KVM: x86: Treat pending TRIPLE_FAULT requests as pending exceptions

Treat pending TRIPLE_FAULTS as pending exceptions.  A triple fault is an
exception for all intents and purposes, it's just not tracked as such
because there's no vector associated the exception.  E.g. if userspace
were to set vcpu->request_interrupt_window while running L2 and L2 hit a
triple fault, a triple fault nested VM-Exit should be synthesized to L1
before exiting to userspace with KVM_EXIT_IRQ_WINDOW_OPEN.

Link: https://lore.kernel.org/all/YoVHAIGcFgJit1qp@google.comSigned-off-by: NSean Christopherson <seanjc@google.com>
Reviewed-by: NMaxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20220830231614.3580124-23-seanjc@google.comSigned-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -12760,9 +12760,6 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
 	if (kvm_xen_has_pending_events(vcpu))
 		return true;
 
-	if (kvm_test_request(KVM_REQ_TRIPLE_FAULT, vcpu))
-		return true;
-
 	return false;
 }
 

arch/x86/kvm/x86.h

@@ -85,7 +85,8 @@ int kvm_check_nested_events(struct kvm_vcpu *vcpu);
 static inline bool kvm_is_exception_pending(struct kvm_vcpu *vcpu)
 {
 	return vcpu->arch.exception.pending ||
-	       vcpu->arch.exception_vmexit.pending;
+	       vcpu->arch.exception_vmexit.pending ||
+	       kvm_test_request(KVM_REQ_TRIPLE_FAULT, vcpu);
 }
 
 static inline void kvm_clear_exception_queue(struct kvm_vcpu *vcpu)