Re: [patch 1/2] KVM: x86: handle double and triple faults for every exception

[Avi Kivity <avi@redhat.com>]

>> Another micro difference is this:
>>
>>      
>>> @@ -184,24 +196,6 @@ void kvm_inject_page_fault(struct kvm_vc
>>>   {
>>>   	++vcpu->stat.pf_guest;
>>>
>>> -	if (vcpu->arch.exception.pending) {
>>> -		switch(vcpu->arch.exception.nr) {
>>> -		case DF_VECTOR:
>>> -			/* triple fault ->  shutdown */
>>> -			set_bit(KVM_REQ_TRIPLE_FAULT,&vcpu->requests);
>>> -			return;
>>> -		case PF_VECTOR:
>>> -			vcpu->arch.exception.nr = DF_VECTOR;
>>> -			vcpu->arch.exception.error_code = 0;
>>> -			return;
>>> -		default:
>>> -			/* replace previous exception with a new one in a hope
>>> -			   that instruction re-execution will regenerate lost
>>> -			   exception */
>>> -			vcpu->arch.exception.pending = false;
>>> -			break;
>>> -		}
>>> -	}
>>>   	vcpu->arch.cr2 = addr;
>>>   	kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
>>>   }
>>>        
>> So far cr2 was not touched on DF, now it is.
>>      
> Yep. The PF was overwritten with DF, which means the cr2 value will not
> be interpreted by the guest?
>    

The note under interrupt 14 documentation in 5.15 indicates that cr2 is 
updated when the page fault is detected, not delivered, so it is correct 
to update cr2 immediately.

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