diff options
Diffstat (limited to 'accel/tcg/tcg-cpus.c')
| -rw-r--r-- | accel/tcg/tcg-cpus.c | 504 |
1 files changed, 8 insertions, 496 deletions
diff --git a/accel/tcg/tcg-cpus.c b/accel/tcg/tcg-cpus.c index da1c63d8f6..e335f9f155 100644 --- a/accel/tcg/tcg-cpus.c +++ b/accel/tcg/tcg-cpus.c @@ -1,5 +1,7 @@ /* - * QEMU System Emulator + * QEMU TCG vCPU common functionality + * + * Functionality common to all TCG vCPU variants: mttcg, rr and icount. * * Copyright (c) 2003-2008 Fabrice Bellard * Copyright (c) 2014 Red Hat Inc. @@ -34,207 +36,19 @@ #include "tcg-cpus.h" -/* Kick all RR vCPUs */ -static void qemu_cpu_kick_rr_cpus(void) -{ - CPUState *cpu; - - CPU_FOREACH(cpu) { - cpu_exit(cpu); - }; -} +/* common functionality among all TCG variants */ -static void tcg_kick_vcpu_thread(CPUState *cpu) +void tcg_cpus_destroy(CPUState *cpu) { - if (qemu_tcg_mttcg_enabled()) { - cpu_exit(cpu); - } else { - qemu_cpu_kick_rr_cpus(); - } -} - -/* - * TCG vCPU kick timer - * - * The kick timer is responsible for moving single threaded vCPU - * emulation on to the next vCPU. If more than one vCPU is running a - * timer event with force a cpu->exit so the next vCPU can get - * scheduled. - * - * The timer is removed if all vCPUs are idle and restarted again once - * idleness is complete. - */ - -static QEMUTimer *tcg_kick_vcpu_timer; -static CPUState *tcg_current_rr_cpu; - -#define TCG_KICK_PERIOD (NANOSECONDS_PER_SECOND / 10) - -static inline int64_t qemu_tcg_next_kick(void) -{ - return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + TCG_KICK_PERIOD; -} - -/* Kick the currently round-robin scheduled vCPU to next */ -static void qemu_cpu_kick_rr_next_cpu(void) -{ - CPUState *cpu; - do { - cpu = qatomic_mb_read(&tcg_current_rr_cpu); - if (cpu) { - cpu_exit(cpu); - } - } while (cpu != qatomic_mb_read(&tcg_current_rr_cpu)); -} - -static void kick_tcg_thread(void *opaque) -{ - timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick()); - qemu_cpu_kick_rr_next_cpu(); -} - -static void start_tcg_kick_timer(void) -{ - assert(!mttcg_enabled); - if (!tcg_kick_vcpu_timer && CPU_NEXT(first_cpu)) { - tcg_kick_vcpu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, - kick_tcg_thread, NULL); - } - if (tcg_kick_vcpu_timer && !timer_pending(tcg_kick_vcpu_timer)) { - timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick()); - } -} - -static void stop_tcg_kick_timer(void) -{ - assert(!mttcg_enabled); - if (tcg_kick_vcpu_timer && timer_pending(tcg_kick_vcpu_timer)) { - timer_del(tcg_kick_vcpu_timer); - } -} - -static void qemu_tcg_destroy_vcpu(CPUState *cpu) -{ -} - -static void qemu_tcg_rr_wait_io_event(void) -{ - CPUState *cpu; - - while (all_cpu_threads_idle()) { - stop_tcg_kick_timer(); - qemu_cond_wait_iothread(first_cpu->halt_cond); - } - - start_tcg_kick_timer(); - - CPU_FOREACH(cpu) { - qemu_wait_io_event_common(cpu); - } -} - -static int64_t tcg_get_icount_limit(void) -{ - int64_t deadline; - - if (replay_mode != REPLAY_MODE_PLAY) { - /* - * Include all the timers, because they may need an attention. - * Too long CPU execution may create unnecessary delay in UI. - */ - deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL, - QEMU_TIMER_ATTR_ALL); - /* Check realtime timers, because they help with input processing */ - deadline = qemu_soonest_timeout(deadline, - qemu_clock_deadline_ns_all(QEMU_CLOCK_REALTIME, - QEMU_TIMER_ATTR_ALL)); - - /* - * Maintain prior (possibly buggy) behaviour where if no deadline - * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than - * INT32_MAX nanoseconds ahead, we still use INT32_MAX - * nanoseconds. - */ - if ((deadline < 0) || (deadline > INT32_MAX)) { - deadline = INT32_MAX; - } - - return icount_round(deadline); - } else { - return replay_get_instructions(); - } -} - -static void notify_aio_contexts(void) -{ - /* Wake up other AioContexts. */ - qemu_clock_notify(QEMU_CLOCK_VIRTUAL); - qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL); -} - -static void handle_icount_deadline(void) -{ - assert(qemu_in_vcpu_thread()); - if (icount_enabled()) { - int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL, - QEMU_TIMER_ATTR_ALL); - - if (deadline == 0) { - notify_aio_contexts(); - } - } -} - -static void prepare_icount_for_run(CPUState *cpu) -{ - if (icount_enabled()) { - int insns_left; - - /* - * These should always be cleared by process_icount_data after - * each vCPU execution. However u16.high can be raised - * asynchronously by cpu_exit/cpu_interrupt/tcg_handle_interrupt - */ - g_assert(cpu_neg(cpu)->icount_decr.u16.low == 0); - g_assert(cpu->icount_extra == 0); - - cpu->icount_budget = tcg_get_icount_limit(); - insns_left = MIN(0xffff, cpu->icount_budget); - cpu_neg(cpu)->icount_decr.u16.low = insns_left; - cpu->icount_extra = cpu->icount_budget - insns_left; - - replay_mutex_lock(); - - if (cpu->icount_budget == 0 && replay_has_checkpoint()) { - notify_aio_contexts(); - } - } -} - -static void process_icount_data(CPUState *cpu) -{ - if (icount_enabled()) { - /* Account for executed instructions */ - icount_update(cpu); - - /* Reset the counters */ - cpu_neg(cpu)->icount_decr.u16.low = 0; - cpu->icount_extra = 0; - cpu->icount_budget = 0; - - replay_account_executed_instructions(); - - replay_mutex_unlock(); - } + cpu_thread_signal_destroyed(cpu); } -static int tcg_cpu_exec(CPUState *cpu) +int tcg_cpus_exec(CPUState *cpu) { int ret; #ifdef CONFIG_PROFILER int64_t ti; #endif - assert(tcg_enabled()); #ifdef CONFIG_PROFILER ti = profile_getclock(); @@ -249,298 +63,11 @@ static int tcg_cpu_exec(CPUState *cpu) return ret; } -/* - * Destroy any remaining vCPUs which have been unplugged and have - * finished running - */ -static void deal_with_unplugged_cpus(void) -{ - CPUState *cpu; - - CPU_FOREACH(cpu) { - if (cpu->unplug && !cpu_can_run(cpu)) { - qemu_tcg_destroy_vcpu(cpu); - cpu_thread_signal_destroyed(cpu); - break; - } - } -} - -/* - * Single-threaded TCG - * - * In the single-threaded case each vCPU is simulated in turn. If - * there is more than a single vCPU we create a simple timer to kick - * the vCPU and ensure we don't get stuck in a tight loop in one vCPU. - * This is done explicitly rather than relying on side-effects - * elsewhere. - */ - -static void *tcg_rr_cpu_thread_fn(void *arg) -{ - CPUState *cpu = arg; - - assert(tcg_enabled()); - rcu_register_thread(); - tcg_register_thread(); - - qemu_mutex_lock_iothread(); - qemu_thread_get_self(cpu->thread); - - cpu->thread_id = qemu_get_thread_id(); - cpu->can_do_io = 1; - cpu_thread_signal_created(cpu); - qemu_guest_random_seed_thread_part2(cpu->random_seed); - - /* wait for initial kick-off after machine start */ - while (first_cpu->stopped) { - qemu_cond_wait_iothread(first_cpu->halt_cond); - - /* process any pending work */ - CPU_FOREACH(cpu) { - current_cpu = cpu; - qemu_wait_io_event_common(cpu); - } - } - - start_tcg_kick_timer(); - - cpu = first_cpu; - - /* process any pending work */ - cpu->exit_request = 1; - - while (1) { - qemu_mutex_unlock_iothread(); - replay_mutex_lock(); - qemu_mutex_lock_iothread(); - /* Account partial waits to QEMU_CLOCK_VIRTUAL. */ - icount_account_warp_timer(); - - /* - * Run the timers here. This is much more efficient than - * waking up the I/O thread and waiting for completion. - */ - handle_icount_deadline(); - - replay_mutex_unlock(); - - if (!cpu) { - cpu = first_cpu; - } - - while (cpu && cpu_work_list_empty(cpu) && !cpu->exit_request) { - - qatomic_mb_set(&tcg_current_rr_cpu, cpu); - current_cpu = cpu; - - qemu_clock_enable(QEMU_CLOCK_VIRTUAL, - (cpu->singlestep_enabled & SSTEP_NOTIMER) == 0); - - if (cpu_can_run(cpu)) { - int r; - - qemu_mutex_unlock_iothread(); - prepare_icount_for_run(cpu); - - r = tcg_cpu_exec(cpu); - - process_icount_data(cpu); - qemu_mutex_lock_iothread(); - - if (r == EXCP_DEBUG) { - cpu_handle_guest_debug(cpu); - break; - } else if (r == EXCP_ATOMIC) { - qemu_mutex_unlock_iothread(); - cpu_exec_step_atomic(cpu); - qemu_mutex_lock_iothread(); - break; - } - } else if (cpu->stop) { - if (cpu->unplug) { - cpu = CPU_NEXT(cpu); - } - break; - } - - cpu = CPU_NEXT(cpu); - } /* while (cpu && !cpu->exit_request).. */ - - /* Does not need qatomic_mb_set because a spurious wakeup is okay. */ - qatomic_set(&tcg_current_rr_cpu, NULL); - - if (cpu && cpu->exit_request) { - qatomic_mb_set(&cpu->exit_request, 0); - } - - if (icount_enabled() && all_cpu_threads_idle()) { - /* - * When all cpus are sleeping (e.g in WFI), to avoid a deadlock - * in the main_loop, wake it up in order to start the warp timer. - */ - qemu_notify_event(); - } - - qemu_tcg_rr_wait_io_event(); - deal_with_unplugged_cpus(); - } - - rcu_unregister_thread(); - return NULL; -} - -/* - * Multi-threaded TCG - * - * In the multi-threaded case each vCPU has its own thread. The TLS - * variable current_cpu can be used deep in the code to find the - * current CPUState for a given thread. - */ - -static void *tcg_cpu_thread_fn(void *arg) -{ - CPUState *cpu = arg; - - assert(tcg_enabled()); - g_assert(!icount_enabled()); - - rcu_register_thread(); - tcg_register_thread(); - - qemu_mutex_lock_iothread(); - qemu_thread_get_self(cpu->thread); - - cpu->thread_id = qemu_get_thread_id(); - cpu->can_do_io = 1; - current_cpu = cpu; - cpu_thread_signal_created(cpu); - qemu_guest_random_seed_thread_part2(cpu->random_seed); - - /* process any pending work */ - cpu->exit_request = 1; - - do { - if (cpu_can_run(cpu)) { - int r; - qemu_mutex_unlock_iothread(); - r = tcg_cpu_exec(cpu); - qemu_mutex_lock_iothread(); - switch (r) { - case EXCP_DEBUG: - cpu_handle_guest_debug(cpu); - break; - case EXCP_HALTED: - /* - * during start-up the vCPU is reset and the thread is - * kicked several times. If we don't ensure we go back - * to sleep in the halted state we won't cleanly - * start-up when the vCPU is enabled. - * - * cpu->halted should ensure we sleep in wait_io_event - */ - g_assert(cpu->halted); - break; - case EXCP_ATOMIC: - qemu_mutex_unlock_iothread(); - cpu_exec_step_atomic(cpu); - qemu_mutex_lock_iothread(); - default: - /* Ignore everything else? */ - break; - } - } - - qatomic_mb_set(&cpu->exit_request, 0); - qemu_wait_io_event(cpu); - } while (!cpu->unplug || cpu_can_run(cpu)); - - qemu_tcg_destroy_vcpu(cpu); - cpu_thread_signal_destroyed(cpu); - qemu_mutex_unlock_iothread(); - rcu_unregister_thread(); - return NULL; -} - -static void tcg_start_vcpu_thread(CPUState *cpu) -{ - char thread_name[VCPU_THREAD_NAME_SIZE]; - static QemuCond *single_tcg_halt_cond; - static QemuThread *single_tcg_cpu_thread; - static int tcg_region_inited; - - assert(tcg_enabled()); - /* - * Initialize TCG regions--once. Now is a good time, because: - * (1) TCG's init context, prologue and target globals have been set up. - * (2) qemu_tcg_mttcg_enabled() works now (TCG init code runs before the - * -accel flag is processed, so the check doesn't work then). - */ - if (!tcg_region_inited) { - tcg_region_inited = 1; - tcg_region_init(); - parallel_cpus = qemu_tcg_mttcg_enabled() && current_machine->smp.max_cpus > 1; - } - - if (qemu_tcg_mttcg_enabled() || !single_tcg_cpu_thread) { - cpu->thread = g_malloc0(sizeof(QemuThread)); - cpu->halt_cond = g_malloc0(sizeof(QemuCond)); - qemu_cond_init(cpu->halt_cond); - - if (qemu_tcg_mttcg_enabled()) { - /* create a thread per vCPU with TCG (MTTCG) */ - snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG", - cpu->cpu_index); - - qemu_thread_create(cpu->thread, thread_name, tcg_cpu_thread_fn, - cpu, QEMU_THREAD_JOINABLE); - - } else { - /* share a single thread for all cpus with TCG */ - snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "ALL CPUs/TCG"); - qemu_thread_create(cpu->thread, thread_name, - tcg_rr_cpu_thread_fn, - cpu, QEMU_THREAD_JOINABLE); - - single_tcg_halt_cond = cpu->halt_cond; - single_tcg_cpu_thread = cpu->thread; - } -#ifdef _WIN32 - cpu->hThread = qemu_thread_get_handle(cpu->thread); -#endif - } else { - /* For non-MTTCG cases we share the thread */ - cpu->thread = single_tcg_cpu_thread; - cpu->halt_cond = single_tcg_halt_cond; - cpu->thread_id = first_cpu->thread_id; - cpu->can_do_io = 1; - cpu->created = true; - } -} - -static int64_t tcg_get_virtual_clock(void) -{ - if (icount_enabled()) { - return icount_get(); - } - return cpu_get_clock(); -} - -static int64_t tcg_get_elapsed_ticks(void) -{ - if (icount_enabled()) { - return icount_get(); - } - return cpu_get_ticks(); -} - /* mask must never be zero, except for A20 change call */ -static void tcg_handle_interrupt(CPUState *cpu, int mask) +void tcg_cpus_handle_interrupt(CPUState *cpu, int mask) { - int old_mask; g_assert(qemu_mutex_iothread_locked()); - old_mask = cpu->interrupt_request; cpu->interrupt_request |= mask; /* @@ -551,20 +78,5 @@ static void tcg_handle_interrupt(CPUState *cpu, int mask) qemu_cpu_kick(cpu); } else { qatomic_set(&cpu_neg(cpu)->icount_decr.u16.high, -1); - if (icount_enabled() && - !cpu->can_do_io - && (mask & ~old_mask) != 0) { - cpu_abort(cpu, "Raised interrupt while not in I/O function"); - } } } - -const CpusAccel tcg_cpus = { - .create_vcpu_thread = tcg_start_vcpu_thread, - .kick_vcpu_thread = tcg_kick_vcpu_thread, - - .handle_interrupt = tcg_handle_interrupt, - - .get_virtual_clock = tcg_get_virtual_clock, - .get_elapsed_ticks = tcg_get_elapsed_ticks, -}; |