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 AECA0C47254 for ; Tue, 5 May 2020 18:36:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85BED206FA for ; Tue, 5 May 2020 18:36:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="YxFtUSCK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726618AbgEESgd (ORCPT ); Tue, 5 May 2020 14:36:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728356AbgEESgc (ORCPT ); Tue, 5 May 2020 14:36:32 -0400 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52E4DC061A10 for ; Tue, 5 May 2020 11:36:32 -0700 (PDT) Received: by mail-qk1-x741.google.com with SMTP id c64so470270qkf.12 for ; Tue, 05 May 2020 11:36:32 -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=eqlnqG0Hw3VMrzuvRcCdGu4ewQLAPeQsUkr54n/Ba44=; b=YxFtUSCKjaM3W/DhClEwL6MT2JsMzpVzLJW8cImgeavPLCOQmKCbaprWQUzSmTPxQt TkhFaSHthPlrIfE7m7euz3TWtITCCv70E6r59bQT/fbfkij9Qm61XrWixDwS6hJcre2K S0NhYhIAK1l0JSHO4yV4bsTJEynaLPmS9eVY9PkLpNN/lX1J38Psw3dkO3NQHPsKsBW3 ZxSArF7+ab99cqFBi7Bsddjcr3DhUX6TUUjztYWBQyOW2oaAl9VXNvFTlA1ggWSvakhR eLXIR17oPrlMlKE/OjepKL2fjaxWqYGPxwOSkXs6D/dmOfSJINu+WIKyS5i7IZYdIGZq Qs6g== 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=eqlnqG0Hw3VMrzuvRcCdGu4ewQLAPeQsUkr54n/Ba44=; b=JHFd1eo/3rX3FT3hpqIKjL/FtPiyvV139DGI2Wdkiyw6HHQbmX+wx74DnlaKskhgWK SOp6WfaySdwyQZbPkbJ+noDqJqCG0CBEyPxEkLWSI4PBi2pmSmfDgQuAmou46O6WMk6x 1guUu5y7M3QWUnWywcLIXTwbSSn+Uuz7OunfiUlQT4Rx/73txJ5SDqwbaGH6ajrQ24dH JKji/Y73v2/YsPinkzTnn554+glZBtq4tW2w5D3GhgYGdgSijv0j3ifbg4lbd7XZTZe5 WS01g2+4szxy8WbyBKRVHPUTAtU4CBEkryIALrLWC8huPLE3eiwpdTvZqbBYYnIeZe/M ihhg== X-Gm-Message-State: AGi0PuZMjR8qvzvHFxE5FQEsry51mKFqsWPo65hllPMMYvEMequ5f6xp VnD2GomdH9sNjeMh4BBVcYUGahuMmDw= X-Google-Smtp-Source: APiQypJ7O8355ctgKfdq6OC10TRz+pU+Ntr4Qbbn9r6Z9ZCC2YPs9LO4Kx0pmGe6yNVVy3N4mhJfNQ== X-Received: by 2002:a37:7904:: with SMTP id u4mr4789865qkc.297.1588703791311; Tue, 05 May 2020 11:36:31 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-68-57-212.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.57.212]) by smtp.gmail.com with ESMTPSA id g12sm2312319qtu.69.2020.05.05.11.36.30 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 05 May 2020 11:36:30 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1jW2Qf-0007Sj-HD; Tue, 05 May 2020 15:36:29 -0300 Date: Tue, 5 May 2020 15:36:29 -0300 From: Jason Gunthorpe To: Alex Williamson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, cohuck@redhat.com, peterx@redhat.com Subject: Re: [PATCH 3/3] vfio-pci: Invalidate mmaps and block MMIO access on disabled memory Message-ID: <20200505183629.GF26002@ziepe.ca> References: <158836742096.8433.685478071796941103.stgit@gimli.home> <158836917028.8433.13715345616117345453.stgit@gimli.home> <20200501234849.GQ26002@ziepe.ca> <20200504122643.52267e44@x1.home> <20200504184436.GZ26002@ziepe.ca> <20200504133552.3d00c77d@x1.home> <20200504200123.GA26002@ziepe.ca> <20200505111227.02ac9cee@w520.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200505111227.02ac9cee@w520.home> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, May 05, 2020 at 11:12:27AM -0600, Alex Williamson wrote: > > As noted in the comment, the fault handler can simply do: > > mutex_lock(&vdev->vma_lock); > down_read(&vdev->memory_lock); > > This should be deadlock free now, so we can drop the retry handling That does look like the right direction, because the memory_lock can be done at the very end it means it doesn't need to be nested inside mmap_sem This is much cleaner! Jason