pc-bios/s390-ccw/virtio-net.c

   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
  23 #ifndef DEBUG_VIRTIO_NET
  24 #define DEBUG_VIRTIO_NET 0
  25 #endif
  26
  27 #define VIRTIO_NET_F_MAC_BIT  (1 << 5)
  28
  29 #define VQ_RX 0         /* Receive queue */
  30 #define VQ_TX 1         /* Transmit queue */
  31
  32 struct VirtioNetHdr {
  33     uint8_t flags;
  34     uint8_t gso_type;
  35     uint16_t hdr_len;
  36     uint16_t gso_size;
  37     uint16_t csum_start;
  38     uint16_t csum_offset;
  39     /*uint16_t num_buffers;*/ /* Only with VIRTIO_NET_F_MRG_RXBUF or VIRTIO1 */
  40 };
  41 typedef struct VirtioNetHdr VirtioNetHdr;
  42
  43 static uint16_t rx_last_idx;  /* Last index in receive queue "used" ring */
  44
  45 int virtio_net_init(void *mac_addr)
  46 {
  47     VDev *vdev = virtio_get_device();
  48     VRing *rxvq = &vdev->vrings[VQ_RX];
  49     void *buf;
  50     int i;
  51
  52     vdev->guest_features[0] = VIRTIO_NET_F_MAC_BIT;
  53     virtio_setup_ccw(vdev);
  54
  55     IPL_assert(vdev->guest_features[0] & VIRTIO_NET_F_MAC_BIT,
  56                "virtio-net device does not support the MAC address feature");
  57     memcpy(mac_addr, vdev->config.net.mac, ETH_ALEN);
  58
  59     for (i = 0; i < 64; i++) {
  60         buf = malloc(ETH_MTU_SIZE + sizeof(VirtioNetHdr));
  61         IPL_assert(buf != NULL, "Can not allocate memory for receive buffers");
  62         vring_send_buf(rxvq, buf, ETH_MTU_SIZE + sizeof(VirtioNetHdr),
  63                        VRING_DESC_F_WRITE);
  64     }
  65     vring_notify(rxvq);
  66
  67     return 0;
  68 }
  69
  70 int send(int fd, const void *buf, int len, int flags)
  71 {
  72     VirtioNetHdr tx_hdr;
  73     VDev *vdev = virtio_get_device();
  74     VRing *txvq = &vdev->vrings[VQ_TX];
  75
  76     /* Set up header - we do not use anything special, so simply clear it */
  77     memset(&tx_hdr, 0, sizeof(tx_hdr));
  78
  79     vring_send_buf(txvq, &tx_hdr, sizeof(tx_hdr), VRING_DESC_F_NEXT);
  80     vring_send_buf(txvq, (void *)buf, len, VRING_HIDDEN_IS_CHAIN);
  81     while (!vr_poll(txvq)) {
  82         yield();
  83     }
  84     if (drain_irqs(txvq->schid)) {
  85         puts("send: drain irqs failed");
  86         return -1;
  87     }
  88
  89     return len;
  90 }
  91
  92 int recv(int fd, void *buf, int maxlen, int flags)
  93 {
  94     VDev *vdev = virtio_get_device();
  95     VRing *rxvq = &vdev->vrings[VQ_RX];
  96     int len, id;
  97     uint8_t *pkt;
  98
  99     if (rx_last_idx == rxvq->used->idx) {
 100         return 0;
 101     }
 102
 103     len = rxvq->used->ring[rx_last_idx % rxvq->num].len - sizeof(VirtioNetHdr);
 104     if (len > maxlen) {
 105         puts("virtio-net: Receive buffer too small");
 106         len = maxlen;
 107     }
 108     id = rxvq->used->ring[rx_last_idx % rxvq->num].id % rxvq->num;
 109     pkt = (uint8_t *)(rxvq->desc[id].addr + sizeof(VirtioNetHdr));
 110
 111 #if DEBUG_VIRTIO_NET   /* Dump packet */
 112     int i;
 113     printf("\nbuf %p: len=%i\n", (void *)rxvq->desc[id].addr, len);
 114     for (i = 0; i < 64; i++) {
 115         printf(" %02x", pkt[i]);
 116         if ((i % 16) == 15) {
 117             printf("\n");
 118         }
 119     }
 120     printf("\n");
 121 #endif
 122
 123     /* Copy data to destination buffer */
 124     memcpy(buf, pkt, len);
 125
 126     /* Mark buffer as available to the host again */
 127     rxvq->avail->ring[rxvq->avail->idx % rxvq->num] = id;
 128     rxvq->avail->idx = rxvq->avail->idx + 1;
 129     vring_notify(rxvq);
 130
 131     /* Move index to next entry */
 132     rx_last_idx = rx_last_idx + 1;
 133
 134     return len;
 135 }