Re: SSE related security hole

Doug Ledford (dledford@redhat.com)
Fri, 19 Apr 2002 14:00:31 -0400

On Fri, Apr 19, 2002 at 04:06:17PM +0200, Andi Kleen wrote:
> "H. Peter Anvin" <hpa@zytor.com> writes:
> >
> > Perhaps the right thing to do is to have a description in data of the
> > desired initialization state and just F[NX]RSTOR it?
>
> Sounds like the cleanest solution. The state could be saved at CPU bootup
> with just MXCSR initialized.
>
> I'll implement that for x86-64.

Ummm...last I knew, fxrstor is *expensive*. The fninit/xor regs setup is
likely *very* much faster. Someone should check this before we sacrifice
100 cycles needlessly or something.

-- 
  Doug Ledford <dledford@redhat.com>     919-754-3700 x44233
         Red Hat, Inc. 
         1801 Varsity Dr.
         Raleigh, NC 27606
  
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