On Mon, Nov 03, 2025 at 12:40:14PM -0500, Nabil S. Alramli wrote: > On 11/3/25 11:38, Maciej Fijalkowski wrote: > > On Thu, Oct 09, 2025 at 03:28:30PM -0400, Nabil S. Alramli wrote: > >> This commit adds support for `ndo_xdp_xmit` in skb mode in the ixgbe > >> ethernet driver, by allowing the call to continue to transmit the packets > >> using `dev_direct_xmit`. > >> > >> Previously, the driver did not support the operation in skb mode. The > >> handler `ixgbe_xdp_xmit` had the following condition: > >> > >> ``` > >> ring = adapter->xdp_prog ? ixgbe_determine_xdp_ring(adapter) : NULL; > >> if (unlikely(!ring)) > >> return -ENXIO; > >> ``` > >> > >> That only works in native mode. In skb mode, `adapter->xdp_prog == NULL` so > >> the call returned an error, which prevented the ability to send packets > >> using `bpf_prog_test_run_opts` with the `BPF_F_TEST_XDP_LIVE_FRAMES` flag. > > > > Hi Nabil, > > > > What stops you from loading a dummy XDP program to interface? This has > > been an approach that we follow when we want to use anything that utilizes > > XDP resources (XDP Tx queues). > > > > Hi Maciej, > > Thank you for your response. In one use case we have multiple XDP programs > already loaded on an interface in SKB mode using the dispatcher, and we want > to use bpf_prog_test_run_opts to egress packets from another XDP program. We > want to avoid having to unload the dispatcher or be forced to use it in native > mode. Without this patch, that does not seem possible currently, correct?
Why does it have to be bpf_prog_test_run_opts? You're trying to use an interface which was designed for native XDP from a different layer. Generic XDP has support for redirect and tx. > > >> > >> Signed-off-by: Nabil S. Alramli <[email protected]> > >> --- > >> drivers/net/ethernet/intel/ixgbe/ixgbe.h | 8 ++++ > >> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 43 +++++++++++++++++-- > >> 2 files changed, 47 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h > >> b/drivers/net/ethernet/intel/ixgbe/ixgbe.h > >> index e6a380d4929b..26c378853755 100644 > >> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h > >> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h > >> @@ -846,6 +846,14 @@ struct ixgbe_ring *ixgbe_determine_xdp_ring(struct > >> ixgbe_adapter *adapter) > >> return adapter->xdp_ring[index]; > >> } > >> > >> +static inline > >> +struct ixgbe_ring *ixgbe_determine_tx_ring(struct ixgbe_adapter *adapter) > >> +{ > >> + int index = ixgbe_determine_xdp_q_idx(smp_processor_id()); > >> + > >> + return adapter->tx_ring[index]; > >> +} > >> + > >> static inline u8 ixgbe_max_rss_indices(struct ixgbe_adapter *adapter) > >> { > >> switch (adapter->hw.mac.type) { > >> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > >> b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > >> index 467f81239e12..fed70cbdb1b2 100644 > >> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > >> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c > >> @@ -10748,7 +10748,8 @@ static int ixgbe_xdp_xmit(struct net_device *dev, > >> int n, > >> /* During program transitions its possible adapter->xdp_prog is assigned > >> * but ring has not been configured yet. In this case simply abort xmit. > >> */ > >> - ring = adapter->xdp_prog ? ixgbe_determine_xdp_ring(adapter) : NULL; > >> + ring = adapter->xdp_prog ? ixgbe_determine_xdp_ring(adapter) : > >> + ixgbe_determine_tx_ring(adapter); > >> if (unlikely(!ring)) > >> return -ENXIO; > >> > >> @@ -10762,9 +10763,43 @@ static int ixgbe_xdp_xmit(struct net_device *dev, > >> int n, > >> struct xdp_frame *xdpf = frames[i]; > >> int err; > >> > >> - err = ixgbe_xmit_xdp_ring(ring, xdpf); > >> - if (err != IXGBE_XDP_TX) > >> - break; > >> + if (adapter->xdp_prog) { > >> + err = ixgbe_xmit_xdp_ring(ring, xdpf); > >> + if (err != IXGBE_XDP_TX) > >> + break; > >> + } else { > >> + struct xdp_buff xdp = {0}; > >> + unsigned int metasize = 0; > >> + unsigned int size = 0; > >> + unsigned int truesize = 0; > >> + struct sk_buff *skb = NULL; > >> + > >> + xdp_convert_frame_to_buff(xdpf, &xdp); > >> + size = xdp.data_end - xdp.data; > >> + metasize = xdp.data - xdp.data_meta; > >> + truesize = SKB_DATA_ALIGN(xdp.data_end - > >> xdp.data_hard_start) + > >> + SKB_DATA_ALIGN(sizeof(struct > >> skb_shared_info)); > >> + > >> + skb = napi_alloc_skb(&ring->q_vector->napi, truesize); > >> + if (likely(skb)) { > >> + skb_reserve(skb, xdp.data - > >> xdp.data_hard_start); > >> + skb_put_data(skb, xdp.data, size); > >> + build_skb_around(skb, skb->data, truesize); > >> + if (metasize) > >> + skb_metadata_set(skb, metasize); > >> + skb->dev = dev; > >> + skb->queue_mapping = ring->queue_index; > >> + > >> + err = dev_direct_xmit(skb, ring->queue_index); > >> + if (!dev_xmit_complete(err)) > >> + break; > >> + } else { > >> + break; > >> + } > >> + > >> + xdp_return_frame_rx_napi(xdpf); > >> + } > >> + > >> nxmit++; > >> } > >> > >> -- > >> 2.43.0 > >> > >> >
