Re: [Xen-devel] [PATCH] Intel(R) Trusted Execution Technology support

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 29/10/07 18:34, "Cihula, Joseph" <joseph.cihula@xxxxxxxxx> wrote:

>> Okay, we should limit the scan to page-aligned addresses in UNUSABLE
> regions
>> below 1MB. It makes sense to put the UNUSABLE->RESERVED hack in Xen
> itself,
>> rather than in tboot. Once the interface is baked into 3.2.0 it's not
>> changing on our side.
> 
> I'd like to allow for the shared page to be moved to a higher memory
> location in the future, so I'd prefer not to limit the search to below
> 1MB.  Since only tboot is using the UNUSABLE type and it should find the
> shared page in the first UNUSABLE section anyway (whether it gets moved
> or not), the search should still be quick.  Also, I'll only change the
> type from UNUSABLE->RESERVED if it is found in the lower 1MB.

Actually I have a better idea to avoid the scan entirely. tboot should
append 'tboot=<address of shared area>' to Xen's command line (e.g.,
tboot=0x71000). This gives a better more guaranteed handoff from tboot to
Xen, it avoids the user needing to manually add any options to Xen's command
line (we can make tboot= imply no-real-mode), and means that rather than
doing a scan we simply need to confirm the UUID is at the given address.

I can easily do the Xen side of this if you agree it makes sense.

 -- Keir



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