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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham 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 55511C43143 for ; Fri, 22 Jun 2018 08:19:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 064DB21722 for ; Fri, 22 Jun 2018 08:19:39 +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="YLyijwEK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 064DB21722 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752151AbeFVITf (ORCPT ); Fri, 22 Jun 2018 04:19:35 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:35796 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751053AbeFVITc (ORCPT ); Fri, 22 Jun 2018 04:19:32 -0400 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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=A4U8hP6rw2wgMEe57XXxeN238PMayIt6TYvvhA3Tv24=; b=YLyijwEKN65RCFrriLFB+CcSC vdCDY2tSD+6LtLkV/NYzAfC779vECcG+NfHErFLY9ChVVYAwpGC2PwaROOE7+33CignF1UkZ+qzIA dToo6r1NloaGHp6e2PNmm+wTnc4HlFRzCnmuszVE2+CA+UA0BccyWeC6pXRSLZ/If/AfebVOp8luR V9tgPp61O26NWu47h8quAMcVn90UeP0tfiPp3uf2AtMh6fCwXshFoE26aJvbWYow8WVbilXJeCRB9 cHDgqEIz/tgc2aNIwng+wfL1ds3z7LrwzNmP8G5qRcMbu+Lkhezk9A04E+A4eqj1v1iqw6tmNN7yK TU2I4Dx6Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fWHHy-0002Yg-Lq; Fri, 22 Jun 2018 08:19:26 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id F28BB2029F1D5; Fri, 22 Jun 2018 10:19:24 +0200 (CEST) Date: Fri, 22 Jun 2018 10:19:24 +0200 From: Peter Zijlstra To: Fenghua Yu Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Ashok Raj , Dave Hansen , Rafael Wysocki , Tony Luck , Alan Cox , Ravi V Shankar , Arjan van de Ven , linux-kernel , x86 Subject: Re: [RFC PATCH 00/16] x86/split_lock: Enable #AC exception for split locked accesses Message-ID: <20180622081924.GH2494@hirez.programming.kicks-ass.net> References: <1527435965-202085-1-git-send-email-fenghua.yu@intel.com> <20180621193738.GA13636@worktop.programming.kicks-ass.net> <20180621201851.GC114883@romley-ivt3.sc.intel.com> <20180621220003.GD114883@romley-ivt3.sc.intel.com> <20180621221006.GC2494@hirez.programming.kicks-ass.net> <20180621230501.GC18979@romley-ivt3.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180621230501.GC18979@romley-ivt3.sc.intel.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 21, 2018 at 04:05:02PM -0700, Fenghua Yu wrote: > But in a real case, when I enable #AC for split lock in kernel, reboot > hits #AC because of split lock in firmware code and firmware handles #AC > as fatal error and stops continuing to run. > > It will take long time/forever for firmware to fix the split lock issue. > Before the firmware issue is fixed, reboot or S4 cannot run if the feature > is enabled by kernel. Then it will take a long time / forever for people to use their machines as they need. Don't you see that is a problem? Either you take this real-time stuff serious and force BIOS monkeys to get with the act, this includes no #AC but also very much force them into abandoning SMM as a fail^Wfeature-platform. Or it's all a joke and we'll continue to complain and shame.. > And if unlucky, I'm afraid the patch set even has no chance to be merged to > upstream if maintainer's test machine has firmware split lock issue and the > machine simply cannot reboot or go to S4 if the feature is enabled. Well, then you'd better get those BIOS monkeys on board and fixing their crap.