linux-kernel - Re: IOMMU+DMAR causing NMIs-s (was: 4.7-rc6: NMI in intel

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Message-ID: <alpine.LRH.2.20.1607131122010.20366@math.ut.ee>
Date:	Wed, 13 Jul 2016 11:31:02 +0300 (EEST)
From:	Meelis Roos <mroos@...ux.ee>
To:	Joerg Roedel <joro@...tes.org>
cc:	iommu@...ts.linux-foundation.org,
	Linux Kernel list <linux-kernel@...r.kernel.org>,
	David Woodhouse <dwmw2@...radead.org>
Subject: Re: IOMMU+DMAR causing NMIs-s (was: 4.7-rc6: NMI in intel_idle on
 HP Proliant G6)

> > 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@...ux.ee)