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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 DC075C433F4 for ; Fri, 24 Aug 2018 19:32:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 83E0E2151C for ; Fri, 24 Aug 2018 19:32:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="XODSPtma" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 83E0E2151C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org 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 S1726992AbeHXXII (ORCPT ); Fri, 24 Aug 2018 19:08:08 -0400 Received: from mail-it0-f50.google.com ([209.85.214.50]:52612 "EHLO mail-it0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726728AbeHXXII (ORCPT ); Fri, 24 Aug 2018 19:08:08 -0400 Received: by mail-it0-f50.google.com with SMTP id g18-v6so3616061itg.2 for ; Fri, 24 Aug 2018 12:32:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=UTGa7sDU/z28MVac97/J+iDgWoqaFqtnUCGAtC6fPGk=; b=XODSPtmamULoJSXqfxmGJR4prRFTbt6iKQKblIbdvfVJp9YRsB9LdaR6eNDmOq0luA kOKxl7oeIXg9aVjGbYaqL47UErl5FkUhvjgZuq3g0qRx4PReaOYNgnE0qI6veUMiYLB/ uSL/QFoza0IikdDc2/FqF4YySYJD2St+RSuLw= 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=UTGa7sDU/z28MVac97/J+iDgWoqaFqtnUCGAtC6fPGk=; b=CP4tKkFCfkKIz3azcBBqAVEtStcsm1iPh8TleuuHBTpEvNOHl4dVIRlFt9wR+S/28t LTE0Z6lZxBC69kiXbc/uwGpH85465Cq5ohzknzYMCFfL1GtlOFVlDfK0B+Hxt5Ig5j/K 8p+bdhKO/A5xdPOtll2gEzqLvHeeELt4h6mZzqJ8kJ8Pj6iZymYrbkxTiQSh/3xOMlSI SEn2ua0SwA/u13OQrYhDHb+uRymto839ncjDb4zPoJ6u/4jT+GZtEGN9HgL/udek0n9i yBmVowjLd8OC6X1rdDbsYxQCDSWkmkWQnfKUDKdzPfS9noWvwddcB6O2UdxiXp/E/g5A 8/GA== X-Gm-Message-State: APzg51C2Uf55u377pYucBeYCUcK5sc99n/HbmJHzASO4y1XZ/EVaqkYt N5lkFeOezmzupjUReZCqvhjm41j0OaCi6fg4bQg= X-Google-Smtp-Source: ANB0VdbAXanCnUVqfoMV3Qmf/wNpGz8LzeDxYsm5W+upahy7y2uob+hUWsmF5eYldSTRtidSSqEPSOKPVUsvMT+WLiA= X-Received: by 2002:a24:3046:: with SMTP id q67-v6mr2620693itq.9.1535139129385; Fri, 24 Aug 2018 12:32:09 -0700 (PDT) MIME-Version: 1.0 References: <20180822153012.173508681@infradead.org> <20180822154046.823850812@infradead.org> <20180822155527.GF24124@hirez.programming.kicks-ass.net> <20180823134525.5f12b0d3@roar.ozlabs.ibm.com> <776104d4c8e4fc680004d69e3a4c2594b638b6d1.camel@au1.ibm.com> <20180823133958.GA1496@brain-police> <20180824084717.GK24124@hirez.programming.kicks-ass.net> <20180824180438.GS24124@hirez.programming.kicks-ass.net> <56A9902F-44BE-4520-A17C-26650FCC3A11@gmail.com> In-Reply-To: <56A9902F-44BE-4520-A17C-26650FCC3A11@gmail.com> From: Linus Torvalds Date: Fri, 24 Aug 2018 12:31:57 -0700 Message-ID: Subject: Re: TLB flushes on fixmap changes To: Nadav Amit Cc: Peter Zijlstra , Will Deacon , Benjamin Herrenschmidt , Nick Piggin , Andrew Lutomirski , "the arch/x86 maintainers" , Borislav Petkov , Rik van Riel , Jann Horn , Adin Scannell , Dave Hansen , Linux Kernel Mailing List , linux-mm , David Miller , Martin Schwidefsky , Michael Ellerman 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, Aug 24, 2018 at 11:36 AM Nadav Amit wrote: > > > > > Urgh.. weren't the fixmaps per cpu? Bah, I remember looking at this > > during PTI, but I seem to have forgotten everything again. > > [ Changed the title. Sorry for hijacking the thread. ] > > Since: > > native_set_fixmap()->set_pte_vaddr()->pgd_offset_k() The fixmaps should be entirely fixed after bootup to constant mappings, except for the KMAP ones, and they are indexed per-cpu. That's what my mental model is, at least. Can you actually find something that changes the fixmaps after boot (again, ignoring kmap)? Maybe worth adding some debugging to verify that? Linus