virtio/vhost: Add support for KVM in-kernel MSI injection

Make use of the new vector notifier to track changes of the MSI-X
configuration of virtio PCI devices. On enabling events, we establish
the required virtual IRQ to MSI-X message route and link the signaling
eventfd file descriptor to this vIRQ line. That way, vhost-generated
interrupts can be directly delivered to an in-kernel MSI-X consumer like
the x86 APIC.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/hw/virtio-pci.h b/hw/virtio-pci.h
index e5604282e5..8d28d4b789 100644
--- a/hw/virtio-pci.h
+++ b/hw/virtio-pci.h
@@ -25,6 +25,11 @@
 #define VIRTIO_PCI_FLAG_USE_IOEVENTFD   (1 << VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT)
 
 typedef struct {
+    int virq;
+    unsigned int users;
+} VirtIOIRQFD;
+
+typedef struct {
     PCIDevice pci_dev;
     VirtIODevice *vdev;
     MemoryRegion bar;
@@ -44,6 +49,7 @@ typedef struct {
     VirtIOSCSIConf scsi;
     bool ioeventfd_disabled;
     bool ioeventfd_started;
+    VirtIOIRQFD *vector_irqfd;
 } VirtIOPCIProxy;
 
 void virtio_init_pci(VirtIOPCIProxy *proxy, VirtIODevice *vdev);