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 } 136