Re: [PATCH] KVM: Fix MAXPHYADDR calculation when cpuid does not support it

[Avi Kivity <avi@redhat.com>]

On 04/11/2010 04:32 PM, Pekka Enberg wrote:
> Avi Kivity wrote:
>> MAXPHYADDR is derived from cpuid 0x80000008, but when that isn't 
>> present, we
>> get some random value.
>>
>> Fix by checking first that cpuid 0x80000008 is supported.
>>
>> Pekka Enberg <penberg@cs.helsinki.fi>
>> Signed-off-by: Avi Kivity <avi@redhat.com>
>> ---
>>  arch/x86/kvm/x86.c |    4 ++++
>>  1 files changed, 4 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index fd5c3d3..b2460cd 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -4165,9 +4165,13 @@ int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
>>  {
>>      struct kvm_cpuid_entry2 *best;
>>
>> +    best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
>> +    if (!best || best->eax < 0x80000008)
>> +        goto not_found;
>>      best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
>>      if (best)
>>          return best->eax & 0xff;
>> +not_found:
>>      return 36;
>>  }
>>
>
> Hmm, doesn't seem to work here. I still that triple fault in guest.

Can you add a printk to see what value is returned and why?

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