Re: lapic & npt

[Gerd Hoffmann <kraxel@redhat.com>]

Avi Kivity wrote:
> Gerd Hoffmann wrote:
>>   Hi,
>>
>> I've just noticed that xenner doesn't work for 64bit xen guest kernels
>> on my new shiny barcelona box.  The VM crashes when trying to access the
>> lapic.  lapic setup is done before idt setup, register dump looks like
>> init state, thus it most likely is a triple fault resetting the vcpu.
>> Turning off npt fixes it.
>>
>> xenner maps the lapic to ffff820000000000 (64bit guests) or fe900000
>> (32bit guests).  32bit works fine even with npt enabled.
>>
>> host kernel is fedora 9 with kvm-69 modules.
>>
>> ideas anyone?
> 
> Turn on logging in lapic.c.  See if something turns up.
> 
> If not, the page tables are probably set up incorrectly, but in a way
> that kvm doesn't notice.

Figured meanwhile the instruction accessing the lapic register somehow
beames me into my gpf handler.  With a quite strange rsp value.  Hmm.
To be analyzed further after kvm forum I guess, unless someone has a
bright idea ...

cheers,
  Gerd

-- 
http://kraxel.fedorapeople.org/xenner/