[PATCH net-next 4/6] eth: mpnic: UDP segmentation offload
From: Daniel Zahka
Date: Fri Nov 06 2026 - 06:38:37 EST
Support segmentation of non-encapsulated udp4/udp6 packets. Like for
tcp, the segmentation engine expects the udp csum to be seeded with 0
length.
The HW inverts UDP checksums computed as 0 during segmentation.
Signed-off-by: Daniel Zahka <daniel.zahka@xxxxxxxxx>
---
drivers/net/ethernet/meta/mpnic/mpnic_csr.h | 2 ++
drivers/net/ethernet/meta/mpnic/mpnic_init.c | 1 +
drivers/net/ethernet/meta/mpnic/mpnic_netdev.c | 3 ++-
drivers/net/ethernet/meta/mpnic/mpnic_txrx.c | 33 +++++++++++++++++++-------
4 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/meta/mpnic/mpnic_csr.h b/drivers/net/ethernet/meta/mpnic/mpnic_csr.h
index 672ce0a98c22..2cd627d62bf5 100644
--- a/drivers/net/ethernet/meta/mpnic/mpnic_csr.h
+++ b/drivers/net/ethernet/meta/mpnic/mpnic_csr.h
@@ -20,6 +20,7 @@
#define MPNIC_TWD_L4_TYPE DESC_GENMASK(33, 32)
enum {
MPNIC_TWD_L4_TYPE_TCP = 1,
+ MPNIC_TWD_L4_TYPE_UDP = 2,
};
#define MPNIC_TWD_FLAG_REQ_LSO DESC_BIT(35)
@@ -335,6 +336,7 @@ enum {
#define MPNIC_TOF_MODE_IPV4_ZERO_CSUM CSR_BIT(1)
#define MPNIC_TOF_MODE_TCP_ZERO_CSUM CSR_BIT(2)
+#define MPNIC_TOF_MODE_UDP_ZERO_CSUM CSR_BIT(3)
#define MPNIC_TOF_MODE_L4_ZERO_CSUM CSR_BIT(4)
#define MPNIC_TOF_TCP_FLAG_CLR 0x7e3030 /* 0x1f8c0c0 */
#define MPNIC_TOF_TCP_FLAG_CLR_FIRST_SEGMENT CSR_GENMASK(8, 0)
diff --git a/drivers/net/ethernet/meta/mpnic/mpnic_init.c b/drivers/net/ethernet/meta/mpnic/mpnic_init.c
index b9a41656f8f7..ab832ec5de0e 100644
--- a/drivers/net/ethernet/meta/mpnic/mpnic_init.c
+++ b/drivers/net/ethernet/meta/mpnic/mpnic_init.c
@@ -304,6 +304,7 @@ static void mpnic_txglb_init(struct mpnic_dev *mpd)
MPNIC_IPV4_ID_MODE_INCREMENT) |
FIELD_PREP(MPNIC_TOF_MODE_IPV4_ZERO_CSUM, 1) |
FIELD_PREP(MPNIC_TOF_MODE_TCP_ZERO_CSUM, 1) |
+ FIELD_PREP(MPNIC_TOF_MODE_UDP_ZERO_CSUM, 0) |
FIELD_PREP(MPNIC_TOF_MODE_L4_ZERO_CSUM, 0));
mpnic_wr64(mpd, MPNIC_TOF_TCP_FLAG_CLR,
FIELD_PREP(MPNIC_TOF_TCP_FLAG_CLR_FIRST_SEGMENT,
diff --git a/drivers/net/ethernet/meta/mpnic/mpnic_netdev.c b/drivers/net/ethernet/meta/mpnic/mpnic_netdev.c
index 3a4aa5be57a1..83be45031a30 100644
--- a/drivers/net/ethernet/meta/mpnic/mpnic_netdev.c
+++ b/drivers/net/ethernet/meta/mpnic/mpnic_netdev.c
@@ -331,7 +331,8 @@ struct net_device *mpnic_netdev_alloc(struct mpnic_dev *mpd)
NETIF_F_RXCSUM |
NETIF_F_TSO |
NETIF_F_TSO_ECN |
- NETIF_F_TSO6;
+ NETIF_F_TSO6 |
+ NETIF_F_GSO_UDP_L4;
netdev->hw_features |= netdev->features;
netdev->vlan_features |= netdev->features;
diff --git a/drivers/net/ethernet/meta/mpnic/mpnic_txrx.c b/drivers/net/ethernet/meta/mpnic/mpnic_txrx.c
index e2e6ab6d3c59..9dd61b6d374c 100644
--- a/drivers/net/ethernet/meta/mpnic/mpnic_txrx.c
+++ b/drivers/net/ethernet/meta/mpnic/mpnic_txrx.c
@@ -223,29 +223,44 @@ static void mpnic_tx_fill_hdrs(struct sk_buff *skb, struct mpnic_tx_hdrs *hdrs)
return;
}
- hdrs->l4_type = MPNIC_TWD_L4_TYPE_TCP;
+ if (skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))
+ hdrs->l4_type = MPNIC_TWD_L4_TYPE_TCP;
+ else
+ hdrs->l4_type = MPNIC_TWD_L4_TYPE_UDP;
+
hdrs->i3len = skb_transport_offset(skb) - skb_network_offset(skb);
hdrs->l3_type = ip_hdr(skb)->version == 4 ?
MPNIC_TWD_L3_TYPE_IPV4 : MPNIC_TWD_L3_TYPE_IPV6;
}
static bool
-mpnic_tx_lso(struct mpnic_ring *ring, struct sk_buff *skb, __le64 *meta)
+mpnic_tx_lso(struct mpnic_ring *ring, struct sk_buff *skb, __le64 *meta,
+ const struct mpnic_tx_hdrs *hdrs)
{
struct skb_shared_info *shinfo;
unsigned int l4len, hdrlen;
- struct tcphdr *tcph;
- __be16 payload_len;
+ unsigned char *l4hdr;
if (skb_cow_head(skb, 0))
return true;
shinfo = skb_shinfo(skb);
+ l4hdr = skb_checksum_start(skb);
+
+ if (hdrs->l4_type == MPNIC_TWD_L4_TYPE_TCP) {
+ struct tcphdr *tcph = (struct tcphdr *)l4hdr;
+ __be16 payload_len;
- tcph = (struct tcphdr *)skb_checksum_start(skb);
- l4len = __tcp_hdrlen(tcph);
- payload_len = cpu_to_be16(skb->len - skb_checksum_start_offset(skb));
- csum_replace_by_diff(&tcph->check, (__force __wsum)payload_len);
+ l4len = __tcp_hdrlen(tcph);
+ payload_len = cpu_to_be16(skb->len -
+ skb_checksum_start_offset(skb));
+ csum_replace_by_diff(&tcph->check, (__force __wsum)payload_len);
+ } else {
+ struct udphdr *udph = (struct udphdr *)l4hdr;
+
+ l4len = sizeof(*udph);
+ csum_replace_by_diff(&udph->check, (__force __wsum)udph->len);
+ }
*meta |= cpu_to_le64(FIELD_PREP(MPNIC_TWD_L4_HLEN, l4len / 4) |
FIELD_PREP(MPNIC_TWD_MSS, shinfo->gso_size) |
@@ -277,7 +292,7 @@ mpnic_tx_offloads(struct mpnic_ring *ring, struct sk_buff *skb, __le64 *meta)
skb->csum_offset / 2));
if (skb_is_gso(skb)) {
- if (mpnic_tx_lso(ring, skb, meta))
+ if (mpnic_tx_lso(ring, skb, meta, &hdrs))
return true;
} else {
*meta |= cpu_to_le64(MPNIC_TWD_FLAG_REQ_CSO);
--
2.52.0