hw/vhost_net.c

   1 /*
   2  * vhost-net support
   3  *
   4  * Copyright Red Hat, Inc. 2010
   5  *
   6  * Authors:
   7  *  Michael S. Tsirkin <mst@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  */
  12
  13 #include "net.h"
  14 #include "net/tap.h"
  15
  16 #include "virtio-net.h"
  17 #include "vhost_net.h"
  18
  19 #include "config.h"
  20
  21 #ifdef CONFIG_VHOST_NET
  22 #include <linux/vhost.h>
  23 #include <sys/socket.h>
  24 #include <linux/kvm.h>
  25 #include <fcntl.h>
  26 #include <sys/ioctl.h>
  27 #include <linux/virtio_ring.h>
  28 #include <netpacket/packet.h>
  29 #include <net/ethernet.h>
  30 #include <net/if.h>
  31 #include <netinet/in.h>
  32
  33 #include <stdio.h>
  34
  35 #include "vhost.h"
  36
  37 struct vhost_net {
  38     struct vhost_dev dev;
  39     struct vhost_virtqueue vqs[2];
  40     int backend;
  41     VLANClientState *vc;
  42 };
  43
  44 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
  45 {
  46     /* Clear features not supported by host kernel. */
  47     if (!(net->dev.features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY))) {
  48         features &= ~(1 << VIRTIO_F_NOTIFY_ON_EMPTY);
  49     }
  50     if (!(net->dev.features & (1 << VIRTIO_RING_F_INDIRECT_DESC))) {
  51         features &= ~(1 << VIRTIO_RING_F_INDIRECT_DESC);
  52     }
  53     if (!(net->dev.features & (1 << VIRTIO_NET_F_MRG_RXBUF))) {
  54         features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
  55     }
  56     return features;
  57 }
  58
  59 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
  60 {
  61     net->dev.acked_features = net->dev.backend_features;
  62     if (features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) {
  63         net->dev.acked_features |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY);
  64     }
  65     if (features & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {
  66         net->dev.acked_features |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
  67     }
  68     if (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
  69         net->dev.acked_features |= (1 << VIRTIO_NET_F_MRG_RXBUF);
  70     }
  71 }
  72
  73 static int vhost_net_get_fd(VLANClientState *backend)
  74 {
  75     switch (backend->info->type) {
  76     case NET_CLIENT_TYPE_TAP:
  77         return tap_get_fd(backend);
  78     default:
  79         fprintf(stderr, "vhost-net requires tap backend\n");
  80         return -EBADFD;
  81     }
  82 }
  83
  84 struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd)
  85 {
  86     int r;
  87     struct vhost_net *net = qemu_malloc(sizeof *net);
  88     if (!backend) {
  89         fprintf(stderr, "vhost-net requires backend to be setup\n");
  90         goto fail;
  91     }
  92     r = vhost_net_get_fd(backend);
  93     if (r < 0) {
  94         goto fail;
  95     }
  96     net->vc = backend;
  97     net->dev.backend_features = tap_has_vnet_hdr(backend) ? 0 :
  98         (1 << VHOST_NET_F_VIRTIO_NET_HDR);
  99     net->backend = r;
 100
 101     r = vhost_dev_init(&net->dev, devfd);
 102     if (r < 0) {
 103         goto fail;
 104     }
 105     if (!tap_has_vnet_hdr_len(backend,
 106                               sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
 107         net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
 108     }
 109     if (~net->dev.features & net->dev.backend_features) {
 110         fprintf(stderr, "vhost lacks feature mask %" PRIu64 " for backend\n",
 111                 (uint64_t)(~net->dev.features & net->dev.backend_features));
 112         vhost_dev_cleanup(&net->dev);
 113         goto fail;
 114     }
 115
 116     /* Set sane init value. Override when guest acks. */
 117     vhost_net_ack_features(net, 0);
 118     return net;
 119 fail:
 120     qemu_free(net);
 121     return NULL;
 122 }
 123
 124 int vhost_net_start(struct vhost_net *net,
 125                     VirtIODevice *dev)
 126 {
 127     struct vhost_vring_file file = { };
 128     int r;
 129     if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
 130         tap_set_vnet_hdr_len(net->vc,
 131                              sizeof(struct virtio_net_hdr_mrg_rxbuf));
 132     }
 133
 134     net->dev.nvqs = 2;
 135     net->dev.vqs = net->vqs;
 136     r = vhost_dev_start(&net->dev, dev);
 137     if (r < 0) {
 138         return r;
 139     }
 140
 141     net->vc->info->poll(net->vc, false);
 142     qemu_set_fd_handler(net->backend, NULL, NULL, NULL);
 143     file.fd = net->backend;
 144     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
 145         r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 146         if (r < 0) {
 147             r = -errno;
 148             goto fail;
 149         }
 150     }
 151     return 0;
 152 fail:
 153     file.fd = -1;
 154     while (--file.index >= 0) {
 155         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 156         assert(r >= 0);
 157     }
 158     net->vc->info->poll(net->vc, true);
 159     vhost_dev_stop(&net->dev, dev);
 160     if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
 161         tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));
 162     }
 163     return r;
 164 }
 165
 166 void vhost_net_stop(struct vhost_net *net,
 167                     VirtIODevice *dev)
 168 {
 169     struct vhost_vring_file file = { .fd = -1 };
 170
 171     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
 172         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 173         assert(r >= 0);
 174     }
 175     net->vc->info->poll(net->vc, true);
 176     vhost_dev_stop(&net->dev, dev);
 177     if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
 178         tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));
 179     }
 180 }
 181
 182 void vhost_net_cleanup(struct vhost_net *net)
 183 {
 184     vhost_dev_cleanup(&net->dev);
 185     if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
 186         tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));
 187     }
 188     qemu_free(net);
 189 }
 190 #else
 191 struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd)
 192 {
 193         return NULL;
 194 }
 195
 196 int vhost_net_start(struct vhost_net *net,
 197                     VirtIODevice *dev)
 198 {
 199         return -ENOSYS;
 200 }
 201 void vhost_net_stop(struct vhost_net *net,
 202                     VirtIODevice *dev)
 203 {
 204 }
 205
 206 void vhost_net_cleanup(struct vhost_net *net)
 207 {
 208 }
 209
 210 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
 211 {
 212         return features;
 213 }
 214 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
 215 {
 216 }
 217 #endif