accel/tcg/tcg-accel-ops-mttcg.c

   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 }