linux-kernel - RE: [PATCH 1/2] x86: mce: kdump: use under_crashdumping to turn off MCE in all CPUs together

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Message-ID: <3908561D78D1C84285E8C5FCA982C28F329EB977@ORSMSX114.amr.corp.intel.com>
Date:	Tue, 24 Feb 2015 18:20:16 +0000
From:	"Luck, Tony" <tony.luck@...el.com>
To:	Borislav Petkov <bp@...en8.de>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
CC:	Naoya Horiguchi <nao.horiguchi@...il.com>,
	Vivek Goyal <vgoyal@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Junichi Nomura <j-nomura@...jp.nec.com>,
	Kiyoshi Ueda <k-ueda@...jp.nec.com>
Subject: RE: [PATCH 1/2] x86: mce: kdump: use under_crashdumping to turn off
 MCE in all CPUs together

> I'd even venture a guess and say that clearing CR4.MCE should be enough
> but I *think* that doesn't prevent errors from being logged. Just to be
> extra sure, you should clear MCG_CTL bits too. It all depends on what
> exactly you want to do.

I'm not sure - the broadcast MCE will still arrive at that cpu - and with CR4.MCE==0, it will shutdown.
Not sure if that just affects that logical thread, or if it pulls a signal line to take down the whole machine.

-Tony