virtfs: enable MSI-X

This patch enables MSI-X for virtfs-9p-pci.  It also adds a
compat property to pc-0.13 which turns it of there to stay
compatible to 0.13-stable.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/pc_piix.c

@@ -225,6 +225,14 @@ static QEMUMachine pc_machine_v0_13 = {
     .desc = "Standard PC",
     .init = pc_init_pci,
     .max_cpus = 255,
+    .compat_props = (GlobalProperty[]) {
+        {
+            .driver   = "virtio-9p-pci",
+            .property = "vectors",
+            .value    = stringify(0),
+        },
+        { /* end of list */ }
+    },
 };
 
 static QEMUMachine pc_machine_v0_12 = {

hw/virtio-pci.c

@@ -684,12 +684,14 @@ static int virtio_9p_init_pci(PCIDevice *pci_dev)
     VirtIODevice *vdev;
 
     vdev = virtio_9p_init(&pci_dev->qdev, &proxy->fsconf);
+    vdev->nvectors = proxy->nvectors;
     virtio_init_pci(proxy, vdev,
                     PCI_VENDOR_ID_REDHAT_QUMRANET,
                     0x1009,
                     0x2,
                     0x00);
-
+    /* make the actual value visible */
+    proxy->nvectors = vdev->nvectors;
     return 0;
 }
 #endif
@@ -758,6 +760,7 @@ static PCIDeviceInfo virtio_info[] = {
         .qdev.size = sizeof(VirtIOPCIProxy),
         .init      = virtio_9p_init_pci,
         .qdev.props = (Property[]) {
+            DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
             DEFINE_VIRTIO_COMMON_FEATURES(VirtIOPCIProxy, host_features),
             DEFINE_PROP_STRING("mount_tag", VirtIOPCIProxy, fsconf.tag),
             DEFINE_PROP_STRING("fsdev", VirtIOPCIProxy, fsconf.fsdev_id),