An I/O domain has direct ownership of and direct access to physical I/O devices. It can be created by assigning a PCI EXPRESS (PCIe) bus, a PCIe endpoint device, or a PCIe SR-IOV virtual function to a domain. Use the ldm add-io command to assign a bus, device, or virtual function to a domain.
You might want to configure I/O domains for the following reasons:
An I/O domain has direct access to a physical I/O device, which avoids the performance overhead that is associated with virtual I/O. As a result, the I/O performance on an I/O domain more closely matches the I/O performance on a bare-metal system.
An I/O domain can host virtual I/O services to be used by guest domains.
For information about configuring I/O domains, see the information in the following chapters: