KVM: MMU: Track page fault data in struct vcpu

This patch introduces a struct with two new fields in
vcpu_arch for x86:

	* fault.address
	* fault.error_code

This will be used to correctly propagate page faults back
into the guest when we could have either an ordinary page
fault or a nested page fault. In the case of a nested page
fault the fault-address is different from the original
address that should be walked. So we need to keep track
about the real fault-address.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/x86.c

@@ -329,11 +329,12 @@ void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr)
 }
 EXPORT_SYMBOL_GPL(kvm_requeue_exception);
 
-void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
-			   u32 error_code)
+void kvm_inject_page_fault(struct kvm_vcpu *vcpu)
 {
+	unsigned error_code = vcpu->arch.fault.error_code;
+
 	++vcpu->stat.pf_guest;
-	vcpu->arch.cr2 = addr;
+	vcpu->arch.cr2 = vcpu->arch.fault.address;
 	kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
 }
 
@@ -4080,7 +4081,7 @@ static void inject_emulated_exception(struct kvm_vcpu *vcpu)
 {
 	struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
 	if (ctxt->exception == PF_VECTOR)
-		kvm_inject_page_fault(vcpu, ctxt->cr2, ctxt->error_code);
+		kvm_inject_page_fault(vcpu);
 	else if (ctxt->error_code_valid)
 		kvm_queue_exception_e(vcpu, ctxt->exception, ctxt->error_code);
 	else