From: Paolo Bonzini <pbonzini@redhat.com>
To: Dave Hansen <dave.hansen@linux.intel.com>, linux-kernel@vger.kernel.org
Cc: x86@kernel.org, luto@amacapital.net, ak@linux.intel.com,
jun.nakajima@intel.com, tim.c.chen@linux.intel.com,
arjan@linux.intel.com, dwmw2@infradead.org, keescook@google.com
Subject: Re: [PATCH] x86/kvm: clear RSB before VMENTER to obscure host addresses
Date: Mon, 5 Feb 2018 15:19:23 +0100 [thread overview]
Message-ID: <6196469d-9766-faef-563d-e278dc92e4e2@redhat.com> (raw)
In-Reply-To: <20180202211028.0A49AAAD@viggo.jf.intel.com>
On 02/02/2018 22:10, Dave Hansen wrote:
> I'm posting this because I went to the trouble of hacking it together
> and writing up a pretty lengthy description of what it does and where
> it _might_ have benefit. But, I'm rather unconvinced that mitigation
> of attacks on ASLR has a lot of value because of how many other
> attacks on ASLR there are.
>
> Thus, the RFC.
I'm a bit afraid that this would be pretty expensive for just an ASLR
attack.
The cost of stuffing the RSB once is about 60 clock cycles, and if you
do it twice we're spending 10-15% of vmexit time (for the low-latency
cases that matter) on RSB stuffing.
Paolo
prev parent reply other threads:[~2018-02-05 14:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-02 21:10 Dave Hansen
2018-02-05 14:19 ` Paolo Bonzini [this message]
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=6196469d-9766-faef-563d-e278dc92e4e2@redhat.com \
--to=pbonzini@redhat.com \
--cc=ak@linux.intel.com \
--cc=arjan@linux.intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=dwmw2@infradead.org \
--cc=jun.nakajima@intel.com \
--cc=keescook@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=tim.c.chen@linux.intel.com \
--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
Powered by JetHome