From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vincent JARDIN Subject: Re: [PATCH 2/2] virtio: allow running w/o vlan filtering Date: Tue, 04 Aug 2015 14:51:48 +0200 Message-ID: <55C0B564.1090509@6wind.com> References: <1425602726-26538-1-git-send-email-stephen@networkplumber.org> <20150306082436.43415409@urahara> <205454145.ebl7zG6qks@xps13> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: dev@dpdk.org To: Thomas Monjalon , "Ouyang, Changchun" Return-path: Received: from mail-wi0-f171.google.com (mail-wi0-f171.google.com [209.85.212.171]) by dpdk.org (Postfix) with ESMTP id 64B9AC340 for ; Tue, 4 Aug 2015 14:51:50 +0200 (CEST) Received: by wibud3 with SMTP id ud3so22419951wib.0 for ; Tue, 04 Aug 2015 05:51:50 -0700 (PDT) In-Reply-To: <205454145.ebl7zG6qks@xps13> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Thomas, Changchun, On 29/07/2015 14:56, Thomas Monjalon wrote: > Back on this old patch, it seems justified but nobody agreed. > > --- a/lib/librte_pmd_virtio/virtio_ethdev.c > +++ b/lib/librte_pmd_virtio/virtio_ethdev.c > @@ -1288,7 +1288,6 @@ virtio_dev_configure(struct rte_eth_dev *dev) > && !vtpci_with_feature(hw, VIRTIO_NET_F_CTRL_VLAN)) { > PMD_DRV_LOG(NOTICE, > "vlan filtering not available on this host"); > - return -ENOTSUP; > } > > 2015-03-06 08:24, Stephen Hemminger: >> "Ouyang, Changchun" wrote: >>>> From: Stephen Hemminger >>>> Vlan filtering is an option, and not a requirement. >>>> If host does not support filtering then it can be done in software. +1 with Stephen, remove return -ENOTSUP; applications must not fail, software stacks will handle it. We did experiment some issues when testpmd was failing while it was supposed to run. A notice would be good enough. >>> >>> The question is that guest only send command, no real action to do the vlan filter. >>> So if both host and guest have no real action for vlan filter, who will do it? >> >> The virtio driver has features. >> Guest can not send commands to host where feature bit not enabled. >> Application can call filter_set and check if filter worked or not. >> >> Our code already had to do MAC and VLAN validation of incoming packets >> therefore if hardware can't do vlan match, there is no problem. >> I would expect other applications would do the same thing. >> >> Failing during configuration is bad. DPDK API should never force >> application to play "guess the working configuration" with the device >> driver or do string match on "which device is this anyway" Agree, it is not a failure of a configuration, it is a failure of negotiation of virtio's capabilities. Let's use another example: we do not expect a guest kernel to panic() because it is not properly negotiated? So why should a DPDK application fail and return -ENOTSUP? Thank you, Vincent