diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index a5f9ee92f43e..14121315d4a5 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -856,7 +856,8 @@ Writes the floating point state to the vcpu.
 Creates an interrupt controller model in the kernel.
 On x86, creates a virtual ioapic, a virtual PIC (two PICs, nested), and sets up
 future vcpus to have a local APIC.  IRQ routing for GSIs 0-15 is set to both
-PIC and IOAPIC; GSI 16-23 only go to the IOAPIC.
+PIC and IOAPIC; GSI 16-23 only go to the IOAPIC.  This ioctl can only be
+called before creating any vcpus.
 On arm64, a GICv2 is created. Any other GIC versions require the usage of
 KVM_CREATE_DEVICE, which also supports creating a GICv2.  Using
 KVM_CREATE_DEVICE is preferred over KVM_CREATE_IRQCHIP for GICv2.