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Date:   Wed, 29 May 2019 19:00:48 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Jiri Kosina <jikos@kernel.org>
Cc:     Josh Poimboeuf <jpoimboe@redhat.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Pavel Machek <pavel@ucw.cz>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] x86/power: Fix 'nosmt' vs. hibernation triple fault
 during resume
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On Wed, May 29, 2019 at 06:26:59PM +0200, Jiri Kosina wrote:
> On Wed, 29 May 2019, Josh Poimboeuf wrote:

> > Is there are reason why maxcpus= doesn't do the CR4.MCE booted_once
> > dance?
> 
> I am not sure whether it's really needed. My understanding is that the MCE 
> issue happens only after primary sibling has been brought up; if that 
> never happened, MCE wouldn't be broadcasted to that core at all in the 
> first place.
> 
> But this needs to be confirmed by Intel.

(I'm not confirming anything, as I've no clue), but that code stems from
long before we found out about that brilliant MCE stuff (which was
fairly recent).