On Fri, Jul 18, 2025 at 4:54 PM Paolo Abeni <pab...@redhat.com> wrote:
>
> Tap devices support GSO over UDP tunnel offload. Probe for such
> feature in a similar manner to other offloads.
>
> GSO over UDP tunnel needs to be enabled in addition to a "plain"
> offload (TSO or USO).
>
> No need to check separately for the outer header checksum offload:
> the kernel is going to support both of them or none.
>
> Signed-off-by: Paolo Abeni <pab...@redhat.com>
> ---
> v2 -> v3:
> - use bool type for tap_probe_has_tunnel()
> - rebased on top of 2deec9ab7d ("virtio-net: Move
> virtio_net_get_features() down")
> - _array -> _ex
>
> v1 -> v2:
> - peer_has_tunnel return a bool
> - move TUN_F definition in net/tun-linux.h
> ---
> hw/net/virtio-net.c | 37 +++++++++++++++++++++++++++++++++++++
> include/net/net.h | 3 +++
> net/net.c | 9 +++++++++
> net/tap-bsd.c | 5 +++++
> net/tap-linux.c | 11 +++++++++++
> net/tap-linux.h | 9 +++++++++
> net/tap-solaris.c | 5 +++++
> net/tap-stub.c | 5 +++++
> net/tap.c | 11 +++++++++++
> net/tap_int.h | 1 +
> 10 files changed, 96 insertions(+)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 53413ec4d5..70c85f7f77 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -649,6 +649,15 @@ static int peer_has_uso(VirtIONet *n)
> return qemu_has_uso(qemu_get_queue(n->nic)->peer);
> }
>
> +static bool peer_has_tunnel(VirtIONet *n)
Nit: it looks better to use peer_has_udp_gso_tunnel().
> +{
> + if (!peer_has_vnet_hdr(n)) {
> + return false;
> + }
> +
> + return qemu_has_tunnel(qemu_get_queue(n->nic)->peer);
> +}
> +
> static void virtio_net_set_mrg_rx_bufs(VirtIONet *n, int mergeable_rx_bufs,
> int version_1, int hash_report)
> {
> @@ -3070,6 +3079,13 @@ static void virtio_net_get_features(VirtIODevice
> *vdev, uint64_t *features,
> virtio_clear_feature_ex(features, VIRTIO_NET_F_GUEST_USO4);
> virtio_clear_feature_ex(features, VIRTIO_NET_F_GUEST_USO6);
>
> + virtio_clear_feature_ex(features, VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO);
> + virtio_clear_feature_ex(features, VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO);
> + virtio_clear_feature_ex(features,
> + VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM);
> + virtio_clear_feature_ex(features,
> + VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO_CSUM);
> +
> virtio_clear_feature_ex(features, VIRTIO_NET_F_HASH_REPORT);
> }
>
> @@ -3083,6 +3099,15 @@ static void virtio_net_get_features(VirtIODevice
> *vdev, uint64_t *features,
> virtio_clear_feature_ex(features, VIRTIO_NET_F_GUEST_USO6);
> }
>
> + if (!peer_has_tunnel(n)) {
> + virtio_clear_feature_ex(features, VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO);
> + virtio_clear_feature_ex(features, VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO);
> + virtio_clear_feature_ex(features,
> + VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM);
> + virtio_clear_feature_ex(features,
> + VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO_CSUM);
> + }
> +
> if (!get_vhost_net(nc->peer)) {
> if (!use_own_hash) {
> virtio_clear_feature_ex(features, VIRTIO_NET_F_HASH_REPORT);
> @@ -4137,6 +4162,10 @@ static const VMStateDescription vmstate_virtio_net = {
> .dev_unplug_pending = dev_unplug_pending,
> };
>
> +#define DEFINE_PROP_FEATURE(_name, _state, _field, _bit, _defval) \
> + DEFINE_PROP_BIT64(_name, _state, _field[VIRTIO_DWORD(_bit)], \
> + (_bit) % 64, _defval)
> +
> static const Property virtio_net_properties[] = {
> DEFINE_PROP_BIT64("csum", VirtIONet, host_features,
> VIRTIO_NET_F_CSUM, true),
> @@ -4245,6 +4274,14 @@ static const Property virtio_net_properties[] = {
> rss_data.specified_hash_types,
> VIRTIO_NET_HASH_REPORT_UDPv6_EX - 1,
> ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_FEATURE("host_tunnel", VirtIONet, host_features_ex,
> + VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO, true),
> + DEFINE_PROP_FEATURE("host_tunnel_csum", VirtIONet, host_features_ex,
> + VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO_CSUM, true),
> + DEFINE_PROP_FEATURE("guest_tunnel", VirtIONet, host_features_ex,
> + VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO, true),
> + DEFINE_PROP_FEATURE("guest_tunnel_csum", VirtIONet, host_features_ex,
> + VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM, true),
> };
Need compatibility work like:
d83f46d189 ("virtio-pci: compat page aligned ATS")
Thanks
