KVM: arm64: Hoist NV+SVE check into KVM_ARM_VCPU_INIT ioctl handler

Move the feature check out of kvm_reset_vcpu() so we can make the
function succeed uncondtitionally.

Link: https://lore.kernel.org/r/20230920195036.1169791-7-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

arch/arm64/kvm/arm.c

@@ -1239,6 +1239,11 @@ static int kvm_vcpu_init_check_features(struct kvm_vcpu *vcpu,
 	    test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, &features))
 		return -EINVAL;
 
+	/* Disallow NV+SVE for the time being */
+	if (test_bit(KVM_ARM_VCPU_HAS_EL2, &features) &&
+	    test_bit(KVM_ARM_VCPU_SVE, &features))
+		return -EINVAL;
+
 	if (!test_bit(KVM_ARM_VCPU_EL1_32BIT, &features))
 		return 0;
 

arch/arm64/kvm/reset.c

@@ -208,12 +208,6 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	if (loaded)
 		kvm_arch_vcpu_put(vcpu);
 
-	/* Disallow NV+SVE for the time being */
-	if (vcpu_has_nv(vcpu) && vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
 		if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features))
 			kvm_vcpu_enable_sve(vcpu);
@@ -267,7 +261,7 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 
 	/* Reset timer */
 	ret = kvm_timer_vcpu_reset(vcpu);
-out:
+
 	if (loaded)
 		kvm_arch_vcpu_load(vcpu, smp_processor_id());
 	preempt_enable();