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 #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
  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     vdev->guest_features[0] = VIRTIO_NET_F_MAC_BIT;
  55     virtio_setup_ccw(vdev);
  56
  57     IPL_assert(vdev->guest_features[0] & VIRTIO_NET_F_MAC_BIT,
  58                "virtio-net device does not support the MAC address feature");
  59     memcpy(mac_addr, vdev->config.net.mac, ETH_ALEN);
  60
  61     for (i = 0; i < 64; i++) {
  62         buf = malloc(ETH_MTU_SIZE + sizeof(VirtioNetHdr));
  63         IPL_assert(buf != NULL, "Can not allocate memory for receive buffers");
  64         vring_send_buf(rxvq, buf, ETH_MTU_SIZE + sizeof(VirtioNetHdr),
  65                        VRING_DESC_F_WRITE);
  66     }
  67     vring_notify(rxvq);
  68
  69     return 0;
  70 }
  71
  72 int send(int fd, const void *buf, int len, int flags)
  73 {
  74     VirtioNetHdr tx_hdr;
  75     VDev *vdev = virtio_get_device();
  76     VRing *txvq = &vdev->vrings[VQ_TX];
  77
  78     /* Set up header - we do not use anything special, so simply clear it */
  79     memset(&tx_hdr, 0, sizeof(tx_hdr));
  80
  81     vring_send_buf(txvq, &tx_hdr, sizeof(tx_hdr), VRING_DESC_F_NEXT);
  82     vring_send_buf(txvq, (void *)buf, len, VRING_HIDDEN_IS_CHAIN);
  83     while (!vr_poll(txvq)) {
  84         yield();
  85     }
  86     if (drain_irqs(txvq->schid)) {
  87         puts("send: drain irqs failed");
  88         return -1;
  89     }
  90
  91     return len;
  92 }
  93
  94 int recv(int fd, void *buf, int maxlen, int flags)
  95 {
  96     VDev *vdev = virtio_get_device();
  97     VRing *rxvq = &vdev->vrings[VQ_RX];
  98     int len, id;
  99     uint8_t *pkt;
 100
 101     if (rx_last_idx == rxvq->used->idx) {
 102         return 0;
 103     }
 104
 105     len = rxvq->used->ring[rx_last_idx % rxvq->num].len - sizeof(VirtioNetHdr);
 106     if (len > maxlen) {
 107         puts("virtio-net: Receive buffer too small");
 108         len = maxlen;
 109     }
 110     id = rxvq->used->ring[rx_last_idx % rxvq->num].id % rxvq->num;
 111     pkt = (uint8_t *)(rxvq->desc[id].addr + sizeof(VirtioNetHdr));
 112
 113 #if DEBUG_VIRTIO_NET   /* Dump packet */
 114     int i;
 115     printf("\nbuf %p: len=%i\n", (void *)rxvq->desc[id].addr, len);
 116     for (i = 0; i < 64; i++) {
 117         printf(" %02x", pkt[i]);
 118         if ((i % 16) == 15) {
 119             printf("\n");
 120         }
 121     }
 122     printf("\n");
 123 #endif
 124
 125     /* Copy data to destination buffer */
 126     memcpy(buf, pkt, len);
 127
 128     /* Mark buffer as available to the host again */
 129     rxvq->avail->ring[rxvq->avail->idx % rxvq->num] = id;
 130     rxvq->avail->idx = rxvq->avail->idx + 1;
 131     vring_notify(rxvq);
 132
 133     /* Move index to next entry */
 134     rx_last_idx = rx_last_idx + 1;
 135
 136     return len;
 137 }