xref: /qemu/net/vhost-user.c (revision 727385c4) 
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         options.nvqs = 2;
89         net = vhost_net_init(&options);
90         if (!net) {
91             error_report("failed to init vhost_net for queue %d", i);
92             goto err;
93         }
94 
95         if (i == 0) {
96             max_queues = vhost_net_get_max_queues(net);
97             if (queues > max_queues) {
98                 error_report("you are asking more queues than supported: %d",
99                              max_queues);
100                 goto err;
101             }
102         }
103 
104         if (s->vhost_net) {
105             vhost_net_cleanup(s->vhost_net);
106             g_free(s->vhost_net);
107         }
108         s->vhost_net = net;
109     }
110 
111     return 0;
112 
113 err:
114     if (net) {
115         vhost_net_cleanup(net);
116         g_free(net);
117     }
118     vhost_user_stop(i, ncs);
119     return -1;
120 }
121 
122 static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
123                                   size_t size)
124 {
125     /* In case of RARP (message size is 60) notify backup to send a fake RARP.
126        This fake RARP will be sent by backend only for guest
127        without GUEST_ANNOUNCE capability.
128      */
129     if (size == 60) {
130         NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
131         int r;
132         static int display_rarp_failure = 1;
133         char mac_addr[6];
134 
135         /* extract guest mac address from the RARP message */
136         memcpy(mac_addr, &buf[6], 6);
137 
138         r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
139 
140         if ((r != 0) && (display_rarp_failure)) {
141             fprintf(stderr,
142                     "Vhost user backend fails to broadcast fake RARP\n");
143             fflush(stderr);
144             display_rarp_failure = 0;
145         }
146     }
147 
148     return size;
149 }
150 
151 static void net_vhost_user_cleanup(NetClientState *nc)
152 {
153     NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
154 
155     if (s->vhost_net) {
156         vhost_net_cleanup(s->vhost_net);
157         g_free(s->vhost_net);
158         s->vhost_net = NULL;
159     }
160     if (nc->queue_index == 0) {
161         if (s->watch) {
162             g_source_remove(s->watch);
163             s->watch = 0;
164         }
165         qemu_chr_fe_deinit(&s->chr, true);
166         if (s->vhost_user) {
167             vhost_user_cleanup(s->vhost_user);
168             g_free(s->vhost_user);
169             s->vhost_user = NULL;
170         }
171     }
172 
173     qemu_purge_queued_packets(nc);
174 }
175 
176 static int vhost_user_set_vnet_endianness(NetClientState *nc,
177                                           bool enable)
178 {
179     /* Nothing to do.  If the server supports
180      * VHOST_USER_PROTOCOL_F_CROSS_ENDIAN, it will get the
181      * vnet header endianness from there.  If it doesn't, negotiation
182      * fails.
183      */
184     return 0;
185 }
186 
187 static bool vhost_user_has_vnet_hdr(NetClientState *nc)
188 {
189     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
190 
191     return true;
192 }
193 
194 static bool vhost_user_has_ufo(NetClientState *nc)
195 {
196     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
197 
198     return true;
199 }
200 
201 static bool vhost_user_check_peer_type(NetClientState *nc, ObjectClass *oc,
202                                        Error **errp)
203 {
204     const char *driver = object_class_get_name(oc);
205 
206     if (!g_str_has_prefix(driver, "virtio-net-")) {
207         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
208         return false;
209     }
210 
211     return true;
212 }
213 
214 static NetClientInfo net_vhost_user_info = {
215         .type = NET_CLIENT_DRIVER_VHOST_USER,
216         .size = sizeof(NetVhostUserState),
217         .receive = vhost_user_receive,
218         .cleanup = net_vhost_user_cleanup,
219         .has_vnet_hdr = vhost_user_has_vnet_hdr,
220         .has_ufo = vhost_user_has_ufo,
221         .set_vnet_be = vhost_user_set_vnet_endianness,
222         .set_vnet_le = vhost_user_set_vnet_endianness,
223         .check_peer_type = vhost_user_check_peer_type,
224 };
225 
226 static gboolean net_vhost_user_watch(void *do_not_use, GIOCondition cond,
227                                      void *opaque)
228 {
229     NetVhostUserState *s = opaque;
230 
231     qemu_chr_fe_disconnect(&s->chr);
232 
233     return TRUE;
234 }
235 
236 static void net_vhost_user_event(void *opaque, QEMUChrEvent event);
237 
238 static void chr_closed_bh(void *opaque)
239 {
240     const char *name = opaque;
241     NetClientState *ncs[MAX_QUEUE_NUM];
242     NetVhostUserState *s;
243     Error *err = NULL;
244     int queues, i;
245 
246     queues = qemu_find_net_clients_except(name, ncs,
247                                           NET_CLIENT_DRIVER_NIC,
248                                           MAX_QUEUE_NUM);
249     assert(queues < MAX_QUEUE_NUM);
250 
251     s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
252 
253     for (i = queues -1; i >= 0; i--) {
254         s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
255 
256         if (s->vhost_net) {
257             s->acked_features = vhost_net_get_acked_features(s->vhost_net);
258         }
259     }
260 
261     qmp_set_link(name, false, &err);
262 
263     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
264                              NULL, opaque, NULL, true);
265 
266     if (err) {
267         error_report_err(err);
268     }
269 }
270 
271 static void net_vhost_user_event(void *opaque, QEMUChrEvent event)
272 {
273     const char *name = opaque;
274     NetClientState *ncs[MAX_QUEUE_NUM];
275     NetVhostUserState *s;
276     Chardev *chr;
277     Error *err = NULL;
278     int queues;
279 
280     queues = qemu_find_net_clients_except(name, ncs,
281                                           NET_CLIENT_DRIVER_NIC,
282                                           MAX_QUEUE_NUM);
283     assert(queues < MAX_QUEUE_NUM);
284 
285     s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
286     chr = qemu_chr_fe_get_driver(&s->chr);
287     trace_vhost_user_event(chr->label, event);
288     switch (event) {
289     case CHR_EVENT_OPENED:
290         if (vhost_user_start(queues, ncs, s->vhost_user) < 0) {
291             qemu_chr_fe_disconnect(&s->chr);
292             return;
293         }
294         s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
295                                          net_vhost_user_watch, s);
296         qmp_set_link(name, true, &err);
297         s->started = true;
298         break;
299     case CHR_EVENT_CLOSED:
300         /* a close event may happen during a read/write, but vhost
301          * code assumes the vhost_dev remains setup, so delay the
302          * stop & clear to idle.
303          * FIXME: better handle failure in vhost code, remove bh
304          */
305         if (s->watch) {
306             AioContext *ctx = qemu_get_current_aio_context();
307 
308             g_source_remove(s->watch);
309             s->watch = 0;
310             qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL,
311                                      NULL, NULL, false);
312 
313             aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque);
314         }
315         break;
316     case CHR_EVENT_BREAK:
317     case CHR_EVENT_MUX_IN:
318     case CHR_EVENT_MUX_OUT:
319         /* Ignore */
320         break;
321     }
322 
323     if (err) {
324         error_report_err(err);
325     }
326 }
327 
328 static int net_vhost_user_init(NetClientState *peer, const char *device,
329                                const char *name, Chardev *chr,
330                                int queues)
331 {
332     Error *err = NULL;
333     NetClientState *nc, *nc0 = NULL;
334     NetVhostUserState *s = NULL;
335     VhostUserState *user;
336     int i;
337 
338     assert(name);
339     assert(queues > 0);
340 
341     user = g_new0(struct VhostUserState, 1);
342     for (i = 0; i < queues; i++) {
343         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
344         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
345                  i, chr->label);
346         nc->queue_index = i;
347         if (!nc0) {
348             nc0 = nc;
349             s = DO_UPCAST(NetVhostUserState, nc, nc);
350             if (!qemu_chr_fe_init(&s->chr, chr, &err) ||
351                 !vhost_user_init(user, &s->chr, &err)) {
352                 error_report_err(err);
353                 goto err;
354             }
355         }
356         s = DO_UPCAST(NetVhostUserState, nc, nc);
357         s->vhost_user = user;
358     }
359 
360     s = DO_UPCAST(NetVhostUserState, nc, nc0);
361     do {
362         if (qemu_chr_fe_wait_connected(&s->chr, &err) < 0) {
363             error_report_err(err);
364             goto err;
365         }
366         qemu_chr_fe_set_handlers(&s->chr, NULL, NULL,
367                                  net_vhost_user_event, NULL, nc0->name, NULL,
368                                  true);
369     } while (!s->started);
370 
371     assert(s->vhost_net);
372 
373     return 0;
374 
375 err:
376     if (user) {
377         vhost_user_cleanup(user);
378         g_free(user);
379         if (s) {
380             s->vhost_user = NULL;
381         }
382     }
383     if (nc0) {
384         qemu_del_net_client(nc0);
385     }
386 
387     return -1;
388 }
389 
390 static Chardev *net_vhost_claim_chardev(
391     const NetdevVhostUserOptions *opts, Error **errp)
392 {
393     Chardev *chr = qemu_chr_find(opts->chardev);
394 
395     if (chr == NULL) {
396         error_setg(errp, "chardev \"%s\" not found", opts->chardev);
397         return NULL;
398     }
399 
400     if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
401         error_setg(errp, "chardev \"%s\" is not reconnectable",
402                    opts->chardev);
403         return NULL;
404     }
405     if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_FD_PASS)) {
406         error_setg(errp, "chardev \"%s\" does not support FD passing",
407                    opts->chardev);
408         return NULL;
409     }
410 
411     return chr;
412 }
413 
414 int net_init_vhost_user(const Netdev *netdev, const char *name,
415                         NetClientState *peer, Error **errp)
416 {
417     int queues;
418     const NetdevVhostUserOptions *vhost_user_opts;
419     Chardev *chr;
420 
421     assert(netdev->type == NET_CLIENT_DRIVER_VHOST_USER);
422     vhost_user_opts = &netdev->u.vhost_user;
423 
424     chr = net_vhost_claim_chardev(vhost_user_opts, errp);
425     if (!chr) {
426         return -1;
427     }
428 
429     queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
430     if (queues < 1 || queues > MAX_QUEUE_NUM) {
431         error_setg(errp,
432                    "vhost-user number of queues must be in range [1, %d]",
433                    MAX_QUEUE_NUM);
434         return -1;
435     }
436 
437     return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
438 }
439