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 #include "qemu-error.h"
  19
  20 #include "config.h"
  21
  22 #ifdef CONFIG_VHOST_NET
  23 #include <linux/vhost.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     if (!(net->dev.features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
  55         features &= ~(1 << VIRTIO_RING_F_EVENT_IDX);
  56     }
  57     if (!(net->dev.features & (1 << VIRTIO_NET_F_MRG_RXBUF))) {
  58         features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
  59     }
  60     return features;
  61 }
  62
  63 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
  64 {
  65     net->dev.acked_features = net->dev.backend_features;
  66     if (features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) {
  67         net->dev.acked_features |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY);
  68     }
  69     if (features & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {
  70         net->dev.acked_features |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
  71     }
  72     if (features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
  73         net->dev.acked_features |= (1 << VIRTIO_RING_F_EVENT_IDX);
  74     }
  75     if (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
  76         net->dev.acked_features |= (1 << VIRTIO_NET_F_MRG_RXBUF);
  77     }
  78 }
  79
  80 static int vhost_net_get_fd(VLANClientState *backend)
  81 {
  82     switch (backend->info->type) {
  83     case NET_CLIENT_TYPE_TAP:
  84         return tap_get_fd(backend);
  85     default:
  86         fprintf(stderr, "vhost-net requires tap backend\n");
  87         return -EBADFD;
  88     }
  89 }
  90
  91 struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd,
  92                                  bool force)
  93 {
  94     int r;
  95     struct vhost_net *net = g_malloc(sizeof *net);
  96     if (!backend) {
  97         fprintf(stderr, "vhost-net requires backend to be setup\n");
  98         goto fail;
  99     }
 100     r = vhost_net_get_fd(backend);
 101     if (r < 0) {
 102         goto fail;
 103     }
 104     net->vc = backend;
 105     net->dev.backend_features = tap_has_vnet_hdr(backend) ? 0 :
 106         (1 << VHOST_NET_F_VIRTIO_NET_HDR);
 107     net->backend = r;
 108
 109     r = vhost_dev_init(&net->dev, devfd, force);
 110     if (r < 0) {
 111         goto fail;
 112     }
 113     if (!tap_has_vnet_hdr_len(backend,
 114                               sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
 115         net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
 116     }
 117     if (~net->dev.features & net->dev.backend_features) {
 118         fprintf(stderr, "vhost lacks feature mask %" PRIu64 " for backend\n",
 119                 (uint64_t)(~net->dev.features & net->dev.backend_features));
 120         vhost_dev_cleanup(&net->dev);
 121         goto fail;
 122     }
 123
 124     /* Set sane init value. Override when guest acks. */
 125     vhost_net_ack_features(net, 0);
 126     return net;
 127 fail:
 128     g_free(net);
 129     return NULL;
 130 }
 131
 132 bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)
 133 {
 134     return vhost_dev_query(&net->dev, dev);
 135 }
 136
 137 int vhost_net_start(struct vhost_net *net,
 138                     VirtIODevice *dev)
 139 {
 140     struct vhost_vring_file file = { };
 141     int r;
 142     if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
 143         tap_set_vnet_hdr_len(net->vc,
 144                              sizeof(struct virtio_net_hdr_mrg_rxbuf));
 145     }
 146
 147     net->dev.nvqs = 2;
 148     net->dev.vqs = net->vqs;
 149     r = vhost_dev_start(&net->dev, dev);
 150     if (r < 0) {
 151         return r;
 152     }
 153
 154     net->vc->info->poll(net->vc, false);
 155     qemu_set_fd_handler(net->backend, NULL, NULL, NULL);
 156     file.fd = net->backend;
 157     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
 158         r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 159         if (r < 0) {
 160             r = -errno;
 161             goto fail;
 162         }
 163     }
 164     return 0;
 165 fail:
 166     file.fd = -1;
 167     while (file.index-- > 0) {
 168         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 169         assert(r >= 0);
 170     }
 171     net->vc->info->poll(net->vc, true);
 172     vhost_dev_stop(&net->dev, dev);
 173     if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
 174         tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));
 175     }
 176     return r;
 177 }
 178
 179 void vhost_net_stop(struct vhost_net *net,
 180                     VirtIODevice *dev)
 181 {
 182     struct vhost_vring_file file = { .fd = -1 };
 183
 184     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
 185         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
 186         assert(r >= 0);
 187     }
 188     net->vc->info->poll(net->vc, true);
 189     vhost_dev_stop(&net->dev, dev);
 190     if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
 191         tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));
 192     }
 193 }
 194
 195 void vhost_net_cleanup(struct vhost_net *net)
 196 {
 197     vhost_dev_cleanup(&net->dev);
 198     if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
 199         tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr));
 200     }
 201     g_free(net);
 202 }
 203 #else
 204 struct vhost_net *vhost_net_init(VLANClientState *backend, int devfd,
 205                                  bool force)
 206 {
 207     error_report("vhost-net support is not compiled in");
 208     return NULL;
 209 }
 210
 211 bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)
 212 {
 213     return false;
 214 }
 215
 216 int vhost_net_start(struct vhost_net *net,
 217                     VirtIODevice *dev)
 218 {
 219     return -ENOSYS;
 220 }
 221 void vhost_net_stop(struct vhost_net *net,
 222                     VirtIODevice *dev)
 223 {
 224 }
 225
 226 void vhost_net_cleanup(struct vhost_net *net)
 227 {
 228 }
 229
 230 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
 231 {
 232     return features;
 233 }
 234 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
 235 {
 236 }
 237 #endif