accel/dummy-cpus.c

   1 /*
   2  * Dummy cpu thread code
   3  *
   4  * Copyright IBM, Corp. 2011
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu/osdep.h"
  15 #include "qemu/rcu.h"
  16 #include "sysemu/cpus.h"
  17 #include "qemu/guest-random.h"
  18 #include "qemu/main-loop.h"
  19 #include "hw/core/cpu.h"
  20
  21 static void *dummy_cpu_thread_fn(void *arg)
  22 {
  23     CPUState *cpu = arg;
  24
  25     rcu_register_thread();
  26
  27     qemu_mutex_lock_iothread();
  28     qemu_thread_get_self(cpu->thread);
  29     cpu->thread_id = qemu_get_thread_id();
  30     cpu->neg.can_do_io = true;
  31     current_cpu = cpu;
  32
  33 #ifndef _WIN32
  34     sigset_t waitset;
  35     int r;
  36
  37     sigemptyset(&waitset);
  38     sigaddset(&waitset, SIG_IPI);
  39 #endif
  40
  41     /* signal CPU creation */
  42     cpu_thread_signal_created(cpu);
  43     qemu_guest_random_seed_thread_part2(cpu->random_seed);
  44
  45     do {
  46         qemu_mutex_unlock_iothread();
  47 #ifndef _WIN32
  48         do {
  49             int sig;
  50             r = sigwait(&waitset, &sig);
  51         } while (r == -1 && (errno == EAGAIN || errno == EINTR));
  52         if (r == -1) {
  53             perror("sigwait");
  54             exit(1);
  55         }
  56 #else
  57         qemu_sem_wait(&cpu->sem);
  58 #endif
  59         qemu_mutex_lock_iothread();
  60         qemu_wait_io_event(cpu);
  61     } while (!cpu->unplug);
  62
  63     qemu_mutex_unlock_iothread();
  64     rcu_unregister_thread();
  65     return NULL;
  66 }
  67
  68 void dummy_start_vcpu_thread(CPUState *cpu)
  69 {
  70     char thread_name[VCPU_THREAD_NAME_SIZE];
  71
  72     cpu->thread = g_malloc0(sizeof(QemuThread));
  73     cpu->halt_cond = g_malloc0(sizeof(QemuCond));
  74     qemu_cond_init(cpu->halt_cond);
  75     snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/DUMMY",
  76              cpu->cpu_index);
  77     qemu_thread_create(cpu->thread, thread_name, dummy_cpu_thread_fn, cpu,
  78                        QEMU_THREAD_JOINABLE);
  79 #ifdef _WIN32
  80     qemu_sem_init(&cpu->sem, 0);
  81 #endif
  82 }