xref: /dpdk/drivers/net/virtio/virtio_rxtx_simple_altivec.c (revision 1f41d98c207aee8982ced709864c96c463d4503a)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2015 Intel Corporation
3  * Copyright(C) 2019 IBM Corporation
4  */
5 
6 #include <stdint.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <string.h>
10 #include <errno.h>
11 
12 #include <altivec.h>
13 
14 #include <rte_byteorder.h>
15 #include <rte_branch_prediction.h>
16 #include <rte_cycles.h>
17 #include <rte_ether.h>
18 #include <rte_ethdev_driver.h>
19 #include <rte_errno.h>
20 #include <rte_memory.h>
21 #include <rte_mempool.h>
22 #include <rte_malloc.h>
23 #include <rte_mbuf.h>
24 #include <rte_prefetch.h>
25 #include <rte_string_fns.h>
26 
27 #include "virtio_rxtx_simple.h"
28 
29 #define RTE_VIRTIO_DESC_PER_LOOP 8
30 
31 /* virtio vPMD receive routine, only accept(nb_pkts >= RTE_VIRTIO_DESC_PER_LOOP)
32  *
33  * This routine is for non-mergeable RX, one desc for each guest buffer.
34  * This routine is based on the RX ring layout optimization. Each entry in the
35  * avail ring points to the desc with the same index in the desc ring and this
36  * will never be changed in the driver.
37  *
38  * - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
39  */
40 uint16_t
41 virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
42 	uint16_t nb_pkts)
43 {
44 	struct virtnet_rx *rxvq = rx_queue;
45 	struct virtqueue *vq = rxvq->vq;
46 	struct virtio_hw *hw = vq->hw;
47 	uint16_t nb_used, nb_total;
48 	uint16_t desc_idx;
49 	struct vring_used_elem *rused;
50 	struct rte_mbuf **sw_ring;
51 	struct rte_mbuf **sw_ring_end;
52 	struct rte_mbuf **ref_rx_pkts;
53 	uint16_t nb_pkts_received = 0;
54 	const vector unsigned char zero = {0};
55 
56 	const vector unsigned char shuf_msk1 = {
57 		0xFF, 0xFF, 0xFF, 0xFF,	/* packet type */
58 		4, 5, 0xFF, 0xFF, /* vlan tci */
59 		4, 5,			/* dat len */
60 		0xFF, 0xFF,		/* vlan tci */
61 		0xFF, 0xFF, 0xFF, 0xFF
62 	};
63 
64 	const vector unsigned char shuf_msk2 = {
65 		0xFF, 0xFF, 0xFF, 0xFF,	/* packet type */
66 		12, 13, 0xFF, 0xFF,	/* pkt len */
67 		12, 13,			/* dat len */
68 		0xFF, 0xFF,		/* vlan tci */
69 		0xFF, 0xFF, 0xFF, 0xFF
70 	};
71 
72 	/*
73 	 * Subtract the header length.
74 	 *  In which case do we need the header length in used->len ?
75 	 */
76 	const vector unsigned short len_adjust = {
77 		0, 0,
78 		(uint16_t)-vq->hw->vtnet_hdr_size, 0,
79 		(uint16_t)-vq->hw->vtnet_hdr_size, 0,
80 		0, 0
81 	};
82 
83 	if (unlikely(hw->started == 0))
84 		return nb_pkts_received;
85 
86 	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
87 		return 0;
88 
89 	nb_used = VIRTQUEUE_NUSED(vq);
90 
91 	rte_compiler_barrier();
92 
93 	if (unlikely(nb_used == 0))
94 		return 0;
95 
96 	nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
97 	nb_used = RTE_MIN(nb_used, nb_pkts);
98 
99 	desc_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
100 	rused = &vq->vq_split.ring.used->ring[desc_idx];
101 	sw_ring  = &vq->sw_ring[desc_idx];
102 	sw_ring_end = &vq->sw_ring[vq->vq_nentries];
103 
104 	rte_prefetch0(rused);
105 
106 	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
107 		virtio_rxq_rearm_vec(rxvq);
108 		if (unlikely(virtqueue_kick_prepare(vq)))
109 			virtqueue_notify(vq);
110 	}
111 
112 	nb_total = nb_used;
113 	ref_rx_pkts = rx_pkts;
114 	for (nb_pkts_received = 0;
115 		nb_pkts_received < nb_total;) {
116 		vector unsigned char desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
117 		vector unsigned char mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
118 		vector unsigned char pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
119 
120 		mbp[0] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 0));
121 		desc[0] = vec_vsx_ld(0, (unsigned char const *)(rused + 0));
122 		*(vector unsigned char *)&rx_pkts[0] = mbp[0];
123 
124 		mbp[1] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 2));
125 		desc[1] = vec_vsx_ld(0, (unsigned char const *)(rused + 2));
126 		*(vector unsigned char *)&rx_pkts[2] = mbp[1];
127 
128 		mbp[2] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 4));
129 		desc[2] = vec_vsx_ld(0, (unsigned char const *)(rused + 4));
130 		*(vector unsigned char *)&rx_pkts[4] = mbp[2];
131 
132 		mbp[3] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 6));
133 		desc[3] = vec_vsx_ld(0, (unsigned char const *)(rused + 6));
134 		*(vector unsigned char *)&rx_pkts[6] = mbp[3];
135 
136 		pkt_mb[0] = vec_perm(desc[0], zero, shuf_msk1);
137 		pkt_mb[1] = vec_perm(desc[0], zero, shuf_msk2);
138 		pkt_mb[0] = (vector unsigned char)
139 			((vector unsigned short)pkt_mb[0] + len_adjust);
140 		pkt_mb[1] = (vector unsigned char)
141 			((vector unsigned short)pkt_mb[1] + len_adjust);
142 		*(vector unsigned char *)&rx_pkts[0]->rx_descriptor_fields1 =
143 			pkt_mb[0];
144 		*(vector unsigned char *)&rx_pkts[1]->rx_descriptor_fields1 =
145 			pkt_mb[1];
146 
147 		pkt_mb[2] = vec_perm(desc[1], zero, shuf_msk1);
148 		pkt_mb[3] = vec_perm(desc[1], zero, shuf_msk2);
149 		pkt_mb[2] = (vector unsigned char)
150 			((vector unsigned short)pkt_mb[2] + len_adjust);
151 		pkt_mb[3] = (vector unsigned char)
152 			((vector unsigned short)pkt_mb[3] + len_adjust);
153 		*(vector unsigned char *)&rx_pkts[2]->rx_descriptor_fields1 =
154 			pkt_mb[2];
155 		*(vector unsigned char *)&rx_pkts[3]->rx_descriptor_fields1 =
156 			pkt_mb[3];
157 
158 		pkt_mb[4] = vec_perm(desc[2], zero, shuf_msk1);
159 		pkt_mb[5] = vec_perm(desc[2], zero, shuf_msk2);
160 		pkt_mb[4] = (vector unsigned char)
161 			((vector unsigned short)pkt_mb[4] + len_adjust);
162 		pkt_mb[5] = (vector unsigned char)
163 			((vector unsigned short)pkt_mb[5] + len_adjust);
164 		*(vector unsigned char *)&rx_pkts[4]->rx_descriptor_fields1 =
165 			pkt_mb[4];
166 		*(vector unsigned char *)&rx_pkts[5]->rx_descriptor_fields1 =
167 			pkt_mb[5];
168 
169 		pkt_mb[6] = vec_perm(desc[3], zero, shuf_msk1);
170 		pkt_mb[7] = vec_perm(desc[3], zero, shuf_msk2);
171 		pkt_mb[6] = (vector unsigned char)
172 			((vector unsigned short)pkt_mb[6] + len_adjust);
173 		pkt_mb[7] = (vector unsigned char)
174 			((vector unsigned short)pkt_mb[7] + len_adjust);
175 		*(vector unsigned char *)&rx_pkts[6]->rx_descriptor_fields1 =
176 			pkt_mb[6];
177 		*(vector unsigned char *)&rx_pkts[7]->rx_descriptor_fields1 =
178 			pkt_mb[7];
179 
180 		if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
181 			if (sw_ring + nb_used <= sw_ring_end)
182 				nb_pkts_received += nb_used;
183 			else
184 				nb_pkts_received += sw_ring_end - sw_ring;
185 			break;
186 		} else {
187 			if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
188 				sw_ring_end)) {
189 				nb_pkts_received += sw_ring_end - sw_ring;
190 				break;
191 			} else {
192 				nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
193 
194 				rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
195 				sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
196 				rused   += RTE_VIRTIO_DESC_PER_LOOP;
197 				nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
198 			}
199 		}
200 	}
201 
202 	vq->vq_used_cons_idx += nb_pkts_received;
203 	vq->vq_free_cnt += nb_pkts_received;
204 	rxvq->stats.packets += nb_pkts_received;
205 	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
206 		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
207 
208 	return nb_pkts_received;
209 }
210