xref: /openbmc/qemu/net/vhost-user.c (revision b917da4c) 
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 } VhostUserChardevProps;
31 
32 VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
33 {
34     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
35     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
36     return s->vhost_net;
37 }
38 
39 static int vhost_user_running(VhostUserState *s)
40 {
41     return (s->vhost_net) ? 1 : 0;
42 }
43 
44 static void vhost_user_stop(int queues, NetClientState *ncs[])
45 {
46     VhostUserState *s;
47     int i;
48 
49     for (i = 0; i < queues; i++) {
50         assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
51 
52         s = DO_UPCAST(VhostUserState, nc, ncs[i]);
53         if (!vhost_user_running(s)) {
54             continue;
55         }
56 
57         if (s->vhost_net) {
58             vhost_net_cleanup(s->vhost_net);
59             s->vhost_net = NULL;
60         }
61     }
62 }
63 
64 static int vhost_user_start(int queues, NetClientState *ncs[])
65 {
66     VhostNetOptions options;
67     VhostUserState *s;
68     int max_queues;
69     int i;
70 
71     options.backend_type = VHOST_BACKEND_TYPE_USER;
72 
73     for (i = 0; i < queues; i++) {
74         assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
75 
76         s = DO_UPCAST(VhostUserState, nc, ncs[i]);
77         if (vhost_user_running(s)) {
78             continue;
79         }
80 
81         options.net_backend = ncs[i];
82         options.opaque      = s->chr;
83         s->vhost_net = vhost_net_init(&options);
84         if (!s->vhost_net) {
85             error_report("failed to init vhost_net for queue %d", i);
86             goto err;
87         }
88 
89         if (i == 0) {
90             max_queues = vhost_net_get_max_queues(s->vhost_net);
91             if (queues > max_queues) {
92                 error_report("you are asking more queues than supported: %d",
93                              max_queues);
94                 goto err;
95             }
96         }
97     }
98 
99     return 0;
100 
101 err:
102     vhost_user_stop(i + 1, ncs);
103     return -1;
104 }
105 
106 static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
107                                   size_t size)
108 {
109     /* In case of RARP (message size is 60) notify backup to send a fake RARP.
110        This fake RARP will be sent by backend only for guest
111        without GUEST_ANNOUNCE capability.
112      */
113     if (size == 60) {
114         VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
115         int r;
116         static int display_rarp_failure = 1;
117         char mac_addr[6];
118 
119         /* extract guest mac address from the RARP message */
120         memcpy(mac_addr, &buf[6], 6);
121 
122         r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
123 
124         if ((r != 0) && (display_rarp_failure)) {
125             fprintf(stderr,
126                     "Vhost user backend fails to broadcast fake RARP\n");
127             fflush(stderr);
128             display_rarp_failure = 0;
129         }
130     }
131 
132     return size;
133 }
134 
135 static void vhost_user_cleanup(NetClientState *nc)
136 {
137     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
138 
139     if (s->vhost_net) {
140         vhost_net_cleanup(s->vhost_net);
141         s->vhost_net = NULL;
142     }
143 
144     qemu_purge_queued_packets(nc);
145 }
146 
147 static bool vhost_user_has_vnet_hdr(NetClientState *nc)
148 {
149     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
150 
151     return true;
152 }
153 
154 static bool vhost_user_has_ufo(NetClientState *nc)
155 {
156     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
157 
158     return true;
159 }
160 
161 static NetClientInfo net_vhost_user_info = {
162         .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER,
163         .size = sizeof(VhostUserState),
164         .receive = vhost_user_receive,
165         .cleanup = vhost_user_cleanup,
166         .has_vnet_hdr = vhost_user_has_vnet_hdr,
167         .has_ufo = vhost_user_has_ufo,
168 };
169 
170 static void net_vhost_user_event(void *opaque, int event)
171 {
172     const char *name = opaque;
173     NetClientState *ncs[MAX_QUEUE_NUM];
174     VhostUserState *s;
175     Error *err = NULL;
176     int queues;
177 
178     queues = qemu_find_net_clients_except(name, ncs,
179                                           NET_CLIENT_OPTIONS_KIND_NIC,
180                                           MAX_QUEUE_NUM);
181     assert(queues < MAX_QUEUE_NUM);
182 
183     s = DO_UPCAST(VhostUserState, nc, ncs[0]);
184     trace_vhost_user_event(s->chr->label, event);
185     switch (event) {
186     case CHR_EVENT_OPENED:
187         if (vhost_user_start(queues, ncs) < 0) {
188             exit(1);
189         }
190         qmp_set_link(name, true, &err);
191         break;
192     case CHR_EVENT_CLOSED:
193         qmp_set_link(name, false, &err);
194         vhost_user_stop(queues, ncs);
195         break;
196     }
197 
198     if (err) {
199         error_report_err(err);
200     }
201 }
202 
203 static int net_vhost_user_init(NetClientState *peer, const char *device,
204                                const char *name, CharDriverState *chr,
205                                int queues)
206 {
207     NetClientState *nc;
208     VhostUserState *s;
209     int i;
210 
211     assert(name);
212     assert(queues > 0);
213 
214     for (i = 0; i < queues; i++) {
215         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
216 
217         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
218                  i, chr->label);
219 
220         nc->queue_index = i;
221 
222         s = DO_UPCAST(VhostUserState, nc, nc);
223         s->chr = chr;
224     }
225 
226     qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, nc[0].name);
227 
228     return 0;
229 }
230 
231 static int net_vhost_chardev_opts(void *opaque,
232                                   const char *name, const char *value,
233                                   Error **errp)
234 {
235     VhostUserChardevProps *props = opaque;
236 
237     if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 0) {
238         props->is_socket = true;
239     } else if (strcmp(name, "path") == 0) {
240         props->is_unix = true;
241     } else if (strcmp(name, "server") == 0) {
242     } else {
243         error_setg(errp,
244                    "vhost-user does not support a chardev with option %s=%s",
245                    name, value);
246         return -1;
247     }
248     return 0;
249 }
250 
251 static CharDriverState *net_vhost_parse_chardev(
252     const NetdevVhostUserOptions *opts, Error **errp)
253 {
254     CharDriverState *chr = qemu_chr_find(opts->chardev);
255     VhostUserChardevProps props;
256 
257     if (chr == NULL) {
258         error_setg(errp, "chardev \"%s\" not found", opts->chardev);
259         return NULL;
260     }
261 
262     /* inspect chardev opts */
263     memset(&props, 0, sizeof(props));
264     if (qemu_opt_foreach(chr->opts, net_vhost_chardev_opts, &props, errp)) {
265         return NULL;
266     }
267 
268     if (!props.is_socket || !props.is_unix) {
269         error_setg(errp, "chardev \"%s\" is not a unix socket",
270                    opts->chardev);
271         return NULL;
272     }
273 
274     qemu_chr_fe_claim_no_fail(chr);
275 
276     return chr;
277 }
278 
279 static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
280 {
281     const char *name = opaque;
282     const char *driver, *netdev;
283     const char virtio_name[] = "virtio-net-";
284 
285     driver = qemu_opt_get(opts, "driver");
286     netdev = qemu_opt_get(opts, "netdev");
287 
288     if (!driver || !netdev) {
289         return 0;
290     }
291 
292     if (strcmp(netdev, name) == 0 &&
293         strncmp(driver, virtio_name, strlen(virtio_name)) != 0) {
294         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
295         return -1;
296     }
297 
298     return 0;
299 }
300 
301 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
302                         NetClientState *peer, Error **errp)
303 {
304     int queues;
305     const NetdevVhostUserOptions *vhost_user_opts;
306     CharDriverState *chr;
307 
308     assert(opts->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
309     vhost_user_opts = opts->u.vhost_user;
310 
311     chr = net_vhost_parse_chardev(vhost_user_opts, errp);
312     if (!chr) {
313         return -1;
314     }
315 
316     /* verify net frontend */
317     if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
318                           (char *)name, errp)) {
319         return -1;
320     }
321 
322     queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
323     if (queues < 1 || queues > MAX_QUEUE_NUM) {
324         error_setg(errp,
325                    "vhost-user number of queues must be in range [1, %d]",
326                    MAX_QUEUE_NUM);
327         return -1;
328     }
329 
330     return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
331 }
332