From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id B56252C2A for ; Wed, 28 Sep 2016 01:11:26 +0200 (CEST) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga102.jf.intel.com with ESMTP; 27 Sep 2016 16:11:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,407,1470726000"; d="scan'208";a="1046712135" Received: from yliu-dev.sh.intel.com (HELO yliu-dev) ([10.239.67.162]) by fmsmga001.fm.intel.com with ESMTP; 27 Sep 2016 16:11:24 -0700 Date: Wed, 28 Sep 2016 07:11:59 +0800 From: Yuanhan Liu To: "Dey, Souvik" Cc: Stephen Hemminger , "Kavanagh, Mark B" , "dev@dpdk.org" Message-ID: <20160927231159.GA5164@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> <20160927115634.428d1b7d@xeon-e3> 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: Tue, 27 Sep 2016 23:11:27 -0000 On Tue, Sep 27, 2016 at 08:44:20PM +0000, Dey, Souvik wrote: > Hi Stephen, > So what should be my next steps , should I submit a v7 for this patch or you suggest otherwise. Yes, please. Another note is please don't use white space for indentation, use TAB instead. -yliu > > -- > Regards, > Souvik > > -----Original Message----- > From: Stephen Hemminger [mailto:stephen@networkplumber.org] > Sent: Tuesday, September 27, 2016 2:57 PM > To: Dey, Souvik > Cc: Kavanagh, Mark B ; Yuanhan Liu ; dev@dpdk.org > Subject: Re: [PATCH v6] net/virtio: add set_mtu in virtio > > On Fri, 23 Sep 2016 15:17:37 +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. > > > > This patch is good enough for now, but not fully correct. > The actual max value depends on the host negotiation protocol, ie merge rx buf is only sometimes used. > > There was some discussion on netdev mailing list to pass MTU from host to guest in virtio, not sure where that landed.