> -----Original Message----- > From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> > Sent: Tuesday, October 29, 2019 5:59 PM > To: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > Cc: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>; sashal@xxxxxxxxxx; > linux-hyperv@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; KY Srinivasan > <kys@xxxxxxxxxxxxx>; Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>; > olaf@xxxxxxxxx; vkuznets <vkuznets@xxxxxxxxxx>; davem@xxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH net-next, 3/4] hv_netvsc: Add XDP support > > On Tue, 29 Oct 2019 19:17:25 +0000 > Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> wrote: > > > > -----Original Message----- > > > From: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx> > > > Sent: Monday, October 28, 2019 5:33 PM > > > To: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > > > Cc: sashal@xxxxxxxxxx; linux-hyperv@xxxxxxxxxxxxxxx; > > > netdev@xxxxxxxxxxxxxxx; KY Srinivasan <kys@xxxxxxxxxxxxx>; Stephen > > > Hemminger <sthemmin@xxxxxxxxxxxxx>; olaf@xxxxxxxxx; vkuznets > > > <vkuznets@xxxxxxxxxx>; davem@xxxxxxxxxxxxx; linux- > > > kernel@xxxxxxxxxxxxxxx > > > Subject: Re: [PATCH net-next, 3/4] hv_netvsc: Add XDP support > > > > > > On Mon, 28 Oct 2019 21:07:04 +0000, Haiyang Zhang wrote: > > > > This patch adds support of XDP in native mode for hv_netvsc driver, > and > > > > transparently sets the XDP program on the associated VF NIC as well. > > > > > > > > XDP program cannot run with LRO (RSC) enabled, so you need to > disable > > > LRO > > > > before running XDP: > > > > ethtool -K eth0 lro off > > > > > > > > XDP actions not yet supported: > > > > XDP_TX, XDP_REDIRECT > > > > > > I don't think we want to merge support without at least XDP_TX these > > > days.. > > Thanks for your detailed comments -- > > I'm working on the XDP_TX... > > > > > > > > And without the ability to prepend headers this may be the least > > > complete initial XDP implementation we've seen :( > > The RNDIS packet buffer received by netvsc doesn't have a head room, but > I'm > > considering copy the packets to the page buffer, with a head room space > > reserved for XDP. > > > There is a small amount of headroom available by reusing the RNDIS > header and packet space. Looks like 40 bytes or so. Yes, I thought about the RNDIS header. But is this space sufficient? I saw some drivers, like virtio_net gives bigger headroom: 256 bytes. Thanks, - Haiyang
