From: Andi Kleen <ak@novell.com>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: "Jan Beulich" <jbeulich@novell.com>,
"Keir Fraser" <Keir.Fraser@cl.cam.ac.uk>,
"Jeremy Fitzhardinge" <jeremy@goop.org>,
"Ingo Molnar" <mingo@elte.hu>,
"Harvey Harrison" <harvey.harrison@gmail.com>,
"Matt Mackall" <mpm@selenic.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH UPDATE] x86: ignore spurious faults
Date: Fri, 25 Jan 2008 10:11:36 +0100 [thread overview]
Message-ID: <200801251011.36934.ak@novell.com> (raw)
In-Reply-To: <200801251938.39231.nickpiggin@yahoo.com.au>
On Friday 25 January 2008 09:38:38 Nick Piggin wrote:
> On Friday 25 January 2008 19:15, Jan Beulich wrote:
> > Actually, another thought: permitting (and handling) spurious faults for
> > kernel mappings conflicts with NMI handling, i.e. great care would be
> > needed to ensure the NMI path cannot touch any such mapping. So
> > even the present Xen/Linux Dom0 implementation may have some
> > (perhaps unlikely) problems here, and it would get worse if we added
> > e.g. a virtual watchdog NMI (something I am considering, which would
> > then extend the problem to DomU-s).
>
> Can you explain how they conflict?
NMI is blocked by the hardware until IRET and when a page fault happens inside
the NMI handler the early IRET unblocks it and then NMIs can nest, which
will lead to stack corruption.
-Andi
next prev parent reply other threads:[~2008-01-25 9:12 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-24 0:05 [PATCH] x86: ignore spurious faults Jeremy Fitzhardinge
2008-01-24 0:18 ` Harvey Harrison
2008-01-24 0:26 ` Jeremy Fitzhardinge
2008-01-24 0:28 ` [PATCH UPDATE] " Jeremy Fitzhardinge
2008-01-24 19:14 ` Matt Mackall
2008-01-24 19:21 ` Jeremy Fitzhardinge
2008-01-24 23:41 ` Nick Piggin
2008-01-25 0:26 ` Jeremy Fitzhardinge
2008-01-25 7:36 ` Keir Fraser
2008-01-25 8:15 ` Jan Beulich
2008-01-25 8:38 ` Nick Piggin
2008-01-25 9:11 ` Andi Kleen [this message]
2008-01-25 9:18 ` Keir Fraser
2008-01-25 9:51 ` Andi Kleen
2008-01-25 10:19 ` Andi Kleen
2008-01-25 13:17 ` Keir Fraser
2008-01-25 9:18 ` Jan Beulich
2008-01-25 15:30 ` Ingo Molnar
2008-01-25 15:54 ` Jeremy Fitzhardinge
2008-01-25 18:08 ` Ingo Molnar
2008-01-25 18:39 ` Jeremy Fitzhardinge
2008-01-24 6:49 ` [PATCH] " Andi Kleen
2008-01-24 7:02 ` Jeremy Fitzhardinge
2008-01-24 7:11 ` Andi Kleen
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