From: Peter Zijlstra <peterz@infradead.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>,
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>
Subject: Re: [RFC][PATCH 3/3] x86: Add workaround to NMI iret woes
Date: Fri, 09 Dec 2011 10:22:01 +0100 [thread overview]
Message-ID: <1323422521.17673.47.camel@twins> (raw)
In-Reply-To: <1323398616.30977.167.camel@frodo>
On Thu, 2011-12-08 at 21:43 -0500, Steven Rostedt wrote:
> On Thu, 2011-12-08 at 14:36 -0500, Steven Rostedt wrote:
>
> > I'm not sure how to handle this case. We could do something similar in
> > the break point code to handle the same thing. But this just seems
> > really ugly.
> >
> > Anyone with any better ideas?
>
> On IRC, Peter Zijlstra mentioned changing the IDT in NMI. I'm not sure
> if he was joking or not. But I decided to try it out. It seems to
> work :)
Its was definitely tongue in cheek, also I did say this'll be a massive
pain with paravirt since I doubt paravirt calls are NMI safe.
But yeah, it might all be slightly less painful than trying to teach the
INT3 handler about this recursion.
This all started with wanting to do pagefaults from NMI context, those
too will have this recursion, although for faults we'll end up in the
double fault handler, which seems to allow a slightly saner way out.
next prev parent reply other threads:[~2011-12-09 9:22 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 [this message]
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
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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