net/virtio: add NEON based Rx handler

Added neon based Rx vector implementation.
Selection of the new handler based neon availability at runtime.
Updated the release notes and MAINTAINERS file.

Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Acked-by: Jianbo Liu <jianbo.liu@linaro.org>

MAINTAINERS

@@ -151,6 +151,7 @@ F: lib/librte_acl/acl_run_neon.*
 F: lib/librte_lpm/rte_lpm_neon.h
 F: lib/librte_hash/rte*_arm64.h
 F: drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c
+F: drivers/net/virtio/virtio_rxtx_simple_neon.c
 
 EZchip TILE-Gx
 M: Zhigang Lu <zlu@ezchip.com>

doc/guides/rel_notes/release_16_11.rst

@@ -48,6 +48,8 @@ New Features
   in case of system perturbations. On the downside, small performance degradation
   is measured when running micro-benchmarks.
 
+* **Added virtio NEON support for ARM.**
+
 
 Resolved Issues
 ---------------

drivers/net/virtio/Makefile

@@ -54,6 +54,8 @@ SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_rxtx_simple.c
 
 ifeq ($(CONFIG_RTE_ARCH_X86),y)
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_rxtx_simple_sse.c
+else ifneq ($(filter y,$(CONFIG_RTE_ARCH_ARM) $(CONFIG_RTE_ARCH_ARM64)),)
+SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_rxtx_simple_neon.c
 endif
 
 ifeq ($(CONFIG_RTE_VIRTIO_USER),y)

drivers/net/virtio/virtio_rxtx.c

@@ -488,6 +488,9 @@ virtio_update_rxtx_handler(struct rte_eth_dev *dev,
 #if defined RTE_ARCH_X86
 	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SSE3))
 		use_simple_rxtx = 1;
+#elif defined RTE_ARCH_ARM64 || defined CONFIG_RTE_ARCH_ARM
+	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_NEON))
+		use_simple_rxtx = 1;
 #endif
 	/* Use simple rx/tx func if single segment and no offloads */
 	if (use_simple_rxtx &&

drivers/net/virtio/virtio_rxtx_simple_neon.c

@@ -0,0 +1,235 @@
+/*
+ *   BSD LICENSE
+ *
+ *   Copyright (C) Cavium networks Ltd. 2016
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Cavium networks nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <rte_byteorder.h>
+#include <rte_branch_prediction.h>
+#include <rte_cycles.h>
+#include <rte_ether.h>
+#include <rte_ethdev.h>
+#include <rte_errno.h>
+#include <rte_memory.h>
+#include <rte_memzone.h>
+#include <rte_mempool.h>
+#include <rte_malloc.h>
+#include <rte_mbuf.h>
+#include <rte_prefetch.h>
+#include <rte_string_fns.h>
+#include <rte_vect.h>
+
+#include "virtio_rxtx_simple.h"
+
+#define RTE_VIRTIO_VPMD_RX_BURST 32
+#define RTE_VIRTIO_DESC_PER_LOOP 8
+#define RTE_VIRTIO_VPMD_RX_REARM_THRESH RTE_VIRTIO_VPMD_RX_BURST
+
+/* virtio vPMD receive routine, only accept(nb_pkts >= RTE_VIRTIO_DESC_PER_LOOP)
+ *
+ * This routine is for non-mergeable RX, one desc for each guest buffer.
+ * This routine is based on the RX ring layout optimization. Each entry in the
+ * avail ring points to the desc with the same index in the desc ring and this
+ * will never be changed in the driver.
+ *
+ * - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
+ */
+uint16_t
+virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
+	uint16_t nb_pkts)
+{
+	struct virtnet_rx *rxvq = rx_queue;
+	struct virtqueue *vq = rxvq->vq;
+	uint16_t nb_used;
+	uint16_t desc_idx;
+	struct vring_used_elem *rused;
+	struct rte_mbuf **sw_ring;
+	struct rte_mbuf **sw_ring_end;
+	uint16_t nb_pkts_received;
+
+	uint8x16_t shuf_msk1 = {
+		0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
+		4, 5, 0xFF, 0xFF,       /* pkt len */
+		4, 5,                   /* dat len */
+		0xFF, 0xFF,             /* vlan tci */
+		0xFF, 0xFF, 0xFF, 0xFF
+	};
+
+	uint8x16_t shuf_msk2 = {
+		0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
+		12, 13, 0xFF, 0xFF,     /* pkt len */
+		12, 13,                 /* dat len */
+		0xFF, 0xFF,             /* vlan tci */
+		0xFF, 0xFF, 0xFF, 0xFF
+	};
+
+	/* Subtract the header length.
+	 *  In which case do we need the header length in used->len ?
+	 */
+	uint16x8_t len_adjust = {
+		0, 0,
+		(uint16_t)vq->hw->vtnet_hdr_size, 0,
+		(uint16_t)vq->hw->vtnet_hdr_size,
+		0,
+		0, 0
+	};
+
+	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
+		return 0;
+
+	nb_used = VIRTQUEUE_NUSED(vq);
+
+	rte_rmb();
+
+	if (unlikely(nb_used == 0))
+		return 0;
+
+	nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
+	nb_used = RTE_MIN(nb_used, nb_pkts);
+
+	desc_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
+	rused = &vq->vq_ring.used->ring[desc_idx];
+	sw_ring  = &vq->sw_ring[desc_idx];
+	sw_ring_end = &vq->sw_ring[vq->vq_nentries];
+
+	rte_prefetch_non_temporal(rused);
+
+	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+		virtio_rxq_rearm_vec(rxvq);
+		if (unlikely(virtqueue_kick_prepare(vq)))
+			virtqueue_notify(vq);
+	}
+
+	for (nb_pkts_received = 0;
+		nb_pkts_received < nb_used;) {
+		uint64x2_t desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
+		uint64x2_t mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
+		uint64x2_t pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
+
+		mbp[0] = vld1q_u64((uint64_t *)(sw_ring + 0));
+		desc[0] = vld1q_u64((uint64_t *)(rused + 0));
+		vst1q_u64((uint64_t *)&rx_pkts[0], mbp[0]);
+
+		mbp[1] = vld1q_u64((uint64_t *)(sw_ring + 2));
+		desc[1] = vld1q_u64((uint64_t *)(rused + 2));
+		vst1q_u64((uint64_t *)&rx_pkts[2], mbp[1]);
+
+		mbp[2] = vld1q_u64((uint64_t *)(sw_ring + 4));
+		desc[2] = vld1q_u64((uint64_t *)(rused + 4));
+		vst1q_u64((uint64_t *)&rx_pkts[4], mbp[2]);
+
+		mbp[3] = vld1q_u64((uint64_t *)(sw_ring + 6));
+		desc[3] = vld1q_u64((uint64_t *)(rused + 6));
+		vst1q_u64((uint64_t *)&rx_pkts[6], mbp[3]);
+
+		pkt_mb[1] = vreinterpretq_u64_u8(vqtbl1q_u8(
+				vreinterpretq_u8_u64(desc[0]), shuf_msk2));
+		pkt_mb[0] = vreinterpretq_u64_u8(vqtbl1q_u8(
+				vreinterpretq_u8_u64(desc[0]), shuf_msk1));
+		pkt_mb[1] = vreinterpretq_u64_u16(vsubq_u16(
+				vreinterpretq_u16_u64(pkt_mb[1]), len_adjust));
+		pkt_mb[0] = vreinterpretq_u64_u16(vsubq_u16(
+				vreinterpretq_u16_u64(pkt_mb[0]), len_adjust));
+		vst1q_u64((void *)&rx_pkts[1]->rx_descriptor_fields1,
+			pkt_mb[1]);
+		vst1q_u64((void *)&rx_pkts[0]->rx_descriptor_fields1,
+			pkt_mb[0]);
+
+		pkt_mb[3] = vreinterpretq_u64_u8(vqtbl1q_u8(
+				vreinterpretq_u8_u64(desc[1]), shuf_msk2));
+		pkt_mb[2] = vreinterpretq_u64_u8(vqtbl1q_u8(
+				vreinterpretq_u8_u64(desc[1]), shuf_msk1));
+		pkt_mb[3] = vreinterpretq_u64_u16(vsubq_u16(
+				vreinterpretq_u16_u64(pkt_mb[3]), len_adjust));
+		pkt_mb[2] = vreinterpretq_u64_u16(vsubq_u16(
+				vreinterpretq_u16_u64(pkt_mb[2]), len_adjust));
+		vst1q_u64((void *)&rx_pkts[3]->rx_descriptor_fields1,
+			pkt_mb[3]);
+		vst1q_u64((void *)&rx_pkts[2]->rx_descriptor_fields1,
+			pkt_mb[2]);
+
+		pkt_mb[5] = vreinterpretq_u64_u8(vqtbl1q_u8(
+				vreinterpretq_u8_u64(desc[2]), shuf_msk2));
+		pkt_mb[4] = vreinterpretq_u64_u8(vqtbl1q_u8(
+				vreinterpretq_u8_u64(desc[2]), shuf_msk1));
+		pkt_mb[5] = vreinterpretq_u64_u16(vsubq_u16(
+				vreinterpretq_u16_u64(pkt_mb[5]), len_adjust));
+		pkt_mb[4] = vreinterpretq_u64_u16(vsubq_u16(
+				vreinterpretq_u16_u64(pkt_mb[4]), len_adjust));
+		vst1q_u64((void *)&rx_pkts[5]->rx_descriptor_fields1,
+			pkt_mb[5]);
+		vst1q_u64((void *)&rx_pkts[4]->rx_descriptor_fields1,
+			pkt_mb[4]);
+
+		pkt_mb[7] = vreinterpretq_u64_u8(vqtbl1q_u8(
+				vreinterpretq_u8_u64(desc[3]), shuf_msk2));
+		pkt_mb[6] = vreinterpretq_u64_u8(vqtbl1q_u8(
+				vreinterpretq_u8_u64(desc[3]), shuf_msk1));
+		pkt_mb[7] = vreinterpretq_u64_u16(vsubq_u16(
+				vreinterpretq_u16_u64(pkt_mb[7]), len_adjust));
+		pkt_mb[6] = vreinterpretq_u64_u16(vsubq_u16(
+				vreinterpretq_u16_u64(pkt_mb[6]), len_adjust));
+		vst1q_u64((void *)&rx_pkts[7]->rx_descriptor_fields1,
+			pkt_mb[7]);
+		vst1q_u64((void *)&rx_pkts[6]->rx_descriptor_fields1,
+			pkt_mb[6]);
+
+		if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
+			if (sw_ring + nb_used <= sw_ring_end)
+				nb_pkts_received += nb_used;
+			else
+				nb_pkts_received += sw_ring_end - sw_ring;
+			break;
+		} else {
+			if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
+				sw_ring_end)) {
+				nb_pkts_received += sw_ring_end - sw_ring;
+				break;
+			} else {
+				nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
+
+				rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
+				sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
+				rused   += RTE_VIRTIO_DESC_PER_LOOP;
+				nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
+			}
+		}
+	}
+
+	vq->vq_used_cons_idx += nb_pkts_received;
+	vq->vq_free_cnt += nb_pkts_received;
+	rxvq->stats.packets += nb_pkts_received;
+	return nb_pkts_received;
+}