From: Pavel Machek <pavel@ucw.cz>
To: Joseph Cihula <joseph.cihula@intel.com>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
arjan@linux.intel.com, hpa@zytor.com, andi@firstfloor.org,
chrisw@sous-sol.org, jmorris@namei.org, jbeulich@novell.com,
peterm@redhat.com, gang.wei@intel.com, shane.wang@intel.com
Subject: Re: [RFC v5][PATCH 2/4] intel_txt: Intel(R) TXT reboot/halt shutdown support
Date: Wed, 24 Jun 2009 17:04:53 +0200 [thread overview]
Message-ID: <20090624150453.GJ1784@ucw.cz> (raw)
In-Reply-To: <4A4024BE.5090206@intel.com>
On Mon 2009-06-22 17:41:34, Joseph Cihula wrote:
> Support for graceful handling of kernel reboots after an Intel(R) TXT launch.
>
> Without this patch, attempting to reboot or halt the system will cause the
> TXT hardware to lock memory upon system restart because the secrets-in-memory
> flag that was set on launch was never cleared. This will in turn cause BIOS
> to execute a TXT Authenticated Code Module (ACM) that will scrub all of memory
> and then unlock it. Depending on the amount of memory in the system and its type,
> this may take some time.
>
> This patch creates a 1:1 address mapping to the tboot module and then calls back
> into tboot so that it may properly and securely clean up system state and clear
> the secrets-in-memory flag. When it has completed these steps, the tboot module
> will reboot or halt the system.
Is it faster to clean memory from OS as opposed to bios doing the
clearing? If so, why?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
prev parent reply other threads:[~2009-06-27 11:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-23 0:41 [RFC v5][PATCH 2/4] intel_txt: Intel(R) TXT reboot/halt shutdown support Joseph Cihula
2009-06-24 10:46 ` James Morris
2009-06-24 15:04 ` Pavel Machek [this message]
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