LKML Archive on lore.kernel.org
 help / Atom feed
* Linux on Intel x86: How to disable Hyperthreading
@ 2018-06-23 10:57 Martin Steigerwald
  0 siblings, 0 replies; 1+ messages in thread
From: Martin Steigerwald @ 2018-06-23 10:57 UTC (permalink / raw)
  To: LKML; +Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86

Cc´d people for X86 architecture in MAINTAINERS.


Hi!

According to

https://www.kuketz-blog.de/tlbleed-neue-sicherheitsluecken-bei-intel-cpus/

in

https://www.blackhat.com/us-18/briefings/schedule/#tlbleed-when-protecting-your-cpu-caches-is-not-enough-10149

(Firefox and Chromium with current settings and add-ons webbrowsers do 
not display the contents of the page)

one can read:

> Our TLBleed exploit successfully leaks a 256-bit EdDSA key from
> libgcrypt (used in e.g. GPG) with a 98% success rate after just a
> single observation of signing operation on a co-resident hyperthread
> and just 17 seconds of analysis time.\0


And this probably would explain the disabling of it in OpenBSD.

What is your take on this?


Also how would you disable it in case you would?

I currently test run with the script I found on:

https://serverfault.com/questions/235825/disable-hyperthreading-from-within-linux-no-access-to-bios

Just to see whether I notice a significant performance drop.

Thanks.
-- 
Martin

^ permalink raw reply	[flat|nested] 1+ messages in thread

only message in thread, back to index

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-06-23 10:57 Linux on Intel x86: How to disable Hyperthreading Martin Steigerwald

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org linux-kernel@archiver.kernel.org
	public-inbox-index lkml


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox