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

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2011-02-28 16:55, Avi Kivity wrote:
> 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.

Does the same test case work with qemu, iothread on and off? Just to
ensure we are not hunting an issue with the patch itself but of the merge.

Will have a look as well.

Jan

> 
> 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);
>>       }
>>   }
>>
> 
> 

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