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=-7.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,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 6D0B0C4708A for ; Thu, 27 May 2021 04:13:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53089613D8 for ; Thu, 27 May 2021 04:13:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229706AbhE0EOq (ORCPT ); Thu, 27 May 2021 00:14:46 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:25014 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229692AbhE0EOp (ORCPT ); Thu, 27 May 2021 00:14:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622088792; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=q3igEycLd8J73C7Vxb8Ui44QuvOprk+cULPfcPtYoIg=; b=QFdc+ari0AIkQho7ZuWviXnT6YLKKHox7vh4d/LpQ7EaRavPHH0nekqPuTcJEIztGRMmuV SXATnMWMK4sDVnHvVXgpJFQAe5RByazoRNWWOxzVEagnHCOwcAZ50xNFfv6JE+m4SO29u9 t/U+pFUY8xRs4sIZ3hoWB37rjK81GuE= Received: from mail-pj1-f72.google.com (mail-pj1-f72.google.com [209.85.216.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-386-FlU6jLdfP4uDEJwk8HLPLQ-1; Thu, 27 May 2021 00:13:08 -0400 X-MC-Unique: FlU6jLdfP4uDEJwk8HLPLQ-1 Received: by mail-pj1-f72.google.com with SMTP id cv23-20020a17090afd17b029015cdd292fe8so1657205pjb.8 for ; Wed, 26 May 2021 21:13:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=q3igEycLd8J73C7Vxb8Ui44QuvOprk+cULPfcPtYoIg=; b=AAYrC/G9TKe7LVNu+cZ+UEtBGUXLTAw6JBc3W5o279Dre+H08O9+yD309gXq5CkHWG rCQboB+7KXngVhegW13YI/GZ9eC/bBVP5gEhLEOxKt1jWUp4Hlh+ybcEBWe/y5e37nRU T2/g/gtUv5DOtVLRGceqFRCdQSfz/0tax16pEIDRbCP0+nCn7b7M9RxTscVLT+fKp5OJ b6i24vjA5RbIScSZjBPS6Dy4HHHzAjdL/h3/wK8zHs+SitKMjhYV0bibHH4U1tRRQJpA YrG1Jj36jERz1VIr0olhbd3xfpz+0uFbLczNBdA41VkyqJzjku1yjO5YfOs2K7S+1XC4 T3dg== X-Gm-Message-State: AOAM530FrWoQu+GSvEx6g0C1b2UGzkwhnFMGpbtFD1xyg1lQUYCXU2xh cahm5zFvJxi3KGxesomxWiiWuzvIuvSNSgtXoo88C1r797c4cOe9i1SGIwNXkVa7hEMCLd5u/YH /xQ1nVTX/16Zi X-Received: by 2002:a63:3c0e:: with SMTP id j14mr1842312pga.427.1622088787573; Wed, 26 May 2021 21:13:07 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzNWCYMnMC1HxMoP07R/3S3m3jilU3dNCIEmruTMAtVdxqR2yiJbYdkUNhO/NZQxyTwe/4ddA== X-Received: by 2002:a63:3c0e:: with SMTP id j14mr1842274pga.427.1622088787269; Wed, 26 May 2021 21:13:07 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id c134sm622801pfb.135.2021.05.26.21.13.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 May 2021 21:13:06 -0700 (PDT) Subject: Re: [PATCH v7 11/12] vduse: Introduce VDUSE - vDPA Device in Userspace To: Xie Yongji , mst@redhat.com, stefanha@redhat.com, sgarzare@redhat.com, parav@nvidia.com, hch@infradead.org, christian.brauner@canonical.com, rdunlap@infradead.org, willy@infradead.org, viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org, corbet@lwn.net, mika.penttila@nextfour.com, dan.carpenter@oracle.com, joro@8bytes.org Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20210517095513.850-1-xieyongji@bytedance.com> <20210517095513.850-12-xieyongji@bytedance.com> From: Jason Wang Message-ID: <3740c7eb-e457-07f3-5048-917c8606275d@redhat.com> Date: Thu, 27 May 2021 12:12:58 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <20210517095513.850-12-xieyongji@bytedance.com> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org ÔÚ 2021/5/17 ÏÂÎç5:55, Xie Yongji дµÀ: > + > +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 forever? It looks like a DOS. If yes, we need to consider a way to fix that. Thanks > + spin_lock(&dev->msg_lock); > + if (!msg->completed) { > + list_del(&msg->list); > + msg->resp.result = VDUSE_REQUEST_FAILED; > + } > + spin_unlock(&dev->msg_lock); > + > + return (msg->resp.result == VDUSE_REQUEST_OK) ? 0 : -1; > +}