Re: [PATCH net-next RFC WIP] Patch for XDP support for virtio_net
From: David Miller <davem@davemloft.net>
Date: 2016-10-26 16:52:49
From: David Miller <davem@davemloft.net>
Date: 2016-10-26 16:52:49
From: "Michael S. Tsirkin" <mst@redhat.com> Date: Wed, 26 Oct 2016 19:36:45 +0300
On Wed, Oct 26, 2016 at 03:52:02PM +0200, Jesper Dangaard Brouer wrote:quoted
On Sat, 22 Oct 2016 04:07:23 +0000 Shrijeet Mukherjee [off-list ref] wrote:quoted
This patch adds support for xdp ndo and also inserts the xdp program call into the merged RX buffers and big buffers pathsI really appreciate you are doing this for virtio_net. My first question is: Is the (packet) page data writable? (MST might be able to answer?) As this is currently an XDP requirement[1].I'm not sure I understand what does writable mean. Could you explain a bit more pls? We do copy data into skb ATM but I plan to change that.
The packet data area must be writable, and the page it lives in must not be shared with any other entity in the system. This is because the eBPF program that executes via XDP must be able to modify and read arbitrary parts of the packet area.