xref: /dpdk/drivers/net/virtio/virtio_rxtx_simple_neon.c (revision 9e190e97c9950cdc580981b1a79521e7d942f57d)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2016 Cavium, Inc
3  */
4 
5 #include <stdint.h>
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <string.h>
9 #include <errno.h>
10 
11 #include <rte_byteorder.h>
12 #include <rte_branch_prediction.h>
13 #include <rte_cycles.h>
14 #include <rte_ether.h>
15 #include <rte_ethdev_driver.h>
16 #include <rte_errno.h>
17 #include <rte_memory.h>
18 #include <rte_mempool.h>
19 #include <rte_malloc.h>
20 #include <rte_mbuf.h>
21 #include <rte_prefetch.h>
22 #include <rte_string_fns.h>
23 #include <rte_vect.h>
24 
25 #include "virtio_rxtx_simple.h"
26 
27 #define RTE_VIRTIO_DESC_PER_LOOP 8
28 
29 /* virtio vPMD receive routine, only accept(nb_pkts >= RTE_VIRTIO_DESC_PER_LOOP)
30  *
31  * This routine is for non-mergeable RX, one desc for each guest buffer.
32  * This routine is based on the RX ring layout optimization. Each entry in the
33  * avail ring points to the desc with the same index in the desc ring and this
34  * will never be changed in the driver.
35  *
36  * - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
37  */
38 uint16_t
39 virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
40 	uint16_t nb_pkts)
41 {
42 	struct virtnet_rx *rxvq = rx_queue;
43 	struct virtqueue *vq = rxvq->vq;
44 	struct virtio_hw *hw = vq->hw;
45 	uint16_t nb_used, nb_total;
46 	uint16_t desc_idx;
47 	struct vring_used_elem *rused;
48 	struct rte_mbuf **sw_ring;
49 	struct rte_mbuf **sw_ring_end;
50 	struct rte_mbuf **ref_rx_pkts;
51 	uint16_t nb_pkts_received = 0;
52 
53 	uint8x16_t shuf_msk1 = {
54 		0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
55 		4, 5, 0xFF, 0xFF,       /* pkt len */
56 		4, 5,                   /* dat len */
57 		0xFF, 0xFF,             /* vlan tci */
58 		0xFF, 0xFF, 0xFF, 0xFF
59 	};
60 
61 	uint8x16_t shuf_msk2 = {
62 		0xFF, 0xFF, 0xFF, 0xFF, /* packet type */
63 		12, 13, 0xFF, 0xFF,     /* pkt len */
64 		12, 13,                 /* dat len */
65 		0xFF, 0xFF,             /* vlan tci */
66 		0xFF, 0xFF, 0xFF, 0xFF
67 	};
68 
69 	/* Subtract the header length.
70 	 *  In which case do we need the header length in used->len ?
71 	 */
72 	uint16x8_t len_adjust = {
73 		0, 0,
74 		(uint16_t)hw->vtnet_hdr_size, 0,
75 		(uint16_t)hw->vtnet_hdr_size,
76 		0,
77 		0, 0
78 	};
79 
80 	if (unlikely(hw->started == 0))
81 		return nb_pkts_received;
82 
83 	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
84 		return 0;
85 
86 	/* virtqueue_nused has a load-acquire or rte_cio_rmb inside */
87 	nb_used = virtqueue_nused(vq);
88 
89 	if (unlikely(nb_used == 0))
90 		return 0;
91 
92 	nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
93 	nb_used = RTE_MIN(nb_used, nb_pkts);
94 
95 	desc_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
96 	rused = &vq->vq_split.ring.used->ring[desc_idx];
97 	sw_ring  = &vq->sw_ring[desc_idx];
98 	sw_ring_end = &vq->sw_ring[vq->vq_nentries];
99 
100 	rte_prefetch_non_temporal(rused);
101 
102 	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
103 		virtio_rxq_rearm_vec(rxvq);
104 		if (unlikely(virtqueue_kick_prepare(vq)))
105 			virtqueue_notify(vq);
106 	}
107 
108 	nb_total = nb_used;
109 	ref_rx_pkts = rx_pkts;
110 	for (nb_pkts_received = 0;
111 		nb_pkts_received < nb_total;) {
112 		uint64x2_t desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
113 		uint64x2_t mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
114 		uint64x2_t pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
115 
116 		mbp[0] = vld1q_u64((uint64_t *)(sw_ring + 0));
117 		desc[0] = vld1q_u64((uint64_t *)(rused + 0));
118 		vst1q_u64((uint64_t *)&rx_pkts[0], mbp[0]);
119 
120 		mbp[1] = vld1q_u64((uint64_t *)(sw_ring + 2));
121 		desc[1] = vld1q_u64((uint64_t *)(rused + 2));
122 		vst1q_u64((uint64_t *)&rx_pkts[2], mbp[1]);
123 
124 		mbp[2] = vld1q_u64((uint64_t *)(sw_ring + 4));
125 		desc[2] = vld1q_u64((uint64_t *)(rused + 4));
126 		vst1q_u64((uint64_t *)&rx_pkts[4], mbp[2]);
127 
128 		mbp[3] = vld1q_u64((uint64_t *)(sw_ring + 6));
129 		desc[3] = vld1q_u64((uint64_t *)(rused + 6));
130 		vst1q_u64((uint64_t *)&rx_pkts[6], mbp[3]);
131 
132 		pkt_mb[1] = vreinterpretq_u64_u8(vqtbl1q_u8(
133 				vreinterpretq_u8_u64(desc[0]), shuf_msk2));
134 		pkt_mb[0] = vreinterpretq_u64_u8(vqtbl1q_u8(
135 				vreinterpretq_u8_u64(desc[0]), shuf_msk1));
136 		pkt_mb[1] = vreinterpretq_u64_u16(vsubq_u16(
137 				vreinterpretq_u16_u64(pkt_mb[1]), len_adjust));
138 		pkt_mb[0] = vreinterpretq_u64_u16(vsubq_u16(
139 				vreinterpretq_u16_u64(pkt_mb[0]), len_adjust));
140 		vst1q_u64((void *)&rx_pkts[1]->rx_descriptor_fields1,
141 			pkt_mb[1]);
142 		vst1q_u64((void *)&rx_pkts[0]->rx_descriptor_fields1,
143 			pkt_mb[0]);
144 
145 		pkt_mb[3] = vreinterpretq_u64_u8(vqtbl1q_u8(
146 				vreinterpretq_u8_u64(desc[1]), shuf_msk2));
147 		pkt_mb[2] = vreinterpretq_u64_u8(vqtbl1q_u8(
148 				vreinterpretq_u8_u64(desc[1]), shuf_msk1));
149 		pkt_mb[3] = vreinterpretq_u64_u16(vsubq_u16(
150 				vreinterpretq_u16_u64(pkt_mb[3]), len_adjust));
151 		pkt_mb[2] = vreinterpretq_u64_u16(vsubq_u16(
152 				vreinterpretq_u16_u64(pkt_mb[2]), len_adjust));
153 		vst1q_u64((void *)&rx_pkts[3]->rx_descriptor_fields1,
154 			pkt_mb[3]);
155 		vst1q_u64((void *)&rx_pkts[2]->rx_descriptor_fields1,
156 			pkt_mb[2]);
157 
158 		pkt_mb[5] = vreinterpretq_u64_u8(vqtbl1q_u8(
159 				vreinterpretq_u8_u64(desc[2]), shuf_msk2));
160 		pkt_mb[4] = vreinterpretq_u64_u8(vqtbl1q_u8(
161 				vreinterpretq_u8_u64(desc[2]), shuf_msk1));
162 		pkt_mb[5] = vreinterpretq_u64_u16(vsubq_u16(
163 				vreinterpretq_u16_u64(pkt_mb[5]), len_adjust));
164 		pkt_mb[4] = vreinterpretq_u64_u16(vsubq_u16(
165 				vreinterpretq_u16_u64(pkt_mb[4]), len_adjust));
166 		vst1q_u64((void *)&rx_pkts[5]->rx_descriptor_fields1,
167 			pkt_mb[5]);
168 		vst1q_u64((void *)&rx_pkts[4]->rx_descriptor_fields1,
169 			pkt_mb[4]);
170 
171 		pkt_mb[7] = vreinterpretq_u64_u8(vqtbl1q_u8(
172 				vreinterpretq_u8_u64(desc[3]), shuf_msk2));
173 		pkt_mb[6] = vreinterpretq_u64_u8(vqtbl1q_u8(
174 				vreinterpretq_u8_u64(desc[3]), shuf_msk1));
175 		pkt_mb[7] = vreinterpretq_u64_u16(vsubq_u16(
176 				vreinterpretq_u16_u64(pkt_mb[7]), len_adjust));
177 		pkt_mb[6] = vreinterpretq_u64_u16(vsubq_u16(
178 				vreinterpretq_u16_u64(pkt_mb[6]), len_adjust));
179 		vst1q_u64((void *)&rx_pkts[7]->rx_descriptor_fields1,
180 			pkt_mb[7]);
181 		vst1q_u64((void *)&rx_pkts[6]->rx_descriptor_fields1,
182 			pkt_mb[6]);
183 
184 		if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
185 			if (sw_ring + nb_used <= sw_ring_end)
186 				nb_pkts_received += nb_used;
187 			else
188 				nb_pkts_received += sw_ring_end - sw_ring;
189 			break;
190 		} else {
191 			if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
192 				sw_ring_end)) {
193 				nb_pkts_received += sw_ring_end - sw_ring;
194 				break;
195 			} else {
196 				nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
197 
198 				rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
199 				sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
200 				rused   += RTE_VIRTIO_DESC_PER_LOOP;
201 				nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
202 			}
203 		}
204 	}
205 
206 	vq->vq_used_cons_idx += nb_pkts_received;
207 	vq->vq_free_cnt += nb_pkts_received;
208 	rxvq->stats.packets += nb_pkts_received;
209 	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
210 		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
211 
212 	return nb_pkts_received;
213 }
214