BIOS option for AMD platform :
1) IOMMU: Advanced >> Advanced Chipset Control >> NorthBridge Configuration >> IOMMU >> Enabled.
2) SR-IOV: Advanced >>PCI/PnP Configuration >> SR-IOV Supported >> Enabled.

Enabling SR-IOV : Can let a physical network adapter be assigned directly to a virtual machine.
Enabling IOMMU : Is used to remap physical memory addresses to the addresses that are used by VMs. Which made your VM access memory directly, and could enhance VM performance.

Intel provides a guide to setup SR-IOV for X540, 82599 10Gb, I350 and 82576. Please note that the NIC which supported SR-IOV must connect to the CPU PCIe link (or add-on card from CPU PCIe slots).
http://www.intel.com/content/dam/www/public/us/en/documents/technology-briefs/ethernet-sr-iov-microsoft-windows-brief.pdf