diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 79e59e4fa3dc..f8be6a3d1aa6 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -196,9 +196,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
 
 	nr_rt_entries += 1;
 
-	new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)),
-		      GFP_KERNEL_ACCOUNT);
-
+	new = kzalloc(struct_size(new, map, nr_rt_entries), GFP_KERNEL_ACCOUNT);
 	if (!new)
 		return -ENOMEM;