Nova/USB device&USB controller

USB device and USB controller Features

Background

Currently, nova has already supported pci-passthrough, but still dosen't support usb-passthrough. In fact usb device is a kind of necessary device in some user scenarios in private cloud.

Use case

1. When i transfer money online, i need a usb-key provided by bank for authentication.
2. When i start a erp software,  i need a usb-key provided by software provider for authentication.
3. I need a usb data disk for transferring business data.