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_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 56518CA9EA0 for ; Fri, 18 Oct 2019 10:43:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A918222BD for ; Fri, 18 Oct 2019 10:43:28 +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="lj+/TILV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392070AbfJRKn0 (ORCPT ); Fri, 18 Oct 2019 06:43:26 -0400 Received: from merlin.infradead.org ([205.233.59.134]:36014 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725906AbfJRKn0 (ORCPT ); Fri, 18 Oct 2019 06:43:26 -0400 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: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=oxApsNYvw66RYq5moaNmeiPbSZysZVQPCrDxkISvsxg=; b=lj+/TILVPr4+8Wq0kbg6+i9q6 +MNAtgBK5pj3tsWPMlgEh9gkCSGNHeH0/PjsFEVmBD3SWLGXlE6Qm+shwtvkTY+3zA6RIX3v/FI1x MnBsHcVL12ndv3QPVj66JqqLpzSeDaqJJrlBFGhXChMts3nyYJSnRXB/cQD8PhxpdSC27rPyoA8Ua Slf5mJ1ftQ4X8JWkavBHsdFmJAG0a+eJoa3XkBpAmI0pwO6o8WbXKdHnfczUQa1Cv21IdPpG14mtO qCKljUY/+KSBGPCTXLfL4ikRgkpQw0TahKphA5iHj1lQpSOqusq9i6Hxgy+mKXKtkxTF0bPHZbr/b U+lyQcIdA==; 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 1iLPix-0002Ib-3W; Fri, 18 Oct 2019 10:43:11 +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 9081A30018A; Fri, 18 Oct 2019 12:42:11 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 56C542B17810B; Fri, 18 Oct 2019 12:43:07 +0200 (CEST) Date: Fri, 18 Oct 2019 12:43:07 +0200 From: Peter Zijlstra To: Xiaoyao Li Cc: Thomas Gleixner , Paolo Bonzini , Sean Christopherson , Fenghua Yu , Ingo Molnar , Borislav Petkov , H Peter Anvin , Andrew Morton , Dave Hansen , Radim Krcmar , Ashok Raj , Tony Luck , Dan Williams , Sai Praneeth Prakhya , Ravi V Shankar , linux-kernel , x86 , kvm@vger.kernel.org Subject: Re: [RFD] x86/split_lock: Request to Intel Message-ID: <20191018104307.GG2328@hirez.programming.kicks-ass.net> References: <57f40083-9063-5d41-f06d-fa1ae4c78ec6@redhat.com> <8808c9ac-0906-5eec-a31f-27cbec778f9c@intel.com> <5da90713-9a0d-6466-64f7-db435ba07dbe@intel.com> <763bb046-e016-9440-55c4-33438e35e436@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <763bb046-e016-9440-55c4-33438e35e436@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 Fri, Oct 18, 2019 at 06:20:44PM +0800, Xiaoyao Li wrote: > We enable #AC on all cores/threads to detect split lock. > -If user space causes #AC, sending SIGBUS to it. > -If kernel causes #AC, we globally disable #AC on all cores/threads, > letting kernel go on working and WARN. (only disabling #AC on the thread > generates it just doesn't help, since the buggy kernel code is possible to > run on any threads and thus disabling #AC on all of them) > > As described above, either enabled globally or disabled globally, so whether > it's per-core or per-thread really doesn't matter Go back and read the friggin' thread already. A big clue: virt ruins it (like it tends to do).