xref: /dpdk/drivers/net/virtio/virtio_rxtx_simple_altivec.c (revision 1cde1b9a9b4dbf31cb5e5ccdfc5da3cb079f43a2)
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;
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 	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 	nb_used = VIRTQUEUE_NUSED(vq);
89 
90 	rte_compiler_barrier();
91 
92 	if (unlikely(nb_used == 0))
93 		return 0;
94 
95 	nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
96 	nb_used = RTE_MIN(nb_used, nb_pkts);
97 
98 	desc_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
99 	rused = &vq->vq_split.ring.used->ring[desc_idx];
100 	sw_ring  = &vq->sw_ring[desc_idx];
101 	sw_ring_end = &vq->sw_ring[vq->vq_nentries];
102 
103 	rte_prefetch0(rused);
104 
105 	if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
106 		virtio_rxq_rearm_vec(rxvq);
107 		if (unlikely(virtqueue_kick_prepare(vq)))
108 			virtqueue_notify(vq);
109 	}
110 
111 	for (nb_pkts_received = 0;
112 		nb_pkts_received < nb_used;) {
113 		vector unsigned char desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
114 		vector unsigned char mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
115 		vector unsigned char pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
116 
117 		mbp[0] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 0));
118 		desc[0] = vec_vsx_ld(0, (unsigned char const *)(rused + 0));
119 		*(vector unsigned char *)&rx_pkts[0] = mbp[0];
120 
121 		mbp[1] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 2));
122 		desc[1] = vec_vsx_ld(0, (unsigned char const *)(rused + 2));
123 		*(vector unsigned char *)&rx_pkts[2] = mbp[1];
124 
125 		mbp[2] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 4));
126 		desc[2] = vec_vsx_ld(0, (unsigned char const *)(rused + 4));
127 		*(vector unsigned char *)&rx_pkts[4] = mbp[2];
128 
129 		mbp[3] = vec_vsx_ld(0, (unsigned char const *)(sw_ring + 6));
130 		desc[3] = vec_vsx_ld(0, (unsigned char const *)(rused + 6));
131 		*(vector unsigned char *)&rx_pkts[6] = mbp[3];
132 
133 		pkt_mb[0] = vec_perm(desc[0], zero, shuf_msk1);
134 		pkt_mb[1] = vec_perm(desc[0], zero, shuf_msk2);
135 		pkt_mb[0] = (vector unsigned char)
136 			((vector unsigned short)pkt_mb[0] + len_adjust);
137 		pkt_mb[1] = (vector unsigned char)
138 			((vector unsigned short)pkt_mb[1] + len_adjust);
139 		*(vector unsigned char *)&rx_pkts[0]->rx_descriptor_fields1 =
140 			pkt_mb[0];
141 		*(vector unsigned char *)&rx_pkts[1]->rx_descriptor_fields1 =
142 			pkt_mb[1];
143 
144 		pkt_mb[2] = vec_perm(desc[1], zero, shuf_msk1);
145 		pkt_mb[3] = vec_perm(desc[1], zero, shuf_msk2);
146 		pkt_mb[2] = (vector unsigned char)
147 			((vector unsigned short)pkt_mb[2] + len_adjust);
148 		pkt_mb[3] = (vector unsigned char)
149 			((vector unsigned short)pkt_mb[3] + len_adjust);
150 		*(vector unsigned char *)&rx_pkts[2]->rx_descriptor_fields1 =
151 			pkt_mb[2];
152 		*(vector unsigned char *)&rx_pkts[3]->rx_descriptor_fields1 =
153 			pkt_mb[3];
154 
155 		pkt_mb[4] = vec_perm(desc[2], zero, shuf_msk1);
156 		pkt_mb[5] = vec_perm(desc[2], zero, shuf_msk2);
157 		pkt_mb[4] = (vector unsigned char)
158 			((vector unsigned short)pkt_mb[4] + len_adjust);
159 		pkt_mb[5] = (vector unsigned char)
160 			((vector unsigned short)pkt_mb[5] + len_adjust);
161 		*(vector unsigned char *)&rx_pkts[4]->rx_descriptor_fields1 =
162 			pkt_mb[4];
163 		*(vector unsigned char *)&rx_pkts[5]->rx_descriptor_fields1 =
164 			pkt_mb[5];
165 
166 		pkt_mb[6] = vec_perm(desc[3], zero, shuf_msk1);
167 		pkt_mb[7] = vec_perm(desc[3], zero, shuf_msk2);
168 		pkt_mb[6] = (vector unsigned char)
169 			((vector unsigned short)pkt_mb[6] + len_adjust);
170 		pkt_mb[7] = (vector unsigned char)
171 			((vector unsigned short)pkt_mb[7] + len_adjust);
172 		*(vector unsigned char *)&rx_pkts[6]->rx_descriptor_fields1 =
173 			pkt_mb[6];
174 		*(vector unsigned char *)&rx_pkts[7]->rx_descriptor_fields1 =
175 			pkt_mb[7];
176 
177 		if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
178 			if (sw_ring + nb_used <= sw_ring_end)
179 				nb_pkts_received += nb_used;
180 			else
181 				nb_pkts_received += sw_ring_end - sw_ring;
182 			break;
183 		} else {
184 			if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
185 				sw_ring_end)) {
186 				nb_pkts_received += sw_ring_end - sw_ring;
187 				break;
188 			} else {
189 				nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
190 
191 				rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
192 				sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
193 				rused   += RTE_VIRTIO_DESC_PER_LOOP;
194 				nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
195 			}
196 		}
197 	}
198 
199 	vq->vq_used_cons_idx += nb_pkts_received;
200 	vq->vq_free_cnt += nb_pkts_received;
201 	rxvq->stats.packets += nb_pkts_received;
202 	return nb_pkts_received;
203 }
204