Re: IOMMU+DMAR causing NMIs-s (was: 4.7-rc6: NMI in intel_idle on HP Proliant G6)

[Meelis Roos]

> > Bisecting kernel configs shows that it's DMAR+IOMMU. When it is 
> > activated, there is high probability of NMI-s in random places.
> 
> Hmm, strange. But nothing could really surprise when you have an HP
> BIOS.

BIOS P64 01/22/2015. There seems to be a newer 2015.08.16 BIOS out but 
the release notes only describe updated CPU microcode for security 
reasons.
 
> Can you probably use the faulty config and bisect this down to a
> specific commit? In v4.7-rc1 some changes to the iova-allocation code
> got merged, but I have no idea how those could cause NMIs.

Will try but I do not know a working base yet - this was broken in both 
4.6 and 4.7-rc.

-- 
Meelis Roos (mroos@xxxxxxxx)