From: Matt Wilson <msw@linux.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: xen-devel@lists.xenproject.org,
Roddy Rodstein <roddy.rodstein@mokumsolutions.com>
Subject: Re: Is there an issue with turning off "scrubbing free RAM" on boot with Xen 4.1.3
Date: Sun, 10 Nov 2013 14:25:11 -0800 [thread overview]
Message-ID: <20131110222511.GA22949@u109add4315675089e695.ant.amazon.com> (raw)
In-Reply-To: <52567676.3010102@citrix.com>
On Thu, Oct 10, 2013 at 10:42:14AM +0100, Andrew Cooper wrote:
> On 09/10/13 19:24, Roddy Rodstein wrote:
[...]
> > Could you please share your comments about turning of RAM scrubbing,
> > i.e. have you seen any consequences, security issues and/or threats,
> > red flags, etc...?
[...]
> In the Xen model, domains are responsible for clearing any sensitive
> data they have out of memory before shutdown.
This isn't strictly true. Memory is scrubbed by Xen when the domain
cannot do it for itself (i.e., when a domain is dying during
shutdown). However by default domains /are/ responsible for scrubbing
pages that are returned to Xen via a reservation adjustment (i.e.,
pages returned via the balloon driver).
--msw
> The bootscrub is a preventative measure to ensure that after a crash,
> stale domain information is cleared from RAM before that RAM is reused
> for a new VM.
>
> If this is not a concern for you, then you can easily turn bootscrub off
> by adding "no-bootscrub" to the Xen command line.
next prev parent reply other threads:[~2013-11-10 22:25 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-09 18:24 Is there an issue with turning off "scrubbing free RAM" on boot with Xen 4.1.3 Roddy Rodstein
2013-10-10 6:27 ` Pasi Kärkkäinen
2013-10-10 8:39 ` Simon Rowe
2013-10-10 8:47 ` Ian Campbell
2013-10-10 9:42 ` Andrew Cooper
2013-11-10 22:25 ` Matt Wilson [this message]
2013-11-11 10:14 ` Ian Campbell
2013-11-11 10:33 ` Jan Beulich
2013-11-11 10:47 ` Ian Campbell
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=20131110222511.GA22949@u109add4315675089e695.ant.amazon.com \
--to=msw@linux.com \
--cc=andrew.cooper3@citrix.com \
--cc=roddy.rodstein@mokumsolutions.com \
--cc=xen-devel@lists.xenproject.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;
as well as URLs for NNTP newsgroup(s).