From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47642C34047 for ; Tue, 18 Feb 2020 20:34:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1ED8B2067D for ; Tue, 18 Feb 2020 20:34:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="abGp84Ch" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727216AbgBRUeK (ORCPT ); Tue, 18 Feb 2020 15:34:10 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:42376 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726283AbgBRUeK (ORCPT ); Tue, 18 Feb 2020 15:34:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=rrgE1QmBht6appaFA2bTRzgOgoL6Gn0NcwciZG8klY4=; b=abGp84Ch0KgWucvvwcavQzPQNv fP0B8sExkdZUqIZxOYXb/eWvUJKK89l2HNvreGyDbqCd0nx/lfhGn8DZjVcXoagy86sONTn+AmctG bjKzWF5P3LoxwmTNb9vXstPPyid+q3KLm1XG9HFwHKq4awKY/XZYt9rUK3jUxHG+wiQh2+FEtkMak oyLPGKTC7yQYorrIRz+P2vBGk9lHlBUioiHgLVxsM3wVyALVhd89lZKfQRDGEWa1qjC6rwPId9yrz ygv7ummzal2sB6SK1qL/kU5tJ2qtohr47Lw8zUXQIHnG605NwyCrg/CU6SOr4+IsRztxdYp2kLYKp 7ZSnwYzw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j49ZH-0006MM-0O; Tue, 18 Feb 2020 20:34:07 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 12FFC980E56; Tue, 18 Feb 2020 21:34:05 +0100 (CET) Date: Tue, 18 Feb 2020 21:34:04 +0100 From: Peter Zijlstra To: "Luck, Tony" Cc: Borislav Petkov , Steven Rostedt , Andy Lutomirski , x86-ml , lkml Subject: Re: [RFC] #MC mess Message-ID: <20200218203404.GI11457@worktop.programming.kicks-ass.net> References: <20200218173150.GK14449@zn.tnic> <3908561D78D1C84285E8C5FCA982C28F7F57B937@ORSMSX115.amr.corp.intel.com> <20200218200200.GE11457@worktop.programming.kicks-ass.net> <3908561D78D1C84285E8C5FCA982C28F7F57BDFB@ORSMSX115.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F7F57BDFB@ORSMSX115.amr.corp.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 18, 2020 at 08:11:10PM +0000, Luck, Tony wrote: > > Then please rewrite the #MC entry code to deal with nested exceptions > > unmasking the MCE, very similr to NMI. > > #MC doesn't work like NMI. It isn't enabled by IRET. Nested #MC cause an > immediate reset. Detection of nested case is by IA32_MCG_STATUS.MCIP. > We don't clear MCG_STATUS until we are ready to return from the machine > check handler. Ooh, excellent! That saves a whole heap of problems. Then I suppose we should work at getting in_nmi() set. Let me have another look at things.