Eric Rossman wrote: >The CPACF is a physically separate chip that runs in lockstep >with the CP that invokes it. So, it is does cost general CP but >much less than implementing it in millicode.
Actually, every processor core includes its own CPACF coprocessor section. In other words, CPACF is “on core.” That includes CPs (general purpose processor cores), IFLs, zIIPs, and all the other main processor core types.(*) You can see a design illustration of this arrangement in IBM Redbook SG24-8951 (“IBM z16 Technical Guide”) in Figure 3-13. If your processor core is configured for SMT2 (typical with zIIPs and IFLs) then the CPACF section will also operate in SMT2 mode. Said another way, every processor core thread has its own CPACF section thread. Really the only thing you need to worry about in terms of having CPACF available is to make sure that Feature Code 3863 is installed on your system. FC 3863 is a zero additional charge feature. It’s available in almost every country and territory, but apparently there are one or a couple odd places with peculiar import regulations. Those few places may still allow FC 3863 but may require some sort of permit or other legal paperwork. Ordinarily your IBM representative or IBM business partner will add FC 3863 to your machine order reflexively in the countries/territories where there’s no local regulatory issue. But that’s something to double check. If you don’t have FC 3863 installed then CPACF still partially works, but it only provides hashing and random number functions. FC 3863 enables the full range of CPACF algorithms/instructions including encrypt/decrypt. (*) I think those other processor types also use CPACF instructions from time to time, if available. For example, the Coupling Facility Control Code (CFCC) likely uses CPACF instructions (if FC 3863 is present) when you configure encryption-related functions to strengthen a CF’s security posture. ————— Timothy Sipples Senior Architect Digital Assets, Industry Solutions, and Cybersecurity IBM Z/LinuxONE, Asia-Pacific [email protected] ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
