KVM: irqfd

KVM provides a complete virtual system environment for guests, including
support for injecting interrupts modeled after the real exception/interrupt
facilities present on the native platform (such as the IDT on x86).
Virtual interrupts can come from a variety of sources (emulated devices,
pass-through devices, etc) but all must be injected to the guest via
the KVM infrastructure.  This patch adds a new mechanism to inject a specific
interrupt to a guest using a decoupled eventfd mechnanism:  Any legal signal
on the irqfd (using eventfd semantics from either userspace or kernel) will
translate into an injected interrupt in the guest at the next available
interrupt window.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f0642396783f..15f39fc08ece 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1126,6 +1126,7 @@ int kvm_dev_ioctl_check_extension(long ext)
         case KVM_CAP_REINJECT_CONTROL:
         case KVM_CAP_IRQ_INJECT_STATUS:
         case KVM_CAP_ASSIGN_DEV_IRQ:
+        case KVM_CAP_IRQFD:
                 r = 1;
                 break;
         case KVM_CAP_COALESCED_MMIO: