virtio: disable ioeventfd as early as possible

Avoid "tricking" virtio-blk-dataplane into thinking that ioeventfd will be
available when it is not.  This bug has always been there, but it will break
TCG+ioeventfd=on once the dataplane code will be always used when ioeventfd=on.
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/s390x/virtio-ccw.c

@@ -709,6 +709,10 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
         sch->cssid, sch->ssid, sch->schid, sch->devno,
         ccw_dev->bus_id.valid ? "user-configured" : "auto-configured");
 
+    if (!kvm_eventfds_enabled()) {
+        dev->flags &= ~VIRTIO_CCW_FLAG_USE_IOEVENTFD;
+    }
+
     if (k->realize) {
         k->realize(dev, &err);
     }
@@ -1311,10 +1315,6 @@ static void virtio_ccw_device_plugged(DeviceState *d, Error **errp)
         return;
     }
 
-    if (!kvm_eventfds_enabled()) {
-        dev->flags &= ~VIRTIO_CCW_FLAG_USE_IOEVENTFD;
-    }
-
     sch->id.cu_model = virtio_bus_get_vdev_id(&dev->bus);
 
 

hw/virtio/virtio-pci.c

@@ -1719,10 +1719,6 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
         pci_register_bar(&proxy->pci_dev, proxy->legacy_io_bar_idx,
                          PCI_BASE_ADDRESS_SPACE_IO, &proxy->bar);
     }
-
-    if (!kvm_has_many_ioeventfds()) {
-        proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;
-    }
 }
 
 static void virtio_pci_device_unplugged(DeviceState *d)
@@ -1751,6 +1747,10 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
     bool pcie_port = pci_bus_is_express(pci_dev->bus) &&
                      !pci_bus_is_root(pci_dev->bus);
 
+    if (!kvm_has_many_ioeventfds()) {
+        proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;
+    }
+
     /*
      * virtio pci bar layout used by default.
      * subclasses can re-arrange things if needed.