WARNING: Intel Skylake/Kaby Lake processors: broken hyper-threading

WARNING: Intel Skylake/Kaby Lake processors: broken hyper-threading

By | June 26th, 2017
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These are: the 6th and 7th generation Intel Core processors (desktop,

embedded, mobile and HEDT), their related server processors (such as Xeon

v5 and Xeon v6), as well as select Intel Pentium processor models.


														
							
Kaby Lake:

Users of systems with Intel Kaby Lake processors should immediately
*disable* hyper-threading in the BIOS/UEFI configuration.  Please
consult your computer/motherboard's manual for instructions, or maybe
contact your system vendor's support line.

The Kaby Lake microcode updates that fix this issue are currently only
available to system vendors, so you will need a BIOS/UEFI update to get
it.  Contact your system vendor: if you are lucky, such a BIOS/UEFI
update might already be available, or undergoing beta testing.

You want your system vendor to provide a BIOS/UEFI update that fixes
"Intel processor errata KBL095, KBW095 or the similar one for my Kaby
Lake processor".

We strongly recommend that you should not re-enable hyper-threading
until you install a BIOS/UEFI update with this fix.


Skylake:

Users of systems with Intel Skylake processors may have two choices:

1. If your processor model (listed in /proc/cpuinfo) is 78 or 94, and
   the stepping is 3, install the non-free "intel-microcode" package
   with base version 3.20170511.1, and reboot the system.  THIS IS
   THE RECOMMENDED SOLUTION FOR THESE SYSTEMS, AS IT FIXES OTHER
   PROCESSOR ISSUES AS WELL.

   Run this command in a command line shell (e.g. xterm) to know the
   model numbers and steppings of your processor.  All processors must
   be either model 78 or 94, and stepping 3, for the intel-microcode fix
   to work:

         grep -E 'model|stepping' /proc/cpuinfo | sort -u

   If you get any lines with a model number that is neither 78 or 94, or
   the stepping is not 3, you will have to disable hyper-threading as
   described on choice 2, below.

   Refer to the section "INSTALLING THE MICROCODE UPDATES FROM NON-FREE"
   for instructions on how to install the intel-microcode package.

2. For other processor models, disable hyper-threading in BIOS/UEFI
   configuration.  Please consult your computer/motherboard's manual for
   instructions on how to do this.  Contact your system vendor for a
   BIOS/UEFI update that fixes "Intel erratum SKW144, SKL150, SKX150,
   SKZ7, or the similar one for my Skylake processor".

Source
Google
Nisheeth Bhakuni