That reference is specific to the 370/145.Different processors often have different internal organizations. The only constraint is that they comply with PoOps.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [[email protected]] on behalf of Joe Monk [[email protected]] Sent: Wednesday, November 23, 2022 8:29 AM To: [email protected] Subject: Re: Storage protection keys I know this is super old information ... but given the discussion so far, it seems reasonable to at least apply the same concept ... "The storage-protect unit has a 64 x 8 monolithic storage protection stack that applies to main storage locations zero through 131,072 (in sequential blocks of 2,048 bytes). Additional stacks are provided in the CPU when main storage capacity extends from 131,072 bytes to 524,288 bytes. Above 524,288 bytes, storage protect is located in the Power Frame (03) and is a mix of 64 x 8 and 64 x 18 monolithic storage cards." http://secure-web.cisco.com/1LBqXotawj836-18u8teDXi0B2Q2pc7P5E97FaeGGyjshS9rUdHkRVsgNbHNwh4vIuRE7h0uEH8BoUyd7eoKyI0USUSFeWzyuHTBB9knDrYKBH4dHP_6PiU74eQ-NHygvEppCGZXjwUzLCiPCVyszh57_xpF81ZNjfuoKhQkkm-8lWOctHpHzbk6lLsfdL-kmaWxCws6QAtKNw1i91JTJ9skSs1uoRzKxKdgbh1xUnDrtQyLJLAuHx4re169Rvabn6uVKrRCXaNRjH493eG-lg_xFt0CF7kGEwBW9uoloHkDA4KJM1QxnY-i1VEno4frfnwpoCTtK251EIXkbyTIUCKR_bQmrA3BQcEY5zumxEOfT3mwX4qEJWUwmI3237Rgief_KoncnFrUXfMT9rznhAX3MrLi4UsqagHvS2Ck_V5eS__nl-v4MzO1Dosd3m3wg/http%3A%2F%2Fwww.bitsavers.org%2Fpdf%2Fibm%2F370%2Ffe%2F3145%2FSY24-3581-4_3145_Processor_Theory_Maintenance.pdf Joe On Wed, Nov 23, 2022 at 6:56 AM Jay Maynard <[email protected]> wrote: > Well, you have to store the key *somewhere* when the page is paged out. But > you're right, the page table entry isn't it. I don't know what I was > thinking. > > I'm sure that VSM maintains its own table of correspondence between virtual > storage addresses and storage key, so the key can be applied to the page > upon page-in, but I don't know the details. > > On Wed, Nov 23, 2022 at 4:12 AM Ian Worthington < > [email protected]> wrote: > > > Many thanks for that Jay. This would certainly seem the logical place to > > store it. > > > > I'm still a bit confused though. The pop section on Page-Table Entries > > (page 3-51 in the 13th edition...) does not mention this (though it does > > have a unused byte at the end). If the intention is to make the storage > > key unaddressable (p 3-9) and alterable only via SSKE (which, given the > > need to propagate it to the caches of all processers would seem make > sense) > > would it not be contraindicated to use this byte to keep it in? > > > > I'd love to see a paper or article which discusses how this is done, > > though, like cpu design, I appreciate it may well change from model to > > model. > > > > > > Best wishes > > > > Ian ... > > > > On Tuesday, November 22, 2022 at 05:28:37 PM GMT+1, Jay Maynard < > > [email protected]> wrote: > > > > They are held in the page tables and set in the hardware - in extra > memory > > that is not software accessible except through a few supervisor-level > > instructions such as SSK (set storage key) - when the page is assigned > to a > > real storage frame. > > > > On Tue, Nov 22, 2022 at 10:24 AM Ian Worthington < > > [email protected]> wrote: > > > > > I don't think the storage keys (and their friends) are held in the page > > > tables though. > > > > > > > > > Best wishes / Mejores deseos / Meilleurs vœux > > > > > > Ian ... > > > > > > On Tuesday, November 22, 2022 at 05:04:08 PM GMT+1, Jay Maynard < > > > [email protected]> wrote: > > > > > > Each page table entry has a byte associated with it that stores the > key, > > > as > > > well as the referenced and changed bits. > > > > > > And yes, 4K page tables do soak up lots of memory, which is why later > > OSes > > > use 1M or 2M pages. > > > > > > On Tue, Nov 22, 2022 at 9:22 AM Ian Worthington < > > > [email protected]> wrote: > > > > > > > Does anyone know where the storage protection keys are kept? It > seems > > > > that the processors maintain recent keys in the TLB to be accessed by > > the > > > > DAT, but where do they live when they're not in the TLB? Surely we > > need > > > > one byte per 4k page per address space, which could be quite a bit of > > > > storage, so I'm assuming this has to be above the bar now? I can't > see > > > any > > > > information in the pop about this. > > > > > > > > > > > > Best wishes / Mejores deseos / Meilleurs vœux > > > > > > > > Ian ... > > > > > > > > > ---------------------------------------------------------------------- > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > > send email to [email protected] with the message: INFO > IBM-MAIN > > > > > > > > > > > > > -- > > > Jay Maynard > > > > > > ---------------------------------------------------------------------- > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > > > > > ---------------------------------------------------------------------- > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > > > > > -- > > Jay Maynard > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > -- > Jay Maynard > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
