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_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 B6050C28CBC for ; Sat, 9 May 2020 09:23:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A13720661 for ; Sat, 9 May 2020 09:23:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TM31AFba" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728015AbgEIJXc (ORCPT ); Sat, 9 May 2020 05:23:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725930AbgEIJXb (ORCPT ); Sat, 9 May 2020 05:23:31 -0400 Received: from mail-io1-xd30.google.com (mail-io1-xd30.google.com [IPv6:2607:f8b0:4864:20::d30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1680C061A0C for ; Sat, 9 May 2020 02:23:31 -0700 (PDT) Received: by mail-io1-xd30.google.com with SMTP id k6so4305608iob.3 for ; Sat, 09 May 2020 02:23:31 -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=npUCSug3UNmvoID4U4QjZrQryTMG/6PUbxsaJOR4T28=; b=TM31AFba3DfHCrEv6efBqjc5asmfKIAX5qK8448CR2SCW4RuZMPfdPDyaPyMU2xgHT 5sueQWG1vPyOt/KzIibm6A0+NMj9kTMmFpWeZQKBxGCGzq6hPMr2onN0RlU4TpBc56Al PctXOx5V46kH2vXzLqOVscXgYxzfsb7T8z51BfozgWXs+qtr4A7oEBB+VfCmmhCLaxvv 3TU4VFyAOzNYymYWoC19ULVREZ1oLpYVigTv0KzeE/RgBk2rpVSlVXiofXlBaVgRM/sd ay0FwbQGqMIqj4q1oGpHCYQQC0M7e8DKGW4fpzWpCM5KdICjq0kwD4HACP7ncUfrxSzB SWyQ== 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=npUCSug3UNmvoID4U4QjZrQryTMG/6PUbxsaJOR4T28=; b=NUSR+1lhd3prZEPPxrQEg9s0e4E8m90dyLz0E5BqUAFjdhHMLTVAzUvbnz2oehiA77 HhNDcRxX86GWuAcwuQzUckOVGWEIxrxQxwQK9oByJqfOFsUackFzz+eTzP1LxhM8UpL1 y9CDouKBn0LSXGhp4uLafBXOZKfqpvn69xa4fcZ2zIs9/7MsqkWIesmNB7zsE1zHUGHW vZ59/XhcCyWeRdboiUJwj9HqFB6CpUYRuooBCHXMRNU6jqQxqMiEvMHA8tMiL64B7R8I /BB6COqilMxd7J59P/GwE9bbh3y7Nqezmwr3NwmD0h70iPsRuwHUuMYVV834oXn2g8WH pcfQ== X-Gm-Message-State: AGi0PuZMw4tMMutcxJ7dEdiSAutAqiqsqG9a9d09r0ZsnENmdwnW+CA6 DXK95E+195aKkwRQZhbChQB8A6xm0/hYDr87slU= X-Google-Smtp-Source: APiQypJTo+iHmgKOwr7znP0jcjAroPrnAacktBKv3E9YmNJoP6PNKBM81igz0/RNbvATdEWY6mYeNODi6BRo1UaqPOk= X-Received: by 2002:a02:6a1e:: with SMTP id l30mr6254957jac.98.1589016211189; Sat, 09 May 2020 02:23:31 -0700 (PDT) MIME-Version: 1.0 References: <20200505131602.633487962@linutronix.de> <20200505134058.272448010@linutronix.de> In-Reply-To: <20200505134058.272448010@linutronix.de> From: Lai Jiangshan Date: Sat, 9 May 2020 17:23:20 +0800 Message-ID: Subject: Re: [patch V4 part 1 02/36] x86/hw_breakpoint: Prevent data breakpoints on cpu_entry_area To: Thomas Gleixner Cc: LKML , x86@kernel.org, "Paul E. McKenney" , Andy Lutomirski , 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 , "Peter Zijlstra (Intel)" 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 Tue, May 5, 2020 at 10:15 PM Thomas Gleixner wrote: > > From: Andy Lutomirski > > A data breakpoint near the top of an IST stack will cause unresoverable > recursion. A data breakpoint on the GDT, IDT, or TSS is terrifying. > Prevent either of these from happening. > What happen when a data breakpoint on the direct GDT (load_direct_gdt()) and the debug IDT (load_debug_idt()) which are not considered in this patch? Thanks Lai