[libvirt-users] how to control usb read write perm

hi,all i have 2 questions. both is related to spice usb redirect. 1. if i can control RW perm of usb device which is producted via spice ? in order to control user's rw operation in guestVM . 2.if user have several usbs, and plug them at the same time when using spice client. if i can control which usb(s) can be accessed by user in guestVM? thanks