usb: make attach optional.

Add a auto_attach field to USBDevice, which is enabled by default.
USB drivers can clear this field in case they do *not* want the device
being attached (i.e. plugged into a usb port) automatically after
successfull init().

Use cases (see next patches):
 * attaching encrypted mass storage devices.
 * -usbdevice host:...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/hw/usb.h b/hw/usb.h
index a875d5b..a01f334 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -133,6 +133,7 @@ struct USBDevice {
     int speed;
     uint8_t addr;
     char devname[32];
+    int auto_attach;
     int attached;
 
     int state;