CVS commit: src/sys/arch/x86

["matthew green" <mrg%netbsd.org@localhost>]

Module Name:    src
Committed By:   mrg
Date:           Tue Jul 25 01:09:05 UTC 2023

Modified Files:
        src/sys/arch/x86/include: specialreg.h
        src/sys/arch/x86/x86: errata.c

Log Message:
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 -r1.206 -r1.207 src/sys/arch/x86/include/specialreg.h
cvs rdiff -u -r1.30 -r1.31 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.