From: Martin Steigerwald <martin@lichtvoll.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org
Subject: Linux on Intel x86: How to disable Hyperthreading
Date: Sat, 23 Jun 2018 12:57:18 +0200 [thread overview]
Message-ID: <1554914.aCy3vs9hif@merkaba> (raw)
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
reply other threads:[~2018-06-23 10:57 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1554914.aCy3vs9hif@merkaba \
--to=martin@lichtvoll.de \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox