xref: /qemu/net/vhost-user.c (revision a942d8fa) 
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     guint watch;
26     uint64_t acked_features;
27 } VhostUserState;
28 
29 typedef struct VhostUserChardevProps {
30     bool is_socket;
31     bool is_unix;
32 } VhostUserChardevProps;
33 
34 VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
35 {
36     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
37     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
38     return s->vhost_net;
39 }
40 
41 uint64_t vhost_user_get_acked_features(NetClientState *nc)
42 {
43     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
44     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
45     return s->acked_features;
46 }
47 
48 static int vhost_user_running(VhostUserState *s)
49 {
50     return (s->vhost_net) ? 1 : 0;
51 }
52 
53 static void vhost_user_stop(int queues, NetClientState *ncs[])
54 {
55     VhostUserState *s;
56     int i;
57 
58     for (i = 0; i < queues; i++) {
59         assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
60 
61         s = DO_UPCAST(VhostUserState, nc, ncs[i]);
62         if (!vhost_user_running(s)) {
63             continue;
64         }
65 
66         if (s->vhost_net) {
67             /* save acked features */
68             s->acked_features = vhost_net_get_acked_features(s->vhost_net);
69             vhost_net_cleanup(s->vhost_net);
70             s->vhost_net = NULL;
71         }
72     }
73 }
74 
75 static int vhost_user_start(int queues, NetClientState *ncs[])
76 {
77     VhostNetOptions options;
78     VhostUserState *s;
79     int max_queues;
80     int i;
81 
82     options.backend_type = VHOST_BACKEND_TYPE_USER;
83 
84     for (i = 0; i < queues; i++) {
85         assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
86 
87         s = DO_UPCAST(VhostUserState, nc, ncs[i]);
88         if (vhost_user_running(s)) {
89             continue;
90         }
91 
92         options.net_backend = ncs[i];
93         options.opaque      = s->chr;
94         options.busyloop_timeout = 0;
95         s->vhost_net = vhost_net_init(&options);
96         if (!s->vhost_net) {
97             error_report("failed to init vhost_net for queue %d", i);
98             goto err;
99         }
100 
101         if (i == 0) {
102             max_queues = vhost_net_get_max_queues(s->vhost_net);
103             if (queues > max_queues) {
104                 error_report("you are asking more queues than supported: %d",
105                              max_queues);
106                 goto err;
107             }
108         }
109     }
110 
111     return 0;
112 
113 err:
114     vhost_user_stop(i + 1, ncs);
115     return -1;
116 }
117 
118 static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
119                                   size_t size)
120 {
121     /* In case of RARP (message size is 60) notify backup to send a fake RARP.
122        This fake RARP will be sent by backend only for guest
123        without GUEST_ANNOUNCE capability.
124      */
125     if (size == 60) {
126         VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
127         int r;
128         static int display_rarp_failure = 1;
129         char mac_addr[6];
130 
131         /* extract guest mac address from the RARP message */
132         memcpy(mac_addr, &buf[6], 6);
133 
134         r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
135 
136         if ((r != 0) && (display_rarp_failure)) {
137             fprintf(stderr,
138                     "Vhost user backend fails to broadcast fake RARP\n");
139             fflush(stderr);
140             display_rarp_failure = 0;
141         }
142     }
143 
144     return size;
145 }
146 
147 static void vhost_user_cleanup(NetClientState *nc)
148 {
149     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
150 
151     if (s->vhost_net) {
152         vhost_net_cleanup(s->vhost_net);
153         s->vhost_net = NULL;
154     }
155     if (s->chr) {
156         qemu_chr_add_handlers(s->chr, NULL, NULL, NULL, NULL);
157         qemu_chr_fe_release(s->chr);
158         s->chr = NULL;
159     }
160 
161     qemu_purge_queued_packets(nc);
162 }
163 
164 static bool vhost_user_has_vnet_hdr(NetClientState *nc)
165 {
166     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
167 
168     return true;
169 }
170 
171 static bool vhost_user_has_ufo(NetClientState *nc)
172 {
173     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
174 
175     return true;
176 }
177 
178 static NetClientInfo net_vhost_user_info = {
179         .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER,
180         .size = sizeof(VhostUserState),
181         .receive = vhost_user_receive,
182         .cleanup = vhost_user_cleanup,
183         .has_vnet_hdr = vhost_user_has_vnet_hdr,
184         .has_ufo = vhost_user_has_ufo,
185 };
186 
187 static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond,
188                                            void *opaque)
189 {
190     VhostUserState *s = opaque;
191     uint8_t buf[1];
192 
193     /* We don't actually want to read anything, but CHR_EVENT_CLOSED will be
194      * raised as a side-effect of the read.
195      */
196     qemu_chr_fe_read_all(s->chr, buf, sizeof(buf));
197 
198     return FALSE;
199 }
200 
201 static void net_vhost_user_event(void *opaque, int event)
202 {
203     const char *name = opaque;
204     NetClientState *ncs[MAX_QUEUE_NUM];
205     VhostUserState *s;
206     Error *err = NULL;
207     int queues;
208 
209     queues = qemu_find_net_clients_except(name, ncs,
210                                           NET_CLIENT_OPTIONS_KIND_NIC,
211                                           MAX_QUEUE_NUM);
212     assert(queues < MAX_QUEUE_NUM);
213 
214     s = DO_UPCAST(VhostUserState, nc, ncs[0]);
215     trace_vhost_user_event(s->chr->label, event);
216     switch (event) {
217     case CHR_EVENT_OPENED:
218         s->watch = qemu_chr_fe_add_watch(s->chr, G_IO_HUP,
219                                          net_vhost_user_watch, s);
220         if (vhost_user_start(queues, ncs) < 0) {
221             qemu_chr_disconnect(s->chr);
222             return;
223         }
224         qmp_set_link(name, true, &err);
225         break;
226     case CHR_EVENT_CLOSED:
227         qmp_set_link(name, false, &err);
228         vhost_user_stop(queues, ncs);
229         g_source_remove(s->watch);
230         s->watch = 0;
231         break;
232     }
233 
234     if (err) {
235         error_report_err(err);
236     }
237 }
238 
239 static int net_vhost_user_init(NetClientState *peer, const char *device,
240                                const char *name, CharDriverState *chr,
241                                int queues)
242 {
243     NetClientState *nc;
244     VhostUserState *s;
245     int i;
246 
247     assert(name);
248     assert(queues > 0);
249 
250     for (i = 0; i < queues; i++) {
251         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
252 
253         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
254                  i, chr->label);
255 
256         nc->queue_index = i;
257 
258         s = DO_UPCAST(VhostUserState, nc, nc);
259         s->chr = chr;
260     }
261 
262     qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, nc[0].name);
263 
264     return 0;
265 }
266 
267 static int net_vhost_chardev_opts(void *opaque,
268                                   const char *name, const char *value,
269                                   Error **errp)
270 {
271     VhostUserChardevProps *props = opaque;
272 
273     if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 0) {
274         props->is_socket = true;
275     } else if (strcmp(name, "path") == 0) {
276         props->is_unix = true;
277     } else if (strcmp(name, "server") == 0) {
278     } else {
279         error_setg(errp,
280                    "vhost-user does not support a chardev with option %s=%s",
281                    name, value);
282         return -1;
283     }
284     return 0;
285 }
286 
287 static CharDriverState *net_vhost_parse_chardev(
288     const NetdevVhostUserOptions *opts, Error **errp)
289 {
290     CharDriverState *chr = qemu_chr_find(opts->chardev);
291     VhostUserChardevProps props;
292 
293     if (chr == NULL) {
294         error_setg(errp, "chardev \"%s\" not found", opts->chardev);
295         return NULL;
296     }
297 
298     /* inspect chardev opts */
299     memset(&props, 0, sizeof(props));
300     if (qemu_opt_foreach(chr->opts, net_vhost_chardev_opts, &props, errp)) {
301         return NULL;
302     }
303 
304     if (!props.is_socket || !props.is_unix) {
305         error_setg(errp, "chardev \"%s\" is not a unix socket",
306                    opts->chardev);
307         return NULL;
308     }
309 
310     qemu_chr_fe_claim_no_fail(chr);
311 
312     return chr;
313 }
314 
315 static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
316 {
317     const char *name = opaque;
318     const char *driver, *netdev;
319     const char virtio_name[] = "virtio-net-";
320 
321     driver = qemu_opt_get(opts, "driver");
322     netdev = qemu_opt_get(opts, "netdev");
323 
324     if (!driver || !netdev) {
325         return 0;
326     }
327 
328     if (strcmp(netdev, name) == 0 &&
329         strncmp(driver, virtio_name, strlen(virtio_name)) != 0) {
330         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
331         return -1;
332     }
333 
334     return 0;
335 }
336 
337 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
338                         NetClientState *peer, Error **errp)
339 {
340     int queues;
341     const NetdevVhostUserOptions *vhost_user_opts;
342     CharDriverState *chr;
343 
344     assert(opts->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
345     vhost_user_opts = opts->u.vhost_user.data;
346 
347     chr = net_vhost_parse_chardev(vhost_user_opts, errp);
348     if (!chr) {
349         return -1;
350     }
351 
352     /* verify net frontend */
353     if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
354                           (char *)name, errp)) {
355         return -1;
356     }
357 
358     queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
359     if (queues < 1 || queues > MAX_QUEUE_NUM) {
360         error_setg(errp,
361                    "vhost-user number of queues must be in range [1, %d]",
362                    MAX_QUEUE_NUM);
363         return -1;
364     }
365 
366     return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
367 }
368