xref: /openbmc/qemu/accel/dummy-cpus.c (revision 989dd906ed5556563a57b32ae7abf9db5e1f38ba)
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 "system/cpus.h"
17 #include "qemu/guest-random.h"
18 #include "qemu/main-loop.h"
19 #include "hw/core/cpu.h"
20 #include "accel/dummy-cpus.h"
21 
dummy_cpu_thread_fn(void * arg)22 static void *dummy_cpu_thread_fn(void *arg)
23 {
24     CPUState *cpu = arg;
25 
26     rcu_register_thread();
27 
28     bql_lock();
29     qemu_thread_get_self(cpu->thread);
30     cpu->thread_id = qemu_get_thread_id();
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         bql_unlock();
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         bql_lock();
60         qemu_wait_io_event(cpu);
61     } while (!cpu->unplug);
62 
63     bql_unlock();
64     rcu_unregister_thread();
65     return NULL;
66 }
67 
dummy_start_vcpu_thread(CPUState * cpu)68 void dummy_start_vcpu_thread(CPUState *cpu)
69 {
70     char thread_name[VCPU_THREAD_NAME_SIZE];
71 
72     snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/DUMMY",
73              cpu->cpu_index);
74     qemu_thread_create(cpu->thread, thread_name, dummy_cpu_thread_fn, cpu,
75                        QEMU_THREAD_JOINABLE);
76 #ifdef _WIN32
77     qemu_sem_init(&cpu->sem, 0);
78 #endif
79 }
80