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[23.128.96.18]) by mx.google.com with ESMTP id zg9si4119474ejb.714.2020.05.28.16.08.17; Thu, 28 May 2020 16:08:39 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=rNkIsmki; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391550AbgE1XGL (ORCPT + 99 others); Thu, 28 May 2020 19:06:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391546AbgE1XGG (ORCPT ); Thu, 28 May 2020 19:06:06 -0400 Received: from mail-il1-x143.google.com (mail-il1-x143.google.com [IPv6:2607:f8b0:4864:20::143]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B081FC08C5C6 for ; Thu, 28 May 2020 16:06:06 -0700 (PDT) Received: by mail-il1-x143.google.com with SMTP id 17so685365ilj.3 for ; Thu, 28 May 2020 16:06:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=g6efeBhEA8jJzf2TongZsZb2kdgbZpcm87yBeRzV8Z8=; b=rNkIsmkictXvRJP/m/oj5PkfPXtaolbz1ryoC1zATCnLBUUI6doLG4GjZQ5Oqin+ND kqCsQaCtltq+o8tYNedwZnMOEJB9/Rkv0mDb3xn7SbluKABQUp/CmhITSLBs9/F2PGjb HKvFBCSHtE4RBUXW+mPDQKbpmqw8UoVwjJDrSPxB0VHKK4N8k8HLp1I84IVB4Hrp3BVb C+/aINZdwV3wbbbK3gNEC21VyUhoNWV2tjEgiJqeTGeYYe+ErxdI+dACy84Jpe/mJk61 P3uj+TjDOdl4DaV+nbrt6knNeAhH+ReGlZmaeE64xKQAYAGAOzX+K5v/WyN1cCm5dBH5 40uw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=g6efeBhEA8jJzf2TongZsZb2kdgbZpcm87yBeRzV8Z8=; b=YxAd21IgkyY6GYSJmOuev2WUUWMaL0eYaXu53WAChER7p1GP1Um0DhximaTwDRsZCG cYfrJtgz8zqzUEBFoFA3ngrULqQBalp7lhd0kgAvHggS5J03B0+Pe211Ik68W2ZNOyc7 MgwzT4YFlbCBN+rzwr+vbNbTG/Jh3KfLfjp9WEzLq7l3XZBciqHTlP7mgi3R0tr2P9cR EjePLRXaOkuoWU4VcMMwGO0hRcKFfHvUaS+HGqhHUGchVGpbR/52AdgZjHXAnUWBx/Hq A93e8/bD5QVT0XCPnQzKudReGA3i+ouDnyNDoumNBGrmaGOqc0oYa5FP1o+IAHIvccsi kRcQ== X-Gm-Message-State: AOAM533fCnf9Dulw/8sOXD6ZOpY9lAEvWxc0w1+ZbWhFo3s/9qKfdwug aQXrtERRnQjJmyOx0wWwd3kiabz5PDQCTc4shGU= X-Received: by 2002:a92:c8d1:: with SMTP id c17mr4806716ilq.308.1590707166189; Thu, 28 May 2020 16:06:06 -0700 (PDT) MIME-Version: 1.0 References: <20200528201937.038455891@infradead.org> <20200528224835.GU2483@worktop.programming.kicks-ass.net> In-Reply-To: <20200528224835.GU2483@worktop.programming.kicks-ass.net> From: Lai Jiangshan Date: Fri, 29 May 2020 07:05:54 +0800 Message-ID: Subject: Re: [PATCH 0/6] x86/entry: disallow #DB more To: Peter Zijlstra Cc: Thomas Gleixner , Andy Lutomirski , LKML , X86 ML , Lai Jiangshan , Sean Christopherson , andrew.cooper3@citrix.com, daniel.thompson@linaro.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 29, 2020 at 6:48 AM Peter Zijlstra wrote: > > On Fri, May 29, 2020 at 06:42:46AM +0800, Lai Jiangshan wrote: > > On Fri, May 29, 2020 at 4:25 AM Peter Zijlstra wrote: > > > > > > These patches disallow #DB during NMI/#MC and allow removing a lot of fugly code. > > > > > > > Hello > > > > Will #DB be allowed in #DF? > > No, that whole thing is noinstr. But it calls many functions, including die(), panic(). We don't want #DB to interfere how it die() and panic(). Since it is in fragile #DF, the #DB may mess it up and make #DF fails to report and die.