KVM: nVMX: Fix injection of PENDING_INTERRUPT and NMI_WINDOW exits to L1

Check if the interrupt or NMI window exit is for L1 by testing if it has
the corresponding controls enabled. This is required when we allow
direct injection from L0 to L2
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

arch/x86/kvm/vmx.c

@@ -6112,14 +6112,9 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 	case EXIT_REASON_TRIPLE_FAULT:
 		return 1;
 	case EXIT_REASON_PENDING_INTERRUPT:
+		return nested_cpu_has(vmcs12, CPU_BASED_VIRTUAL_INTR_PENDING);
 	case EXIT_REASON_NMI_WINDOW:
-		/*
-		 * prepare_vmcs02() set the CPU_BASED_VIRTUAL_INTR_PENDING bit
-		 * (aka Interrupt Window Exiting) only when L1 turned it on,
-		 * so if we got a PENDING_INTERRUPT exit, this must be for L1.
-		 * Same for NMI Window Exiting.
-		 */
-		return 1;
+		return nested_cpu_has(vmcs12, CPU_BASED_VIRTUAL_NMI_PENDING);
 	case EXIT_REASON_TASK_SWITCH:
 		return 1;
 	case EXIT_REASON_CPUID: