On 2011-02-28 17:45, Avi Kivity wrote:
> On 02/28/2011 06:16 PM, Jan Kiszka wrote:
>> On 2011-02-28 16:55, Avi Kivity wrote:
>>> On 02/01/2011 11:15 PM, Jan Kiszka wrote:
>>>> From: Jan Kiszka<jan.kiszka@xxxxxxxxxxx>
>>>>
>>>> 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);
>>
>> Just comment that out as long as qemu-kvm is (mis-)using !IOTHREAD mode.
>> I thought it would run before setup_kernel_sigmask, but it's the other
>> way around, and then the wrong non-iothread signal setup is applied.
>
> That's what I tried, and it didn't work?! Maybe I forgot to compile or
> something.
Well, it maybe failed to build as qemu_kvm_init_cpu_signals became
unused and the compiler should have bailed out? Probably it's better to
disable it directly in the function.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
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