[Qemu-devel] Odd code in cpus.c

[Frediano Ziglio]

I  don't know that much this code however qemu_kvm_init_cpu_signals
seems a bit strange and duplicate to me, in cpus.c


static void qemu_kvm_init_cpu_signals(CPUState *env)
{
    int r;
    sigset_t set;
    struct sigaction sigact;

    memset(&sigact, 0, sizeof(sigact));
    sigact.sa_handler = dummy_signal;
    sigaction(SIG_IPI, &sigact, NULL);

#ifdef CONFIG_IOTHREAD
    pthread_sigmask(SIG_BLOCK, NULL, &set);
    sigdelset(&set, SIG_IPI);
    sigdelset(&set, SIGBUS);
    r = kvm_set_signal_mask(env, &set);
    if (r) {
        fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(-r));
        exit(1);
    }
#else
    sigemptyset(&set);
    sigaddset(&set, SIG_IPI);
    sigaddset(&set, SIGIO);
    sigaddset(&set, SIGALRM);
    pthread_sigmask(SIG_BLOCK, &set, NULL);

    pthread_sigmask(SIG_BLOCK, NULL, &set);
    sigdelset(&set, SIGIO);
    sigdelset(&set, SIGALRM);
#endif
    sigdelset(&set, SIG_IPI);
    sigdelset(&set, SIGBUS);
    r = kvm_set_signal_mask(env, &set);
    if (r) {
        fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(-r));
        exit(1);
    }
}


if CONFIG_IOTHREAD is set you get


static void qemu_kvm_init_cpu_signals(CPUState *env)
{
    int r;
    sigset_t set;
    struct sigaction sigact;

    memset(&sigact, 0, sizeof(sigact));
    sigact.sa_handler = dummy_signal;
    sigaction(SIG_IPI, &sigact, NULL);

    pthread_sigmask(SIG_BLOCK, NULL, &set);
    sigdelset(&set, SIG_IPI);
    sigdelset(&set, SIGBUS);
    r = kvm_set_signal_mask(env, &set);
    if (r) {
        fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(-r));
        exit(1);
    }
    sigdelset(&set, SIG_IPI);
    sigdelset(&set, SIGBUS);
    r = kvm_set_signal_mask(env, &set);
    if (r) {
        fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(-r));
        exit(1);
    }
}


which seems to set kvm signal twice with same values (taking into
account that in kvm_set_signal_mask the set is copied before the call
to kvm_vcpu_ioctl).

Frediano