net/ixgbe: fix UDP zero checksum on Arm

There is an 82599 errata that UDP frames with a zero checksum are
incorrectly marked as checksum invalid by the hardware.  This was
leading to misleading PKT_RX_L4_CKSUM_BAD flag.

To fix it for the NEON path in Arm platform, change the bad UDP checksum to
unknown, and then let software application to recompute the checksum.

NICs: 82599(igb)
Driver: ixgbe(vector)
Architecture: arm64
$:./app/dpdk-testpmd -c 0x3 -w 0002:f9:00.0 -- -i
--port-topology=chained --enable-rx-cksum
test-pmd> set fwd rxonly
test-pmd> set verbose 1
test-pmd> start

1. UDP Test:
Package: (Ether()/IP()/UDP(checksum=0)
ol_flags: PKT_RX_L4_CKSUM_UNKNOWN PKT_RX_IP_CKSUM_GOOD

2. TCP Test:
Package: (Ether()/IP()/TCP(checksum=0)
ol_flags: PKT_RX_L4_CKSUM_BAD PKT_RX_IP_CKSUM_GOOD

Bugzilla ID: 629
Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org
Reported-by: Paolo Valerio <pvalerio@redhat.com>
Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

diff --git a/drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c b/drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c
index f83b800..c541f53 100644 (file)
--- a/drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c
@@ -83,9 +83,12 @@ ixgbe_rxq_rearm(struct ixgbe_rx_queue *rxq)
 
 static inline void
 desc_to_olflags_v(uint8x16x2_t sterr_tmp1, uint8x16x2_t sterr_tmp2,
-                 uint8x16_t staterr, uint8_t vlan_flags, struct rte_mbuf **rx_pkts)
+                 uint8x16_t staterr, uint8_t vlan_flags, uint16_t udp_p_flag,
+                 struct rte_mbuf **rx_pkts)
 {
-       uint8x16_t ptype;
+       uint16_t udp_p_flag_hi;
+       uint8x16_t ptype, udp_csum_skip;
+       uint32x4_t temp_udp_csum_skip = {0, 0, 0, 0};
        uint8x16_t vtag_lo, vtag_hi, vtag;
        uint8x16_t temp_csum;
        uint32x4_t csum = {0, 0, 0, 0};
@@ -139,7 +142,31 @@ desc_to_olflags_v(uint8x16x2_t sterr_tmp1, uint8x16x2_t sterr_tmp2,
                        PKT_RX_L4_CKSUM_GOOD >> sizeof(uint8_t), 0,
                        0, 0, 0, 0};
 
+       /* change mask from 0x200(IXGBE_RXDADV_PKTTYPE_UDP) to 0x2 */
+       udp_p_flag_hi = udp_p_flag >> 8;
+
+       /* mask everything except UDP header present if specified */
+       const uint8x16_t udp_hdr_p_msk = {
+                       0, 0, 0, 0,
+                       udp_p_flag_hi, udp_p_flag_hi, udp_p_flag_hi, udp_p_flag_hi,
+                       0, 0, 0, 0,
+                       0, 0, 0, 0};
+
+       const uint8x16_t udp_csum_bad_shuf = {
+                       0xFF, ~(uint8_t)PKT_RX_L4_CKSUM_BAD, 0, 0,
+                       0, 0, 0, 0,
+                       0, 0, 0, 0,
+                       0, 0, 0, 0};
+
        ptype = vzipq_u8(sterr_tmp1.val[0], sterr_tmp2.val[0]).val[0];
+
+       /* save the UDP header present information */
+       udp_csum_skip = vandq_u8(ptype, udp_hdr_p_msk);
+
+       /* move UDP header present information to low 32bits */
+       temp_udp_csum_skip = vcopyq_laneq_u32(temp_udp_csum_skip, 0,
+                               vreinterpretq_u32_u8(udp_csum_skip), 1);
+
        ptype = vandq_u8(ptype, rsstype_msk);
        ptype = vqtbl1q_u8(rss_flags, ptype);
 
@@ -166,6 +193,15 @@ desc_to_olflags_v(uint8x16x2_t sterr_tmp1, uint8x16x2_t sterr_tmp2,
        vtag_lo = vqtbl1q_u8(vlan_csum_map_lo, vtag);
        vtag_lo = vorrq_u8(ptype, vtag_lo);
 
+       /* convert the UDP header present 0x2 to 0x1 for aligning with each
+        * PKT_RX_L4_CKSUM_BAD value in low byte of 8 bits word ol_flag in
+        * vtag_lo (4x8). Then mask out the bad checksum value by shuffle and
+        * bit-mask.
+        */
+       udp_csum_skip = vshrq_n_u8(vreinterpretq_u8_u32(temp_udp_csum_skip), 1);
+       udp_csum_skip = vqtbl1q_u8(udp_csum_bad_shuf, udp_csum_skip);
+       vtag_lo = vandq_u8(vtag_lo, udp_csum_skip);
+
        vtag = vzipq_u8(vtag_lo, vtag_hi).val[0];
        vol.word = vgetq_lane_u64(vreinterpretq_u64_u8(vtag), 0);
 
@@ -267,6 +303,7 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
        uint16x8_t crc_adjust = {0, 0, rxq->crc_len, 0,
                                 rxq->crc_len, 0, 0, 0};
        uint8_t vlan_flags;
+       uint16_t udp_p_flag = 0; /* Rx Descriptor UDP header present */
 
        /* nb_pkts has to be floor-aligned to RTE_IXGBE_DESCS_PER_LOOP */
        nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_IXGBE_DESCS_PER_LOOP);
@@ -291,6 +328,9 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
                                rte_cpu_to_le_32(IXGBE_RXDADV_STAT_DD)))
                return 0;
 
+       if (rxq->rx_udp_csum_zero_err)
+               udp_p_flag = IXGBE_RXDADV_PKTTYPE_UDP;
+
        /* Cache is empty -> need to scan the buffer rings, but first move
         * the next 'n' mbufs into the cache
         */
@@ -362,7 +402,7 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
 
                /* set ol_flags with vlan packet type */
                desc_to_olflags_v(sterr_tmp1, sterr_tmp2, staterr, vlan_flags,
-                                 &rx_pkts[pos]);
+                                 udp_p_flag, &rx_pkts[pos]);
 
                /* D.2 pkt 3,4 set in_port/nb_seg and remove crc */
                tmp = vsubq_u16(vreinterpretq_u16_u8(pkt_mb4), crc_adjust);