From mboxrd@z Thu Jan  1 00:00:00 1970
From: Juergen Gross <juergen.gross@ts.fujitsu.com>
Subject: Re: c/s 21886 change to DMAR table hiding
Date: Fri, 29 Oct 2010 08:54:27 +0200
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To: "Cihula, Joseph" <joseph.cihula@intel.com>
Cc: "Wang, Shane" <shane.wang@intel.com>, Xen-devel <xen-devel@lists.xensource.com>, "Kay,
	Allen M" <allen.m.kay@intel.com>, Keir Fraser <keir.fraser@eu.citrix.com>
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On 10/29/10 08:06, Cihula, Joseph wrote:
> Keir,
>
> In c/s 21886, you changed the method by which the DMAR ACPI table was hidden from dom0.  Why was this change needed?
> -    dmar->header.signature[0] = '\0';
> +    dmar->header.signature[0] = 'X';
> +    dmar->header.checksum -= 'X'-'D';
>
> I ask because tboot was using the original method to unhide/re-hide the table during S3 (because the TXT launch on S3 resume requires a valid DMAR table) and this has broken S3 w/ TXT.

Please see discussion under
http://lists.xensource.com/archives/html/xen-devel/2010-07/msg01517.html

Problem was crash kernel not comig up with the original DMAR hide.


Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
TSP ES&S SWE OS6                       Telephone: +49 (0) 89 3222 2967
Fujitsu Technology Solutions              e-mail: juergen.gross@ts.fujitsu.com
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