1 /*
2 * Virtio-net driver for the s390-ccw firmware
3 *
4 * Copyright 2017 Thomas Huth, Red Hat Inc.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 */
11
12 #include <stdint.h>
13 #include <stdbool.h>
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #include <unistd.h>
18 #include <sys/socket.h>
19 #include <ethernet.h>
20 #include "s390-ccw.h"
21 #include "virtio.h"
22 #include "s390-time.h"
23 #include "helper.h"
24
25 #ifndef DEBUG_VIRTIO_NET
26 #define DEBUG_VIRTIO_NET 0
27 #endif
28
29 #define VIRTIO_NET_F_MAC_BIT (1 << 5)
30
31 #define VQ_RX 0 /* Receive queue */
32 #define VQ_TX 1 /* Transmit queue */
33
34 struct VirtioNetHdr {
35 uint8_t flags;
36 uint8_t gso_type;
37 uint16_t hdr_len;
38 uint16_t gso_size;
39 uint16_t csum_start;
40 uint16_t csum_offset;
41 /*uint16_t num_buffers;*/ /* Only with VIRTIO_NET_F_MRG_RXBUF or VIRTIO1 */
42 };
43 typedef struct VirtioNetHdr VirtioNetHdr;
44
45 static uint16_t rx_last_idx; /* Last index in receive queue "used" ring */
46
virtio_net_init(void * mac_addr)47 int virtio_net_init(void *mac_addr)
48 {
49 VDev *vdev = virtio_get_device();
50 VRing *rxvq = &vdev->vrings[VQ_RX];
51 void *buf;
52 int i;
53
54 rx_last_idx = 0;
55
56 vdev->guest_features[0] = VIRTIO_NET_F_MAC_BIT;
57 virtio_setup_ccw(vdev);
58
59 if (!(vdev->guest_features[0] & VIRTIO_NET_F_MAC_BIT)) {
60 puts("virtio-net device does not support the MAC address feature");
61 return -1;
62 }
63
64 memcpy(mac_addr, vdev->config.net.mac, ETH_ALEN);
65
66 for (i = 0; i < 64; i++) {
67 buf = malloc(ETH_MTU_SIZE + sizeof(VirtioNetHdr));
68 IPL_assert(buf != NULL, "Can not allocate memory for receive buffers");
69 vring_send_buf(rxvq, buf, ETH_MTU_SIZE + sizeof(VirtioNetHdr),
70 VRING_DESC_F_WRITE);
71 }
72 vring_notify(rxvq);
73
74 return 0;
75 }
76
send(int fd,const void * buf,int len,int flags)77 int send(int fd, const void *buf, int len, int flags)
78 {
79 VirtioNetHdr tx_hdr;
80 VDev *vdev = virtio_get_device();
81 VRing *txvq = &vdev->vrings[VQ_TX];
82
83 /* Set up header - we do not use anything special, so simply clear it */
84 memset(&tx_hdr, 0, sizeof(tx_hdr));
85
86 vring_send_buf(txvq, &tx_hdr, sizeof(tx_hdr), VRING_DESC_F_NEXT);
87 vring_send_buf(txvq, (void *)buf, len, VRING_HIDDEN_IS_CHAIN);
88 while (!vr_poll(txvq)) {
89 yield();
90 }
91 if (drain_irqs(txvq->schid)) {
92 puts("send: drain irqs failed");
93 return -1;
94 }
95
96 return len;
97 }
98
recv(int fd,void * buf,int maxlen,int flags)99 int recv(int fd, void *buf, int maxlen, int flags)
100 {
101 VDev *vdev = virtio_get_device();
102 VRing *rxvq = &vdev->vrings[VQ_RX];
103 int len, id;
104 uint8_t *pkt;
105
106 if (rx_last_idx == rxvq->used->idx) {
107 return 0;
108 }
109
110 len = rxvq->used->ring[rx_last_idx % rxvq->num].len - sizeof(VirtioNetHdr);
111 if (len > maxlen) {
112 puts("virtio-net: Receive buffer too small");
113 len = maxlen;
114 }
115 id = rxvq->used->ring[rx_last_idx % rxvq->num].id % rxvq->num;
116 pkt = (uint8_t *)(rxvq->desc[id].addr + sizeof(VirtioNetHdr));
117
118 #if DEBUG_VIRTIO_NET /* Dump packet */
119 int i;
120 printf("\nbuf %p: len=%i\n", (void *)rxvq->desc[id].addr, len);
121 for (i = 0; i < 64; i++) {
122 printf(" %02x", pkt[i]);
123 if ((i % 16) == 15) {
124 printf("\n");
125 }
126 }
127 printf("\n");
128 #endif
129
130 /* Copy data to destination buffer */
131 memcpy(buf, pkt, len);
132
133 /* Mark buffer as available to the host again */
134 rxvq->avail->ring[rxvq->avail->idx % rxvq->num] = id;
135 rxvq->avail->idx = rxvq->avail->idx + 1;
136 vring_notify(rxvq);
137
138 /* Move index to next entry */
139 rx_last_idx = rx_last_idx + 1;
140
141 return len;
142 }
143