msix: Introduce vector notifiers

Vector notifiers shall be triggered by the MSI/MSI-X core whenever a
relevant configuration change is programmed by the guest. In case of
MSI-X, changes are reported when the effective mask (global &&
per-vector) alters its state. On unmask, the current vector
configuration is included in the event report. This allows users - e.g.
virtio-pci layer - to transfer this information to external MSI-X
routing subsystems - like vhost + KVM in-kernel irqchip.

This implementation only provides MSI-X support, but extension to MSI is
feasible and will be provided later on when adding support for KVM PCI
device assignment.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/hw/msix.h b/hw/msix.h
index 5aba22b858..f33f18b484 100644
--- a/hw/msix.h
+++ b/hw/msix.h
@@ -29,4 +29,8 @@ void msix_notify(PCIDevice *dev, unsigned vector);
 
 void msix_reset(PCIDevice *dev);
 
+int msix_set_vector_notifiers(PCIDevice *dev,
+                              MSIVectorUseNotifier use_notifier,
+                              MSIVectorReleaseNotifier release_notifier);
+void msix_unset_vector_notifiers(PCIDevice *dev);
 #endif