1 /* 2 * QEMU TCG Multi Threaded vCPUs implementation 3 * 4 * Copyright (c) 2003-2008 Fabrice Bellard 5 * Copyright (c) 2014 Red Hat Inc. 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this software and associated documentation files (the "Software"), to deal 9 * in the Software without restriction, including without limitation the rights 10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 * copies of the Software, and to permit persons to whom the Software is 12 * furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 23 * THE SOFTWARE. 24 */ 25 26 #include "qemu/osdep.h" 27 #include "sysemu/tcg.h" 28 #include "sysemu/replay.h" 29 #include "sysemu/cpu-timers.h" 30 #include "qemu/main-loop.h" 31 #include "qemu/notify.h" 32 #include "qemu/guest-random.h" 33 #include "exec/exec-all.h" 34 #include "hw/boards.h" 35 36 #include "tcg-accel-ops.h" 37 #include "tcg-accel-ops-mttcg.h" 38 39 typedef struct MttcgForceRcuNotifier { 40 Notifier notifier; 41 CPUState *cpu; 42 } MttcgForceRcuNotifier; 43 44 static void do_nothing(CPUState *cpu, run_on_cpu_data d) 45 { 46 } 47 48 static void mttcg_force_rcu(Notifier *notify, void *data) 49 { 50 CPUState *cpu = container_of(notify, MttcgForceRcuNotifier, notifier)->cpu; 51 52 /* 53 * Called with rcu_registry_lock held, using async_run_on_cpu() ensures 54 * that there are no deadlocks. 55 */ 56 async_run_on_cpu(cpu, do_nothing, RUN_ON_CPU_NULL); 57 } 58 59 /* 60 * In the multi-threaded case each vCPU has its own thread. The TLS 61 * variable current_cpu can be used deep in the code to find the 62 * current CPUState for a given thread. 63 */ 64 65 static void *mttcg_cpu_thread_fn(void *arg) 66 { 67 MttcgForceRcuNotifier force_rcu; 68 CPUState *cpu = arg; 69 70 assert(tcg_enabled()); 71 g_assert(!icount_enabled()); 72 73 tcg_cpu_init_cflags(cpu, current_machine->smp.max_cpus > 1); 74 75 rcu_register_thread(); 76 force_rcu.notifier.notify = mttcg_force_rcu; 77 force_rcu.cpu = cpu; 78 rcu_add_force_rcu_notifier(&force_rcu.notifier); 79 tcg_register_thread(); 80 81 qemu_mutex_lock_iothread(); 82 qemu_thread_get_self(cpu->thread); 83 84 cpu->thread_id = qemu_get_thread_id(); 85 cpu->can_do_io = 1; 86 current_cpu = cpu; 87 cpu_thread_signal_created(cpu); 88 qemu_guest_random_seed_thread_part2(cpu->random_seed); 89 90 /* process any pending work */ 91 cpu->exit_request = 1; 92 93 do { 94 if (cpu_can_run(cpu)) { 95 int r; 96 qemu_mutex_unlock_iothread(); 97 r = tcg_cpus_exec(cpu); 98 qemu_mutex_lock_iothread(); 99 switch (r) { 100 case EXCP_DEBUG: 101 cpu_handle_guest_debug(cpu); 102 break; 103 case EXCP_HALTED: 104 /* 105 * during start-up the vCPU is reset and the thread is 106 * kicked several times. If we don't ensure we go back 107 * to sleep in the halted state we won't cleanly 108 * start-up when the vCPU is enabled. 109 * 110 * cpu->halted should ensure we sleep in wait_io_event 111 */ 112 g_assert(cpu->halted); 113 break; 114 case EXCP_ATOMIC: 115 qemu_mutex_unlock_iothread(); 116 cpu_exec_step_atomic(cpu); 117 qemu_mutex_lock_iothread(); 118 default: 119 /* Ignore everything else? */ 120 break; 121 } 122 } 123 124 qatomic_mb_set(&cpu->exit_request, 0); 125 qemu_wait_io_event(cpu); 126 } while (!cpu->unplug || cpu_can_run(cpu)); 127 128 tcg_cpus_destroy(cpu); 129 qemu_mutex_unlock_iothread(); 130 rcu_remove_force_rcu_notifier(&force_rcu.notifier); 131 rcu_unregister_thread(); 132 return NULL; 133 } 134 135 void mttcg_kick_vcpu_thread(CPUState *cpu) 136 { 137 cpu_exit(cpu); 138 } 139 140 void mttcg_start_vcpu_thread(CPUState *cpu) 141 { 142 char thread_name[VCPU_THREAD_NAME_SIZE]; 143 144 cpu->thread = g_new0(QemuThread, 1); 145 cpu->halt_cond = g_malloc0(sizeof(QemuCond)); 146 qemu_cond_init(cpu->halt_cond); 147 148 /* create a thread per vCPU with TCG (MTTCG) */ 149 snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG", 150 cpu->cpu_index); 151 152 qemu_thread_create(cpu->thread, thread_name, mttcg_cpu_thread_fn, 153 cpu, QEMU_THREAD_JOINABLE); 154 155 #ifdef _WIN32 156 cpu->hThread = qemu_thread_get_handle(cpu->thread); 157 #endif 158 } 159