On Tue, Jan 24, 2017 at 03:09:59PM -0500, David Miller wrote: > From: "Michael S. Tsirkin" <mst@xxxxxxxxxx> > Date: Tue, 24 Jan 2017 21:53:13 +0200 > > > I didn't realise. Why can't we? I thought that adjust_header is an > > optional feature that userspace can test for, so no rush. > > No, we want the base set of XDP features to be present in all drivers > supporting XDP. I see, I didn't realize this. In light of this, is there any guidance *how much* head room is required to be considered valid? We already have 12 bytes of headroom. I'm generally sorry it's taking long, a large part of that is difficulty figuring out the requirements: when we discussed this on LPC my take-away was that one of the first users will be fighting DDOS attacks. In light of this, I assumed that - supporting just DROP (or DROP+TX) would already be useful - XDP_PASS shouldn't be too slow as some people will run all their traffic with XDP enabled - people actually want this in virtio because they run in a vm Since then I heard opinions that seem to imply that - you must support all features, not just DROP, otherwise it's useless - XDP_PASS is a slow path fallback as people are not expected to mix XDP with regular sockets - DDOS protection and by extension XDP in virtio is a developer's toy anyway Thus, expect some slowness while I figure it all out. -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
