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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 74A86C433E0 for ; Thu, 4 Jun 2020 13:26:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B22620772 for ; Thu, 4 Jun 2020 13:26:40 +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="Q9RiV1dI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728481AbgFDN0j (ORCPT ); Thu, 4 Jun 2020 09:26:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728224AbgFDN0i (ORCPT ); Thu, 4 Jun 2020 09:26:38 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D947C08C5C0 for ; Thu, 4 Jun 2020 06:26:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=qdNli0NEHd43fwml9PHoxGbEchkTHhQ67oW6OcyjWWg=; b=Q9RiV1dIL5RZNEJrMOBFr4t6Uo zQItk4JSKEFB/aQqsDcK8xTCN8m2s0SzrQ4OUAuc1l79u5cEYOhiCCuotAihVSRUtMaCszZSahE+f AutRgArbGxQta6BsGc7eJ/Fb+B79A1xO5XR9wtDa/MwnJLsLt2k4/13X+0in/TsxSfx5fPu/1F9ME 21BbNGa1r0wqAozqh2NY2O7HD6u72Nv2Q+YtYpOOfPhr3+KnuStZU4jWq2L+WOh4hTqqaQQIw6+30 K/0Tz+ovcG2si5yrovDCs9uSqWxePvk+q4Vk7NMJqXkYMLN0F+ceN98T4qdLj4rKmswfwq/37Aw+h PRbFHt0g==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jgpsL-0000mk-4C; Thu, 04 Jun 2020 13:25:41 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 1E87E301DFD; Thu, 4 Jun 2020 15:25:37 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id DDF5B20C333CF; Thu, 4 Jun 2020 15:25:37 +0200 (CEST) Date: Thu, 4 Jun 2020 15:25:37 +0200 From: Peter Zijlstra To: Andrew Cooper Cc: Thomas Gleixner , LKML , Andy Lutomirski , X86 ML , "Paul E. McKenney" , Alexandre Chartre , Frederic Weisbecker , Paolo Bonzini , Sean Christopherson , Masami Hiramatsu , Petr Mladek , Steven Rostedt , Joel Fernandes , Boris Ostrovsky , Juergen Gross , Brian Gerst , Mathieu Desnoyers , Josh Poimboeuf , Will Deacon , Tom Lendacky , Wei Liu , Michael Kelley , Jason Chen CJ , Zhao Yakui , "H. Peter Anvin" Subject: Re: [patch V9 00/39] x86/entry: Rework leftovers (was part V) Message-ID: <20200604132537.GA3976@hirez.programming.kicks-ass.net> References: <20200521200513.656533920@linutronix.de> <5e68aa83-feac-2aa7-10ee-aebebc60c83e@citrix.com> <20200522211706.GZ2483@worktop.programming.kicks-ass.net> <83474edd-195f-f10b-9fe9-8ee168344e29@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <83474edd-195f-f10b-9fe9-8ee168344e29@citrix.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 03, 2020 at 08:18:44PM +0100, Andrew Cooper wrote: > Well that didn't last long... > > The new ISE (rev 39, published today) introduces BUS LOCK DEBUG > EXCEPTION which is now a second inverted polarity sticky bit (bit 11) in > %dr6. > > This one is liable to get more traction than RTM debugging, so something > probably does want fixing in the #DB handler. Well that's crap :-( It being enabled through IA32_DEBUGCTL instead of through DR7 means that the current code doesn't disable it and this then means we can have nested #DB again. Who sodding throught this was a good idea ?! What happened to #AC that SLD currently uses? What hardware will this be in and can we get this fixed?