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From: Borislav Petkov <bp@amd64.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Jason Baron <jbaron@redhat.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	"H. Peter Anvin" <hpa@linux.intel.com>,
	Paul Turner <pjt@google.com>, Borislav Petkov <bp@amd64.org>
Subject: Re: [RFC][PATCH 3/3] x86: Add workaround to NMI iret woes
Date: Fri, 9 Dec 2011 18:49:11 +0100	[thread overview]
Message-ID: <20111209174911.GD14900@aftab> (raw)
In-Reply-To: <1323451171.1937.33.camel@frodo>

Hey Steve,

On Fri, Dec 09, 2011 at 12:19:31PM -0500, Steven Rostedt wrote:
> Could you shed some light on this. Can an NMI interrupt an MCE in
> progress?

Easy, http://support.amd.com/us/Processor_TechDocs/APM_V2_24593.pdf,
section 8.5.

On amd64 #MC is along with processor reset the highest prio. Judging
from the text, an NMI occurring during an #MC is held until we return
from the #MC handler:

"When simultaneous interrupts occur, the processor transfers control
to the highest-priority interrupt handler. Lower-priority interrupts
from external sources are held pending by the processor, and they are
handled after the higher-priority interrupt is handled. Lower-priority
interrupts that result from internal sources are discarded. Those
interrupts reoccur when the high-priority interrupt handler completes
and transfers control back to the interrupted instruction."

HTH.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551

  reply	other threads:[~2011-12-09 17:49 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-08 19:30 [RFC][PATCH 0/3] x86: Find a way to allow breakpoints in NMIs Steven Rostedt
2011-12-08 19:30 ` [RFC][PATCH 1/3] x86: Do not schedule while still in NMI context Steven Rostedt
2011-12-08 19:30 ` [RFC][PATCH 2/3] x86: Document the NMI handler about not using paranoid_exit Steven Rostedt
2011-12-08 19:30 ` [RFC][PATCH 3/3] x86: Add workaround to NMI iret woes Steven Rostedt
2011-12-08 19:36   ` Steven Rostedt
2011-12-09  2:43     ` Steven Rostedt
2011-12-09  9:22       ` Peter Zijlstra
2011-12-09 15:00         ` Steven Rostedt
2011-12-09 15:10           ` Peter Zijlstra
2011-12-09 15:25             ` Steven Rostedt
2011-12-09 15:20       ` Steven Rostedt
2011-12-09 16:34       ` Steven Rostedt
2011-12-09 17:19         ` Steven Rostedt
2011-12-09 17:49           ` Borislav Petkov [this message]
2011-12-09 18:20             ` Steven Rostedt
2011-12-09 16:49       ` Jason Baron
2011-12-09 17:14         ` Steven Rostedt
2011-12-09 12:40     ` Mathieu Desnoyers
2011-12-09 13:02       ` Mathieu Desnoyers
2011-12-09 14:49         ` Steven Rostedt
2011-12-09 15:02           ` Mathieu Desnoyers

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