xref: /openbmc/qemu/net/vhost-user.c (revision c964b660) 
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 "sysemu/char.h"
16 #include "qemu/config-file.h"
17 #include "qemu/error-report.h"
18 #include "qmp-commands.h"
19 #include "trace.h"
20 
21 typedef struct VhostUserState {
22     NetClientState nc;
23     CharDriverState *chr;
24     VHostNetState *vhost_net;
25 } VhostUserState;
26 
27 typedef struct VhostUserChardevProps {
28     bool is_socket;
29     bool is_unix;
30     bool is_server;
31 } VhostUserChardevProps;
32 
33 VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
34 {
35     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
36     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
37     return s->vhost_net;
38 }
39 
40 static int vhost_user_running(VhostUserState *s)
41 {
42     return (s->vhost_net) ? 1 : 0;
43 }
44 
45 static void vhost_user_stop(int queues, NetClientState *ncs[])
46 {
47     VhostUserState *s;
48     int i;
49 
50     for (i = 0; i < queues; i++) {
51         assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
52 
53         s = DO_UPCAST(VhostUserState, nc, ncs[i]);
54         if (!vhost_user_running(s)) {
55             continue;
56         }
57 
58         if (s->vhost_net) {
59             vhost_net_cleanup(s->vhost_net);
60             s->vhost_net = NULL;
61         }
62     }
63 }
64 
65 static int vhost_user_start(int queues, NetClientState *ncs[])
66 {
67     VhostNetOptions options;
68     VhostUserState *s;
69     int max_queues;
70     int i;
71 
72     options.backend_type = VHOST_BACKEND_TYPE_USER;
73 
74     for (i = 0; i < queues; i++) {
75         assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
76 
77         s = DO_UPCAST(VhostUserState, nc, ncs[i]);
78         if (vhost_user_running(s)) {
79             continue;
80         }
81 
82         options.net_backend = ncs[i];
83         options.opaque      = s->chr;
84         s->vhost_net = vhost_net_init(&options);
85         if (!s->vhost_net) {
86             error_report("failed to init vhost_net for queue %d", i);
87             goto err;
88         }
89 
90         if (i == 0) {
91             max_queues = vhost_net_get_max_queues(s->vhost_net);
92             if (queues > max_queues) {
93                 error_report("you are asking more queues than supported: %d",
94                              max_queues);
95                 goto err;
96             }
97         }
98     }
99 
100     return 0;
101 
102 err:
103     vhost_user_stop(i + 1, ncs);
104     return -1;
105 }
106 
107 static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
108                                   size_t size)
109 {
110     /* In case of RARP (message size is 60) notify backup to send a fake RARP.
111        This fake RARP will be sent by backend only for guest
112        without GUEST_ANNOUNCE capability.
113      */
114     if (size == 60) {
115         VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
116         int r;
117         static int display_rarp_failure = 1;
118         char mac_addr[6];
119 
120         /* extract guest mac address from the RARP message */
121         memcpy(mac_addr, &buf[6], 6);
122 
123         r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
124 
125         if ((r != 0) && (display_rarp_failure)) {
126             fprintf(stderr,
127                     "Vhost user backend fails to broadcast fake RARP\n");
128             fflush(stderr);
129             display_rarp_failure = 0;
130         }
131     }
132 
133     return size;
134 }
135 
136 static void vhost_user_cleanup(NetClientState *nc)
137 {
138     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
139 
140     if (s->vhost_net) {
141         vhost_net_cleanup(s->vhost_net);
142         s->vhost_net = NULL;
143     }
144 
145     qemu_purge_queued_packets(nc);
146 }
147 
148 static bool vhost_user_has_vnet_hdr(NetClientState *nc)
149 {
150     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
151 
152     return true;
153 }
154 
155 static bool vhost_user_has_ufo(NetClientState *nc)
156 {
157     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
158 
159     return true;
160 }
161 
162 static NetClientInfo net_vhost_user_info = {
163         .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER,
164         .size = sizeof(VhostUserState),
165         .receive = vhost_user_receive,
166         .cleanup = vhost_user_cleanup,
167         .has_vnet_hdr = vhost_user_has_vnet_hdr,
168         .has_ufo = vhost_user_has_ufo,
169 };
170 
171 static void net_vhost_user_event(void *opaque, int event)
172 {
173     const char *name = opaque;
174     NetClientState *ncs[MAX_QUEUE_NUM];
175     VhostUserState *s;
176     Error *err = NULL;
177     int queues;
178 
179     queues = qemu_find_net_clients_except(name, ncs,
180                                           NET_CLIENT_OPTIONS_KIND_NIC,
181                                           MAX_QUEUE_NUM);
182     s = DO_UPCAST(VhostUserState, nc, ncs[0]);
183     trace_vhost_user_event(s->chr->label, event);
184     switch (event) {
185     case CHR_EVENT_OPENED:
186         if (vhost_user_start(queues, ncs) < 0) {
187             exit(1);
188         }
189         qmp_set_link(name, true, &err);
190         break;
191     case CHR_EVENT_CLOSED:
192         qmp_set_link(name, false, &err);
193         vhost_user_stop(queues, ncs);
194         break;
195     }
196 
197     if (err) {
198         error_report_err(err);
199     }
200 }
201 
202 static int net_vhost_user_init(NetClientState *peer, const char *device,
203                                const char *name, CharDriverState *chr,
204                                int queues)
205 {
206     NetClientState *nc;
207     VhostUserState *s;
208     int i;
209 
210     for (i = 0; i < queues; i++) {
211         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
212 
213         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
214                  i, chr->label);
215 
216         nc->queue_index = i;
217 
218         s = DO_UPCAST(VhostUserState, nc, nc);
219         s->chr = chr;
220     }
221 
222     qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, (void*)name);
223 
224     return 0;
225 }
226 
227 static int net_vhost_chardev_opts(void *opaque,
228                                   const char *name, const char *value,
229                                   Error **errp)
230 {
231     VhostUserChardevProps *props = opaque;
232 
233     if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 0) {
234         props->is_socket = true;
235     } else if (strcmp(name, "path") == 0) {
236         props->is_unix = true;
237     } else if (strcmp(name, "server") == 0) {
238         props->is_server = true;
239     } else {
240         error_setg(errp,
241                    "vhost-user does not support a chardev with option %s=%s",
242                    name, value);
243         return -1;
244     }
245     return 0;
246 }
247 
248 static CharDriverState *net_vhost_parse_chardev(
249     const NetdevVhostUserOptions *opts, Error **errp)
250 {
251     CharDriverState *chr = qemu_chr_find(opts->chardev);
252     VhostUserChardevProps props;
253 
254     if (chr == NULL) {
255         error_setg(errp, "chardev \"%s\" not found", opts->chardev);
256         return NULL;
257     }
258 
259     /* inspect chardev opts */
260     memset(&props, 0, sizeof(props));
261     if (qemu_opt_foreach(chr->opts, net_vhost_chardev_opts, &props, errp)) {
262         return NULL;
263     }
264 
265     if (!props.is_socket || !props.is_unix) {
266         error_setg(errp, "chardev \"%s\" is not a unix socket",
267                    opts->chardev);
268         return NULL;
269     }
270 
271     qemu_chr_fe_claim_no_fail(chr);
272 
273     return chr;
274 }
275 
276 static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
277 {
278     const char *name = opaque;
279     const char *driver, *netdev;
280     const char virtio_name[] = "virtio-net-";
281 
282     driver = qemu_opt_get(opts, "driver");
283     netdev = qemu_opt_get(opts, "netdev");
284 
285     if (!driver || !netdev) {
286         return 0;
287     }
288 
289     if (strcmp(netdev, name) == 0 &&
290         strncmp(driver, virtio_name, strlen(virtio_name)) != 0) {
291         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
292         return -1;
293     }
294 
295     return 0;
296 }
297 
298 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
299                         NetClientState *peer, Error **errp)
300 {
301     int queues;
302     const NetdevVhostUserOptions *vhost_user_opts;
303     CharDriverState *chr;
304 
305     assert(opts->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
306     vhost_user_opts = opts->u.vhost_user;
307 
308     chr = net_vhost_parse_chardev(vhost_user_opts, errp);
309     if (!chr) {
310         return -1;
311     }
312 
313     /* verify net frontend */
314     if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
315                           (char *)name, errp)) {
316         return -1;
317     }
318 
319     queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
320     if (queues < 1) {
321         error_setg(errp,
322                    "vhost-user number of queues must be bigger than zero");
323         return -1;
324     }
325 
326     return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
327 }
328