LoongArch: KVM: Move LBT capability check in exception handler

Like FPU exception handler, check LBT capability in the LBT exception
handler rather than function kvm_own_lbt().

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: bibo-mao

arch/loongarch/kvm/exit.c

@@ -820,8 +820,10 @@ static int kvm_handle_lasx_disabled(struct kvm_vcpu *vcpu, int ecode)
 
 static int kvm_handle_lbt_disabled(struct kvm_vcpu *vcpu, int ecode)
 {
-	if (kvm_own_lbt(vcpu))
+	if (!kvm_guest_has_lbt(&vcpu->arch))
 		kvm_queue_exception(vcpu, EXCCODE_INE, 0);
+	else
+		kvm_own_lbt(vcpu);
 
 	return RESUME_GUEST;
 }

arch/loongarch/kvm/vcpu.c

@@ -1304,9 +1304,6 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
 #ifdef CONFIG_CPU_HAS_LBT
 int kvm_own_lbt(struct kvm_vcpu *vcpu)
 {
-	if (!kvm_guest_has_lbt(&vcpu->arch))
-		return -EINVAL;
-
 	preempt_disable();
 	if (!(vcpu->arch.aux_inuse & KVM_LARCH_LBT)) {
 		set_csr_euen(CSR_EUEN_LBTEN);