KVM: Document KVM_IRQFD

Commit Message

Sasha Levin Aug. 29, 2011, 12:32 p.m. UTC

Avi Kivity <[e-mail]>
Marcelo Tosatti <[e-mail]>
Signed-off-by: Sasha Levin <[e-mail]>
---
 Documentation/virtual/kvm/api.txt |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)

Patch

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 2d510b6..d1150b6 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1450,6 +1450,33 @@  is supported; 2 if the processor requires all virtual machines to have
 an RMA, or 1 if the processor can use an RMA but doesn't require it,
 because it supports the Virtual RMA (VRMA) facility.
 
+4.64 KVM_IRQFD
+
+Capability: KVM_CAP_IRQFD
+Architectures: all
+Type: vm ioctl
+Parameters: struct kvm_irqfd (in)
+Returns: 0 on success, !0 on error
+
+This ioctl attaches or detaches an eventfd to a GSI within the guest.
+While the eventfd is assigned to the guest, any write to the eventfd
+would trigger the GSI within the guest.
+
+struct kvm_irqfd {
+	__u32 fd;
+	__u32 gsi;
+	__u32 flags;
+	__u8  pad[20];
+};
+
+The following flags are defined:
+
+#define KVM_IRQFD_FLAG_DEASSIGN (1 << 0)
+
+If deassign flag is set, the eventfd will be deassigned from the GSI and
+further writes to the eventfd won't trigger the GSI.
+
+
 5. The kvm_run structure
 
 Application code obtains a pointer to the kvm_run structure by