Re: [Syllable-kernel] Syllable security and "trusted computing"

[Daniel G. <da...@fp...>]

On Fri, 2005-04-29 at 08:52 -0700, Kip Macy wrote:
> > Microsoft/Intel "trusted computing" initiative.
> > 
> > First, every UNIX OS as well as Windows uses only two of the four
> > "rings" of protection on x86.  The kernel and all modules run in Ring 0
> > and all user programs run in Ring 3.  Ring 0 can bypass all protections.
> >   What's interesting about the special hardware support that is being
> > added for "Palladium" (what Intel calls "LaGrande Technology", or LT),
> > is that they've essentially had to add a new "Ring -1" that is more
> > privileged than the layer at which the normal operating system runs, in
> > order to be able to assure the privacy and security that Windows itself
> > is apparently not able to provide.  This is stupid:  if we have Rings 1
> 
> No it isn't, it is necessary if they are to support running Windows
> _unmodified_ on top of a hypervisor. See VT-x.
> 

Aside from that, rings 1 and 2 don't really exist anymore, because
they're not there in amd64.  This means that, for all intents and
purposes, you cannot depend on them.  Within 2 years, x86 as such won't
exist anymore, and all processors sold will be amd64.

Daniel