Received: by 2002:a25:2c96:0:0:0:0:0 with SMTP id s144csp1584749ybs; Mon, 25 May 2020 21:22:04 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwlvLySCbSLow2umhmwk4jBSOD/s/469E+ktHXMfcIKIf33Q6eMXXTvo5lMByLz//kgxuJv X-Received: by 2002:a17:906:b859:: with SMTP id ga25mr22494272ejb.523.1590466923997; Mon, 25 May 2020 21:22:03 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1590466923; cv=none; d=google.com; s=arc-20160816; b=k0bmrRt9iOJkSEvn9Z5TFFTbjXrJsAbUVSbyafGCXGNYse/gvB/ug15y4HHlBLTDoM 3JnKkY1o7uhMHnA0rKmz0uLa/RZXDdi9OQ51EVFzKLe83a4rDvx0vg7g+QHV3f2cFQhF UbSHkPLg7/aowMBhXQx+3hhQ+YqEedm10o8zLNZRh4hfrUTGzY7vnb5hH+JTmBre+9FV /1tbPcBkMSgSTkFiOBsEeWFNFXyfAq5DKamvNh4eIilryo0HOdwejXjGGcmLE3lTd1ft h+6w2pLSamncH1K64Jx0sS0k23s3JMD+YpTuQoGTtDGiQVFeCF87hY76rhZx3AzJDj6T sN+A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature; bh=x1WAXI2MxxnLa4yFnZKA0idaQEQ3kvC3jplhuJpq+Gg=; b=PBcrKmzGM5dxd525cwjLTBN/JLMsj0Szs9xrrEnYfvzjaGKKc8iTbQIDw6pDuLQ692 fI87uCdAepM9BYOSmQr3EQS9VPI2xqV/0YE2pizbVHN8KXgvu/AhCiTlW4CNgroeke4N dR3PJ4KiuxnJW5IF9Xiu7KngFIG4iDjVpV/9h+1MjAq30+JNrAzX8aw98lE1fh4u1cka LLim9Dvh5FuHFrKmF4cvdHuG6xjGzeuB/OL0tZFtdLqeXeXqoBAulYrJxI7/coR2s97S yfOkC6xX/GkiKWl4zkOCTNDhqJCrHC/GYRIsfsIe4GPjBmC15eBQdzLYvnfsh7rDfK/m CqkQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=CkJNgSWs; 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=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id dd15si10485521edb.187.2020.05.25.21.21.41; Mon, 25 May 2020 21:22:03 -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=@kernel.org header.s=default header.b=CkJNgSWs; 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=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725944AbgEZERq (ORCPT + 99 others); Tue, 26 May 2020 00:17:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:37226 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725271AbgEZERq (ORCPT ); Tue, 26 May 2020 00:17:46 -0400 Received: from mail-wm1-f48.google.com (mail-wm1-f48.google.com [209.85.128.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8C8AA208A7 for ; Tue, 26 May 2020 04:17:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590466665; bh=x1WAXI2MxxnLa4yFnZKA0idaQEQ3kvC3jplhuJpq+Gg=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=CkJNgSWspGqG+zaxQZ+W/RVZ0+lyQy4xHJ/F/ea1z9YYkY4tLlJW265/socMYUrY8 VWT6rzvAKyCjKdoqQQt46fRKpzrSf6tOCo8gxNYnlz1gcl5P4aVK6834J7LSL+XyFU ti05uGY+z0cbUYoLQxCwgkgKP20z9CIZD/UDijNU= Received: by mail-wm1-f48.google.com with SMTP id c71so1823845wmd.5 for ; Mon, 25 May 2020 21:17:45 -0700 (PDT) X-Gm-Message-State: AOAM5328dz7YWHeFcsscOpKOwEEaM2//s9SAfPEEOw2URh82FqGFFwf0 Umi1e/oYz+Hee6GjinBwGVNxUjjlc8FKLVfKUXppCg== X-Received: by 2002:a1c:7f96:: with SMTP id a144mr22008255wmd.176.1590466664042; Mon, 25 May 2020 21:17:44 -0700 (PDT) MIME-Version: 1.0 References: <20200525152517.GY325280@hirez.programming.kicks-ass.net> <20200526014221.2119-1-laijs@linux.alibaba.com> <20200526014221.2119-5-laijs@linux.alibaba.com> In-Reply-To: <20200526014221.2119-5-laijs@linux.alibaba.com> From: Andy Lutomirski Date: Mon, 25 May 2020 21:17:32 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH V2 4/7] x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask To: Lai Jiangshan Cc: LKML , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , X86 ML , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Alexandre Chartre 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 Mon, May 25, 2020 at 6:42 PM Lai Jiangshan wrote: > > The percpu user_pcid_flush_mask is used for CPU entry > If a data breakpoint on it, it will cause an unwanted #DB. > Protect the full cpu_tlbstate structure to be sure. > > There are some other percpu data used in CPU entry, but they are > either in already-protected cpu_tss_rw or are safe to trigger #DB > (espfix_waddr, espfix_stack). How hard would it be to rework this to have DECLARE_PERCPU_NODEBUG() and DEFINE_PERCPU_NODEBUG() or similar?