I suspect I know the answer here, but is qemu-kvm-0.12 simply incapable of passing a USB 3.0 device to a guest? USB 2 devices work fine, but USB 3 — nothing. USB 3.0 works fine in the host, of course.
Currently using qemu-kvm-0.12.1.2-2.479.el6_7.4.x86_64 in CentOS 6.7.
I’m guessing I have to upgrade to CentOS 7 to pass USB 3.0 devices to the guest. Hoping to avoid that just now.