Hi, I want to clarify my AF_XDP understanding for a particular scenario. Consider a single UMEM with 1 Fill Ring and 1 Completion Ring and single XDP socket bound to queue 0 with 1 Tx Ring but NO Rx Ring. Assume the NIC has only a single queue (to keep things simple for explaining this scenario). There is a XDP program attached to Queue 0 which does either a XDP_DROP or XDP_PASS for all Rx packets. We are running in Driver mode. What happens to RX packets received on Queue 0? Here's my understanding - * Even though there is no AF_XDP Rx Ring, there will be a NIC Rx Ring for queue 0 * The NIC Rx Ring for queue 0 is populated by the driver with UMEM buffers taken from the Fill ring * A Rx packet will be received in the NIC Rx Ring for Queue 0 first * The driver will run the XDP program on the Rx packet buffer (a UMEM buffer) * If the program results in XDP_DROP, the driver will "free" the Umem buffer by putting it on the Completion Ring * If the program results in XDP_PASS, the driver will allocate a standard Linux kernel SKB, copy the packet buffer contents into the SKB and queue it up for standard netdev processing; It will then "free" the RX Umem buffer by putting it on the Completion Ring (since we have already copied packet into the skb) Is this understanding correct or am I mistaken anywhere? Thanks in advance, Srivats
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