virtio-pci: cache msix messages

Some guests mask a vector then unmask without changing it.
Store vectors to avoid kvm system calls in this case.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/hw/virtio-pci.h b/hw/virtio-pci.h
index b0f17e2b16..9ff3139fe9 100644
--- a/hw/virtio-pci.h
+++ b/hw/virtio-pci.h
@@ -27,6 +27,7 @@
 #define VIRTIO_PCI_FLAG_USE_IOEVENTFD   (1 << VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT)
 
 typedef struct {
+    MSIMessage msg;
     int virq;
     unsigned int users;
 } VirtIOIRQFD;