CSRSI — System information service

Use the CSRSI service to retrieve system information. You can request information about the machine itself, the logical partition (LPAR) in which the machine is running, or the virtual machine hypervisor (VM) under which the system is running. The returned information is mapped by DSECTs in macro CSRSIIDF (for assembler language callers) or structures in header file CSRSIC (for C language callers).

The information available depends upon the availability of the Store System Information (STSI) instruction. When the STSI instruction is not available (which would be indicated by receiving the return code 4 (equate symbol CSRSI_STSINOTAVAILABLE), only the SI00PCCACPID, SI00PCCACPUA, and SI00PCCACAFM fields within the returned infoarea are valid. When the STSI instruction is available, the validity of the returned infoarea depends upon the system:

If the system is running neither under LPAR nor VM, then only the CSRSI_Request_V1CPC_Machine data are valid.
If the system is running under a logical partition (LPAR), then both the CSRSI_Request_V1CPC_Machine data and CSRSI_Request_V2CPC_LPAR data are valid.
If the system is running under a virtual machine hypervisor (VM), then all of the data (CSRSI_Request_V1CPC_Machine, CSRSI_Request_V2CPC_LPAR, and CSRSI_Request_V3CPC_VM) are valid.

You can request any or all of the information regardless of your system, and validity bits will indicate which returned areas are valid.