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 "qemu-common.h" 28 #include "sysemu/tcg.h" 29 #include "sysemu/replay.h" 30 #include "qemu/main-loop.h" 31 #include "qemu/guest-random.h" 32 #include "exec/exec-all.h" 33 #include "hw/boards.h" 34 35 #include "tcg-accel-ops.h" 36 #include "tcg-accel-ops-mttcg.h" 37 38 /* 39 * In the multi-threaded case each vCPU has its own thread. The TLS 40 * variable current_cpu can be used deep in the code to find the 41 * current CPUState for a given thread. 42 */ 43 44 static void *mttcg_cpu_thread_fn(void *arg) 45 { 46 CPUState *cpu = arg; 47 48 assert(tcg_enabled()); 49 g_assert(!icount_enabled()); 50 51 rcu_register_thread(); 52 tcg_register_thread(); 53 54 qemu_mutex_lock_iothread(); 55 qemu_thread_get_self(cpu->thread); 56 57 cpu->thread_id = qemu_get_thread_id(); 58 cpu->can_do_io = 1; 59 current_cpu = cpu; 60 cpu_thread_signal_created(cpu); 61 qemu_guest_random_seed_thread_part2(cpu->random_seed); 62 63 /* process any pending work */ 64 cpu->exit_request = 1; 65 66 do { 67 if (cpu_can_run(cpu)) { 68 int r; 69 qemu_mutex_unlock_iothread(); 70 r = tcg_cpus_exec(cpu); 71 qemu_mutex_lock_iothread(); 72 switch (r) { 73 case EXCP_DEBUG: 74 cpu_handle_guest_debug(cpu); 75 break; 76 case EXCP_HALTED: 77 /* 78 * during start-up the vCPU is reset and the thread is 79 * kicked several times. If we don't ensure we go back 80 * to sleep in the halted state we won't cleanly 81 * start-up when the vCPU is enabled. 82 * 83 * cpu->halted should ensure we sleep in wait_io_event 84 */ 85 g_assert(cpu->halted); 86 break; 87 case EXCP_ATOMIC: 88 qemu_mutex_unlock_iothread(); 89 cpu_exec_step_atomic(cpu); 90 qemu_mutex_lock_iothread(); 91 default: 92 /* Ignore everything else? */ 93 break; 94 } 95 } 96 97 qatomic_mb_set(&cpu->exit_request, 0); 98 qemu_wait_io_event(cpu); 99 } while (!cpu->unplug || cpu_can_run(cpu)); 100 101 tcg_cpus_destroy(cpu); 102 qemu_mutex_unlock_iothread(); 103 rcu_unregister_thread(); 104 return NULL; 105 } 106 107 void mttcg_kick_vcpu_thread(CPUState *cpu) 108 { 109 cpu_exit(cpu); 110 } 111 112 void mttcg_start_vcpu_thread(CPUState *cpu) 113 { 114 char thread_name[VCPU_THREAD_NAME_SIZE]; 115 116 g_assert(tcg_enabled()); 117 tcg_cpu_init_cflags(cpu, current_machine->smp.max_cpus > 1); 118 119 cpu->thread = g_malloc0(sizeof(QemuThread)); 120 cpu->halt_cond = g_malloc0(sizeof(QemuCond)); 121 qemu_cond_init(cpu->halt_cond); 122 123 /* create a thread per vCPU with TCG (MTTCG) */ 124 snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG", 125 cpu->cpu_index); 126 127 qemu_thread_create(cpu->thread, thread_name, mttcg_cpu_thread_fn, 128 cpu, QEMU_THREAD_JOINABLE); 129 130 #ifdef _WIN32 131 cpu->hThread = qemu_thread_get_handle(cpu->thread); 132 #endif 133 } 134