How can I passthrough PCI devices that are not listed?

Hi all,

I want to passthrough my on-board sound card to a VM, but the sound card does not show up in the list of PCI devices.

Is it possible to add devices to the list?

I also would like to passthrough on USB controller that is also not showing up.

My hardware is Gigabyte MB 990FXA-UD3 with a FX-8120.

I succefully passed through 2 AMD Radeon video cards to 2 diferent VMs.

Thanks