xref: /dpdk/drivers/net/virtio/virtio_rxtx_simple_altivec.c (revision d5284f0d593337f57bd21f890189ab306ff8c37d)
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 <rte_altivec.h>
13 #include <rte_byteorder.h>
14 #include <rte_branch_prediction.h>
15 #include <rte_cycles.h>
16 #include <rte_ether.h>
17 #include <ethdev_driver.h>
18 #include <rte_errno.h>
19 #include <rte_memory.h>
20 #include <rte_mempool.h>
21 #include <rte_malloc.h>
22 #include <rte_mbuf.h>
23 #include <rte_prefetch.h>
24 #include <rte_string_fns.h>
25 
26 #include "virtio_rxtx_simple.h"
27 
28 #define RTE_VIRTIO_DESC_PER_LOOP 8
29 
30 /* virtio vPMD receive routine, only accept(nb_pkts >= RTE_VIRTIO_DESC_PER_LOOP)
31  *
32  * This routine is for non-mergeable RX, one desc for each guest buffer.
33  * This routine is based on the RX ring layout optimization. Each entry in the
34  * avail ring points to the desc with the same index in the desc ring and this
35  * will never be changed in the driver.
36  *
37  * - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
38  */
39 uint16_t
virtio_recv_pkts_vec(void * rx_queue,struct rte_mbuf ** rx_pkts,uint16_t nb_pkts)40 virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
41 	uint16_t nb_pkts)
42 {
43 	struct virtnet_rx *rxvq = rx_queue;
44 	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
45 	struct virtio_hw *hw = vq->hw;
46 	uint16_t nb_used, nb_total;
47 	uint16_t desc_idx;
48 	struct vring_used_elem *rused;
49 	struct rte_mbuf **sw_ring;
50 	struct rte_mbuf **sw_ring_end;
51 	struct rte_mbuf **ref_rx_pkts;
52 	uint16_t nb_pkts_received = 0;
53 	const __vector unsigned char zero = {0};
54 
55 	const __vector unsigned char shuf_msk1 = {
56 		0xFF, 0xFF, 0xFF, 0xFF,	/* packet type */
57 		4, 5, 0xFF, 0xFF, /* vlan tci */
58 		4, 5,			/* dat len */
59 		0xFF, 0xFF,		/* vlan tci */
60 		0xFF, 0xFF, 0xFF, 0xFF
61 	};
62 
63 	const __vector unsigned char shuf_msk2 = {
64 		0xFF, 0xFF, 0xFF, 0xFF,	/* packet type */
65 		12, 13, 0xFF, 0xFF,	/* pkt len */
66 		12, 13,			/* dat len */
67 		0xFF, 0xFF,		/* vlan tci */
68 		0xFF, 0xFF, 0xFF, 0xFF
69 	};
70 
71 	/*
72 	 * Subtract the header length.
73 	 *  In which case do we need the header length in used->len ?
74 	 */
75 	const __vector unsigned short len_adjust = {
76 		0, 0,
77 		(uint16_t)-vq->hw->vtnet_hdr_size, 0,
78 		(uint16_t)-vq->hw->vtnet_hdr_size, 0,
79 		0, 0
80 	};
81 
82 	if (unlikely(hw->started == 0))
83 		return nb_pkts_received;
84 
85 	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
86 		return 0;
87 
88 	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
89 		virtio_rxq_rearm_vec(rxvq);
90 		if (unlikely(virtqueue_kick_prepare(vq)))
91 			virtqueue_notify(vq);
92 	}
93 
94 	nb_used = virtqueue_nused(vq);
95 
96 	rte_compiler_barrier();
97 
98 	if (unlikely(nb_used == 0))
99 		return 0;
100 
101 	nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
102 	nb_used = RTE_MIN(nb_used, nb_pkts);
103 
104 	desc_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
105 	rused = &vq->vq_split.ring.used->ring[desc_idx];
106 	sw_ring = &vq->rxq.sw_ring[desc_idx];
107 	sw_ring_end = &vq->rxq.sw_ring[vq->vq_nentries];
108 
109 	rte_prefetch0(rused);
110 
111 	nb_total = nb_used;
112 	ref_rx_pkts = rx_pkts;
113 	for (nb_pkts_received = 0;
114 		nb_pkts_received < nb_total;) {
115 		__vector unsigned char desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
116 		__vector unsigned char mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
117 		__vector unsigned char pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
118 
119 		mbp[0] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 0));
120 		desc[0] = vec_vsx_ld(0, (unsigned char const *)(rused + 0));
121 		*(__vector unsigned char *)&rx_pkts[0] = mbp[0];
122 
123 		mbp[1] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 2));
124 		desc[1] = vec_vsx_ld(0, (unsigned char const *)(rused + 2));
125 		*(__vector unsigned char *)&rx_pkts[2] = mbp[1];
126 
127 		mbp[2] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 4));
128 		desc[2] = vec_vsx_ld(0, (unsigned char const *)(rused + 4));
129 		*(__vector unsigned char *)&rx_pkts[4] = mbp[2];
130 
131 		mbp[3] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 6));
132 		desc[3] = vec_vsx_ld(0, (unsigned char const *)(rused + 6));
133 		*(__vector unsigned char *)&rx_pkts[6] = mbp[3];
134 
135 		pkt_mb[0] = vec_perm(desc[0], zero, shuf_msk1);
136 		pkt_mb[1] = vec_perm(desc[0], zero, shuf_msk2);
137 		pkt_mb[0] = (__vector unsigned char)
138 			((__vector unsigned short)pkt_mb[0] + len_adjust);
139 		pkt_mb[1] = (__vector unsigned char)
140 			((__vector unsigned short)pkt_mb[1] + len_adjust);
141 		*(__vector unsigned char *)&rx_pkts[0]->rx_descriptor_fields1 =
142 			pkt_mb[0];
143 		*(__vector unsigned char *)&rx_pkts[1]->rx_descriptor_fields1 =
144 			pkt_mb[1];
145 
146 		pkt_mb[2] = vec_perm(desc[1], zero, shuf_msk1);
147 		pkt_mb[3] = vec_perm(desc[1], zero, shuf_msk2);
148 		pkt_mb[2] = (__vector unsigned char)
149 			((__vector unsigned short)pkt_mb[2] + len_adjust);
150 		pkt_mb[3] = (__vector unsigned char)
151 			((__vector unsigned short)pkt_mb[3] + len_adjust);
152 		*(__vector unsigned char *)&rx_pkts[2]->rx_descriptor_fields1 =
153 			pkt_mb[2];
154 		*(__vector unsigned char *)&rx_pkts[3]->rx_descriptor_fields1 =
155 			pkt_mb[3];
156 
157 		pkt_mb[4] = vec_perm(desc[2], zero, shuf_msk1);
158 		pkt_mb[5] = vec_perm(desc[2], zero, shuf_msk2);
159 		pkt_mb[4] = (__vector unsigned char)
160 			((__vector unsigned short)pkt_mb[4] + len_adjust);
161 		pkt_mb[5] = (__vector unsigned char)
162 			((__vector unsigned short)pkt_mb[5] + len_adjust);
163 		*(__vector unsigned char *)&rx_pkts[4]->rx_descriptor_fields1 =
164 			pkt_mb[4];
165 		*(__vector unsigned char *)&rx_pkts[5]->rx_descriptor_fields1 =
166 			pkt_mb[5];
167 
168 		pkt_mb[6] = vec_perm(desc[3], zero, shuf_msk1);
169 		pkt_mb[7] = vec_perm(desc[3], zero, shuf_msk2);
170 		pkt_mb[6] = (__vector unsigned char)
171 			((__vector unsigned short)pkt_mb[6] + len_adjust);
172 		pkt_mb[7] = (__vector unsigned char)
173 			((__vector unsigned short)pkt_mb[7] + len_adjust);
174 		*(__vector unsigned char *)&rx_pkts[6]->rx_descriptor_fields1 =
175 			pkt_mb[6];
176 		*(__vector unsigned char *)&rx_pkts[7]->rx_descriptor_fields1 =
177 			pkt_mb[7];
178 
179 		if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
180 			if (sw_ring + nb_used <= sw_ring_end)
181 				nb_pkts_received += nb_used;
182 			else
183 				nb_pkts_received += sw_ring_end - sw_ring;
184 			break;
185 		} else {
186 			if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
187 				sw_ring_end)) {
188 				nb_pkts_received += sw_ring_end - sw_ring;
189 				break;
190 			} else {
191 				nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
192 
193 				rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
194 				sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
195 				rused   += RTE_VIRTIO_DESC_PER_LOOP;
196 				nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
197 			}
198 		}
199 	}
200 
201 	vq->vq_used_cons_idx += nb_pkts_received;
202 	vq->vq_free_cnt += nb_pkts_received;
203 	rxvq->stats.packets += nb_pkts_received;
204 	for (nb_used = 0; nb_used < nb_pkts_received; nb_used++)
205 		virtio_update_packet_stats(&rxvq->stats, ref_rx_pkts[nb_used]);
206 
207 	return nb_pkts_received;
208 }
209