Received: by 2002:ac0:a5a6:0:0:0:0:0 with SMTP id m35-v6csp209799imm; Tue, 28 Aug 2018 20:46:43 -0700 (PDT) X-Google-Smtp-Source: ANB0Vdb9GqpLz9SIjp1G/zz78AVBGT8P/MjhG47eso2nhD6fNgmjmqv1jIlLwtSaWB+VZcOYIjGY X-Received: by 2002:a63:2f45:: with SMTP id v66-v6mr3991800pgv.91.1535514403447; Tue, 28 Aug 2018 20:46:43 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1535514403; cv=none; d=google.com; s=arc-20160816; b=fvTo3C2OkTX4wJw8Ds2c51eeTId7az/QJmjCV9RSgh8gUmur8NfqBm988m9LE92KvY 8Se7cASY3E2ykyO4nrzIVWx4rsQyyRR1RIb0XfGXx4uRMmB71ZDm/dCcZP8AuYv8iMoS Z8nvFxxkmZvCA+awnDlu2+B1b8NA1A3XUoICWkLGq3mwrLKu/qrcptyQBOXF35Bery+p /N2TLT2oUenkzRfMOMvIh6CMTu5Wf5uSfIs1WUzOWa/yJ0+nKTcsnw/SLQd6hEw+hNjV ROSiio7gA+Kkq0+hIH4j1GYGjMuSq8SBxGOfN6axA4kjFA/XZiR8q6i8De2cc0iH2tVO wOEA== 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 :references:in-reply-to:mime-version:dkim-signature :arc-authentication-results; bh=byI8t9PMEBgpS++oNffVgPEeIRazod7SEM/dOES7EIs=; b=Y5HgLS4zKAMDtZ2mj98ZNZK4DGMr5qlm27Z7Jwq6I4+M8+CUM6IoHft+oGFKhsYn8c oDuKUEqhKw25JcFNgRuKWNnOMfqv3EpdURbTFN2acKHOhiR1XyyvSjDyhAsNXPPjuvZm 1X2lZp3ec+GzUZqKBHVHlH10d2BbArkkiaVLFPDb6awMvmd7ZSBFlBrzP2OlTDpt3L3x 8mmx3qE/tvF8PC5Zx2CF8ClWBqSJlkQpS/h772JDWHC9Zdb8EetqUBQS3lgjjm4Arp/v p3VkBM5kSIQm9GisPWhe/wJ4eYDrfdzPUqPEt5dKGFsjEh21taoavN6cWZbMTMtcIOhW ABrQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=uwPnDdaQ; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 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. [209.132.180.67]) by mx.google.com with ESMTP id z128-v6si2981459pgb.185.2018.08.28.20.46.27; Tue, 28 Aug 2018 20:46:43 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=uwPnDdaQ; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 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 S1727278AbeH2HkJ (ORCPT + 99 others); Wed, 29 Aug 2018 03:40:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:46802 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726857AbeH2HkJ (ORCPT ); Wed, 29 Aug 2018 03:40:09 -0400 Received: from mail-wr1-f44.google.com (mail-wr1-f44.google.com [209.85.221.44]) (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 7667220850 for ; Wed, 29 Aug 2018 03:45:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1535514323; bh=cDs/n96Euvj3q36LKroQWZbUZzRHi//KYTsGwjyu8+Y=; h=In-Reply-To:References:From:Date:Subject:To:Cc:From; b=uwPnDdaQa4fLKZ23/yR9/hF9e40U4CgfcgTyxfIoSJpczbC/j53vhl6mb9T1d0Ije NPt+WyHC8WMCay6BkfMJB2eBTk5X/cv1nvBSIEHsDcPi+arxKPY6e5cxjcDod4qqpq c2UrTVg97vY5KWFWw4mDSUIRM6jzRjV3zx8cTbPM= Received: by mail-wr1-f44.google.com with SMTP id v16-v6so3354016wro.11 for ; Tue, 28 Aug 2018 20:45:23 -0700 (PDT) X-Gm-Message-State: APzg51AK1VLICKLXR+z2EhDIgTF7260SfjZzAYbM1T3rfjeburCKLCLu Gz3wRtCvJLNNaofumx8ccKoK1heeGAKRXaMwu5J3PA== X-Received: by 2002:adf:dcc1:: with SMTP id x1-v6mr3007415wrm.21.1535514322006; Tue, 28 Aug 2018 20:45:22 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a1c:548:0:0:0:0:0 with HTTP; Tue, 28 Aug 2018 20:45:01 -0700 (PDT) In-Reply-To: <8F811430-A9D5-446C-9D6A-C4CA82555559@gmail.com> References: <8F811430-A9D5-446C-9D6A-C4CA82555559@gmail.com> From: Andy Lutomirski Date: Tue, 28 Aug 2018 20:45:01 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: Flushing user entries for kernel mappings in x86 To: Nadav Amit Cc: Andy Lutomirski , Linux Kernel Mailing List 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, Aug 28, 2018 at 6:46 PM, Nadav Amit wrote: > Hello Andy, > > Is there a reason for __flush_tlb_one_kernel() to flush the PTE not only in > the kernel address space, but also in the user one (as part of > __flush_tlb_one_user)? [ I obviously regard the case when PTI is on ]. In most cases, probably not, but it's fairly cheap, I think. And it makes it so that we're okay if the TLB entry we're flushing is used by the entry code.