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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 D4BE9C47089 for ; Thu, 27 May 2021 05:08:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B84CD613BF for ; Thu, 27 May 2021 05:08:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234999AbhE0FKW (ORCPT ); Thu, 27 May 2021 01:10:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234962AbhE0FKR (ORCPT ); Thu, 27 May 2021 01:10:17 -0400 Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95265C061761 for ; Wed, 26 May 2021 22:08:44 -0700 (PDT) Received: by mail-ed1-x530.google.com with SMTP id b17so4255877ede.0 for ; Wed, 26 May 2021 22:08:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=OSXVSdir/DQunBxCaZTpvHNoZRd/zQTm4r2dtcDMWtM=; b=Vvbum0ssCd8+XnEyC968VOahIXXgmU4IKNsN1jaAy3Xi/Zyluk86fXwOUkXVv5q7x/ ozlOvBIfzB1Q0EnDWElPBUftNOhIElGXoPronS67+OqjMPJRl5M5HthQ16NOU+QVXTGl d06nj18jqbGi2FvwgruGJ5TDg5/5zzS4OhkjCOMPT0BW+QvZJONn/jHhKOjEitB/g9un uZ4zKJUR2lpgON/Vp7ZjI079lUM8BeSNTciJ42C49qtM/axt9XR+CcVSZ0458FatAO0r rAWLRS7Md7dgEprNMklW4zdtk0vbgfXqf5n3KcD2/HLY5Qk7sOX9RIcXkfOmt4k6eLvn ntFw== 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:content-transfer-encoding; bh=OSXVSdir/DQunBxCaZTpvHNoZRd/zQTm4r2dtcDMWtM=; b=aYFJnL+rQFP0ei3jRnD2bvwQtTnrdwv3DFeSDQNvQrwOrLp27epUwBOfqnNLFDJdeo X4HuIWbpI9gHOkayElmgJUcJFAuttik1K/H1AXg5PAjB7lgzVUTPkf+An+x12QkmZ1KY T9WXeSSWL46DFPGukB5YdKhAGBVK0GXSiHrwDocgAm5r8GmmE69Z5EgVoot8QXifD8H5 yn8KiotB2NVj/1o88K1IAWNWxtO1/PqC+qX3ZyRWUvMD2CHxFExgPQ4xQU2CUNaQxChY 0lxSqUL3MWs3pyS86/INbWvj2yOiTunjrBdRsDilQVxKps9hp+CCwpw4RDmy3VyW8JZw ri2w== X-Gm-Message-State: AOAM532enee25+3gv4E7PrNQKnqe68rGpurGkM8jeDRa1qaG8Tzd+Hyv ahV3NUFj75Mo+L+yJjeHo9HXOPlMdhjjS5CujoMN X-Google-Smtp-Source: ABdhPJytcepFP+t2llkhnOjy77FXDbUbzl/ELg4KeaSs2pPDgpTzNqnNIXgN4Trhj3Sx1RCi2B01qTSVklc5dH0EiY8= X-Received: by 2002:a05:6402:22fa:: with SMTP id dn26mr2005986edb.5.1622092123094; Wed, 26 May 2021 22:08:43 -0700 (PDT) MIME-Version: 1.0 References: <20210517095513.850-1-xieyongji@bytedance.com> <20210517095513.850-12-xieyongji@bytedance.com> <3740c7eb-e457-07f3-5048-917c8606275d@redhat.com> <5a68bb7c-fd05-ce02-cd61-8a601055c604@redhat.com> In-Reply-To: <5a68bb7c-fd05-ce02-cd61-8a601055c604@redhat.com> From: Yongji Xie Date: Thu, 27 May 2021 13:08:32 +0800 Message-ID: Subject: Re: Re: [PATCH v7 11/12] vduse: Introduce VDUSE - vDPA Device in Userspace To: Jason Wang Cc: "Michael S. Tsirkin" , Stefan Hajnoczi , Stefano Garzarella , Parav Pandit , Christoph Hellwig , Christian Brauner , Randy Dunlap , Matthew Wilcox , Al Viro , Jens Axboe , bcrl@kvack.org, Jonathan Corbet , =?UTF-8?Q?Mika_Penttil=C3=A4?= , Dan Carpenter , joro@8bytes.org, virtualization , netdev@vger.kernel.org, kvm , linux-fsdevel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 27, 2021 at 1:00 PM Jason Wang wrote: > > > =E5=9C=A8 2021/5/27 =E4=B8=8B=E5=8D=8812:57, Yongji Xie =E5=86=99=E9=81= =93: > > On Thu, May 27, 2021 at 12:13 PM Jason Wang wrote= : > >> > >> =E5=9C=A8 2021/5/17 =E4=B8=8B=E5=8D=885:55, Xie Yongji =E5=86=99=E9=81= =93: > >>> + > >>> +static int vduse_dev_msg_sync(struct vduse_dev *dev, > >>> + struct vduse_dev_msg *msg) > >>> +{ > >>> + init_waitqueue_head(&msg->waitq); > >>> + spin_lock(&dev->msg_lock); > >>> + vduse_enqueue_msg(&dev->send_list, msg); > >>> + wake_up(&dev->waitq); > >>> + spin_unlock(&dev->msg_lock); > >>> + wait_event_killable(msg->waitq, msg->completed); > >> > >> What happens if the userspace(malicous) doesn't give a response foreve= r? > >> > >> It looks like a DOS. If yes, we need to consider a way to fix that. > >> > > How about using wait_event_killable_timeout() instead? > > > Probably, and then we need choose a suitable timeout and more important, > need to report the failure to virtio. > Makes sense to me. But it looks like some vdpa_config_ops/virtio_config_ops such as set_status() didn't have a return value. Now I add a WARN_ON() for the failure. Do you mean we need to add some change for virtio core to handle the failure? Thanks, Yongji