lkml.org 
[lkml]   [2018]   [Jan]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 6/7] x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature
From
Date
On 01/04/2018 10:33 AM, Borislav Petkov wrote:
>> 2. At run time
>> echo 0 > /sys/kernel/debug/ibrs_enabled will turn off IBRS
>> echo 1 > /sys/kernel/debug/ibrs_enabled will turn on IBRS in kernel
>> echo 2 > /sys/kernel/debug/ibrs_enabled will turn on IBRS in both userspace and kernel
> I am not sure that tristate is really needed. What's wrong with on/off
> only?

Lots of things:

Distros have the tri-state already deployed.
Paranoid people want "IBRS always" aka "ibrs 2".
Future CPUs may have cheap-enough IBRS to not be worth switching it.

\
 
 \ /
  Last update: 2018-01-04 19:37    [W:0.209 / U:0.544 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site