Messages in this thread | | | Date | Wed, 23 Nov 2016 17:55:25 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v2] x86/mce: Include the PPIN in machine check records when it is available |
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On Wed, Nov 23, 2016 at 08:42:40AM -0800, Tony Luck wrote: > If the BIOS writes 10b, then PPIN is disabled and will remain so until > the processor is reset. Bit 1 is a one way trip, it can be set by s/w, > but not cleared again.
10b means bit 1, i.e., Enable_PPIN is set, right? Which actually *enables* PPIN. Or am I confused again?
Otherwise, this explains the "Once set" wording - if Enable_PPIN is 1, there's no changing until next reboot.
> All this is because of the huge stink last time Intel tried to add > a serial number to CPUs a decade and a half ago.
It certainly rang a bell when you sent v1. :-)
> The lockout bit is so that this can be turned off in a way that you > can be sure that it can't be turned on again.
... in order to protect ourselves from root doing wrmsr? Or why are we doing this?
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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