From: Steven Rostedt <rostedt@goodmis.org>
To: Jason Baron <jbaron@redhat.com>
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>,
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 12:14:11 -0500 [thread overview]
Message-ID: <1323450851.1937.28.camel@frodo> (raw)
In-Reply-To: <20111209164917.GA2444@redhat.com>
On Fri, 2011-12-09 at 11:49 -0500, Jason Baron wrote:
> >
>
> Then, I'm wondering if the same technique can be used for the original
> nmi->int3->nmi case. That is, switch the IDT when the int3 comes in, so
> that the subsequent nmi will be handled on the debug stack. As you pointed out,
> these nesting and thus the IDT switching would be rare in
> practice. (I know you don't want to touch any code outside of nmi :))
Right, I NMIs are ugly and we shouldn't uglify other code because of it.
Anyway, when could we do the switch in the int3 handler? As I said, the
NMI could come in at that moment the int3 is being processed, before it
does anything. If the NMI hits an int3, it just stomped over the
previous int3's interrupt frame.
The more I look at this, the more I like the original idea.
-- Steve
next prev parent reply other threads:[~2011-12-09 17:14 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
2011-12-09 18:20 ` Steven Rostedt
2011-12-09 16:49 ` Jason Baron
2011-12-09 17:14 ` Steven Rostedt [this message]
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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