + cc->debug_excp_handler(cpu); +} + +/* main execution loop */ + +int cpu_exec(CPUState *cpu) +{ + CPUClass *cc = CPU_GET_CLASS(cpu); +#ifdef TARGET_I386 + X86CPU *x86_cpu = X86_CPU(cpu); + CPUArchState *env = &x86_cpu->env; +#endif + int ret, interrupt_request; + TranslationBlock *tb; + uint8_t *tc_ptr; + uintptr_t next_tb; + SyncClocks sc; + + /* replay_interrupt may need current_cpu */ + current_cpu = cpu; + + if (cpu->halted) { +#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY) + if ((cpu->interrupt_request & CPU_INTERRUPT_POLL) + && replay_interrupt()) { + apic_poll_irq(x86_cpu->apic_state); + cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL); + } +#endif + if (!cpu_has_work(cpu)) { + current_cpu = NULL; + return EXCP_HALTED; + } + + cpu->halted = 0; + } + + atomic_mb_set(&tcg_current_cpu, cpu); + rcu_read_lock(); + + if (unlikely(atomic_mb_read(&exit_request))) { + cpu->exit_request = 1; + } + + cc->cpu_exec_enter(cpu); + + /* Calculate difference between guest clock and host clock. + * This delay includes the delay of the last cycle, so + * what we have to do is sleep until it is 0. As for the + * advance/delay we gain here, we try to fix it next time. + */ + init_delay_params(&sc, cpu); + + /* prepare setjmp context for exception handling */ + for(;;) { + if (sigsetjmp(cpu->jmp_env, 0) == 0) { + /* if an exception is pending, we execute it here */ + if (cpu->exception_index >= 0) { + if (cpu->exception_index >= EXCP_INTERRUPT) { + /* exit request from the cpu execution loop */ + ret = cpu->exception_index; + if (ret == EXCP_DEBUG) { + cpu_handle_debug_exception(cpu); + } + cpu->exception_index = -1; + break; + } else { +#if defined(CONFIG_USER_ONLY) + /* if user mode only, we simulate a fake exception + which will be handled outside the cpu execution + loop */ +#if defined(TARGET_I386) + cc->do_interrupt(cpu); +#endif + ret = cpu->exception_index; + cpu->exception_index = -1; + break; +#else + if (replay_exception()) { + cc->do_interrupt(cpu); + cpu->exception_index = -1; + } else if (!replay_has_interrupt()) { + /* give a chance to iothread in replay mode */ + ret = EXCP_INTERRUPT; + break; + } +#endif + } + } else if (replay_has_exception() + && cpu->icount_decr.u16.low + cpu->icount_extra == 0) { + /* try to cause an exception pending in the log */ + cpu_exec_nocache(cpu, 1, tb_find_fast(cpu), true); + ret = -1; + break; + } + + next_tb = 0; /* force lookup of first TB */ + for(;;) { + interrupt_request = cpu->interrupt_request; + if (unlikely(interrupt_request)) { + if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) { + /* Mask out external interrupts for this step. */ + interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK; + } + if (interrupt_request & CPU_INTERRUPT_DEBUG) { + cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG; + cpu->exception_index = EXCP_DEBUG; + cpu_loop_exit(cpu); + } + if (replay_mode == REPLAY_MODE_PLAY + && !replay_has_interrupt()) { + /* Do nothing */ + } else if (interrupt_request & CPU_INTERRUPT_HALT) { + replay_interrupt(); + cpu->interrupt_request &= ~CPU_INTERRUPT_HALT; + cpu->halted = 1; + cpu->exception_index = EXCP_HLT; + cpu_loop_exit(cpu); + } +#if defined(TARGET_I386) + else if (interrupt_request & CPU_INTERRUPT_INIT) { + replay_interrupt(); + cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0); + do_cpu_init(x86_cpu); + cpu->exception_index = EXCP_HALTED; + cpu_loop_exit(cpu); + } +#else + else if (interrupt_request & CPU_INTERRUPT_RESET) { + replay_interrupt(); + cpu_reset(cpu); + cpu_loop_exit(cpu); + } +#endif + /* The target hook has 3 exit conditions: + False when the interrupt isn't processed, + True when it is, and we should restart on a new TB, + and via longjmp via cpu_loop_exit. */ + else { + replay_interrupt(); + if (cc->cpu_exec_interrupt(cpu, interrupt_request)) { + next_tb = 0; + } + } + /* Don't use the cached interrupt_request value, + do_interrupt may have updated the EXITTB flag. */ + if (cpu->interrupt_request & CPU_INTERRUPT_EXITTB) { + cpu->interrupt_request &= ~CPU_INTERRUPT_EXITTB; + /* ensure that no TB jump will be modified as + the program flow was changed */ + next_tb = 0; + } + } + if (unlikely(cpu->exit_request + || replay_has_interrupt())) { + cpu->exit_request = 0; + cpu->exception_index = EXCP_INTERRUPT; + cpu_loop_exit(cpu); + } + tb_lock(); + tb = tb_find_fast(cpu); + /* Note: we do it here to avoid a gcc bug on Mac OS X when + doing it in tb_find_slow */ + if (tcg_ctx.tb_ctx->tb_invalidated_flag) { + /* as some TB could have been invalidated because + of memory exceptions while generating the code, we + must recompute the hash index here */ + next_tb = 0; + tcg_ctx.tb_ctx->tb_invalidated_flag = 0; + } + if (qemu_loglevel_mask(CPU_LOG_EXEC)) { + qemu_log("Trace %p [" TARGET_FMT_lx "] %s\n", + tb->tc_ptr, tb->pc, lookup_symbol(tb->pc)); + } + + tracer_exec_tb(cpu->env_ptr, next_tb, tb); + tb_unlock(); + if (likely(!cpu->exit_request)) { + trace_exec_tb(tb, tb->pc); + tc_ptr = tb->opt_ptr; + /* execute the generated code */ + cpu->current_tb = tb; + next_tb = cpu_tb_exec(cpu, tc_ptr); + cpu->current_tb = NULL; + switch (next_tb & TB_EXIT_MASK) { + case TB_EXIT_REQUESTED: + /* Something asked us to stop executing + * chained TBs; just continue round the main + * loop. Whatever requested the exit will also + * have set something else (eg exit_request or + * interrupt_request) which we will handle + * next time around the loop. But we need to + * ensure the tcg_exit_req read in generated code + * comes before the next read of cpu->exit_request + * or cpu->interrupt_request. + */ + smp_rmb(); + next_tb = 0; + + tracer_reset(cpu->env_ptr); + break; + case TB_EXIT_ICOUNT_EXPIRED: + { +#if defined(CONFIG_LLVM) + break; +#endif + /* Instruction counter expired. */ + int insns_left = cpu->icount_decr.u32; + if (cpu->icount_extra && insns_left >= 0) { + /* Refill decrementer and continue execution. */ + cpu->icount_extra += insns_left; + insns_left = MIN(0xffff, cpu->icount_extra); + cpu->icount_extra -= insns_left; + cpu->icount_decr.u16.low = insns_left; + } else { + if (insns_left > 0) { + /* Execute remaining instructions. */ + tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK); + cpu_exec_nocache(cpu, insns_left, tb, false); + align_clocks(&sc, cpu); + } + cpu->exception_index = EXCP_INTERRUPT; + next_tb = 0; + cpu_loop_exit(cpu); + } + break; + } + default: + break; + } + } + /* Try to align the host and virtual clocks + if the guest is in advance */ + align_clocks(&sc, cpu); + /* reset soft MMU for next block (it can currently + only be set by a memory fault) */ + } /* for(;;) */ + } else { +#if defined(__clang__) || !QEMU_GNUC_PREREQ(4, 6) + /* Some compilers wrongly smash all local variables after + * siglongjmp. There were bug reports for gcc 4.5.0 and clang. + * Reload essential local variables here for those compilers. + * Newer versions of gcc would complain about this code (-Wclobbered). */ + cpu = current_cpu; + cc = CPU_GET_CLASS(cpu); +#ifdef TARGET_I386 + x86_cpu = X86_CPU(cpu); + env = &x86_cpu->env; +#endif +#else /* buggy compiler */ + /* Assert that the compiler does not smash local variables. */ + g_assert(cpu == current_cpu); + g_assert(cc == CPU_GET_CLASS(cpu)); +#ifdef TARGET_I386 + g_assert(x86_cpu == X86_CPU(cpu)); + g_assert(env == &x86_cpu->env); +#endif +#endif /* buggy compiler */ + cpu->can_do_io = 1; + tb_lock_reset(); + + tracer_reset(cpu->env_ptr); + } + } /* for(;;) */ + + cc->cpu_exec_exit(cpu); + rcu_read_unlock(); + + /* fail safe : never use current_cpu outside cpu_exec() */ + current_cpu = NULL; + + /* Does not need atomic_mb_set because a spurious wakeup is okay. */ + atomic_set(&tcg_current_cpu, NULL); + return ret; +} |
