Re: kvm causing memory corruption? now 2.6.26-rc4

Avi Kivity
2008-06-12T13:12:11Z

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.