From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v2 0/3] Restore UFO support to virtio_net devices Date: Sun, 01 Feb 2015 22:19:35 -0800 (PST) Message-ID: <20150201.221935.283572621026340671.davem@davemloft.net> References: <1422646047-13168-1-git-send-email-vyasevic@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: eric.dumazet@gmail.com, mst@redhat.com, netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, hannes@stressinduktion.org, ben@decadent.org.uk To: vyasevich@gmail.com Return-path: In-Reply-To: <1422646047-13168-1-git-send-email-vyasevic@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org From: Vladislav Yasevich Date: Fri, 30 Jan 2015 14:27:24 -0500 > commit 3d0ad09412ffe00c9afa201d01effdb6023d09b4 > Author: Ben Hutchings > Date: Thu Oct 30 18:27:12 2014 +0000 > > drivers/net: Disable UFO through virtio > > Turned off UFO support to virtio-net based devices due to issues > with IPv6 fragment id generation for UFO packets. The issue > was that IPv6 UFO/GSO implementation expects the fragment id > to be supplied in skb_shinfo(). However, for packets generated > by the VMs, the fragment id is not supplied which causes all > IPv6 fragments to have the id of 0. > > The problem is that turning off UFO support on tap/macvtap > as well as virtio devices caused issues with migrations. > Migrations would fail when moving a vm from a kernel supporting > expecting UFO to work to the newer kernels that disabled UFO. > > This series provides a partial solution to address the migration > issue. The series allows us to track whether skb_shinfo()->ip6_frag_id > has been set by treating value of 0 as unset. > This lets GSO code to generate fragment ids if they are necessary > (ex: packet was generated by VM or packet socket). > > Since v1: > - Removed the skb bit and use value of 0 as tracker. > - Used Eric's suggestion to set fragment id as 0x80000000 if id > generation procedure yeilded a 0 result. > - Consolidated ipv6 id genration code. Series applied and queued up for -stable. There was some trailing whitespace in patch #1, which I fixed up.