[PATCH v3 2/3] kvm: Add missing KVM_IRQFD API documentation

[Alex Williamson <alex.williamson@redhat.com>]

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---

 Documentation/virtual/kvm/api.txt |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 310fe50..100acde 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1965,6 +1965,22 @@ return the hash table order in the parameter.  (If the guest is using
 the virtualized real-mode area (VRMA) facility, the kernel will
 re-create the VMRA HPTEs on the next KVM_RUN of any vcpu.)
 
+4.76 KVM_IRQFD
+
+Capability: KVM_CAP_IRQFD
+Architectures: x86
+Type: vm ioctl
+Parameters: struct kvm_irqfd (in)
+Returns: 0 on success, -1 on error
+
+Allows setting an eventfd to directly trigger a guest interrupt.
+kvm_irqfd.fd specifies the file descriptor to use as the eventfd and
+kvm_irqfd.gsi specifies the irqchip pin toggled by this event.  When
+an event is triggered on the eventfd, an interrupt is injected into
+the guest using the specified gsi pin.  The irqfd is removed using
+the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd
+and kvm_irqfd.gsi.
+
 
 5. The kvm_run structure
 ------------------------