Re: Problem with KVM guest switching to x86 long mode

[Avi Kivity <avi@redhat.com>]

On 04/11/2010 12:48 PM, Pekka Enberg wrote:
>> So the guest is in long mode, happily trying to access pci config space.
>>
>> MAXPHYADDR comes from cpuid 80000008.eax[0:7].  Typical values are 
>> 36-40 (number of physical address bits supported by the processor).  
>> What value does your guest see?
>
>
> Ah, nice catch! The host cpuid doesn't seem to support 80000008 at so 
> I didn't set it up in the guest either. I now added dummy emulation 
> for it and the triple fault is fixed.

It should work without 80000008 set up - failure should happen only if 
it is setup incorrectly:

int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
{
     struct kvm_cpuid_entry2 *best;

     best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
     if (best)
         return best->eax & 0xff;
     return 36;
}


-- 
error compiling committee.c: too many arguments to function