xref: /openbmc/qemu/net/vhost-user.c (revision 2a53cff4) 
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 int vhost_user_set_vnet_endianness(NetClientState *nc,
176                                           bool enable)
177 {
178     /* Nothing to do.  If the server supports
179      * VHOST_USER_PROTOCOL_F_CROSS_ENDIAN, it will get the
180      * vnet header endianness from there.  If it doesn't, negotiation
181      * fails.
182      */
183     return 0;
184 }
185 
186 static bool vhost_user_has_vnet_hdr(NetClientState *nc)
187 {
188     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
189 
190     return true;
191 }
192 
193 static bool vhost_user_has_ufo(NetClientState *nc)
194 {
195     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
196 
197     return true;
198 }
199 
200 static NetClientInfo net_vhost_user_info = {
201         .type = NET_CLIENT_DRIVER_VHOST_USER,
202         .size = sizeof(NetVhostUserState),
203         .receive = vhost_user_receive,
204         .cleanup = net_vhost_user_cleanup,
205         .has_vnet_hdr = vhost_user_has_vnet_hdr,
206         .has_ufo = vhost_user_has_ufo,
207         .set_vnet_be = vhost_user_set_vnet_endianness,
208         .set_vnet_le = vhost_user_set_vnet_endianness,
209 };
210 
211 static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond,
212                                            void *opaque)
213 {
214     NetVhostUserState *s = opaque;
215 
216     qemu_chr_fe_disconnect(&s->chr);
217 
218     return TRUE;
219 }
220 
221 static void net_vhost_user_event(void *opaque, int event);
222 
223 static void chr_closed_bh(void *opaque)
224 {
225     const char *name = opaque;
226     NetClientState *ncs[MAX_QUEUE_NUM];
227     NetVhostUserState *s;
228     Error *err = NULL;
229     int queues;
230 
231     queues = qemu_find_net_clients_except(name, ncs,
232                                           NET_CLIENT_DRIVER_NIC,
233                                           MAX_QUEUE_NUM);
234     assert(queues < MAX_QUEUE_NUM);
235 
236     s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
237 
238     qmp_set_link(name, false, &err);
239     vhost_user_stop(queues, ncs);
240 
241     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
242                              NULL, opaque, NULL, true);
243 
244     if (err) {
245         error_report_err(err);
246     }
247 }
248 
249 static void net_vhost_user_event(void *opaque, int event)
250 {
251     const char *name = opaque;
252     NetClientState *ncs[MAX_QUEUE_NUM];
253     NetVhostUserState *s;
254     Chardev *chr;
255     Error *err = NULL;
256     int queues;
257 
258     queues = qemu_find_net_clients_except(name, ncs,
259                                           NET_CLIENT_DRIVER_NIC,
260                                           MAX_QUEUE_NUM);
261     assert(queues < MAX_QUEUE_NUM);
262 
263     s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
264     chr = qemu_chr_fe_get_driver(&s->chr);
265     trace_vhost_user_event(chr->label, event);
266     switch (event) {
267     case CHR_EVENT_OPENED:
268         if (vhost_user_start(queues, ncs, s->vhost_user) < 0) {
269             qemu_chr_fe_disconnect(&s->chr);
270             return;
271         }
272         s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
273                                          net_vhost_user_watch, s);
274         qmp_set_link(name, true, &err);
275         s->started = true;
276         break;
277     case CHR_EVENT_CLOSED:
278         /* a close event may happen during a read/write, but vhost
279          * code assumes the vhost_dev remains setup, so delay the
280          * stop & clear to idle.
281          * FIXME: better handle failure in vhost code, remove bh
282          */
283         if (s->watch) {
284             AioContext *ctx = qemu_get_current_aio_context();
285 
286             g_source_remove(s->watch);
287             s->watch = 0;
288             qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL,
289                                      NULL, NULL, false);
290 
291             aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque);
292         }
293         break;
294     }
295 
296     if (err) {
297         error_report_err(err);
298     }
299 }
300 
301 static int net_vhost_user_init(NetClientState *peer, const char *device,
302                                const char *name, Chardev *chr,
303                                int queues)
304 {
305     Error *err = NULL;
306     NetClientState *nc, *nc0 = NULL;
307     VhostUserState *user = NULL;
308     NetVhostUserState *s = NULL;
309     int i;
310 
311     assert(name);
312     assert(queues > 0);
313 
314     user = vhost_user_init();
315     if (!user) {
316         error_report("failed to init vhost_user");
317         goto err;
318     }
319 
320     for (i = 0; i < queues; i++) {
321         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
322         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
323                  i, chr->label);
324         nc->queue_index = i;
325         if (!nc0) {
326             nc0 = nc;
327             s = DO_UPCAST(NetVhostUserState, nc, nc);
328             if (!qemu_chr_fe_init(&s->chr, chr, &err)) {
329                 error_report_err(err);
330                 goto err;
331             }
332             user->chr = &s->chr;
333         }
334         s = DO_UPCAST(NetVhostUserState, nc, nc);
335         s->vhost_user = user;
336     }
337 
338     s = DO_UPCAST(NetVhostUserState, nc, nc0);
339     do {
340         if (qemu_chr_fe_wait_connected(&s->chr, &err) < 0) {
341             error_report_err(err);
342             goto err;
343         }
344         qemu_chr_fe_set_handlers(&s->chr, NULL, NULL,
345                                  net_vhost_user_event, NULL, nc0->name, NULL,
346                                  true);
347     } while (!s->started);
348 
349     assert(s->vhost_net);
350 
351     return 0;
352 
353 err:
354     if (user) {
355         vhost_user_cleanup(user);
356         g_free(user);
357         if (s) {
358             s->vhost_user = NULL;
359         }
360     }
361     if (nc0) {
362         qemu_del_net_client(nc0);
363     }
364 
365     return -1;
366 }
367 
368 static Chardev *net_vhost_claim_chardev(
369     const NetdevVhostUserOptions *opts, Error **errp)
370 {
371     Chardev *chr = qemu_chr_find(opts->chardev);
372 
373     if (chr == NULL) {
374         error_setg(errp, "chardev \"%s\" not found", opts->chardev);
375         return NULL;
376     }
377 
378     if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
379         error_setg(errp, "chardev \"%s\" is not reconnectable",
380                    opts->chardev);
381         return NULL;
382     }
383     if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_FD_PASS)) {
384         error_setg(errp, "chardev \"%s\" does not support FD passing",
385                    opts->chardev);
386         return NULL;
387     }
388 
389     return chr;
390 }
391 
392 static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
393 {
394     const char *name = opaque;
395     const char *driver, *netdev;
396 
397     driver = qemu_opt_get(opts, "driver");
398     netdev = qemu_opt_get(opts, "netdev");
399 
400     if (!driver || !netdev) {
401         return 0;
402     }
403 
404     if (strcmp(netdev, name) == 0 &&
405         !g_str_has_prefix(driver, "virtio-net-")) {
406         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
407         return -1;
408     }
409 
410     return 0;
411 }
412 
413 int net_init_vhost_user(const Netdev *netdev, const char *name,
414                         NetClientState *peer, Error **errp)
415 {
416     int queues;
417     const NetdevVhostUserOptions *vhost_user_opts;
418     Chardev *chr;
419 
420     assert(netdev->type == NET_CLIENT_DRIVER_VHOST_USER);
421     vhost_user_opts = &netdev->u.vhost_user;
422 
423     chr = net_vhost_claim_chardev(vhost_user_opts, errp);
424     if (!chr) {
425         return -1;
426     }
427 
428     /* verify net frontend */
429     if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
430                           (char *)name, errp)) {
431         return -1;
432     }
433 
434     queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
435     if (queues < 1 || queues > MAX_QUEUE_NUM) {
436         error_setg(errp,
437                    "vhost-user number of queues must be in range [1, %d]",
438                    MAX_QUEUE_NUM);
439         return -1;
440     }
441 
442     return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
443 }
444