On 7/18/25 3:22 PM, Stefano Garzarella wrote:
> On Fri, Jul 18, 2025 at 10:52:39AM +0200, Paolo Abeni wrote:
>> diff --git a/net/tap.c b/net/tap.c
>> index 23c6c118e7..2dfa843547 100644
>> --- a/net/tap.c
>> +++ b/net/tap.c
>> @@ -62,6 +62,8 @@ static const int kernel_feature_bits[] = {
>> VIRTIO_F_NOTIFICATION_DATA,
>> VIRTIO_NET_F_RSC_EXT,
>> VIRTIO_NET_F_HASH_REPORT,
>> + VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO,
>> + VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO,
>
> The *_GSO_CSUM are not supported by vhost-net, right?
> (sorry, I don't know the details, it just occurred to me by looking at
> the fetaures we enable in the other patch.)
Yes, the kernel module supports/exposes only the 2 features above:
vhost-net need only to be aware of the exact virtio_net_header size,
which in turn depends just on them. Enabling/disabling the outer header
csum offload does not change the virtio_net_header struct.
The actual csum offload is implemented by the tun device.
Please LMK if the above solves your doubt.
Thanks,
Paolo
