SR-IOV capable PCIe cards are initially in “dedicated” operating mode. This corresponds to classic cards without SR-IOV support. The card must then be assigned to an LPAR (usually a virtual I/O server) and can only be used by this LPAR. Direct access from other LPARs is not possible.

A list of the SR-IOV capable PCIe adapters can be displayed with the help of the command “ms lssriov” (list SR-IOV):

$ ms lssriov ms03
PHYS_LOC                  SLOT_ID   CONFIG_STATE  SRIOV_STATUS  ADAPTER_ID  PHYS_PORTS  LOGICAL_PORTS
U78AA.001.VYRGU0Q-P1-C4   21010020  dedicated     null          null        null        null
U78AA.001.VYRGU0Q-P1-C6   2102001b  dedicated     null          null        null        null
U78AA.001.VYRGU0Q-P1-C11  21020013  dedicated     null          null        null        null
U78AA.001.VYRGU0Q-P1-C12  21030014  dedicated     null          null        null        null
$

There are 4 PCIe adapter cards in slots P1-C4, P1-C6, P1-C11 and P1-C12. All 4 cards are still in dedicated mode (column CONFIG_STATE). In order to be able to use the virtualization with SR-IOV, the cards must first be brought into the so-called “shared mode“. This is done with the help of the command “ms chsriov” (change SR-IOV), whereby the slot ID (column SLOT_ID) or a unique suffix of the physical location code must be specified:

$ ms chsriov ms03 21010020 shared
$ ms chsriov ms03 P1-C6 shared
$ ms chsriov ms03 21020013 shared
$ ms chsriov ms03 P1-C12 shared
$

Each SR-IOV adapter is assigned a unique adapter ID when switching to shared mode. The adapters are simply numbered consecutively. If you want to use a specific adapter ID for an adapter, you can use the adapter_id attribute:

$ ms chsriov ms03 21020013 shared adapter_id=1
$ ms chsriov ms03 P1-C6 shared adapter_id=2
$ ms chsriov ms03 21010020 shared adapter_id=3
$ ms chsriov ms03 P1-C12 shared adapter_id=4
$

When switching to shared mode, the adapters are reinitialized. This can take some time. Not all information is available while an adapter is initializing, as shown in the following output:

$ ms lssriov ms03
PHYS_LOC                  SLOT_ID   CONFIG_STATE  SRIOV_STATUS  ADAPTER_ID   PHYS_PORTS   LOGICAL_PORTS
U78AA.001.VYRGU0Q-P1-C4   21010020  sriov         initializing  unavailable  unavailable  unavailable
U78AA.001.VYRGU0Q-P1-C6   2102001b  sriov         running       2            4            48
U78AA.001.VYRGU0Q-P1-C11  21020013  sriov         initializing  unavailable  unavailable  unavailable
U78AA.001.VYRGU0Q-P1-C12  21030014  sriov         missing       unavailable  unavailable  unavailable
$

The adapter in slot P1-C6 is initialized and ready for operation (running), the two adapters in slot P1-C4 and P1-C11 are still initializing and the adapter in slot P1-C12 has not yet started initializing.

After a few seconds (usually less than a minute) all adapters are initialized and the output looks like this:

$ ms lssriov ms03
PHYS_LOC                  SLOT_ID   CONFIG_STATE  SRIOV_STATUS  ADAPTER_ID  PHYS_PORTS  LOGICAL_PORTS
U78AA.001.VYRGU0Q-P1-C11  21020013  sriov         running       1           4           48
U78AA.001.VYRGU0Q-P1-C6   2102001b  sriov         running       2           4           48
U78AA.001.VYRGU0Q-P1-C4   21010020  sriov         running       3           4           48
U78AA.001.VYRGU0Q-P1-C12  21030014  sriov         running       4           4           48
$

Each of the 4 adapters has 4 physical ports (column PHYS_PORTS) and support up to 48 logical ports (LOGICAL_PORTS). Logical ports can be created by the administrator, whereby these are then assigned to an LPAR at the same time. One of the available virtual functions is assigned to each logical port. The physical functions can only be used by the hypervisor. This ensures that LPARs cannot make any changes to the configuration of an SR-IOV adapter.