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, 12 insertions, 0 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2884baf1d5f9..dee321e58894 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -986,6 +986,7 @@ static struct kvm *kvm_create_vm(void)
         spin_lock_init(&kvm->mmu_lock);
         spin_lock_init(&kvm->requests_lock);
         kvm_io_bus_init(&kvm->pio_bus);
+        kvm_irqfd_init(kvm);
         mutex_init(&kvm->lock);
         kvm_io_bus_init(&kvm->mmio_bus);
         init_rwsem(&kvm->slots_lock);
@@ -1071,6 +1072,8 @@ static int kvm_vm_release(struct inode *inode, struct file *filp)
 {
         struct kvm *kvm = filp->private_data;
 
+        kvm_irqfd_release(kvm);
+
         kvm_put_kvm(kvm);
         return 0;
 }
@@ -2222,6 +2225,15 @@ static long kvm_vm_ioctl(struct file *filp,
         }
 #endif
 #endif /* KVM_CAP_IRQ_ROUTING */
+        case KVM_IRQFD: {
+                struct kvm_irqfd data;
+
+                r = -EFAULT;
+                if (copy_from_user(&data, argp, sizeof data))
+                        goto out;
+                r = kvm_irqfd(kvm, data.fd, data.gsi, data.flags);
+                break;
+        }
         default:
                 r = kvm_arch_vm_ioctl(filp, ioctl, arg);
         }