CVS commit: [netbsd-8] src/sys/arch/x86

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

Module Name:    src
Committed By:   martin
Date:           Tue Jul 25 09:15:28 UTC 2023

Modified Files:
        src/sys/arch/x86/include [netbsd-8]: specialreg.h
        src/sys/arch/x86/x86 [netbsd-8]: errata.c

Log Message:
Pull up following revision(s) (requested by mrg in ticket #1851):

        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 -r1.98.2.26 -r1.98.2.27 src/sys/arch/x86/include/specialreg.h
cvs rdiff -u -r1.23.10.1 -r1.23.10.2 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.