[PATCH v2 net-next 0/3] virtio_net: Implement VIRTIO_NET_F_OUT_NET_HEADER from virtio spec 1.4

[Kommula Shiva Shankar <kshankar@marvell.com>]

This series implements the VIRTIO_NET_F_OUT_NET_HEADER feature which was introduced in the virtio specification 1.4 recently.
With this change, segmentation offload functionality now propagates outer IP header offset information to the device/apps running on NIC.

The virtio 1.4 spec introduced VIRTIO_NET_F_OUT_NET_HEADER feature[1] to address the performance issue caused by reading packet data
to determine outer network header offset and to support Inline IPSec functionality,
where vendor hardware devices need to know the outer network header offset for Inline IPSec acceleration.

Currently, devices must parse through packet headers to determine the outer network header which impacts performance.
This patch series implements the outer_nh_offset field in virtio_net_hdr to avoid parsing overhead.

This series was tested on ARM platform with virtio-net driver where ~4% performance improvement was measured
for device applications.

V1 -> V2: Added IPv6 support to outer network header offset feature 
	  Fixed sparse build warnings

[1] https://lore.kernel.org/virtio-comment/20250401195655.486230-1-kshankar@marvell.com/

Kommula Shiva Shankar (3):
  net: implement virtio helper to handle outer nw offset
  virtio_net: enable outer nw header offset support
  vhost/net: enable outer nw header offset support

 drivers/net/virtio_net.c        | 23 +++++++++++++++----
 drivers/vhost/net.c             |  4 ++++
 include/linux/virtio_net.h      | 40 +++++++++++++++++++++++++++++++++
 include/uapi/linux/virtio_net.h |  8 +++++++
 4 files changed, 71 insertions(+), 4 deletions(-)

-- 
2.48.1