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Commit 366a88fe authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

bpf, ixgbe: add meta data support 



Implement support for transferring XDP meta data into skb for
ixgbe driver; before calling into the program, xdp.data_meta points
to xdp.data, where on program return with pass verdict, we call
into skb_metadata_set().

We implement this for the default ixgbe_build_skb() variant. For the
ixgbe_construct_skb() that is used when legacy-rx buffer mananagement
mode is turned on via ethtool, I found that XDP gets 0 headroom, so
neither xdp_adjust_head() nor xdp_adjust_meta() can be used with this.
Just add a comment with explanation for this operating mode.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 65d88fd0

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

+26 −4
Original line number Diff line number Diff line
@@ -2133,6 +2133,21 @@ static struct sk_buff *ixgbe_construct_skb(struct ixgbe_ring *rx_ring, 
#if L1_CACHE_BYTES < 128

	prefetch(xdp->data + L1_CACHE_BYTES);

#endif

	/* Note, we get here by enabling legacy-rx via:

	 *

	 *    ethtool --set-priv-flags <dev> legacy-rx on

	 *

	 * In this mode, we currently get 0 extra XDP headroom as

	 * opposed to having legacy-rx off, where we process XDP

	 * packets going to stack via ixgbe_build_skb(). The latter

	 * provides us currently with 192 bytes of headroom.

	 *

	 * For ixgbe_construct_skb() mode it means that the

	 * xdp->data_meta will always point to xdp->data, since

	 * the helper cannot expand the head. Should this ever

	 * change in future for legacy-rx mode on, then lets also

	 * add xdp->data_meta handling here.

	 */



	/* allocate a skb to store the frags */

	skb = napi_alloc_skb(&rx_ring->q_vector->napi, IXGBE_RX_HDR_SIZE);
@@ -2165,6 +2180,7 @@ static struct sk_buff *ixgbe_build_skb(struct ixgbe_ring *rx_ring, 
				       struct xdp_buff *xdp,

				       union ixgbe_adv_rx_desc *rx_desc)

{

	unsigned int metasize = xdp->data - xdp->data_meta;

#if (PAGE_SIZE < 8192)

	unsigned int truesize = ixgbe_rx_pg_size(rx_ring) / 2;

#else
@@ -2174,10 +2190,14 @@ static struct sk_buff *ixgbe_build_skb(struct ixgbe_ring *rx_ring, 
#endif

	struct sk_buff *skb;



	/* prefetch first cache line of first page */

	prefetch(xdp->data);

	/* Prefetch first cache line of first page. If xdp->data_meta

	 * is unused, this points extactly as xdp->data, otherwise we

	 * likely have a consumer accessing first few bytes of meta

	 * data, and then actual data.

	 */

	prefetch(xdp->data_meta);

#if L1_CACHE_BYTES < 128

	prefetch(xdp->data + L1_CACHE_BYTES);

	prefetch(xdp->data_meta + L1_CACHE_BYTES);

#endif



	/* build an skb to around the page buffer */
@@ -2188,6 +2208,8 @@ static struct sk_buff *ixgbe_build_skb(struct ixgbe_ring *rx_ring, 
	/* update pointers within the skb to store the data */

	skb_reserve(skb, xdp->data - xdp->data_hard_start);

	__skb_put(skb, xdp->data_end - xdp->data);

	if (metasize)

		skb_metadata_set(skb, metasize);



	/* record DMA address if this is the start of a chain of buffers */

	if (!ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))
@@ -2326,7 +2348,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, 
		if (!skb) {

			xdp.data = page_address(rx_buffer->page) +

				   rx_buffer->page_offset;

			xdp_set_data_meta_invalid(&xdp);

			xdp.data_meta = xdp.data;

			xdp.data_hard_start = xdp.data -

					      ixgbe_rx_offset(rx_ring);

			xdp.data_end = xdp.data + size;