[2/3] net/ice: fix segment fault in AVX512

  Fix segment fault when failing to get the memory from the pool.

Fixes: 7f85d5ebcfe1 ("net/ice: add AVX512 vector path")
Cc: stable@dpdk.org

Reported-by: David Coyle <David.Coyle@intel.com>
Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
---
 drivers/net/ice/ice_rxtx_vec_avx512.c | 129 ++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
  

Hi Wenzhuo

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Wenzhuo Lu
> Sent: Friday, March 12, 2021 1:27 AM
> To: dev@dpdk.org
> Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; stable@dpdk.org
> Subject: [dpdk-dev] [PATCH 2/3] net/ice: fix segment fault in AVX512
> 
> Fix segment fault when failing to get the memory from the pool.
> 
> Fixes: 7f85d5ebcfe1 ("net/ice: add AVX512 vector path")
> Cc: stable@dpdk.org
> 
> Reported-by: David Coyle <David.Coyle@intel.com>
> Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
> ---
>  drivers/net/ice/ice_rxtx_vec_avx512.c | 129
> ++++++++++++++++++++++++++++++++++
>  1 file changed, 129 insertions(+)
> 
> diff --git a/drivers/net/ice/ice_rxtx_vec_avx512.c
> b/drivers/net/ice/ice_rxtx_vec_avx512.c
> index 0e5a676..7c458d5 100644
> --- a/drivers/net/ice/ice_rxtx_vec_avx512.c
> +++ b/drivers/net/ice/ice_rxtx_vec_avx512.c
> @@ -24,6 +24,9 @@
> 
>  	rxdp = rxq->rx_ring + rxq->rxrearm_start;
> 
> +	if (!cache)
> +		goto normal;

[DC] Same as IAVF, in the Tx path, in ice_tx_free_bufs_avx512(), it also checks for
cache->len == 0.
Not sure if the extra check is necessary though - I don't know if 'cache' can be valid pointer
but have a length of 0

                if (!cache || cache->len == 0)
                        goto normal;

> +
>  	/* We need to pull 'n' more MBUFs into the software ring */
>  	if (cache->len < ICE_RXQ_REARM_THRESH) {
>  		uint32_t req = ICE_RXQ_REARM_THRESH + (cache->size -
> @@ -115,6 +118,132 @@
>  		rxep += 8, rxdp += 8, cache->len -= 8;
>  	}
> 
> +	goto done;
> +
> +normal:
> +	/* Pull 'n' more MBUFs into the software ring */
> +	if (rte_mempool_get_bulk(rxq->mp,
> +				 (void *)rxep,
> +				 ICE_RXQ_REARM_THRESH) < 0) {
> +		if (rxq->rxrearm_nb + ICE_RXQ_REARM_THRESH >=
> +		    rxq->nb_rx_desc) {
> +			__m128i dma_addr0;
> +
> +			dma_addr0 = _mm_setzero_si128();
> +			for (i = 0; i < ICE_DESCS_PER_LOOP; i++) {
> +				rxep[i].mbuf = &rxq->fake_mbuf;
> +				_mm_store_si128((__m128i *)&rxdp[i].read,
> +						dma_addr0);
> +			}
> +		}
> +		rte_eth_devices[rxq->port_id].data->rx_mbuf_alloc_failed
> +=
> +			ICE_RXQ_REARM_THRESH;
> +		return;
> +	}
> +
> +#ifndef RTE_LIBRTE_ICE_16BYTE_RX_DESC
> +	struct rte_mbuf *mb0, *mb1;
> +	__m128i dma_addr0, dma_addr1;
> +	__m128i hdr_room = _mm_set_epi64x(RTE_PKTMBUF_HEADROOM,
> +			RTE_PKTMBUF_HEADROOM);
> +	/* Initialize the mbufs in vector, process 4 mbufs in one loop */

[DC] Comment above should say 2 mbufs

> +	for (i = 0; i < ICE_RXQ_REARM_THRESH; i += 2, rxep += 2) {
> +		__m128i vaddr0, vaddr1;
> +
> +		mb0 = rxep[0].mbuf;
> +		mb1 = rxep[1].mbuf;
> +
> +		/* load buf_addr(lo 64bit) and buf_physaddr(hi 64bit) */
> +		RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, buf_iova) !=
> +				offsetof(struct rte_mbuf, buf_addr) + 8);
> +		vaddr0 = _mm_loadu_si128((__m128i *)&mb0->buf_addr);
> +		vaddr1 = _mm_loadu_si128((__m128i *)&mb1->buf_addr);
> +
> +		/* convert pa to dma_addr hdr/data */
> +		dma_addr0 = _mm_unpackhi_epi64(vaddr0, vaddr0);
> +		dma_addr1 = _mm_unpackhi_epi64(vaddr1, vaddr1);
> +
> +		/* add headroom to pa values */
> +		dma_addr0 = _mm_add_epi64(dma_addr0, hdr_room);
> +		dma_addr1 = _mm_add_epi64(dma_addr1, hdr_room);
> +
> +		/* flush desc with pa dma_addr */
> +		_mm_store_si128((__m128i *)&rxdp++->read, dma_addr0);
> +		_mm_store_si128((__m128i *)&rxdp++->read, dma_addr1);
> +	}

[DC] As in IAVF, the code above is the same as in avx2 file... any possibility to have a common function
or functions for the 2 files?

And there is also commonality between IAVF and ICE PMDs.
There doesn't seem to be any shared code between net PMDs at the moment though, so maybe it's
practical to have common functions

> +#else
> +	struct rte_mbuf *mb0, *mb1, *mb2, *mb3;
> +	struct rte_mbuf *mb4, *mb5, *mb6, *mb7;
> +	__m512i dma_addr0_3, dma_addr4_7;
> +	__m512i hdr_room =
> _mm512_set1_epi64(RTE_PKTMBUF_HEADROOM);
> +	/* Initialize the mbufs in vector, process 4 mbufs in one loop */

[DC] Comment above should say 8 mbufs

> +	for (i = 0; i < ICE_RXQ_REARM_THRESH;
> +			i += 8, rxep += 8, rxdp += 8) {

<snip>

> +
> +		/**
> +		 * merge 0 & 1, by casting 0 to 256-bit and inserting 1
> +		 * into the high lanes. Similarly for 2 & 3
> +		 */

[DC] Comment above should say "Similarly for 2 & 3, 4 & 5, 6 & 7"

> +		vaddr0_1 =
> +
> 	_mm256_inserti128_si256(_mm256_castsi128_si256(vaddr0),
> +						vaddr1, 1);
> +		vaddr2_3 =

The patch fixes the seg fault, but note I have only tested the default '#ifndef RTE_LIBRTE_ICE_16BYTE_RX_DESC' path

Tested-by: David Coyle <david.coyle@intel.com>
  

Hi David,
Thanks for the comments. I see they're the same as the i40e patch. Will handle them in V2.

Best regards
Wenzhuo Lu