diff options
Diffstat (limited to 'accel/tcg/cpu-exec.c')
| -rw-r--r-- | accel/tcg/cpu-exec.c | 683 |
1 files changed, 683 insertions, 0 deletions
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c new file mode 100644 index 0000000000..3581618bc0 --- /dev/null +++ b/accel/tcg/cpu-exec.c @@ -0,0 +1,683 @@ +/* + * 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 "qemu/osdep.h" +#include "cpu.h" +#include "trace.h" +#include "disas/disas.h" +#include "exec/exec-all.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" +#include "exec/log.h" +#include "qemu/main-loop.h" +#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY) +#include "hw/i386/apic.h" +#endif +#include "sysemu/cpus.h" +#include "sysemu/replay.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) +{ + 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, TranslationBlock *itb) +{ + CPUArchState *env = cpu->env_ptr; + uintptr_t ret; + TranslationBlock *last_tb; + int tb_exit; + uint8_t *tb_ptr = itb->tc_ptr; + + qemu_log_mask_and_addr(CPU_LOG_EXEC, itb->pc, + "Trace %p [%d: " TARGET_FMT_lx "] %s\n", + itb->tc_ptr, cpu->cpu_index, itb->pc, + lookup_symbol(itb->pc)); + +#if defined(DEBUG_DISAS) + if (qemu_loglevel_mask(CPU_LOG_TB_CPU) + && qemu_log_in_addr_range(itb->pc)) { + qemu_log_lock(); +#if defined(TARGET_I386) + log_cpu_state(cpu, CPU_DUMP_CCOP); +#else + log_cpu_state(cpu, 0); +#endif + qemu_log_unlock(); + } +#endif /* DEBUG_DISAS */ + + cpu->can_do_io = !use_icount; + ret = tcg_qemu_tb_exec(env, tb_ptr); + cpu->can_do_io = 1; + last_tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK); + tb_exit = ret & TB_EXIT_MASK; + trace_exec_tb_exit(last_tb, tb_exit); + + if (tb_exit > 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); + qemu_log_mask_and_addr(CPU_LOG_EXEC, last_tb->pc, + "Stopped execution of TB chain before %p [" + TARGET_FMT_lx "] %s\n", + last_tb->tc_ptr, last_tb->pc, + lookup_symbol(last_tb->pc)); + if (cc->synchronize_from_tb) { + cc->synchronize_from_tb(cpu, last_tb); + } else { + assert(cc->set_pc); + cc->set_pc(cpu, last_tb->pc); + } + } + return ret; +} + +#ifndef CONFIG_USER_ONLY +/* 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_lock(); + 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 = orig_tb; + tb_unlock(); + + /* execute the generated code */ + trace_exec_tb_nocache(tb, tb->pc); + cpu_tb_exec(cpu, tb); + + tb_lock(); + tb_phys_invalidate(tb, -1); + tb_free(tb); + tb_unlock(); +} +#endif + +static void cpu_exec_step(CPUState *cpu) +{ + CPUClass *cc = CPU_GET_CLASS(cpu); + CPUArchState *env = (CPUArchState *)cpu->env_ptr; + TranslationBlock *tb; + target_ulong cs_base, pc; + uint32_t flags; + + cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags); + if (sigsetjmp(cpu->jmp_env, 0) == 0) { + mmap_lock(); + tb_lock(); + tb = tb_gen_code(cpu, pc, cs_base, flags, + 1 | CF_NOCACHE | CF_IGNORE_ICOUNT); + tb->orig_tb = NULL; + tb_unlock(); + mmap_unlock(); + + cc->cpu_exec_enter(cpu); + /* execute the generated code */ + trace_exec_tb_nocache(tb, pc); + cpu_tb_exec(cpu, tb); + cc->cpu_exec_exit(cpu); + + tb_lock(); + tb_phys_invalidate(tb, -1); + tb_free(tb); + tb_unlock(); + } else { + /* We may have exited due to another problem here, so we need + * to reset any tb_locks we may have taken but didn't release. + * The mmap_lock is dropped by tb_gen_code if it runs out of + * memory. + */ +#ifndef CONFIG_SOFTMMU + tcg_debug_assert(!have_mmap_lock()); +#endif + tb_lock_reset(); + } +} + +void cpu_exec_step_atomic(CPUState *cpu) +{ + start_exclusive(); + + /* Since we got here, we know that parallel_cpus must be true. */ + parallel_cpus = false; + cpu_exec_step(cpu); + parallel_cpus = true; + + end_exclusive(); +} + +struct tb_desc { + target_ulong pc; + target_ulong cs_base; + CPUArchState *env; + tb_page_addr_t phys_page1; + uint32_t flags; +}; + +static bool tb_cmp(const void *p, const void *d) +{ + const TranslationBlock *tb = p; + const struct tb_desc *desc = d; + + if (tb->pc == desc->pc && + tb->page_addr[0] == desc->phys_page1 && + tb->cs_base == desc->cs_base && + tb->flags == desc->flags && + !atomic_read(&tb->invalid)) { + /* check next page if needed */ + if (tb->page_addr[1] == -1) { + return true; + } else { + tb_page_addr_t phys_page2; + target_ulong virt_page2; + + virt_page2 = (desc->pc & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE; + phys_page2 = get_page_addr_code(desc->env, virt_page2); + if (tb->page_addr[1] == phys_page2) { + return true; + } + } + } + return false; +} + +TranslationBlock *tb_htable_lookup(CPUState *cpu, target_ulong pc, + target_ulong cs_base, uint32_t flags) +{ + tb_page_addr_t phys_pc; + struct tb_desc desc; + uint32_t h; + + desc.env = (CPUArchState *)cpu->env_ptr; + desc.cs_base = cs_base; + desc.flags = flags; + desc.pc = pc; + phys_pc = get_page_addr_code(desc.env, pc); + desc.phys_page1 = phys_pc & TARGET_PAGE_MASK; + h = tb_hash_func(phys_pc, pc, flags); + return qht_lookup(&tcg_ctx.tb_ctx.htable, tb_cmp, &desc, h); +} + +static inline TranslationBlock *tb_find(CPUState *cpu, + TranslationBlock *last_tb, + int tb_exit) +{ + CPUArchState *env = (CPUArchState *)cpu->env_ptr; + TranslationBlock *tb; + target_ulong cs_base, pc; + uint32_t flags; + bool have_tb_lock = false; + + /* 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 = atomic_rcu_read(&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_htable_lookup(cpu, pc, cs_base, flags); + if (!tb) { + + /* mmap_lock is needed by tb_gen_code, and mmap_lock must be + * taken outside tb_lock. As system emulation is currently + * single threaded the locks are NOPs. + */ + mmap_lock(); + tb_lock(); + have_tb_lock = true; + + /* There's a chance that our desired tb has been translated while + * taking the locks so we check again inside the lock. + */ + tb = tb_htable_lookup(cpu, pc, cs_base, flags); + if (!tb) { + /* if no translated code available, then translate it now */ + tb = tb_gen_code(cpu, pc, cs_base, flags, 0); + } + + mmap_unlock(); + } + + /* We add the TB in the virtual pc hash table for the fast lookup */ + atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb); + } +#ifndef CONFIG_USER_ONLY + /* We don't take care of direct jumps when address mapping changes in + * system emulation. So it's not safe to make a direct jump to a TB + * spanning two pages because the mapping for the second page can change. + */ + if (tb->page_addr[1] != -1) { + last_tb = NULL; + } +#endif + /* See if we can patch the calling TB. */ + if (last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) { + if (!have_tb_lock) { + tb_lock(); + have_tb_lock = true; + } + if (!tb->invalid) { + tb_add_jump(last_tb, tb_exit, tb); + } + } + if (have_tb_lock) { + tb_unlock(); + } + return tb; +} + +static inline bool cpu_handle_halt(CPUState *cpu) +{ + if (cpu->halted) { +#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY) + if ((cpu->interrupt_request & CPU_INTERRUPT_POLL) + && replay_interrupt()) { + X86CPU *x86_cpu = X86_CPU(cpu); + qemu_mutex_lock_iothread(); + apic_poll_irq(x86_cpu->apic_state); + cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL); + qemu_mutex_unlock_iothread(); + } +#endif + if (!cpu_has_work(cpu)) { + return true; + } + + cpu->halted = 0; + } + + return false; +} + +static inline 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); +} + +static inline bool cpu_handle_exception(CPUState *cpu, int *ret) +{ + 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; + return true; + } 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) + CPUClass *cc = CPU_GET_CLASS(cpu); + cc->do_interrupt(cpu); +#endif + *ret = cpu->exception_index; + cpu->exception_index = -1; + return true; +#else + if (replay_exception()) { + CPUClass *cc = CPU_GET_CLASS(cpu); + qemu_mutex_lock_iothread(); + cc->do_interrupt(cpu); + qemu_mutex_unlock_iothread(); + cpu->exception_index = -1; + } else if (!replay_has_interrupt()) { + /* give a chance to iothread in replay mode */ + *ret = EXCP_INTERRUPT; + return true; + } +#endif + } +#ifndef CONFIG_USER_ONLY + } 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(cpu, NULL, 0), true); + *ret = -1; + return true; +#endif + } + + return false; +} + +static inline bool cpu_handle_interrupt(CPUState *cpu, + TranslationBlock **last_tb) +{ + CPUClass *cc = CPU_GET_CLASS(cpu); + + if (unlikely(atomic_read(&cpu->interrupt_request))) { + int interrupt_request; + qemu_mutex_lock_iothread(); + interrupt_request = cpu->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; + qemu_mutex_unlock_iothread(); + return true; + } + 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; + qemu_mutex_unlock_iothread(); + return true; + } +#if defined(TARGET_I386) + else if (interrupt_request & CPU_INTERRUPT_INIT) { + X86CPU *x86_cpu = X86_CPU(cpu); + CPUArchState *env = &x86_cpu->env; + replay_interrupt(); + cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0, 0); + do_cpu_init(x86_cpu); + cpu->exception_index = EXCP_HALTED; + qemu_mutex_unlock_iothread(); + return true; + } +#else + else if (interrupt_request & CPU_INTERRUPT_RESET) { + replay_interrupt(); + cpu_reset(cpu); + qemu_mutex_unlock_iothread(); + return true; + } +#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 { + if (cc->cpu_exec_interrupt(cpu, interrupt_request)) { + replay_interrupt(); + *last_tb = NULL; + } + /* The target hook may have updated the 'cpu->interrupt_request'; + * reload the 'interrupt_request' value */ + interrupt_request = cpu->interrupt_request; + } + if (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 */ + *last_tb = NULL; + } + + /* If we exit via cpu_loop_exit/longjmp it is reset in cpu_exec */ + qemu_mutex_unlock_iothread(); + } + + /* Finally, check if we need to exit to the main loop. */ + if (unlikely(atomic_read(&cpu->exit_request) + || (use_icount && cpu->icount_decr.u16.low + cpu->icount_extra == 0))) { + atomic_set(&cpu->exit_request, 0); + cpu->exception_index = EXCP_INTERRUPT; + return true; + } + + return false; +} + +static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb, + TranslationBlock **last_tb, int *tb_exit) +{ + uintptr_t ret; + int32_t insns_left; + + trace_exec_tb(tb, tb->pc); + ret = cpu_tb_exec(cpu, tb); + tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK); + *tb_exit = ret & TB_EXIT_MASK; + if (*tb_exit != TB_EXIT_REQUESTED) { + *last_tb = tb; + return; + } + + *last_tb = NULL; + insns_left = atomic_read(&cpu->icount_decr.u32); + atomic_set(&cpu->icount_decr.u16.high, 0); + if (insns_left < 0) { + /* 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 zeroing of icount_decr + * comes before the next read of cpu->exit_request + * or cpu->interrupt_request. + */ + smp_mb(); + return; + } + + /* Instruction counter expired. */ + assert(use_icount); +#ifndef CONFIG_USER_ONLY + /* Ensure global icount has gone forward */ + cpu_update_icount(cpu); + /* Refill decrementer and continue execution. */ + insns_left = MIN(0xffff, cpu->icount_budget); + cpu->icount_decr.u16.low = insns_left; + cpu->icount_extra = cpu->icount_budget - insns_left; + if (!cpu->icount_extra) { + /* Execute any remaining instructions, then let the main loop + * handle the next event. + */ + if (insns_left > 0) { + cpu_exec_nocache(cpu, insns_left, tb, false); + } + } +#endif +} + +/* main execution loop */ + +int cpu_exec(CPUState *cpu) +{ + CPUClass *cc = CPU_GET_CLASS(cpu); + int ret; + SyncClocks sc = { 0 }; + + /* replay_interrupt may need current_cpu */ + current_cpu = cpu; + + if (cpu_handle_halt(cpu)) { + return EXCP_HALTED; + } + + rcu_read_lock(); + + 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 */ + if (sigsetjmp(cpu->jmp_env, 0) != 0) { +#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); +#else /* buggy compiler */ + /* Assert that the compiler does not smash local variables. */ + g_assert(cpu == current_cpu); + g_assert(cc == CPU_GET_CLASS(cpu)); +#endif /* buggy compiler */ + cpu->can_do_io = 1; + tb_lock_reset(); + if (qemu_mutex_iothread_locked()) { + qemu_mutex_unlock_iothread(); + } + } + + /* if an exception is pending, we execute it here */ + while (!cpu_handle_exception(cpu, &ret)) { + TranslationBlock *last_tb = NULL; + int tb_exit = 0; + + while (!cpu_handle_interrupt(cpu, &last_tb)) { + TranslationBlock *tb = tb_find(cpu, last_tb, tb_exit); + cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit); + /* Try to align the host and virtual clocks + if the guest is in advance */ + align_clocks(&sc, cpu); + } + } + + cc->cpu_exec_exit(cpu); + rcu_read_unlock(); + + return ret; +} |