xref: /qemu/net/vhost-user.c (revision e7b3af81) 
1 /*
2  * vhost-user.c
3  *
4  * Copyright (c) 2013 Virtual Open Systems Sarl.
5  *
6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
7  * See the COPYING file in the top-level directory.
8  *
9  */
10 
11 #include "qemu/osdep.h"
12 #include "clients.h"
13 #include "net/vhost_net.h"
14 #include "net/vhost-user.h"
15 #include "hw/virtio/vhost-user.h"
16 #include "chardev/char-fe.h"
17 #include "qapi/error.h"
18 #include "qapi/qapi-commands-net.h"
19 #include "qemu/config-file.h"
20 #include "qemu/error-report.h"
21 #include "qemu/option.h"
22 #include "trace.h"
23 
24 typedef struct NetVhostUserState {
25     NetClientState nc;
26     CharBackend chr; /* only queue index 0 */
27     VhostUserState *vhost_user;
28     VHostNetState *vhost_net;
29     guint watch;
30     uint64_t acked_features;
31     bool started;
32 } NetVhostUserState;
33 
34 VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
35 {
36     NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
37     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
38     return s->vhost_net;
39 }
40 
41 uint64_t vhost_user_get_acked_features(NetClientState *nc)
42 {
43     NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
44     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
45     return s->acked_features;
46 }
47 
48 static void vhost_user_stop(int queues, NetClientState *ncs[])
49 {
50     NetVhostUserState *s;
51     int i;
52 
53     for (i = 0; i < queues; i++) {
54         assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
55 
56         s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
57 
58         if (s->vhost_net) {
59             /* save acked features */
60             uint64_t features = vhost_net_get_acked_features(s->vhost_net);
61             if (features) {
62                 s->acked_features = features;
63             }
64             vhost_net_cleanup(s->vhost_net);
65         }
66     }
67 }
68 
69 static int vhost_user_start(int queues, NetClientState *ncs[],
70                             VhostUserState *be)
71 {
72     VhostNetOptions options;
73     struct vhost_net *net = NULL;
74     NetVhostUserState *s;
75     int max_queues;
76     int i;
77 
78     options.backend_type = VHOST_BACKEND_TYPE_USER;
79 
80     for (i = 0; i < queues; i++) {
81         assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
82 
83         s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
84 
85         options.net_backend = ncs[i];
86         options.opaque      = be;
87         options.busyloop_timeout = 0;
88         net = vhost_net_init(&options);
89         if (!net) {
90             error_report("failed to init vhost_net for queue %d", i);
91             goto err;
92         }
93 
94         if (i == 0) {
95             max_queues = vhost_net_get_max_queues(net);
96             if (queues > max_queues) {
97                 error_report("you are asking more queues than supported: %d",
98                              max_queues);
99                 goto err;
100             }
101         }
102 
103         if (s->vhost_net) {
104             vhost_net_cleanup(s->vhost_net);
105             g_free(s->vhost_net);
106         }
107         s->vhost_net = net;
108     }
109 
110     return 0;
111 
112 err:
113     if (net) {
114         vhost_net_cleanup(net);
115         g_free(net);
116     }
117     vhost_user_stop(i, ncs);
118     return -1;
119 }
120 
121 static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
122                                   size_t size)
123 {
124     /* In case of RARP (message size is 60) notify backup to send a fake RARP.
125        This fake RARP will be sent by backend only for guest
126        without GUEST_ANNOUNCE capability.
127      */
128     if (size == 60) {
129         NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
130         int r;
131         static int display_rarp_failure = 1;
132         char mac_addr[6];
133 
134         /* extract guest mac address from the RARP message */
135         memcpy(mac_addr, &buf[6], 6);
136 
137         r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
138 
139         if ((r != 0) && (display_rarp_failure)) {
140             fprintf(stderr,
141                     "Vhost user backend fails to broadcast fake RARP\n");
142             fflush(stderr);
143             display_rarp_failure = 0;
144         }
145     }
146 
147     return size;
148 }
149 
150 static void net_vhost_user_cleanup(NetClientState *nc)
151 {
152     NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
153 
154     if (s->vhost_net) {
155         vhost_net_cleanup(s->vhost_net);
156         g_free(s->vhost_net);
157         s->vhost_net = NULL;
158     }
159     if (nc->queue_index == 0) {
160         if (s->watch) {
161             g_source_remove(s->watch);
162             s->watch = 0;
163         }
164         qemu_chr_fe_deinit(&s->chr, true);
165         if (s->vhost_user) {
166             vhost_user_cleanup(s->vhost_user);
167             g_free(s->vhost_user);
168             s->vhost_user = NULL;
169         }
170     }
171 
172     qemu_purge_queued_packets(nc);
173 }
174 
175 static bool vhost_user_has_vnet_hdr(NetClientState *nc)
176 {
177     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
178 
179     return true;
180 }
181 
182 static bool vhost_user_has_ufo(NetClientState *nc)
183 {
184     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
185 
186     return true;
187 }
188 
189 static NetClientInfo net_vhost_user_info = {
190         .type = NET_CLIENT_DRIVER_VHOST_USER,
191         .size = sizeof(NetVhostUserState),
192         .receive = vhost_user_receive,
193         .cleanup = net_vhost_user_cleanup,
194         .has_vnet_hdr = vhost_user_has_vnet_hdr,
195         .has_ufo = vhost_user_has_ufo,
196 };
197 
198 static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond,
199                                            void *opaque)
200 {
201     NetVhostUserState *s = opaque;
202 
203     qemu_chr_fe_disconnect(&s->chr);
204 
205     return TRUE;
206 }
207 
208 static void net_vhost_user_event(void *opaque, int event);
209 
210 static void chr_closed_bh(void *opaque)
211 {
212     const char *name = opaque;
213     NetClientState *ncs[MAX_QUEUE_NUM];
214     NetVhostUserState *s;
215     Error *err = NULL;
216     int queues;
217 
218     queues = qemu_find_net_clients_except(name, ncs,
219                                           NET_CLIENT_DRIVER_NIC,
220                                           MAX_QUEUE_NUM);
221     assert(queues < MAX_QUEUE_NUM);
222 
223     s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
224 
225     qmp_set_link(name, false, &err);
226     vhost_user_stop(queues, ncs);
227 
228     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
229                              NULL, opaque, NULL, true);
230 
231     if (err) {
232         error_report_err(err);
233     }
234 }
235 
236 static void net_vhost_user_event(void *opaque, int event)
237 {
238     const char *name = opaque;
239     NetClientState *ncs[MAX_QUEUE_NUM];
240     NetVhostUserState *s;
241     Chardev *chr;
242     Error *err = NULL;
243     int queues;
244 
245     queues = qemu_find_net_clients_except(name, ncs,
246                                           NET_CLIENT_DRIVER_NIC,
247                                           MAX_QUEUE_NUM);
248     assert(queues < MAX_QUEUE_NUM);
249 
250     s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
251     chr = qemu_chr_fe_get_driver(&s->chr);
252     trace_vhost_user_event(chr->label, event);
253     switch (event) {
254     case CHR_EVENT_OPENED:
255         if (vhost_user_start(queues, ncs, s->vhost_user) < 0) {
256             qemu_chr_fe_disconnect(&s->chr);
257             return;
258         }
259         s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
260                                          net_vhost_user_watch, s);
261         qmp_set_link(name, true, &err);
262         s->started = true;
263         break;
264     case CHR_EVENT_CLOSED:
265         /* a close event may happen during a read/write, but vhost
266          * code assumes the vhost_dev remains setup, so delay the
267          * stop & clear to idle.
268          * FIXME: better handle failure in vhost code, remove bh
269          */
270         if (s->watch) {
271             AioContext *ctx = qemu_get_current_aio_context();
272 
273             g_source_remove(s->watch);
274             s->watch = 0;
275             qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL,
276                                      NULL, NULL, false);
277 
278             aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque);
279         }
280         break;
281     }
282 
283     if (err) {
284         error_report_err(err);
285     }
286 }
287 
288 static int net_vhost_user_init(NetClientState *peer, const char *device,
289                                const char *name, Chardev *chr,
290                                int queues)
291 {
292     Error *err = NULL;
293     NetClientState *nc, *nc0 = NULL;
294     VhostUserState *user = NULL;
295     NetVhostUserState *s = NULL;
296     int i;
297 
298     assert(name);
299     assert(queues > 0);
300 
301     user = vhost_user_init();
302     if (!user) {
303         error_report("failed to init vhost_user");
304         goto err;
305     }
306 
307     for (i = 0; i < queues; i++) {
308         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
309         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
310                  i, chr->label);
311         nc->queue_index = i;
312         if (!nc0) {
313             nc0 = nc;
314             s = DO_UPCAST(NetVhostUserState, nc, nc);
315             if (!qemu_chr_fe_init(&s->chr, chr, &err)) {
316                 error_report_err(err);
317                 goto err;
318             }
319             user->chr = &s->chr;
320         }
321         s = DO_UPCAST(NetVhostUserState, nc, nc);
322         s->vhost_user = user;
323     }
324 
325     s = DO_UPCAST(NetVhostUserState, nc, nc0);
326     do {
327         if (qemu_chr_fe_wait_connected(&s->chr, &err) < 0) {
328             error_report_err(err);
329             goto err;
330         }
331         qemu_chr_fe_set_handlers(&s->chr, NULL, NULL,
332                                  net_vhost_user_event, NULL, nc0->name, NULL,
333                                  true);
334     } while (!s->started);
335 
336     assert(s->vhost_net);
337 
338     return 0;
339 
340 err:
341     if (user) {
342         vhost_user_cleanup(user);
343         g_free(user);
344         if (s) {
345             s->vhost_user = NULL;
346         }
347     }
348     if (nc0) {
349         qemu_del_net_client(nc0);
350     }
351 
352     return -1;
353 }
354 
355 static Chardev *net_vhost_claim_chardev(
356     const NetdevVhostUserOptions *opts, Error **errp)
357 {
358     Chardev *chr = qemu_chr_find(opts->chardev);
359 
360     if (chr == NULL) {
361         error_setg(errp, "chardev \"%s\" not found", opts->chardev);
362         return NULL;
363     }
364 
365     if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
366         error_setg(errp, "chardev \"%s\" is not reconnectable",
367                    opts->chardev);
368         return NULL;
369     }
370     if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_FD_PASS)) {
371         error_setg(errp, "chardev \"%s\" does not support FD passing",
372                    opts->chardev);
373         return NULL;
374     }
375 
376     return chr;
377 }
378 
379 static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
380 {
381     const char *name = opaque;
382     const char *driver, *netdev;
383 
384     driver = qemu_opt_get(opts, "driver");
385     netdev = qemu_opt_get(opts, "netdev");
386 
387     if (!driver || !netdev) {
388         return 0;
389     }
390 
391     if (strcmp(netdev, name) == 0 &&
392         !g_str_has_prefix(driver, "virtio-net-")) {
393         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
394         return -1;
395     }
396 
397     return 0;
398 }
399 
400 int net_init_vhost_user(const Netdev *netdev, const char *name,
401                         NetClientState *peer, Error **errp)
402 {
403     int queues;
404     const NetdevVhostUserOptions *vhost_user_opts;
405     Chardev *chr;
406 
407     assert(netdev->type == NET_CLIENT_DRIVER_VHOST_USER);
408     vhost_user_opts = &netdev->u.vhost_user;
409 
410     chr = net_vhost_claim_chardev(vhost_user_opts, errp);
411     if (!chr) {
412         return -1;
413     }
414 
415     /* verify net frontend */
416     if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
417                           (char *)name, errp)) {
418         return -1;
419     }
420 
421     queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
422     if (queues < 1 || queues > MAX_QUEUE_NUM) {
423         error_setg(errp,
424                    "vhost-user number of queues must be in range [1, %d]",
425                    MAX_QUEUE_NUM);
426         return -1;
427     }
428 
429     return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
430 }
431