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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 068CAC433E0 for ; Mon, 25 May 2020 12:26:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CBFF020812 for ; Mon, 25 May 2020 12:26:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="M8B6svJX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390571AbgEYM0K (ORCPT ); Mon, 25 May 2020 08:26:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390505AbgEYM0J (ORCPT ); Mon, 25 May 2020 08:26:09 -0400 Received: from mail-qt1-x841.google.com (mail-qt1-x841.google.com [IPv6:2607:f8b0:4864:20::841]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53917C05BD43 for ; Mon, 25 May 2020 05:26:09 -0700 (PDT) Received: by mail-qt1-x841.google.com with SMTP id i68so13647849qtb.5 for ; Mon, 25 May 2020 05:26:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=v+B1785OZUouPASW2jrMekMBCWgZaLFpUTHdleb2VxA=; b=M8B6svJXr54wgpkQnxJoxOPnFoG3xoaPb76kANRmbKzt4nMw3qxD/q1sXASpcEEWgF gHuA1+7j+0GHGEQqXQhNV3CKJGJ9y8q3jm3bRbRkWZKx1ilA8ceQcZUG0kUCYhtO2MZ7 o4kqO2LyZq2faf/NlIVIMBkKLeXoa88R/AW3tpprsWHR3SjzEi7iaSys03D2VbMtewxD KWhdY5a9O/4fZ5uesQirQ2lMyaFJfuB2R2HsT37n64J/gUu+48rbi4zf1W71+HPlLCgg RS6kJEq84BAk2ESnQHLB8txIWUSWrjJBBQcE2f/WAF2FVslapUIbMMvrwY16wMa3EvYc Oywg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=v+B1785OZUouPASW2jrMekMBCWgZaLFpUTHdleb2VxA=; b=oC7WKjOyRX1sPtMYcz5URt5vsWLUAyK1jnhK7rHw4kcUtO7Qr8dyRDQHzjjMcGrjLu Jese0AVGs3tJYJvFNldPUOkRtjtep2jZjNEjSCYSsLBWPRuyxV8ZA7JiY1keyM/8o18E S55mUmqMGBMpeHUQJH1A7wkj7ClNTZn4gSG+CB/TQTYLhk94a87gwpwg2V3nI3/OJ+9T HpQI+/mIO7RD876R3/Q6Qm9lZFn/1dlMzQS7pqUmZYqGVS6eOC//lWrTALHl9UREfd5Q iRfjbqe+KdiPK8VdRcyj+zZNHtpfm9cVk/gjjhhb9PbrPobhHuSbIkluPN3kEpUluX2l whYA== X-Gm-Message-State: AOAM531HqMUbeaUsi4NRiEC55wW7z7ACv6bK/4YGeWPZOaYC2QQlEx4E vsfrdpyyA05vF8NJz6mzpBzY9w== X-Google-Smtp-Source: ABdhPJwk7SIlqGjBIUWz/0hGbccyh9qfHeyY8qv0Rau9jFzIYCDNLUkjNci7H9c03NXVt63ilIK9QA== X-Received: by 2002:aed:278d:: with SMTP id a13mr2961124qtd.23.1590409568569; Mon, 25 May 2020 05:26:08 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id l2sm13637889qkd.57.2020.05.25.05.26.07 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Mon, 25 May 2020 05:26:08 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1jdCBD-0007ON-FH; Mon, 25 May 2020 09:26:07 -0300 Date: Mon, 25 May 2020 09:26:07 -0300 From: Jason Gunthorpe To: Peter Xu Cc: Alex Williamson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, cohuck@redhat.com, cai@lca.pw Subject: Re: [PATCH v3 3/3] vfio-pci: Invalidate mmaps and block MMIO access on disabled memory Message-ID: <20200525122607.GC744@ziepe.ca> References: <159017449210.18853.15037950701494323009.stgit@gimli.home> <159017506369.18853.17306023099999811263.stgit@gimli.home> <20200523193417.GI766834@xz-x1> <20200523170602.5eb09a66@x1.home> <20200523235257.GC939059@xz-x1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200523235257.GC939059@xz-x1> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 23, 2020 at 07:52:57PM -0400, Peter Xu wrote: > For what I understand now, IMHO we should still need all those handlings of > FAULT_FLAG_RETRY_NOWAIT like in the initial version. E.g., IIUC KVM gup will > try with FOLL_NOWAIT when async is allowed, before the complete slow path. I'm > not sure what would be the side effect of that if fault() blocked it. E.g., > the caller could be in an atomic context. AFAICT FAULT_FLAG_RETRY_NOWAIT only impacts what happens when VM_FAULT_RETRY is returned, which this doesn't do? It is not a generic 'do not sleep' Do you know different? Jason