[Qemu-devel] Re: Bugs in kvm guest migration

[Jan Kiszka]

Avi Kivity wrote:
> On 12/03/2009 09:23 PM, Jan Kiszka wrote:
>> Jan Kiszka wrote:
>>    
>>> Problem 2
>>> ---------
>>> Setup: qemu head with vmstate fixes. kvm-kmod master, 64-bit host&  guest.
>>> Effect: The migration target either locks up or reboots immediately.
>>> I've nailed this down to 84d0b66c778d881eafca2a5d0d66678211c4e861. Every
>>> kvm module build before that works, everything including and after
>>> 26ede77f536d1bb369527a96c7fe7fdc8ba2f890 shows the effect (everything in
>>> between crashes the host for known reasons). It's still unclear if this
>>> is an kvm-kmod wrapping issue of the user-space return notifiers. Will
>>> check once problem #1 is understood.
>>>      
>> It is kernel-related, using kvm.git as host kernel makes no difference.
>>
>> This may now mean that kvm is buggy or that it triggers some msr
>> save/restore related issues in qemu. Digging even deeper...
>>    
> 
> Does calling drop_user_return_notifiers() (static in x86.c, will need 
> exporting) in vmx_load_host_state() within the preempt-disable region help?
> 

Nope.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux