CVS commit: [netbsd-10] src/sys/arch/x86

["Martin Husemann" <martin%netbsd.org@localhost>]

Module Name:    src
Committed By:   martin
Date:           Tue Jul 25 09:10:32 UTC 2023

Modified Files:
        src/sys/arch/x86/include [netbsd-10]: specialreg.h
        src/sys/arch/x86/x86 [netbsd-10]: errata.c

Log Message:
Pull up following revision(s) (requested by mrg in ticket #243):

        sys/arch/x86/include/specialreg.h: revision 1.207
        sys/arch/x86/x86/errata.c: revision 1.31

x86: turn off zenbleed chicken bit on Zen2 cpus.

this is based upon Taylor's original work.  i just made the list
of CPUs to run on correct as i could determine.  (also, add some
Zen3 and Zen4 cpuids not yet used by any errata.)

(might be nice to have a better way to expression revision ranges
rather than specific cpuid matches, eg, 0x30-0x4f models in a cpu
family, etc.)

tested on ryzen 3600, and a ported zenbleed PoC that no longer
shows any obtained text.  (a similar module-version of it stopped
the PoC on a ryzen 3950x without having to reboot.)

https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7008.html
https://lock.cmpxchg8b.com/zenbleed.html


To generate a diff of this commit:
cvs rdiff -u -r1.198.2.2 -r1.198.2.3 src/sys/arch/x86/include/specialreg.h
cvs rdiff -u -r1.27 -r1.27.4.1 src/sys/arch/x86/x86/errata.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.