Re: [RFC v5][PATCH 3/4] intel_txt: Intel(R) TXT Sx shutdown support

From: Pavel Machek
Date: Sat Jun 27 2009 - 07:29:47 EST


On Mon 2009-06-22 17:41:38, Joseph Cihula wrote:
> Support for graceful handling of sleep states (S3/S4/S5) after an Intel(R) TXT launch.
>
> Without this patch, attempting to place the system in one of the ACPI sleep
> states (S3/S4/S5) will cause the TXT hardware to treat this as an attack and
> will cause a system reset, with memory locked. Not only may the subsequent
> memory scrub take some time, but the platform will be unable to enter the
> requested power state.
>
> This patch calls back into the tboot so that it may properly and securely clean
> up system state and clear the secrets-in-memory flag, after which it will place
> the system into the requested sleep state using ACPI information passed by the kernel.

I don't get this. In case of hibernation... how do you 'protect' the
data in memory?

This really needs big Documentation/ patch explaining the design
before it can be reviewed properly.

What does it protect? All kernel memory? How does it handle S3? Who
does encryption for hibernation?

--
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