Re: [Xen-devel] [PATCH] [RFC PATCH] xen: vmx: Use an INT 2 call to process real NMI's instead of self_nmi() in VMEXIT handler

[Tim Deegan <tim@xxxxxxx>]

Hi, 

Would need to go and read manuals to comment on much of this, but...

At 11:38 +0000 on 13 Nov (1352806689), Jan Beulich wrote:
> > diff -r 62885b3c34c8 -r ea756059a8da xen/arch/x86/hvm/vmx/vmx.c
> > --- a/xen/arch/x86/hvm/vmx/vmx.c
> > +++ b/xen/arch/x86/hvm/vmx/vmx.c
> > @@ -2442,7 +2442,7 @@ void vmx_vmexit_handler(struct cpu_user_
> >                   (X86_EVENTTYPE_NMI << 8) )
> >                  goto exit_and_crash;
> >              HVMTRACE_0D(NMI);
> > -            self_nmi(); /* Real NMI, vector 2: normal processing. */
> > +            asm("int $2"); /* Real NMI, vector 2: normal processing. */
> 
> In any case - why can't you call do_nmi() directly from here?

... this is my doing.  There used to be a call to do_nmi() here, but
do_nmi() doesn't block NMIs, so you can't just call it here in case you
get _another_ NMI while you're in the NMI handler.

Tim.

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