diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index e46f267585f4..acabe9d898cf 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2253,14 +2253,14 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 
 	switch (hc.code) {
 	case HVCALL_NOTIFY_LONG_SPIN_WAIT:
-		if (unlikely(hc.rep)) {
+		if (unlikely(hc.rep || hc.var_cnt)) {
 			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
 			break;
 		}
 		kvm_vcpu_on_spin(vcpu, true);
 		break;
 	case HVCALL_SIGNAL_EVENT:
-		if (unlikely(hc.rep)) {
+		if (unlikely(hc.rep || hc.var_cnt)) {
 			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
 			break;
 		}
@@ -2270,7 +2270,7 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 		fallthrough;	/* maybe userspace knows this conn_id */
 	case HVCALL_POST_MESSAGE:
 		/* don't bother userspace if it has no way to handle it */
-		if (unlikely(hc.rep || !to_hv_synic(vcpu)->active)) {
+		if (unlikely(hc.rep || hc.var_cnt || !to_hv_synic(vcpu)->active)) {
 			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
 			break;
 		}
@@ -2283,14 +2283,14 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 				kvm_hv_hypercall_complete_userspace;
 		return 0;
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
-		if (unlikely(!hc.rep_cnt || hc.rep_idx)) {
+		if (unlikely(!hc.rep_cnt || hc.rep_idx || hc.var_cnt)) {
 			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
 			break;
 		}
 		ret = kvm_hv_flush_tlb(vcpu, &hc, false);
 		break;
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
-		if (unlikely(hc.rep)) {
+		if (unlikely(hc.rep || hc.var_cnt)) {
 			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
 			break;
 		}
@@ -2311,7 +2311,7 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 		ret = kvm_hv_flush_tlb(vcpu, &hc, true);
 		break;
 	case HVCALL_SEND_IPI:
-		if (unlikely(hc.rep)) {
+		if (unlikely(hc.rep || hc.var_cnt)) {
 			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
 			break;
 		}