Always reserve root complexes pci_1, pci_17, pci_33, and pci_49 for use by the control domain. Never assign these root complexes to a non-primary domain. Control domains use paths through these reserved root complexes to maintain synchronized lists of faults in the PDomain host and the active SP.
Caution - If a control domain cannot access the reserved root complexes, it cannot synchronize the FMA fault lists. You will not be warned if this failure occurs.
These reserved root complexes are part of private internal networks (interconnects) that connect DCUs and SPPs to the SPs.
If a PDomain has more than one DCU, the PDomain's interconnect uses only one of these paths. However, any SPP can become a Pdomain-SPP, so all root complexes in a PDomain must continue to be owned by the control domain.
Caution - Do not assign an empty DCU to a PDomain. If the system selects the SPP for the empty DCU to be the PDomain-SPP, the DCU-to-SP interconnect will fail, and FMA fault lists on the host and the SP will be unsynchronized.
Note - You can assign PCIe slot 2 in a fully-populated DCU to a non-primary domain. The adapter card in that slot must support DIO. Similarly, in a half-populated DCU, you can assign both slots 1 and 2 to non-primary domains. For details, see the Oracle VM Server for SPARC 3.1 Administration Guide, creating an I/O domain by assigning PCIe endpoint devices at: http://www.oracle.com/goto/VM-SPARC/docs.