[PATCH 8/9] net: thunderx: Support for XDP header adjustment
sunil.kovvuri at gmail.com
sunil.kovvuri at gmail.com
Tue May 2 06:06:57 PDT 2017
From: Sunil Goutham <sgoutham at cavium.com>
When in XDP mode reserve XDP_PACKET_HEADROOM bytes at the start
of receive buffer for XDP program to modify headers and adjust
packet start. Additional code changes done to handle such packets.
Signed-off-by: Sunil Goutham <sgoutham at cavium.com>
---
drivers/net/ethernet/cavium/thunder/nicvf_main.c | 63 ++++++++++++++++------
drivers/net/ethernet/cavium/thunder/nicvf_queues.c | 9 +++-
2 files changed, 55 insertions(+), 17 deletions(-)
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index bb13dee..d6477af 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -502,13 +502,15 @@ static int nicvf_init_resources(struct nicvf *nic)
}
static inline bool nicvf_xdp_rx(struct nicvf *nic, struct bpf_prog *prog,
- struct cqe_rx_t *cqe_rx, struct snd_queue *sq)
+ struct cqe_rx_t *cqe_rx, struct snd_queue *sq,
+ struct sk_buff **skb)
{
struct xdp_buff xdp;
struct page *page;
u32 action;
- u16 len;
+ u16 len, offset = 0;
u64 dma_addr, cpu_addr;
+ void *orig_data;
/* Retrieve packet buffer's DMA address and length */
len = *((u16 *)((void *)cqe_rx + (3 * sizeof(u64))));
@@ -517,17 +519,47 @@ static inline bool nicvf_xdp_rx(struct nicvf *nic, struct bpf_prog *prog,
cpu_addr = nicvf_iova_to_phys(nic, dma_addr);
if (!cpu_addr)
return false;
+ cpu_addr = (u64)phys_to_virt(cpu_addr);
+ page = virt_to_page((void *)cpu_addr);
- xdp.data = phys_to_virt(cpu_addr);
+ xdp.data_hard_start = page_address(page);
+ xdp.data = (void *)cpu_addr;
xdp.data_end = xdp.data + len;
+ orig_data = xdp.data;
rcu_read_lock();
action = bpf_prog_run_xdp(prog, &xdp);
rcu_read_unlock();
+ /* Check if XDP program has changed headers */
+ if (orig_data != xdp.data) {
+ len = xdp.data_end - xdp.data;
+ offset = orig_data - xdp.data;
+ dma_addr -= offset;
+ }
+
switch (action) {
case XDP_PASS:
- /* Pass on packet to network stack */
+ /* Check if it's a recycled page, if not
+ * unmap the DMA mapping.
+ *
+ * Recycled page holds an extra reference.
+ */
+ if (page_ref_count(page) == 1) {
+ dma_addr &= PAGE_MASK;
+ dma_unmap_page_attrs(&nic->pdev->dev, dma_addr,
+ RCV_FRAG_LEN + XDP_PACKET_HEADROOM,
+ DMA_FROM_DEVICE,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ }
+
+ /* Build SKB and pass on packet to network stack */
+ *skb = build_skb(xdp.data,
+ RCV_FRAG_LEN - cqe_rx->align_pad + offset);
+ if (!*skb)
+ put_page(page);
+ else
+ skb_put(*skb, len);
return false;
case XDP_TX:
nicvf_xdp_sq_append_pkt(nic, sq, (u64)xdp.data, dma_addr, len);
@@ -537,7 +569,6 @@ static inline bool nicvf_xdp_rx(struct nicvf *nic, struct bpf_prog *prog,
case XDP_ABORTED:
trace_xdp_exception(nic->netdev, prog, action);
case XDP_DROP:
- page = virt_to_page(xdp.data);
/* Check if it's a recycled page, if not
* unmap the DMA mapping.
*
@@ -546,7 +577,8 @@ static inline bool nicvf_xdp_rx(struct nicvf *nic, struct bpf_prog *prog,
if (page_ref_count(page) == 1) {
dma_addr &= PAGE_MASK;
dma_unmap_page_attrs(&nic->pdev->dev, dma_addr,
- RCV_FRAG_LEN, DMA_FROM_DEVICE,
+ RCV_FRAG_LEN + XDP_PACKET_HEADROOM,
+ DMA_FROM_DEVICE,
DMA_ATTR_SKIP_CPU_SYNC);
}
put_page(page);
@@ -654,7 +686,7 @@ static void nicvf_rcv_pkt_handler(struct net_device *netdev,
struct napi_struct *napi,
struct cqe_rx_t *cqe_rx, struct snd_queue *sq)
{
- struct sk_buff *skb;
+ struct sk_buff *skb = NULL;
struct nicvf *nic = netdev_priv(netdev);
struct nicvf *snic = nic;
int err = 0;
@@ -676,15 +708,17 @@ static void nicvf_rcv_pkt_handler(struct net_device *netdev,
}
/* For XDP, ignore pkts spanning multiple pages */
- if (nic->xdp_prog && (cqe_rx->rb_cnt == 1))
- if (nicvf_xdp_rx(snic, nic->xdp_prog, cqe_rx, sq))
+ if (nic->xdp_prog && (cqe_rx->rb_cnt == 1)) {
+ /* Packet consumed by XDP */
+ if (nicvf_xdp_rx(snic, nic->xdp_prog, cqe_rx, sq, &skb))
return;
+ } else {
+ skb = nicvf_get_rcv_skb(snic, cqe_rx,
+ nic->xdp_prog ? true : false);
+ }
- skb = nicvf_get_rcv_skb(snic, cqe_rx, nic->xdp_prog ? true : false);
- if (!skb) {
- netdev_dbg(nic->netdev, "Packet not received\n");
+ if (!skb)
return;
- }
if (netif_msg_pktdata(nic)) {
netdev_info(nic->netdev, "%s: skb 0x%p, len=%d\n", netdev->name,
@@ -1672,9 +1706,6 @@ static int nicvf_xdp_setup(struct nicvf *nic, struct bpf_prog *prog)
return -EOPNOTSUPP;
}
- if (prog && prog->xdp_adjust_head)
- return -EOPNOTSUPP;
-
/* ALL SQs attached to CQs i.e same as RQs, are treated as
* XDP Tx queues and more Tx queues are allocated for
* network stack to send pkts out.
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
index ec234b6..43428ce 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
@@ -164,6 +164,11 @@ static inline int nicvf_alloc_rcv_buffer(struct nicvf *nic, struct rbdr *rbdr,
}
nic->rb_page_offset = 0;
+
+ /* Reserve space for header modifications by BPF program */
+ if (rbdr->is_xdp)
+ buf_len += XDP_PACKET_HEADROOM;
+
/* Check if it's recycled */
if (pgcache)
nic->rb_page = pgcache->page;
@@ -183,7 +188,7 @@ static inline int nicvf_alloc_rcv_buffer(struct nicvf *nic, struct rbdr *rbdr,
return -ENOMEM;
}
if (pgcache)
- pgcache->dma_addr = *rbuf;
+ pgcache->dma_addr = *rbuf + XDP_PACKET_HEADROOM;
nic->rb_page_offset += buf_len;
}
@@ -1575,6 +1580,8 @@ static void nicvf_unmap_rcv_buffer(struct nicvf *nic, u64 dma_addr,
*/
if (page_ref_count(page) != 1)
return;
+
+ len += XDP_PACKET_HEADROOM;
/* Receive buffers in XDP mode are mapped from page start */
dma_addr &= PAGE_MASK;
}
--
2.7.4
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