Re: [patch 1/2] x86_64 page fault NMI-safe

[Avi Kivity]

On 07/18/2010 09:22 PM, Linus Torvalds wrote:
> On Sun, Jul 18, 2010 at 11:04 AM, Avi Kivity<avi@xxxxxxxxxx>  wrote:
>    
> > Too simple - an MCE will switch to its own stack, failing the test.  Now
> > that we have correctable MCEs, that's not a good idea.
> >      
> Ahh, true. And I think we do DEBUG traps with IST too.
>
> So we do need the explicit flag over the region. Too bad. I was hoping
> to handle the nested case without having to set up the percpu segment
> (that whole conditional swapgs thing, which is extra painful in NMI).
>    

Well, we have to do that anyway for the non-nested case.  So we just do 
it before checking whether we're nested or not, and undo it on the popf; 
retf path.

--
error compiling committee.c: too many arguments to function

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