Re: [Qemu-devel] qemu-kvm-1.0.1 - unable to exit if vcpu is in infinite loop

[Jan Kiszka]

On 2012-07-01 21:18, Peter Lieven wrote:
> 
> Am 01.07.2012 um 10:19 schrieb Avi Kivity:
> 
>> On 06/28/2012 10:27 PM, Peter Lieven wrote:
>>>
>>> Am 28.06.2012 um 18:32 schrieb Avi Kivity:
>>>
>>>> On 06/28/2012 07:29 PM, Peter Lieven wrote:
>>>>>> Yes. A signal is sent, and KVM returns from the guest to userspace on
>>>>>> pending signals.
>>>>
>>>>> is there a description available how this process exactly works?
>>>>
>>>> The kernel part is in vcpu_enter_guest(), see the check for
>>>> signal_pending().  But this hasn't seen changes for quite a long while.
>>>
>>> Thank you, i will have a look. I noticed a few patches that where submitted
>>> during the last year, maybe one of them is related:
>>>
>>> Switch SIG_IPI to SIGUSR1
>>> Fix signal handling of SIG_IPI when io-thread is enabled
>>>
>>> In the first commit there is mentioned a "32-on-64-bit Linux kernel bug"
>>> is there any reference to that?
>>
>>
>> http://web.archiveorange.com/archive/v/1XS1vwGSFLyYygwTXg1K.  Are you
>> running 32-on-64?
> 
> I think the issue occurs when running a 32-bit guest on a 64-bit system. 
> Afaik, the
> isolinux loader where is see the race is 32-bit altough it is a 64-bit ubuntu 
> lts
> cd image. The second case where i have seen the race is on shutdown of a
> Windows 2000 Server which is also 32-bit.

"32-on-64" particularly means using a 32-bit QEMU[-kvm] binary on a
64-bit host kernel. What does "file qemu-system-x86_64" report about yours?

Jan

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