Tested this series of patches V4 with virtio-net regression tests,
everything works fine.
Tested-by: Lei Yang <leiyang@redhat.com>
On Thu, Jul 24, 2025 at 3:34 AM Paolo Abeni <pabeni@redhat.com> wrote:
>
> Some virtualized deployments use UDP tunnel pervasively and are impacted
> negatively by the lack of GSO support for such kind of traffic in the
> virtual NIC driver.
>
> The virtio_net specification recently introduced support for GSO over
> UDP tunnel, and the kernel side of the implementation has been merged
> into the net-next tree; this series updates the virtio implementation to
> support such a feature.
>
> Currently the qemu virtio support limits the feature space to 64 bits,
> while the virtio specification allows for a larger number of features.
> Specifically the GSO-over-UDP-tunnel-related virtio features use bits
> 65-69; the larger part of this series (patches 4-12) actually deals with
> extending the features space.
>
> The extended features are carried by fixed size uint64_t arrays,
> bringing the current maximum features number to 128.
>
> The patches use some syntactic sugar to try to minimize the otherwise
> very large code churn. Specifically the extended features are boundled
> in an union with 'legacy' features definition, allowing no changes in
> the virtio devices not needing the extended features set.
>
> The actual offload implementation is in patches 13 and 14 and boils down
> to propagating the new offload to the tun devices and the vhost backend.
>
> Patch 1 is a small pre-req refactor that ideally could enter the
> tree separately; it's presented here in the same series to help
> reviewers more easily getting the full picture, patch 2 updates to
> linux headers update script to deal with annotations recently introduce
> in the kernel and patch 3 is a needed linux headers update.
>
> Tested with basic stream transfer with all the possible permutations of
> host kernel/qemu/guest kernel with/without GSO over UDP tunnel support,
> vs snapshots creation and restore and vs migration.
>
> Sharing again as RFC as the kernel bits have not entered the Linus tree
> yet - but they should on next merge window.
>
> ---
> Note: next revision will be after the Linux merge window to allow
> dropping the 'RFC' tag and also due to myself being off-the-grid
> meanwhile.
>
> v3 -> v4:
> - more sparse cleanups
> - fix build failures on a couple of targets
>
> v2 -> v3:
> - consolidated suffixes for new fields to '_ex'
> - avoid pre/post load trickery and relay on reset zeroing the features
> - cleaned-up virtio store implementation deduplicating a bit of code
> - many more cleanups, see the individual patches changelog for the
> details
> - I left patch 1 unmodified, still some hope we could live with that;)
>
> Paolo Abeni (14):
> net: bundle all offloads in a single struct
> linux-headers: deal with counted_by annotation
> linux-headers: Update to Linux ~v6.16-rc7 net-next
> virtio: introduce extended features type
> virtio: serialize extended features state
> virtio: add support for negotiating extended features
> virtio-pci: implement support for extended features
> vhost: add support for negotiating extended features
> qmp: update virtio features map to support extended features
> vhost-backend: implement extended features support
> vhost-net: implement extended features support
> virtio-net: implement extended features support
> net: implement tunnel probing
> net: implement UDP tunnel features offloading
>
> hw/net/e1000e_core.c | 5 +-
> hw/net/igb_core.c | 5 +-
> hw/net/vhost_net-stub.c | 8 +-
> hw/net/vhost_net.c | 45 ++--
> hw/net/virtio-net.c | 222 +++++++++++++------
> hw/net/vmxnet3.c | 13 +-
> hw/virtio/vhost-backend.c | 62 +++++-
> hw/virtio/vhost.c | 68 ++++--
> hw/virtio/virtio-bus.c | 11 +-
> hw/virtio/virtio-hmp-cmds.c | 3 +-
> hw/virtio/virtio-pci.c | 69 +++++-
> hw/virtio/virtio-qmp.c | 91 +++++---
> hw/virtio/virtio-qmp.h | 3 +-
> hw/virtio/virtio.c | 102 ++++++---
> include/hw/virtio/vhost-backend.h | 6 +
> include/hw/virtio/vhost.h | 56 ++++-
> include/hw/virtio/virtio-features.h | 127 +++++++++++
> include/hw/virtio/virtio-net.h | 2 +-
> include/hw/virtio/virtio-pci.h | 2 +-
> include/hw/virtio/virtio.h | 11 +-
> include/net/net.h | 20 +-
> include/net/vhost_net.h | 33 ++-
> include/standard-headers/linux/ethtool.h | 4 +-
> include/standard-headers/linux/vhost_types.h | 5 +
> include/standard-headers/linux/virtio_net.h | 33 +++
> linux-headers/linux/vhost.h | 7 +
> net/net.c | 17 +-
> net/netmap.c | 3 +-
> net/tap-bsd.c | 8 +-
> net/tap-linux.c | 38 +++-
> net/tap-linux.h | 9 +
> net/tap-solaris.c | 9 +-
> net/tap-stub.c | 8 +-
> net/tap.c | 21 +-
> net/tap_int.h | 5 +-
> qapi/virtio.json | 9 +-
> scripts/update-linux-headers.sh | 1 +
> 37 files changed, 875 insertions(+), 266 deletions(-)
> create mode 100644 include/hw/virtio/virtio-features.h
>
> --
> 2.50.0
>
>