diff --git a/cpu-exec.c b/cpu-exec.c index cdaab1dbcd852ec5102eabd32a9b114ffb01d7d3..7ca2b71a894c7e9450b795c9e92d774ee435a74f 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -287,35 +287,29 @@ static TranslationBlock *tb_find_slow(CPUState *cpu, TranslationBlock *tb; tb = tb_find_physical(cpu, pc, cs_base, flags); - if (tb) { - goto found; - } + if (!tb) { -#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 + /* 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(); - /* if no translated code available, then translate it now */ - tb = tb_gen_code(cpu, pc, cs_base, flags, 0); + /* There's a chance that our desired tb has been translated while + * taking the locks so we check again inside the lock. + */ + tb = tb_find_physical(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); + } -#ifdef CONFIG_USER_ONLY - mmap_unlock(); -#endif + tb_unlock(); + mmap_unlock(); + } -found: - /* we add the TB in the virtual pc hash table */ + /* 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); return tb; } @@ -333,7 +327,6 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu, always be the same before a given translated block is executed. */ cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags); - tb_lock(); 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)) { @@ -350,14 +343,15 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu, #endif /* See if we can patch the calling TB. */ if (last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) { + tb_lock(); /* Check if translation buffer has been flushed */ if (cpu->tb_flushed) { cpu->tb_flushed = false; } else if (!tb->invalid) { tb_add_jump(last_tb, tb_exit, tb); } + tb_unlock(); } - tb_unlock(); return tb; }