RE: [Xen-devel] more segment/selector handling woes

To:	"Jan Beulich" <jbeulich@xxxxxxxxxx>
Subject:	RE: [Xen-devel] more segment/selector handling woes
From:	"Petersson, Mats" <Mats.Petersson@xxxxxxx>
Date:	Thu, 23 Nov 2006 14:06:06 +0100
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Thread-topic:	[Xen-devel] more segment/selector handling woes

> Note the wording 'as if' - this doesn't tell me whether the 
> internal base
> address field (which gets stored to the vmcb) can indeed be 
> relied upon.
> But obviously the code would be simpler if that was the case 
> in reality
> (and then perhaps the documentation could be updated accordingly).

Indeed, you're right: You need to check if the processor is in 64-bit
mode and if so, return base as zero, as the base value may not be zero
when the processor is storing it. This is so that 64-bit OS's can load a
32-bit segment before jumping to the actual code. 

I just got this confirmed by Ben Serebrin... 

--
Mats



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RE: [Xen-devel] more segment/selector handling woes