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net/bnxt: fix reordering in NEON Rx

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Rx descriptor contains a valid bit which indicates readiness of the rest
of descriptor words. Hence, the word contains valid bit must be read
prior to other words.

In NEON vector path, two contiguous 8B descriptor are loaded to a single
NEON register. Given vector load ensures no 16B atomicity, read of the
word that includes valid bit could be reordered after read of other words.
In this case, data could be invalid.

Reloaded lower 64b after read barrier. This ensures what fetched is
correct.

Also fixed comments that not pertains to Arm platform architecture.

Fixes: deae85145c64 ("net/bnxt: handle multiple packets per loop in vector Rx")
Cc: stable@dpdk.org

Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
This commit is contained in:
Ruifeng Wang 2022-04-13 18:31:56 +08:00 committed by Ajit Khaparde
parent 761edd4b09
commit e7f2effc92
1 changed files with 15 additions and 2 deletions
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17
drivers/net/bnxt/bnxt_rxtx_vec_neon.c
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@ -231,25 +231,38 @@ recv_burst_vec_neon(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
}
/*
* Load the four current descriptors into SSE registers in
* reverse order to ensure consistent state.
* Load the four current descriptors into NEON registers.
* IO barriers are used to ensure consistent state.
*/
rxcmp1[3] = vld1q_u32((void *)&cpr->cp_desc_ring[cons + 7]);
rte_io_rmb();
/* Reload lower 64b of descriptors to make it ordered after info3_v. */
rxcmp1[3] = vreinterpretq_u32_u64(vld1q_lane_u64
((void *)&cpr->cp_desc_ring[cons + 7],
vreinterpretq_u64_u32(rxcmp1[3]), 0));
rxcmp[3] = vld1q_u32((void *)&cpr->cp_desc_ring[cons + 6]);
rxcmp1[2] = vld1q_u32((void *)&cpr->cp_desc_ring[cons + 5]);
rte_io_rmb();
rxcmp1[2] = vreinterpretq_u32_u64(vld1q_lane_u64
((void *)&cpr->cp_desc_ring[cons + 5],
vreinterpretq_u64_u32(rxcmp1[2]), 0));
rxcmp[2] = vld1q_u32((void *)&cpr->cp_desc_ring[cons + 4]);
t1 = vreinterpretq_u64_u32(vzip2q_u32(rxcmp1[2], rxcmp1[3]));
rxcmp1[1] = vld1q_u32((void *)&cpr->cp_desc_ring[cons + 3]);
rte_io_rmb();
rxcmp1[1] = vreinterpretq_u32_u64(vld1q_lane_u64
((void *)&cpr->cp_desc_ring[cons + 3],
vreinterpretq_u64_u32(rxcmp1[1]), 0));
rxcmp[1] = vld1q_u32((void *)&cpr->cp_desc_ring[cons + 2]);
rxcmp1[0] = vld1q_u32((void *)&cpr->cp_desc_ring[cons + 1]);
rte_io_rmb();
rxcmp1[0] = vreinterpretq_u32_u64(vld1q_lane_u64
((void *)&cpr->cp_desc_ring[cons + 1],
vreinterpretq_u64_u32(rxcmp1[0]), 0));
rxcmp[0] = vld1q_u32((void *)&cpr->cp_desc_ring[cons + 0]);
t0 = vreinterpretq_u64_u32(vzip2q_u32(rxcmp1[0], rxcmp1[1]));