From: "H. Peter Anvin" <hpa@zytor.com>
To: "Theodore Ts'o" <tytso@mit.edu>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@amacapital.net>,
linux-kernel@vger.kernel.org, x86@kernel.org,
Andrew Lutomirski <luto@mit.edu>
Subject: Re: [PATCH v5] x86: Enable fast strings on Intel if BIOS hasn't already
Date: Wed, 01 May 2013 09:42:30 -0700 [thread overview]
Message-ID: <518145F6.3060800@zytor.com> (raw)
In-Reply-To: <20130501163404.GA6286@thunk.org>
On 05/01/2013 09:34 AM, Theodore Ts'o wrote:
>
> In fact, there is the question of whether we should be checking to see
> if the CPU stepping is one of the ones with the bug, and if so, to
> have Linux disable fast strings even if the BIOS didn't, instead of
> blindly enabling fast strings....
>
The erratum reads seriously, but it only affects crossings between pages
of different page types, which is rare in itself. WT and WP are not
even used in Linux; the UC case we end up doing 8-byte stores instead of
the proper size, which is wrong, but for the case where the user is
malicious the user could just do that directly, and it seems extremely
hard to envision a scenario where someone would do that intentionally.
-hpa
next prev parent reply other threads:[~2013-05-01 17:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-01 5:46 [PATCH v5] x86: Enable fast strings on Intel if BIOS hasn't already Andy Lutomirski
2013-05-01 11:15 ` Ingo Molnar
2013-05-01 11:33 ` Borislav Petkov
2013-05-01 16:34 ` Theodore Ts'o
2013-05-01 16:42 ` H. Peter Anvin [this message]
2013-05-01 16:54 ` Andy Lutomirski
2013-05-01 17:35 ` H. Peter Anvin
2013-05-01 17:50 ` Andy Lutomirski
2013-05-01 17:54 ` H. Peter Anvin
2013-05-01 18:18 ` Andy Lutomirski
2013-05-10 8:25 ` Ingo Molnar
2013-05-01 17:20 ` Theodore Ts'o
2013-05-01 17:35 ` H. Peter Anvin
2013-05-01 16:51 ` Andi Kleen
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=518145F6.3060800@zytor.com \
--to=hpa@zytor.com \
--cc=bp@alien8.de \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=luto@mit.edu \
--cc=tytso@mit.edu \
--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