xref: /openbmc/qemu/net/vhost-user.c (revision 35658f6e) 
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     int 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         s->vhost_net = vhost_net_init(&options);
95         if (!s->vhost_net) {
96             error_report("failed to init vhost_net for queue %d", i);
97             goto err;
98         }
99 
100         if (i == 0) {
101             max_queues = vhost_net_get_max_queues(s->vhost_net);
102             if (queues > max_queues) {
103                 error_report("you are asking more queues than supported: %d",
104                              max_queues);
105                 goto err;
106             }
107         }
108     }
109 
110     return 0;
111 
112 err:
113     vhost_user_stop(i + 1, ncs);
114     return -1;
115 }
116 
117 static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
118                                   size_t size)
119 {
120     /* In case of RARP (message size is 60) notify backup to send a fake RARP.
121        This fake RARP will be sent by backend only for guest
122        without GUEST_ANNOUNCE capability.
123      */
124     if (size == 60) {
125         VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
126         int r;
127         static int display_rarp_failure = 1;
128         char mac_addr[6];
129 
130         /* extract guest mac address from the RARP message */
131         memcpy(mac_addr, &buf[6], 6);
132 
133         r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
134 
135         if ((r != 0) && (display_rarp_failure)) {
136             fprintf(stderr,
137                     "Vhost user backend fails to broadcast fake RARP\n");
138             fflush(stderr);
139             display_rarp_failure = 0;
140         }
141     }
142 
143     return size;
144 }
145 
146 static void vhost_user_cleanup(NetClientState *nc)
147 {
148     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
149 
150     if (s->vhost_net) {
151         vhost_net_cleanup(s->vhost_net);
152         s->vhost_net = NULL;
153     }
154 
155     qemu_purge_queued_packets(nc);
156 }
157 
158 static bool vhost_user_has_vnet_hdr(NetClientState *nc)
159 {
160     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
161 
162     return true;
163 }
164 
165 static bool vhost_user_has_ufo(NetClientState *nc)
166 {
167     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
168 
169     return true;
170 }
171 
172 static NetClientInfo net_vhost_user_info = {
173         .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER,
174         .size = sizeof(VhostUserState),
175         .receive = vhost_user_receive,
176         .cleanup = vhost_user_cleanup,
177         .has_vnet_hdr = vhost_user_has_vnet_hdr,
178         .has_ufo = vhost_user_has_ufo,
179 };
180 
181 static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond,
182                                            void *opaque)
183 {
184     VhostUserState *s = opaque;
185     uint8_t buf[1];
186 
187     /* We don't actually want to read anything, but CHR_EVENT_CLOSED will be
188      * raised as a side-effect of the read.
189      */
190     qemu_chr_fe_read_all(s->chr, buf, sizeof(buf));
191 
192     return FALSE;
193 }
194 
195 static void net_vhost_user_event(void *opaque, int event)
196 {
197     const char *name = opaque;
198     NetClientState *ncs[MAX_QUEUE_NUM];
199     VhostUserState *s;
200     Error *err = NULL;
201     int queues;
202 
203     queues = qemu_find_net_clients_except(name, ncs,
204                                           NET_CLIENT_OPTIONS_KIND_NIC,
205                                           MAX_QUEUE_NUM);
206     assert(queues < MAX_QUEUE_NUM);
207 
208     s = DO_UPCAST(VhostUserState, nc, ncs[0]);
209     trace_vhost_user_event(s->chr->label, event);
210     switch (event) {
211     case CHR_EVENT_OPENED:
212         s->watch = qemu_chr_fe_add_watch(s->chr, G_IO_HUP,
213                                          net_vhost_user_watch, s);
214         if (vhost_user_start(queues, ncs) < 0) {
215             qemu_chr_disconnect(s->chr);
216             return;
217         }
218         qmp_set_link(name, true, &err);
219         break;
220     case CHR_EVENT_CLOSED:
221         qmp_set_link(name, false, &err);
222         vhost_user_stop(queues, ncs);
223         g_source_remove(s->watch);
224         s->watch = 0;
225         break;
226     }
227 
228     if (err) {
229         error_report_err(err);
230     }
231 }
232 
233 static int net_vhost_user_init(NetClientState *peer, const char *device,
234                                const char *name, CharDriverState *chr,
235                                int queues)
236 {
237     NetClientState *nc;
238     VhostUserState *s;
239     int i;
240 
241     assert(name);
242     assert(queues > 0);
243 
244     for (i = 0; i < queues; i++) {
245         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
246 
247         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
248                  i, chr->label);
249 
250         nc->queue_index = i;
251 
252         s = DO_UPCAST(VhostUserState, nc, nc);
253         s->chr = chr;
254     }
255 
256     qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, nc[0].name);
257 
258     return 0;
259 }
260 
261 static int net_vhost_chardev_opts(void *opaque,
262                                   const char *name, const char *value,
263                                   Error **errp)
264 {
265     VhostUserChardevProps *props = opaque;
266 
267     if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 0) {
268         props->is_socket = true;
269     } else if (strcmp(name, "path") == 0) {
270         props->is_unix = true;
271     } else if (strcmp(name, "server") == 0) {
272     } else {
273         error_setg(errp,
274                    "vhost-user does not support a chardev with option %s=%s",
275                    name, value);
276         return -1;
277     }
278     return 0;
279 }
280 
281 static CharDriverState *net_vhost_parse_chardev(
282     const NetdevVhostUserOptions *opts, Error **errp)
283 {
284     CharDriverState *chr = qemu_chr_find(opts->chardev);
285     VhostUserChardevProps props;
286 
287     if (chr == NULL) {
288         error_setg(errp, "chardev \"%s\" not found", opts->chardev);
289         return NULL;
290     }
291 
292     /* inspect chardev opts */
293     memset(&props, 0, sizeof(props));
294     if (qemu_opt_foreach(chr->opts, net_vhost_chardev_opts, &props, errp)) {
295         return NULL;
296     }
297 
298     if (!props.is_socket || !props.is_unix) {
299         error_setg(errp, "chardev \"%s\" is not a unix socket",
300                    opts->chardev);
301         return NULL;
302     }
303 
304     qemu_chr_fe_claim_no_fail(chr);
305 
306     return chr;
307 }
308 
309 static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
310 {
311     const char *name = opaque;
312     const char *driver, *netdev;
313     const char virtio_name[] = "virtio-net-";
314 
315     driver = qemu_opt_get(opts, "driver");
316     netdev = qemu_opt_get(opts, "netdev");
317 
318     if (!driver || !netdev) {
319         return 0;
320     }
321 
322     if (strcmp(netdev, name) == 0 &&
323         strncmp(driver, virtio_name, strlen(virtio_name)) != 0) {
324         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
325         return -1;
326     }
327 
328     return 0;
329 }
330 
331 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
332                         NetClientState *peer, Error **errp)
333 {
334     int queues;
335     const NetdevVhostUserOptions *vhost_user_opts;
336     CharDriverState *chr;
337 
338     assert(opts->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
339     vhost_user_opts = opts->u.vhost_user.data;
340 
341     chr = net_vhost_parse_chardev(vhost_user_opts, errp);
342     if (!chr) {
343         return -1;
344     }
345 
346     /* verify net frontend */
347     if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
348                           (char *)name, errp)) {
349         return -1;
350     }
351 
352     queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
353     if (queues < 1 || queues > MAX_QUEUE_NUM) {
354         error_setg(errp,
355                    "vhost-user number of queues must be in range [1, %d]",
356                    MAX_QUEUE_NUM);
357         return -1;
358     }
359 
360     return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
361 }
362