[Qemu-devel] Re: [PATCH v2 13/24] kvm: Set up signal mask also for !CONFIG_IOTHREAD

[Avi Kivity <avi@redhat.com>]

On 02/01/2011 11:15 PM, Jan Kiszka wrote:
> From: Jan Kiszka<jan.kiszka@siemens.com>
>
> Block SIG_IPI, unblock it during KVM_RUN, just like in io-thread mode.
> It's unused so far, but this infrastructure will be required for
> self-IPIs and to process SIGBUS plus, in KVM mode, SIGIO and SIGALRM. As
> Windows doesn't support signal services, we need to provide a stub for
> the init function.
>

This patch breaks qemu-kvm after merging.  The symptoms are that Windows 
XP x64 does not respond when netcat connects to some server in it, via 
-net user,hostfwd.  The vcpu thread loops indefinitely on KVM_EXIT_INTR, 
which is consistent with signals being messed up.

I verified that 981085dd465c1 merged with ff48eb5fe79ad works,
while 981085dd465c1 merged with ff48eb5fe79ad^ fails.


> diff --git a/cpus.c b/cpus.c
> index 42717ba..a33e470 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -231,11 +231,9 @@ fail:
>       return err;
>   }
>
> -#ifdef CONFIG_IOTHREAD
>   static void dummy_signal(int sig)
>   {
>   }
> -#endif
>
>   #else /* _WIN32 */
>
> @@ -267,6 +265,32 @@ static void qemu_event_increment(void)
>   #endif /* _WIN32 */
>
>   #ifndef CONFIG_IOTHREAD
> +static void qemu_kvm_init_cpu_signals(CPUState *env)
> +{
> +#ifndef _WIN32
> +    int r;
> +    sigset_t set;
> +    struct sigaction sigact;
> +
> +    memset(&sigact, 0, sizeof(sigact));
> +    sigact.sa_handler = dummy_signal;
> +    sigaction(SIG_IPI,&sigact, NULL);
> +
> +    sigemptyset(&set);
> +    sigaddset(&set, SIG_IPI);
> +    pthread_sigmask(SIG_BLOCK,&set, 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);
> +    }
> +#endif
> +}
> +
>   int qemu_init_main_loop(void)
>   {
>       cpu_set_debug_excp_handler(cpu_debug_handler);
> @@ -292,6 +316,7 @@ void qemu_init_vcpu(void *_env)
>               fprintf(stderr, "kvm_init_vcpu failed: %s\n", strerror(-r));
>               exit(1);
>           }
> +        qemu_kvm_init_cpu_signals(env);
>       }
>   }
>


-- 
error compiling committee.c: too many arguments to function