Re: [PATCH] KVM: VMX: Fix locking order in handle_invalid_guest_state

[Jan Kiszka <jan.kiszka@web.de>]

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Avi Kivity wrote:
> On 07/26/2009 05:38 PM, Jan Kiszka wrote:
>> Avi Kivity wrote:
>>   
>>> On 07/26/2009 05:23 PM, Jan Kiszka wrote:
>>>     
>>>>> btw, what does it fix?  a debug warning?
>>>>>
>>>>>
>>>>>          
>>>> I haven't seen anything in the wild, and I don't think it would raise a
>>>> warning. All it should cause is a potential delay of some pending
>>>> reschedule as preempt_enable will not fire under local_irq_disable.
>>>>
>>>>        
>>> Ah, okay, then it is a real fix.  Preempt-correctness is important.
>>>
>>> (but won't local_irq_enable() reschedule?)
>>>      
>>
>> The last time I checked it was essentially a plain 'sti'.
>>
>>    
> 
> Presumably there's a reschedule interrupt queued; I think if you set the
> reschedule bit you have to IPI the cpu running the task.
> 

Yeah. But as we preempt_disable first, that one might have been
processed already.

Jan


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