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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 EAD62C433E6 for ; Wed, 10 Mar 2021 20:07:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B287F64FCD for ; Wed, 10 Mar 2021 20:07:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232098AbhCJUGk (ORCPT ); Wed, 10 Mar 2021 15:06:40 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:39766 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232089AbhCJUGO (ORCPT ); Wed, 10 Mar 2021 15:06:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615406773; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=MZqOerku4ka3IhMUBjG/XTRlN6lYxBxQ2MLf7EPvQE8=; b=YsVScwomaOWWykcBchGPe3qU1/WmuiEM6y25aPuNOYYhURbOAWgconkgYwyFDpvKAU00qR dRQV9YUN+Z4ETpWFqTrMNEu2hu/HBIKkMHZFAdzU9mnKYg8ed2mIpQ5I9uSDs9zzlUFKxu s/oW1AjgKbt5a/q+q9eKjE05BYm6LAk= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-318-3bzfaoFoN6qBV-X5jo3hhA-1; Wed, 10 Mar 2021 15:06:09 -0500 X-MC-Unique: 3bzfaoFoN6qBV-X5jo3hhA-1 Received: by mail-qk1-f198.google.com with SMTP id x11so10469830qki.22 for ; Wed, 10 Mar 2021 12:06:09 -0800 (PST) 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; bh=MZqOerku4ka3IhMUBjG/XTRlN6lYxBxQ2MLf7EPvQE8=; b=UzXgzP2y1tbMo6lu3NhOHHztiaSyQhUMaeLqcw7nHNXrEwFeWG5zpG2bstYjg20j8F hy6tgtay9L1X8Obcogcmxc1G4iYITxaBX/XXvvUkh3yNHmwM9/FX3564XccdA5sWfcM5 CLi9XadBUQGB59QFq3uuOPTUtRCXc4Wk0wdbNmvtlboNjMUjsuc9fVuclCJ/tQQS8D5i UF+5MXbtShRXY6h7NTk8rgPO+MUYSX7zgSfsZcQyScWEMk8WbplwcLioJvFEb7LIxQBX G678ZyFNUZGEGF0ODHb+K7hjcNh5rPV5O9R7nFGYUXKc9uBIbIavLYZMoj9cGqLhcW0e NHeA== X-Gm-Message-State: AOAM531bEPV7VtKVSTFBL8Ep+joDNnJUFt+X3wDSsHQhqAx7lvZgLQ3o xcVFSrt7wcoBEVcczgulQUwRDkV2eeEcFSiLKFtO0Mo2S0Pz1oaoMgFTqngIO4dmwhKKW84iDnR tik8Boj0vl8xVT9OgXqtueSeE X-Received: by 2002:aed:3741:: with SMTP id i59mr2410753qtb.303.1615406769019; Wed, 10 Mar 2021 12:06:09 -0800 (PST) X-Google-Smtp-Source: ABdhPJzT3IYnqEF4ggAfCl202qrDbK8JrUuXkacUIxpIN6UHTxsbOnQgsrU2TqIx7iJ6zbkiigwpgA== X-Received: by 2002:aed:3741:: with SMTP id i59mr2410742qtb.303.1615406768814; Wed, 10 Mar 2021 12:06:08 -0800 (PST) Received: from xz-x1 ([142.126.89.138]) by smtp.gmail.com with ESMTPSA id 131sm284373qkl.74.2021.03.10.12.06.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Mar 2021 12:06:08 -0800 (PST) Date: Wed, 10 Mar 2021 15:06:07 -0500 From: Peter Xu To: Jason Gunthorpe Cc: Alex Williamson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, prime.zeng@hisilicon.com, cohuck@redhat.com Subject: Re: [PATCH] vfio/pci: Handle concurrent vma faults Message-ID: <20210310200607.GG6530@xz-x1> References: <161539852724.8302.17137130175894127401.stgit@gimli.home> <20210310181446.GZ2356281@nvidia.com> <20210310113406.6f029fcf@omen.home.shazbot.org> <20210310184011.GA2356281@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210310184011.GA2356281@nvidia.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 10, 2021 at 02:40:11PM -0400, Jason Gunthorpe wrote: > On Wed, Mar 10, 2021 at 11:34:06AM -0700, Alex Williamson wrote: > > > > I think after the address_space changes this should try to stick with > > > a normal io_rmap_pfn_range() done outside the fault handler. > > > > I assume you're suggesting calling io_remap_pfn_range() when device > > memory is enabled, > > Yes, I think I saw Peter thinking along these lines too > > Then fault just always causes SIGBUS if it gets called Indeed that looks better than looping in the fault(). But I don't know whether it'll be easy to move io_remap_pfn_range() to device memory enablement. If it's a two-step thing, we can fix the BUG_ON and vma duplication issue first, then the full rework can be done in the bigger series as what be chosen as the last approach. Thanks, -- Peter Xu