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

["Cihula, Joseph" <joseph.cihula@xxxxxxxxx>]

On Monday, October 29, 2007 11:05 AM, Keir Fraser wrote:
> On 29/10/07 18:00, "Cihula, Joseph" <joseph.cihula@xxxxxxxxx> wrote:
> 
>>> By low memory, do you mean the signature is in the bottom megabyte
of
>>> memory? If that's guaranteed then can we just scan the whole lot
>>> 0x00000-0xfffff (excluding VGA hole)?
>> 
>> Yes, it's in the lower 1MB and that is where dom0 has problems with
>> gaps.  But I think that the UNUSABLE->RESERVED approach will be just
as
>> effective and reduce the amount of memory to scan as well.
> 
> 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.

Joe

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