Hi, 

I am trying to test RX Checksum offloading to work with a net_virtio PMD. I have gotten offloading to be enabled by requesting and ensuring that guest_csum is enabled on the qemu-kvm device. But then, I don't get any flags (ol_flags=0). I was expecting at least the IP_CKSUM_UNKNOWN flag. 

Through a debugger, I can see I go into virtio_rx_offload but then it returns early because hdr->flags == 0 (https://github.com/DPDK/dpdk/blob/v23.11/drivers/net/virtio/virtio_rxtx.c#L924).

Do I need any more configuration on the hypervisor or guest to get checksum offloads?

I am using DPDK 23.11. 

Thanks

Baptiste