On Tue, 29 Apr 2014 06:29:04 -0700
"H. Peter Anvin" <h...@linux.intel.com> wrote:

 
> > [2]         "A special case can occur if an SMI handler nests inside an NMI 
> >      handler and then another NMI occurs. During NMI interrupt 
> >      handling, NMI interrupts are disabled, so normally NMI interrupts 
> >      are serviced and completed with an IRET instruction one at a 
> >      time. When the processor enters SMM while executing an NMI 
> >      handler, the processor saves the SMRAM state save map but does 
> >      not save the attribute to keep NMI interrupts disabled. 
> >      Potentially, an NMI could be latched (while in SMM or upon exit) 
> >      and serviced upon exit of SMM even though the previous NMI  
> >      handler has still not completed."
> 
> I believe [2] only applies if there is an IRET executing inside the SMM
> handler, which should not normally be the case.  It might also have been
> addressed since that was written, but I don't know.

Bad behaving BIOS? But I'm sure there's no such thing ;-)

-- Steve

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