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
