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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 A6FBEC433F4 for ; Wed, 29 Aug 2018 08:38:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45E6A206B7 for ; Wed, 29 Aug 2018 08:38:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="P6xEniE9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 45E6A206B7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727951AbeH2Md7 (ORCPT ); Wed, 29 Aug 2018 08:33:59 -0400 Received: from mail-pl1-f179.google.com ([209.85.214.179]:42744 "EHLO mail-pl1-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727268AbeH2Md6 (ORCPT ); Wed, 29 Aug 2018 08:33:58 -0400 Received: by mail-pl1-f179.google.com with SMTP id g23-v6so1978164plq.9 for ; Wed, 29 Aug 2018 01:38:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=+4Mhwns+g3RMeGa5TK7Mcv01PQnwPYQk/1LhjugUUrc=; b=P6xEniE9gIDNVo1WZmKT6a5t7ifk9AbNQlLCSXWsORLtHD45uY90Aa/yOWwSiKKtGz +U1Y/JXry94nvC+frFRYuxj+rJMKsmlLrAnWPduU39Oy8VCc9BVHohvNughVUhnHtSUn 02iAcCkArKP95tHYUum2zyRyek1SHPKt98s3mguhaLznsO5U2kwm37T2kdtIFtFID3lX gAhfZFfLswXJfBNgyhlXYDw8onMOAxvYQ6aisI4aFHvT/JPyX+mXEKvD6WSzQAdDXmiq CNDP8PVcEaNlHGU9xWoRGiG/4mEbwHHmiTPKm2iBlh/JmcncZD8msQksTW37ZSzT+Oqf 9vvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=+4Mhwns+g3RMeGa5TK7Mcv01PQnwPYQk/1LhjugUUrc=; b=LPip7LL8lszX3RhPte/g9Hs8fh3/rwoknuOW4pXxHgY0Fl6a7H8qy2CbTW5pf5Grom cv8ZkOEyhrTaTObqRv+c1IBbGbVrt6WMje0vzpMwZY3maufZ4j/253bfo1pbDPPI/BWg 6ojCfYa2xbtyqXK0ARaGcIM6BtLzbbY1JW/iCldr2EnNOjm5ccUoTzoyJuJ9FU/DM7uy EiovTZ3crrSu9a1A1mN3tIc6cxe6KRXHmIDHS3MjywRq8+7RTqymzJdJFJym5mykMCpR 6/TZwV+2ML/RQwn415saBO0ifZAoXnb3JqhsQ9FG2ruSIxzEg1egFqrptA4QKrHYBXNY NIWw== X-Gm-Message-State: APzg51Ae+K16Z496XIwbgv4uDqV5Qkaaa2NrCk9tIhRdT/6tGczmbGJ5 2g6oS5C+QFCk5IRlRMbS/bQ= X-Google-Smtp-Source: ANB0VdaydCf+S8TKtU6iRezEAjxa+5SA2h6VRhveyyMCTHX4UuKlkN4fmqOsp6/QNZx9HWsI/W7S7w== X-Received: by 2002:a17:902:b70f:: with SMTP id d15-v6mr5126250pls.53.1535531890121; Wed, 29 Aug 2018 01:38:10 -0700 (PDT) Received: from ?IPv6:2601:647:4580:b719:fdb9:18c9:b2e3:3456? ([2601:647:4580:b719:fdb9:18c9:b2e3:3456]) by smtp.gmail.com with ESMTPSA id s195-v6sm5591525pgs.76.2018.08.29.01.38.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Aug 2018 01:38:09 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) Subject: Re: Flushing user entries for kernel mappings in x86 From: Nadav Amit In-Reply-To: Date: Wed, 29 Aug 2018 01:37:55 -0700 Cc: Linux Kernel Mailing List Content-Transfer-Encoding: quoted-printable Message-Id: <7EDEB913-E4F8-481F-93D3-EE158641A366@gmail.com> References: <8F811430-A9D5-446C-9D6A-C4CA82555559@gmail.com> To: Andy Lutomirski X-Mailer: Apple Mail (2.3445.9.1) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org at 8:45 PM, Andy Lutomirski wrote: > On Tue, Aug 28, 2018 at 6:46 PM, Nadav Amit = wrote: >> Hello Andy, >>=20 >> 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 = ]. >=20 > 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. Thanks. I assumed that=E2=80=99s the case. I don=E2=80=99t know how = cheap they are (especially if INVPCID is not supported) but I guess they are not that frequent.