Hello, Qemu upstream had achieved USB Passthrough Device Autoconnect Feature for the guest. Such as a USB device is unplugged from the host then plugged back in to the same USB physical port. the patch was: https://lists.gnu.org/archive/html/qemu-devel/2011-05/msg02341.html However, Libvirt has not provided such an interface that identifies a USB device for pass through with physical port, rather than the device number. Do you have any ideas or plans about this problem? Thanks in advance. Best Regards, -WangYufei