On 7/22/25 5:50 AM, Jason Wang wrote:
> 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")
If I read correctly the only missing pieces are the hw_compat_10_1
entries, am I correct?
If so, as mentioned here:
https://lists.gnu.org/archive/html/qemu-devel/2025-07/msg05032.html
I'll add the needed entries after that the hw_compat_10_1 will be created.
Thanks,
Paolo
