| /* |
| * QEMU System Emulator |
| * |
| * Copyright (c) 2003-2008 Fabrice Bellard |
| * Copyright (c) 2014 Red Hat Inc. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qemu-common.h" |
| #include "sysemu/tcg.h" |
| #include "sysemu/replay.h" |
| #include "qemu/main-loop.h" |
| #include "qemu/guest-random.h" |
| #include "exec/exec-all.h" |
| #include "hw/boards.h" |
| |
| #include "tcg-cpus.h" |
| |
| /* Kick all RR vCPUs */ |
| static void qemu_cpu_kick_rr_cpus(void) |
| { |
| CPUState *cpu; |
| |
| CPU_FOREACH(cpu) { |
| cpu_exit(cpu); |
| }; |
| } |
| |
| static void tcg_kick_vcpu_thread(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(); |
| } |
| } |
| |
| static int tcg_cpu_exec(CPUState *cpu) |
| { |
| int ret; |
| #ifdef CONFIG_PROFILER |
| int64_t ti; |
| #endif |
| |
| assert(tcg_enabled()); |
| #ifdef CONFIG_PROFILER |
| ti = profile_getclock(); |
| #endif |
| cpu_exec_start(cpu); |
| ret = cpu_exec(cpu); |
| cpu_exec_end(cpu); |
| #ifdef CONFIG_PROFILER |
| qatomic_set(&tcg_ctx->prof.cpu_exec_time, |
| tcg_ctx->prof.cpu_exec_time + profile_getclock() - ti); |
| #endif |
| 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) |
| { |
| int old_mask; |
| g_assert(qemu_mutex_iothread_locked()); |
| |
| old_mask = cpu->interrupt_request; |
| cpu->interrupt_request |= mask; |
| |
| /* |
| * If called from iothread context, wake the target cpu in |
| * case its halted. |
| */ |
| if (!qemu_cpu_is_self(cpu)) { |
| 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, |
| }; |