CVSROOT: /cvs
Module name: src
Changes by: j...@cvs.openbsd.org 2025/09/09 18:07:29
Modified files:
sys/arch/i386/i386: machdep.c
Log message:
correct family test when setting Zenbleed chicken bit on i386
For AMD Zen 2 based systems a microcode update is the preferred way of
mitigating Zenbleed. An MSR to set a chicken bit is another way. The
CPU family test around this MSR was wrong.
When testing for CPU family 0x17 the extended value must be checked.
A non-extended family id of 0x17 is impossible as the mask is & 15.
So the previous test would never match.
In i386 identifycpu(), the function local family variable is always the
non-extended value. This problem does not apply to amd64. The amd64
change to move this part of identifycpu() to cpu_fix_msrs() uses an
extended family id.
ok bluhm@ deraadt@ mlarkin@
