[PATCH net v10 0/2] virtio-net: fix for VIRTIO_NET_F_GUEST_HDRLEN

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

v10:
  1. fix http://lore.kernel.org/all/202603122214.8Anoxrmq-lkp@intel.com

v9:
  1. Introduce new helpers to set hdr len, and virtio_net_hdr_tnl_from_skb
  calls them directly.

v8:
  1. move changes of virtio_net_hdr_from_skb for udp tunnel to #2
  2. remove change for num_sg

v7:
  1. fix bug reported by robot
  2. Still splitting into two commits, as the issues fixed originate from
     different commits. This separation makes it easier to selectively revert to
     previous versions.

v6:
  1. rename to guest_hdrlen
  2. introduce a function virtio_net_set_hdrlen to set the hdrlen

The commit be50da3e9d4a ("net: virtio_net: implement exact header length
guest feature") introduces support for the VIRTIO_NET_F_GUEST_HDRLEN
feature in virtio-net.

This feature requires virtio-net to set hdr_len to the actual header
length of the packet when transmitting, the number of
bytes from the start of the packet to the beginning of the
transport-layer payload.

However, in practice, hdr_len was being set using skb_headlen(skb),
which is clearly incorrect. This path set fixes that issue.

As discussed in [0], this version checks the VIRTIO_NET_F_GUEST_HDRLEN is
negotiated.


[0]: http://lore.kernel.org/all/20251029030913.20423-1-xuanzhuo@linux.alibaba.com






Xuan Zhuo (2):
  virtio-net: correct hdr_len handling for VIRTIO_NET_F_GUEST_HDRLEN
  virtio-net: correct hdr_len handling for tunnel gso

 drivers/net/tun_vnet.h     |  2 +-
 drivers/net/virtio_net.c   |  6 ++++-
 include/linux/virtio_net.h | 51 +++++++++++++++++++++++++++++++++++---
 3 files changed, 53 insertions(+), 6 deletions(-)

--
2.32.0.3.g01195cf9f