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     bql_lock();
  28     qemu_thread_get_self(cpu->thread);
  29     cpu->thread_id = qemu_get_thread_id();
  30     current_cpu = cpu;
  31
  32 #ifndef _WIN32
  33     sigset_t waitset;
  34     int r;
  35
  36     sigemptyset(&waitset);
  37     sigaddset(&waitset, SIG_IPI);
  38 #endif
  39
  40     /* signal CPU creation */
  41     cpu_thread_signal_created(cpu);
  42     qemu_guest_random_seed_thread_part2(cpu->random_seed);
  43
  44     do {
  45         bql_unlock();
  46 #ifndef _WIN32
  47         do {
  48             int sig;
  49             r = sigwait(&waitset, &sig);
  50         } while (r == -1 && (errno == EAGAIN || errno == EINTR));
  51         if (r == -1) {
  52             perror("sigwait");
  53             exit(1);
  54         }
  55 #else
  56         qemu_sem_wait(&cpu->sem);
  57 #endif
  58         bql_lock();
  59         qemu_wait_io_event(cpu);
  60     } while (!cpu->unplug);
  61
  62     bql_unlock();
  63     rcu_unregister_thread();
  64     return NULL;
  65 }
  66
  67 void dummy_start_vcpu_thread(CPUState *cpu)
  68 {
  69     char thread_name[VCPU_THREAD_NAME_SIZE];
  70
  71     snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/DUMMY",
  72              cpu->cpu_index);
  73     qemu_thread_create(cpu->thread, thread_name, dummy_cpu_thread_fn, cpu,
  74                        QEMU_THREAD_JOINABLE);
  75 #ifdef _WIN32
  76     qemu_sem_init(&cpu->sem, 0);
  77 #endif
  78 }