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From: Steven Rostedt <rostedt@goodmis.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH][GIT PULL][v3.3] x86: Test saved %rip in NMI to determine nested NMI
Date: Sun, 19 Feb 2012 16:00:31 -0500	[thread overview]
Message-ID: <1329685231.1561.24.camel@acer.local.home> (raw)
In-Reply-To: <4F415F55.6050902@zytor.com>

On Sun, 2012-02-19 at 12:45 -0800, H. Peter Anvin wrote:

> User space can change %cs, but it can never set it to __KERNEL_CS; 
> specifically user space can never set the bottom two bits in CS to zero.
> 
> So this should be a better test.

Great! That means that my original patch (the one never submitted, but
tested) would be the best.

Ingo,

I'll send out another pull request with the old patch. I'll still run it
through tests just to be sure, so it may take a day before I send it.

(I hope I still have it)

> 
> (Now, doing the test that way plays havoc with the braindamage knows as 
> Xen paravirt, but I don't think it's subject to this particular NMI code.)

Xen paravirt shouldn't be doing nested NMIs. I hope :-)

-- Steve



  reply	other threads:[~2012-02-19 21:00 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-19  2:06 [PATCH][GIT PULL][v3.3] x86: Test saved %rip in NMI to determine nested NMI Steven Rostedt
2012-02-19 12:56 ` Ingo Molnar
2012-02-19 13:46   ` hpanvin@gmail.com
2012-02-19 13:48     ` Ingo Molnar
2012-02-19 20:34     ` Steven Rostedt
2012-02-19 20:45       ` H. Peter Anvin
2012-02-19 21:00         ` Steven Rostedt [this message]
2012-02-19 14:57   ` Steven Rostedt
2012-02-20  8:10     ` Ingo Molnar
2012-02-20 14:41       ` Steven Rostedt
2012-02-20 15:34         ` Ingo Molnar
2012-02-20 17:07           ` H. Peter Anvin
2012-02-19 21:43   ` [PATCH v2][GIT PULL][v3.3] x86: Test saved %cs " Steven Rostedt
2012-02-20 11:47     ` [tip:x86/urgent] x86/nmi: Test saved %cs in NMI to determine nested NMI case tip-bot for Steven Rostedt
2012-02-20 16:51       ` Steven Rostedt
2012-02-27 21:29         ` Greg KH
2012-02-20 18:03       ` Linus Torvalds
2012-02-20 18:26         ` Steven Rostedt
2012-02-21 22:08         ` [tip:x86/urgent] x86: Specify a size for the cmp in the NMI handler tip-bot for Steven Rostedt

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