From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757135Ab2CLURW (ORCPT ); Mon, 12 Mar 2012 16:17:22 -0400 Received: from terminus.zytor.com ([198.137.202.10]:52694 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756961Ab2CLURV (ORCPT ); Mon, 12 Mar 2012 16:17:21 -0400 Message-ID: <4F5E59AC.7090708@zytor.com> Date: Mon, 12 Mar 2012 13:16:44 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120209 Thunderbird/10.0.1 MIME-Version: 1.0 To: "Eric W. Biederman" CC: =?UTF-8?B?RmVybmFuZG8gTHVpcyBWw6F6cXVleiBDYW8=?= , Don Zickus , linux-tip-commits@vger.kernel.org, torvalds@linux-foundation.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, mingo@elte.hu, Yinghai Lu , akpm@linux-foundation.org, vgoyal@redhat.com Subject: Re: [PATCH 1/2] boot: ignore early NMIs References: <20120216215603.GH9751@redhat.com> <20120217195430.GO9751@redhat.com> <20120220151419.GU9751@redhat.com> <20120221135934.GF26998@redhat.com> <4F573E1C.2060909@oss.ntt.co.jp> <4F573E74.5040504@oss.ntt.co.jp> <4F58495B.5080308@oss.ntt.co.jp> <4F5A6D87.4050809@zytor.com> <4F5D8D0E.8060702@oss.ntt.co.jp> <4F5D8E63.60606@zytor.com> <4F5D943C.5020403@oss.ntt.co.jp> <4F5E431D.8010305@zytor.com> <4F5E56EB.1090807@zytor.com> In-Reply-To: <4F5E56EB.1090807@zytor.com> X-Enigmail-Version: 1.3.5 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/12/2012 01:04 PM, H. Peter Anvin wrote: > On 03/12/2012 01:01 PM, Eric W. Biederman wrote: >> >> The basic problem is which source do we block this at? How many >> sources are their? And architecturally last I looked x86 no longer >> has a NMI disable EFI and similar systems want to get away without >> a CMOS legacy clock because designers so often get them wrong. >> > > On all processors which have an LAPIC you can block all NMI sources at > the LAPIC. I think it's safe to assume that if you don't have an LAPIC > -- an ancient system by now -- you have port 70h. > One thing: *disabling* the LAPIC will allow external NMIs coming in on LINT1 through, since the LAPIC in the disabled state tries to mimic the no-LAPIC configuration. So I don't think you want to disable LAPIC as much as disable the interrupt vectors within. -hpa