[PATCH 1/2] KVM: x86: Document that KVM_CREATE_IRQCHIP must precede vcpu creation

[Tim Wiederhake]

The kernel rejects KVM_CREATE_IRQCHIP with -EINVAL if any vcpus have
already been created, but the API documentation does not mention this
constraint.  Add a note.

Signed-off-by: Tim Wiederhake <twiederh@xxxxxxxxxx>
---
 Documentation/virt/kvm/api.rst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 52bbbb553ce1..270c3f0d668f 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.
-- 
2.52.0