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/eventfd.h>
  24 #include <sys/socket.h>
  25 #include <linux/kvm.h>
  26 #include <fcntl.h>
  27 #include <sys/ioctl.h>
  28 #include <linux/virtio_ring.h>
  29 #include <netpacket/packet.h>
  30 #include <net/ethernet.h>
  31 #include <net/if.h>
  32 #include <netinet/in.h>
  33
  34 #include <stdio.h>
  35
  36 #include "vhost.h"
  37
  38 struct vhost_net {
  39     struct vhost_dev dev;
  40     struct vhost_virtqueue vqs[2];
  41     int backend;
  42     VLANClientState *vc;
  43 };
  44
  45 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
  46 {
  47     /* Clear features not supported by host kernel. */
  48     if (!(net->dev.features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY))) {
  49         features &= ~(1 << VIRTIO_F_NOTIFY_ON_EMPTY);
  50     }
  51     if (!(net->dev.features & (1 << VIRTIO_RING_F_INDIRECT_DESC))) {
  52         features &= ~(1 << VIRTIO_RING_F_INDIRECT_DESC);
  53     }
  54     return features;
  55 }
  56
  57 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
  58 {
  59     net->dev.acked_features = net->dev.backend_features;
  60     if (features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) {
  61         net->dev.acked_features |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY);
  62     }
  63     if (features & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {
  64         net->dev.acked_features |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
  65     }
  66 }
  67
  68 static int vhost_net_get_fd(VLANClientState *backend)
  69 {
  70     switch (backend->info->type) {
  71     case NET_CLIENT_TYPE_TAP:
  72         return tap_get_fd(backend);
  73     default:
  74         fprintf(stderr, "vhost-net requires tap backend\n");
  75         return -EBADFD;
  76     }
  77 }
  78
  79 struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd)
  80 {
  81     int r;
  82     struct vhost_net *net = qemu_malloc(sizeof *net);
  83     if (!backend) {
  84         fprintf(stderr, "vhost-net requires backend to be setup\n");
  85         goto fail;
  86     }
  87     r = vhost_net_get_fd(backend);
  88     if (r < 0) {
  89         goto fail;
  90     }
  91     net->vc = backend;
  92     net->dev.backend_features = tap_has_vnet_hdr(backend) ? 0 :
  93         (1 << VHOST_NET_F_VIRTIO_NET_HDR);
  94     net->backend = r;
  95
  96     r = vhost_dev_init(&net->dev, devfd);
  97     if (r < 0) {
  98         goto fail;
  99     }
 100     if (~net->dev.features & net->dev.backend_features) {
 101         fprintf(stderr, "vhost lacks feature mask %llu for backend\n",
 102                 ~net->dev.features & net->dev.backend_features);
 103         vhost_dev_cleanup(&net->dev);
 104         goto fail;
 105     }
 106
 107     /* Set sane init value. Override when guest acks. */
 108     vhost_net_ack_features(net, 0);
 109     return net;
 110 fail:
 111     qemu_free(net);
 112     return NULL;
 113 }
 114
 115 int vhost_net_start(struct vhost_net *net,
 116                     VirtIODevice *dev)
 117 {
 118     struct vhost_vring_file file = { };
 119     int r;
 120
 121     net->dev.nvqs = 2;
 122     net->dev.vqs = net->vqs;
 123     r = vhost_dev_start(&net->dev, dev);
 124     if (r < 0) {
 125         return r;
 126     }
 127
 128     net->vc->info->poll(net->vc, false);
 129     qemu_set_fd_handler(net->backend, NULL, NULL, NULL);
 130     file.fd = net->backend;
 131     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
 132         r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 133         if (r < 0) {
 134             r = -errno;
 135             goto fail;
 136         }
 137     }
 138     return 0;
 139 fail:
 140     file.fd = -1;
 141     while (--file.index >= 0) {
 142         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 143         assert(r >= 0);
 144     }
 145     net->vc->info->poll(net->vc, true);
 146     vhost_dev_stop(&net->dev, dev);
 147     return r;
 148 }
 149
 150 void vhost_net_stop(struct vhost_net *net,
 151                     VirtIODevice *dev)
 152 {
 153     struct vhost_vring_file file = { .fd = -1 };
 154
 155     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
 156         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 157         assert(r >= 0);
 158     }
 159     net->vc->info->poll(net->vc, true);
 160     vhost_dev_stop(&net->dev, dev);
 161 }
 162
 163 void vhost_net_cleanup(struct vhost_net *net)
 164 {
 165     vhost_dev_cleanup(&net->dev);
 166     qemu_free(net);
 167 }
 168 #else
 169 struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd)
 170 {
 171         return NULL;
 172 }
 173
 174 int vhost_net_start(struct vhost_net *net,
 175                     VirtIODevice *dev)
 176 {
 177         return -ENOSYS;
 178 }
 179 void vhost_net_stop(struct vhost_net *net,
 180                     VirtIODevice *dev)
 181 {
 182 }
 183
 184 void vhost_net_cleanup(struct vhost_net *net)
 185 {
 186 }
 187
 188 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
 189 {
 190         return features;
 191 }
 192 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
 193 {
 194 }
 195 #endif