Re: nmi is broken?

[Avi Kivity <avi@redhat.com>]

On 05/01/2011 04:45 AM, OGAWA Hirofumi wrote:
> >
> >  Hm.., if smp was enabled, what configuration model is used by kvm? I
> >  think this configuration model can't work on smp.
>
> As far as I can see, kvm is not configured (from MADT and some of
> behaviors) like you said.

We may well have an error there; and our NMI-from-PIT emulation bypasses 
all the wiring I described, so we may be emulating a configuration that 
can't possibly exist on hardware.

> So, I think there are some solutions, a) current behavior is right (I
> don't know why it's right though), b) fix the behavior of IO-APIC and
> MADT like you said, then linux can detect it, c) change the model to
> like mpspec figure 5-2, d) other.
>
> My suggestion is c) if there is no good d). Because current behavior
> looks like almost c), and non-legacy chipsets are using c) model as far
> as I know.

You're probably right.  However we can't just change it, we need to make 
it an option, keeping the current configuration as the default.  This is 
so that live migration can work, and because 5-2 requires a new 
kernel/user interface, to set IMCR.E0.

Looking at figures 3-3 and 3-4 of the mpspec, the current model supports 
3-3 but not 3-4.  Do we report that IMCR exists in the mptables?

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