KVM: x86: Break kvm_for_each_vcpu loop after finding the VP_INDEX

No need to scan the entire VCPU array.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -2328,9 +2328,12 @@ static int get_msr_hyperv(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
 	case HV_X64_MSR_VP_INDEX: {
 		int r;
 		struct kvm_vcpu *v;
-		kvm_for_each_vcpu(r, v, vcpu->kvm)
-			if (v == vcpu)
+		kvm_for_each_vcpu(r, v, vcpu->kvm) {
+			if (v == vcpu) {
 				data = r;
+				break;
+			}
+		}
 		break;
 	}
 	case HV_X64_MSR_EOI: