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 or a PCIe endpoint device to a domain. Use the ldm add-io command to assign a bus or device 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 other guest domains.
For information about configuring I/O domains, see the following:
Note - You cannot migrate an I/O domain that is configured with PCIe endpoint devices. For information about other migration limitations, see Chapter 9, Migrating Domains.