Re: soft lockup after stop/cont

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Dong, Eddie wrote:
> Avi Kivity wrote:
>   
>> Dong, Eddie wrote:
>>     
>>> kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org wrote:
>>>
>>>       
>>>> It may be that the timer correction code detects that zillions of
>>>> timer interrupts have not been serviced by the guest so it floods
>>>> the guest with these interrupts.  Does -no-kvm-irqchip help?
>>>>
>>>>
>>>>         
>>> In Xen, we decide to froze the guest time after save/restore. In this
>>> way the guest see contiguous timer and thus avoid this issue.
>>>
>>> Probably we should do similar here, comments?
>>>
>>>       
>> This is pause/resume, not save/restore.  I think save/restore now has
>> contiguous lapic timer and discontiguous real time.
>>
>>     
>
> If save/restore means live migration here, yes you are right.
>   

No, I didn't mean that.

> save to file and later resume from file will have this issue.
>   

Why? after saving to a file, the local apic in the kernel is destroyed
when qemu quits.

Or is the timer saved in absolute time?  if so you are right, and yes,
your solution is needed.


-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.


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