xref: /openbmc/qemu/hw/net/vhost_net.c (revision 6e790746) 
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  * Contributions after 2012-01-13 are licensed under the terms of the
13  * GNU GPL, version 2 or (at your option) any later version.
14  */
15 
16 #include "net/net.h"
17 #include "net/tap.h"
18 
19 #include "hw/virtio/virtio-net.h"
20 #include "net/vhost_net.h"
21 #include "qemu/error-report.h"
22 
23 #include "config.h"
24 
25 #ifdef CONFIG_VHOST_NET
26 #include <linux/vhost.h>
27 #include <sys/socket.h>
28 #include <linux/kvm.h>
29 #include <fcntl.h>
30 #include <sys/ioctl.h>
31 #include <linux/virtio_ring.h>
32 #include <netpacket/packet.h>
33 #include <net/ethernet.h>
34 #include <net/if.h>
35 #include <netinet/in.h>
36 
37 #include <stdio.h>
38 
39 #include "hw/virtio/vhost.h"
40 
41 struct vhost_net {
42     struct vhost_dev dev;
43     struct vhost_virtqueue vqs[2];
44     int backend;
45     NetClientState *nc;
46 };
47 
48 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
49 {
50     /* Clear features not supported by host kernel. */
51     if (!(net->dev.features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY))) {
52         features &= ~(1 << VIRTIO_F_NOTIFY_ON_EMPTY);
53     }
54     if (!(net->dev.features & (1 << VIRTIO_RING_F_INDIRECT_DESC))) {
55         features &= ~(1 << VIRTIO_RING_F_INDIRECT_DESC);
56     }
57     if (!(net->dev.features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
58         features &= ~(1 << VIRTIO_RING_F_EVENT_IDX);
59     }
60     if (!(net->dev.features & (1 << VIRTIO_NET_F_MRG_RXBUF))) {
61         features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
62     }
63     return features;
64 }
65 
66 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
67 {
68     net->dev.acked_features = net->dev.backend_features;
69     if (features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) {
70         net->dev.acked_features |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY);
71     }
72     if (features & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {
73         net->dev.acked_features |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
74     }
75     if (features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
76         net->dev.acked_features |= (1 << VIRTIO_RING_F_EVENT_IDX);
77     }
78     if (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
79         net->dev.acked_features |= (1 << VIRTIO_NET_F_MRG_RXBUF);
80     }
81 }
82 
83 static int vhost_net_get_fd(NetClientState *backend)
84 {
85     switch (backend->info->type) {
86     case NET_CLIENT_OPTIONS_KIND_TAP:
87         return tap_get_fd(backend);
88     default:
89         fprintf(stderr, "vhost-net requires tap backend\n");
90         return -EBADFD;
91     }
92 }
93 
94 struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
95                                  bool force)
96 {
97     int r;
98     struct vhost_net *net = g_malloc(sizeof *net);
99     if (!backend) {
100         fprintf(stderr, "vhost-net requires backend to be setup\n");
101         goto fail;
102     }
103     r = vhost_net_get_fd(backend);
104     if (r < 0) {
105         goto fail;
106     }
107     net->nc = backend;
108     net->dev.backend_features = tap_has_vnet_hdr(backend) ? 0 :
109         (1 << VHOST_NET_F_VIRTIO_NET_HDR);
110     net->backend = r;
111 
112     net->dev.nvqs = 2;
113     net->dev.vqs = net->vqs;
114 
115     r = vhost_dev_init(&net->dev, devfd, "/dev/vhost-net", force);
116     if (r < 0) {
117         goto fail;
118     }
119     if (!tap_has_vnet_hdr_len(backend,
120                               sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
121         net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
122     }
123     if (~net->dev.features & net->dev.backend_features) {
124         fprintf(stderr, "vhost lacks feature mask %" PRIu64 " for backend\n",
125                 (uint64_t)(~net->dev.features & net->dev.backend_features));
126         vhost_dev_cleanup(&net->dev);
127         goto fail;
128     }
129 
130     /* Set sane init value. Override when guest acks. */
131     vhost_net_ack_features(net, 0);
132     return net;
133 fail:
134     g_free(net);
135     return NULL;
136 }
137 
138 bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)
139 {
140     return vhost_dev_query(&net->dev, dev);
141 }
142 
143 static int vhost_net_start_one(struct vhost_net *net,
144                                VirtIODevice *dev,
145                                int vq_index)
146 {
147     struct vhost_vring_file file = { };
148     int r;
149 
150     if (net->dev.started) {
151         return 0;
152     }
153 
154     net->dev.nvqs = 2;
155     net->dev.vqs = net->vqs;
156     net->dev.vq_index = vq_index;
157 
158     r = vhost_dev_enable_notifiers(&net->dev, dev);
159     if (r < 0) {
160         goto fail_notifiers;
161     }
162 
163     r = vhost_dev_start(&net->dev, dev);
164     if (r < 0) {
165         goto fail_start;
166     }
167 
168     net->nc->info->poll(net->nc, false);
169     qemu_set_fd_handler(net->backend, NULL, NULL, NULL);
170     file.fd = net->backend;
171     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
172         r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
173         if (r < 0) {
174             r = -errno;
175             goto fail;
176         }
177     }
178     return 0;
179 fail:
180     file.fd = -1;
181     while (file.index-- > 0) {
182         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
183         assert(r >= 0);
184     }
185     net->nc->info->poll(net->nc, true);
186     vhost_dev_stop(&net->dev, dev);
187 fail_start:
188     vhost_dev_disable_notifiers(&net->dev, dev);
189 fail_notifiers:
190     return r;
191 }
192 
193 static void vhost_net_stop_one(struct vhost_net *net,
194                                VirtIODevice *dev)
195 {
196     struct vhost_vring_file file = { .fd = -1 };
197 
198     if (!net->dev.started) {
199         return;
200     }
201 
202     for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
203         int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);
204         assert(r >= 0);
205     }
206     net->nc->info->poll(net->nc, true);
207     vhost_dev_stop(&net->dev, dev);
208     vhost_dev_disable_notifiers(&net->dev, dev);
209 }
210 
211 int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
212                     int total_queues)
213 {
214     int r, i = 0;
215 
216     if (!dev->binding->set_guest_notifiers) {
217         error_report("binding does not support guest notifiers");
218         r = -ENOSYS;
219         goto err;
220     }
221 
222     for (i = 0; i < total_queues; i++) {
223         r = vhost_net_start_one(tap_get_vhost_net(ncs[i].peer), dev, i * 2);
224 
225         if (r < 0) {
226             goto err;
227         }
228     }
229 
230     r = dev->binding->set_guest_notifiers(dev->binding_opaque,
231                                           total_queues * 2,
232                                           true);
233     if (r < 0) {
234         error_report("Error binding guest notifier: %d", -r);
235         goto err;
236     }
237 
238     return 0;
239 
240 err:
241     while (--i >= 0) {
242         vhost_net_stop_one(tap_get_vhost_net(ncs[i].peer), dev);
243     }
244     return r;
245 }
246 
247 void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs,
248                     int total_queues)
249 {
250     int i, r;
251 
252     r = dev->binding->set_guest_notifiers(dev->binding_opaque,
253                                           total_queues * 2,
254                                           false);
255     if (r < 0) {
256         fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);
257         fflush(stderr);
258     }
259     assert(r >= 0);
260 
261     for (i = 0; i < total_queues; i++) {
262         vhost_net_stop_one(tap_get_vhost_net(ncs[i].peer), dev);
263     }
264 }
265 
266 void vhost_net_cleanup(struct vhost_net *net)
267 {
268     vhost_dev_cleanup(&net->dev);
269     g_free(net);
270 }
271 
272 bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)
273 {
274     return vhost_virtqueue_pending(&net->dev, idx);
275 }
276 
277 void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
278                               int idx, bool mask)
279 {
280     vhost_virtqueue_mask(&net->dev, dev, idx, mask);
281 }
282 #else
283 struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
284                                  bool force)
285 {
286     error_report("vhost-net support is not compiled in");
287     return NULL;
288 }
289 
290 bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)
291 {
292     return false;
293 }
294 
295 int vhost_net_start(VirtIODevice *dev,
296                     NetClientState *ncs,
297                     int total_queues)
298 {
299     return -ENOSYS;
300 }
301 void vhost_net_stop(VirtIODevice *dev,
302                     NetClientState *ncs,
303                     int total_queues)
304 {
305 }
306 
307 void vhost_net_cleanup(struct vhost_net *net)
308 {
309 }
310 
311 unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
312 {
313     return features;
314 }
315 void vhost_net_ack_features(struct vhost_net *net, unsigned features)
316 {
317 }
318 
319 bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)
320 {
321     return -ENOSYS;
322 }
323 
324 void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
325                               int idx, bool mask)
326 {
327 }
328 #endif
329