From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by dpdk.org (Postfix) with ESMTP id 839682BA1 for ; Mon, 26 Sep 2016 05:21:04 +0200 (CEST) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP; 25 Sep 2016 20:21:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,397,1470726000"; d="scan'208";a="1056548201" Received: from yliu-dev.sh.intel.com (HELO yliu-dev) ([10.239.67.162]) by orsmga002.jf.intel.com with ESMTP; 25 Sep 2016 20:21:02 -0700 Date: Mon, 26 Sep 2016 11:21:28 +0800 From: Yuanhan Liu To: Stephen Hemminger Cc: "Dey, Souvik" , "Kavanagh, Mark B" , "dev@dpdk.org" Message-ID: <20160926032128.GH23158@yliu-dev.sh.intel.com> References: <20160921231147.26820-1-sodey@sonusnet.com> <20160921162213.4b79d1ce@xeon-e3> <20160921184505.584367ef@xeon-e3> <20160923075320.GY23158@yliu-dev.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Subject: Re: [dpdk-dev] [PATCH v6] net/virtio: add set_mtu in virtio X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Sep 2016 03:21:05 -0000 Hi Stephen, Are you okay with this change? --yliu On Fri, Sep 23, 2016 at 03:17:37PM +0000, Dey, Souvik wrote: > Hi Liu/Mark/Stephen, > > I have tried to modify the code with all of your latest comments. > Do let me know if this looks fine or you have more comments. > > > > Changes done : > > -- max frame ize is compare to VIRTIO_MAX_RX_PKTLEN instead of > dev_info.max_rx_pktlen > > -- removed the CRC_LEN from the ether_len calculation and added the merge rx > buf hdr len. ether_hdr_len = ETHER_HDR_LEN + VLAN_TAG_SIZE + hw->vtnet_hdr_size > > -- Still retained the VLAN Size as the worst case scenario. > > > > > > -- > > drivers/net/virtio/virtio_ethdev.c | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/ > virtio_ethdev.c > > index 423c597..1dbfea6 100644 > > --- a/drivers/net/virtio/virtio_ethdev.c > > +++ b/drivers/net/virtio/virtio_ethdev.c > > @@ -653,12 +653,20 @@ virtio_dev_allmulticast_disable(struct rte_eth_dev *dev) > > PMD_INIT_LOG(ERR, "Failed to disable allmulticast"); > > } > > > > +#define VLAN_TAG_SIZE 4 /* 802.3ac tag (not DMA'd) */ > > + > > +static int virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu) > > +{ > > + struct virtio_hw *hw = dev->data->dev_private; > > + uint32_t ether_hdr_len = ETHER_HDR_LEN + VLAN_TAG_SIZE + hw-> > vtnet_hdr_size; > > + uint32_t frame_size = mtu + ether_hdr_len; > > + > > + if (mtu < ETHER_MIN_MTU || frame_size > VIRTIO_MAX_RX_PKTLEN ) { > > + PMD_INIT_LOG(ERR, "MTU should be between %d and %d\ > n", > > + ETHER_MIN_MTU, VIRTIO_MAX_RX_PKTLEN); > > + return -EINVAL; > > + } > > + return 0; > > +} > > > > /* > > * dev_ops for virtio, bare necessities for basic operation > > */ > > @@ -677,7 +685,6 @@ static const struct eth_dev_ops virtio_eth_dev_ops = { > > .allmulticast_enable = virtio_dev_allmulticast_enable, > > .allmulticast_disable = virtio_dev_allmulticast_disable, > > + .mtu_set = virtio_mtu_set, > > .dev_infos_get = virtio_dev_info_get, > > .stats_get = virtio_dev_stats_get, > > .xstats_get = virtio_dev_xstats_get, > > -- > > Please do let me know if this looks good to you all. Thanks > > > > -- > > Regards, > > Souvik > > > > -----Original Message----- > From: Kavanagh, Mark B [mailto:mark.b.kavanagh@intel.com] > Sent: Friday, September 23, 2016 5:08 AM > To: Yuanhan Liu ; Stephen Hemminger > > Cc: Dey, Souvik ; dev@dpdk.org > Subject: RE: [PATCH v6] net/virtio: add set_mtu in virtio > > > > >Subject: Re: [PATCH v6] net/virtio: add set_mtu in virtio > > > > > >On Wed, Sep 21, 2016 at 06:45:05PM -0700, Stephen Hemminger wrote: > > >> On Thu, 22 Sep 2016 00:08:38 +0000 > > >> "Dey, Souvik" wrote: > > >> > > >> > Answers inline. > > >> > > > >> > -- > > >> > Regards, > > >> > Souvik > > >> > > > >> > -----Original Message----- > > >> > From: Stephen Hemminger [mailto:stephen@networkplumber.org] > > >> > Sent: Wednesday, September 21, 2016 7:22 PM > > >> > To: Dey, Souvik > > >> > Cc: mark.b.kavanagh@intel.com; yuanhan.liu@linux.intel.com; > > >> > dev@dpdk.org > > >> > Subject: Re: [PATCH v6] net/virtio: add set_mtu in virtio > > >> > > > >> > On Wed, 21 Sep 2016 19:11:47 -0400 > > >> > Dey wrote: > > >> > > > >> > > > > >> > > + > > >> > > +#define VLAN_TAG_SIZE 4 /* 802.3ac tag (not DMA'd) */ > > >> > > + > > >> > > +static int virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu) { > > >> > > + struct rte_eth_dev_info dev_info; > > >> > > + uint32_t ether_hdr_len = ETHER_HDR_LEN + ETHER_CRC_LEN + > VLAN_TAG_SIZE; > > >> > > + uint32_t frame_size = mtu + ether_hdr_len; > > >> > > + > > >> > > + virtio_dev_info_get(dev, &dev_info); > > >> > > + > > >> > > + if (mtu < ETHER_MIN_MTU || frame_size > dev_info.max_rx_pktlen) > { > > >> > > + PMD_INIT_LOG(ERR, "MTU should be between %d and %d\n", > > >> > > + ETHER_MIN_MTU, > > >> > > + (dev_info.max_rx_pktlen - > ether_hdr_len)); > > >> > > + return -EINVAL; > > >> > > + } > > >> > > + return 0; > > >> > > +} > > >> > > > >> > I am fine with the general idea of this patch but: > > >> > 1. Calling virtio_dev_info_get is needlessly wasteful when all you want > > >> > is to access the max packet length. Since max_rx_pktlen is always > > >> > VIRTIO_MAX_RX_PKTLEN, please just use that. > > >> > [Dey, Souvik] I am using the virtio_dev_info_get as in future > > >> > can/may support the > > >max_rx_pktlen as a variable to be set by the application. This will > > >keep the changes future proof. As we need to support till 65535 instead of > 9728 as the linux does. > > >> > > >> Fine, then just dereference hw->rx_max_pktlen. Driver code can/should > > >> reference its own data directly. > > > > > >Dey, maybe you could just use VIRTIO_MAX_RX_PKTLEN here, like what you > > >did in early versions. > > > > > >> > > > >> > 2. Defining VLAN_TAG_SIZE is irrelevant if doing vlan offload. > > >> > [Dey, Souvik] vlan offload is not mandatory. Se again still have > > >> > vlan being sent up to > > >the application. In that case we need to consider the vlan length in the > Ethernet size. > > >> > > >> The code needs to handle both vlan offload (or not), correctly. You > > >> are assuming the worst case here. > > > > > >I think we are fine here to assume worst case. > > > > > >> > > > >> > 3. Virtio doesn't insert CRC, therefore CRC_LEN is irrelevant > > >> > [Dey, Souvik] I am not sure of this. Mark commented earlier to consider > this length too. > > >Mark what do you suggest ? > > >> > > >> Actually, the thing that matters is the size of the merge rx buf header, not > the CRC. > > > > > >Right. > > > > My comments were based on my experience with DPDK ethdev PMDs - Stephen and > Yuanhan have much more experience with virtio, so I'd go with their suggestion. > > > > > > > > --yliu > > >> > > >> The patch is still buggy. > > >> >