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     features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
  55     return features;
  56 }
  57
  58 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
  59 {
  60     net->dev.acked_features = net->dev.backend_features;
  61     if (features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) {
  62         net->dev.acked_features |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY);
  63     }
  64     if (features & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {
  65         net->dev.acked_features |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
  66     }
  67 }
  68
  69 static int vhost_net_get_fd(VLANClientState *backend)
  70 {
  71     switch (backend->info->type) {
  72     case NET_CLIENT_TYPE_TAP:
  73         return tap_get_fd(backend);
  74     default:
  75         fprintf(stderr, "vhost-net requires tap backend\n");
  76         return -EBADFD;
  77     }
  78 }
  79
  80 struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd)
  81 {
  82     int r;
  83     struct vhost_net *net = qemu_malloc(sizeof *net);
  84     if (!backend) {
  85         fprintf(stderr, "vhost-net requires backend to be setup\n");
  86         goto fail;
  87     }
  88     r = vhost_net_get_fd(backend);
  89     if (r < 0) {
  90         goto fail;
  91     }
  92     net->vc = backend;
  93     net->dev.backend_features = tap_has_vnet_hdr(backend) ? 0 :
  94         (1 << VHOST_NET_F_VIRTIO_NET_HDR);
  95     net->backend = r;
  96
  97     r = vhost_dev_init(&net->dev, devfd);
  98     if (r < 0) {
  99         goto fail;
 100     }
 101     if (~net->dev.features & net->dev.backend_features) {
 102         fprintf(stderr, "vhost lacks feature mask %" PRIu64 " for backend\n",
 103                 (uint64_t)(~net->dev.features & net->dev.backend_features));
 104         vhost_dev_cleanup(&net->dev);
 105         goto fail;
 106     }
 107
 108     /* Set sane init value. Override when guest acks. */
 109     vhost_net_ack_features(net, 0);
 110     return net;
 111 fail:
 112     qemu_free(net);
 113     return NULL;
 114 }
 115
 116 int vhost_net_start(struct vhost_net *net,
 117                     VirtIODevice *dev)
 118 {
 119     struct vhost_vring_file file = { };
 120     int r;
 121
 122     net->dev.nvqs = 2;
 123     net->dev.vqs = net->vqs;
 124     r = vhost_dev_start(&net->dev, dev);
 125     if (r < 0) {
 126         return r;
 127     }
 128
 129     net->vc->info->poll(net->vc, false);
 130     qemu_set_fd_handler(net->backend, NULL, NULL, NULL);
 131     file.fd = net->backend;
 132     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
 133         r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 134         if (r < 0) {
 135             r = -errno;
 136             goto fail;
 137         }
 138     }
 139     return 0;
 140 fail:
 141     file.fd = -1;
 142     while (--file.index >= 0) {
 143         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 144         assert(r >= 0);
 145     }
 146     net->vc->info->poll(net->vc, true);
 147     vhost_dev_stop(&net->dev, dev);
 148     return r;
 149 }
 150
 151 void vhost_net_stop(struct vhost_net *net,
 152                     VirtIODevice *dev)
 153 {
 154     struct vhost_vring_file file = { .fd = -1 };
 155
 156     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
 157         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 158         assert(r >= 0);
 159     }
 160     net->vc->info->poll(net->vc, true);
 161     vhost_dev_stop(&net->dev, dev);
 162 }
 163
 164 void vhost_net_cleanup(struct vhost_net *net)
 165 {
 166     vhost_dev_cleanup(&net->dev);
 167     qemu_free(net);
 168 }
 169 #else
 170 struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd)
 171 {
 172         return NULL;
 173 }
 174
 175 int vhost_net_start(struct vhost_net *net,
 176                     VirtIODevice *dev)
 177 {
 178         return -ENOSYS;
 179 }
 180 void vhost_net_stop(struct vhost_net *net,
 181                     VirtIODevice *dev)
 182 {
 183 }
 184
 185 void vhost_net_cleanup(struct vhost_net *net)
 186 {
 187 }
 188
 189 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
 190 {
 191         return features;
 192 }
 193 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
 194 {
 195 }
 196 #endif