Re: kvm causing memory corruption? now 2.6.26-rc4

[Avi Kivity <avi@qumranet.com>]

Dave Hansen wrote:
> On Wed, 2008-06-04 at 16:42 +0300, Avi Kivity wrote:
>   
>> Dave Hansen wrote:
>>     
> ...
>   
>>> After collecting all those, I turned on CONFIG_DEBUG_HIGHMEM and the
>>> oopses miraculously stopped.  But, the guest hung (for at least 5
>>> minutes or so) during windows bootup, pegging my host CPU.  Most of the
>>> CPU was going to klogd, so I checked dmesg.
>>>
>>>       
>> Can you check with mem=900 (and CONFIG_HIGHMEM_DEBUG=n)?  That will 
>> confirm that the problems are highmem related, but not physical address 
>> truncation related.
>>     
>
> Do you mean 800M? ;) Highmem begins at 896MB if I remember correctly.
>
> Anyway, it still oopses on current git with mem=800M
>
>   

Stumped.  Please post .config, will try to reproduce.

>>> I was seeing messages like this
>>>
>>> [  428.918108] kvm_handle_exit: unexpected, valid vectoring info and exit reason is 0x9
>>>
>>> And quite a few of them, like 100,000/sec.  That's why klogd was pegging
>>> the CPU.  Any idea on a next debugging step?
>>>
>>>       
>> That's a task switch.  Newer kvms handle them.
>>     
>
> Newer userspace?  I'm running current kvm-git userspace as of a day or
> two ago.
>   

No, it's kernel code.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.