[PATCH net-next v3 02/10] eth: bnxt: don't run xdp programs on fallback traffic

[Jakub Kicinski <kuba@kernel.org>]

The XDP program attached to the PF should not be executed
on the fallback traffic. Pass the desired dev to bnxt_rx_xdp()
and abort if the packet is for a representor. bnxt_rx_xdp()
has a lot of arguments already, so presumably adding one
more is okay.

Compile tested only.

Well behaved drivers (nfp) do not execute XDP on fallback
traffic, but perhaps this is a matter of opinion rather than
a hard rule, therefore I'm not considering this a fix.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
v2:
 - pass dev to bnxt_rx_xdp(), and skip just the BPF execution,
   to avoid unintentionally skipping the Tx ring handling
v1: https://lore.kernel.org/20250226211003.2790916-3-kuba@kernel.org
---
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h |  3 ++-
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     | 11 +++++++----
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c |  8 ++++++--
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
index 0122782400b8..752b6cf0022c 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
@@ -17,7 +17,8 @@ struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
 				   dma_addr_t mapping, u32 len,
 				   struct xdp_buff *xdp);
 void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int budget);
-bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
+bool bnxt_rx_xdp(struct bnxt *bp, struct net_device *dev,
+		 struct bnxt_rx_ring_info *rxr, u16 cons,
 		 struct xdp_buff *xdp, struct page *page, u8 **data_ptr,
 		 unsigned int *len, u8 *event);
 int bnxt_xdp(struct net_device *dev, struct netdev_bpf *xdp);
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index f6a26f6f85bb..94bc9121d3f9 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -2036,7 +2036,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 {
 	struct bnxt_napi *bnapi = cpr->bnapi;
 	struct bnxt_rx_ring_info *rxr = bnapi->rx_ring;
-	struct net_device *dev = bp->dev;
+	struct net_device *dev;
 	struct rx_cmp *rxcmp;
 	struct rx_cmp_ext *rxcmp1;
 	u32 tmp_raw_cons = *raw_cons;
@@ -2159,6 +2159,10 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	len = flags >> RX_CMP_LEN_SHIFT;
 	dma_addr = rx_buf->mapping;
 
+	dev = bp->dev;
+	if (cmp_type == CMP_TYPE_RX_L2_CMP)
+		dev = bnxt_get_pkt_dev(bp, RX_CMP_CFA_CODE(rxcmp1));
+
 	if (bnxt_xdp_attached(bp, rxr)) {
 		bnxt_xdp_buff_init(bp, rxr, cons, data_ptr, len, &xdp);
 		if (agg_bufs) {
@@ -2172,7 +2176,8 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	}
 
 	if (xdp_active) {
-		if (bnxt_rx_xdp(bp, rxr, cons, &xdp, data, &data_ptr, &len, event)) {
+		if (bnxt_rx_xdp(bp, dev, rxr, cons, &xdp, data, &data_ptr, &len,
+				event)) {
 			rc = 1;
 			goto next_rx;
 		}
@@ -2239,8 +2244,6 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 		skb_set_hash(skb, le32_to_cpu(rxcmp->rx_cmp_rss_hash), type);
 	}
 
-	if (cmp_type == CMP_TYPE_RX_L2_CMP)
-		dev = bnxt_get_pkt_dev(bp, RX_CMP_CFA_CODE(rxcmp1));
 	skb->protocol = eth_type_trans(skb, dev);
 
 	if (skb->dev->features & BNXT_HW_FEATURE_VLAN_ALL_RX) {
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
index e6c64e4bd66c..aba49ddb0e66 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -221,7 +221,8 @@ void bnxt_xdp_buff_frags_free(struct bnxt_rx_ring_info *rxr,
  * true    - packet consumed by XDP and new buffer is allocated.
  * false   - packet should be passed to the stack.
  */
-bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
+bool bnxt_rx_xdp(struct bnxt *bp, struct net_device *dev,
+		 struct bnxt_rx_ring_info *rxr, u16 cons,
 		 struct xdp_buff *xdp, struct page *page, u8 **data_ptr,
 		 unsigned int *len, u8 *event)
 {
@@ -246,7 +247,10 @@ bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
 	/* BNXT_RX_PAGE_MODE(bp) when XDP enabled */
 	orig_data = xdp->data;
 
-	act = bpf_prog_run_xdp(xdp_prog, xdp);
+	if (bp->dev == dev)
+		act = bpf_prog_run_xdp(xdp_prog, xdp);
+	else /* packet is for a VF representor */
+		act = XDP_PASS;
 
 	tx_avail = bnxt_tx_avail(bp, txr);
 	/* If the tx ring is not full, we must not update the rx producer yet
-- 
2.48.1