xref: /openbmc/qemu/net/vhost-user.c (revision 9a48e367) 
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         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     if (s->chr) {
155         qemu_chr_add_handlers(s->chr, NULL, NULL, NULL, NULL);
156         qemu_chr_fe_release(s->chr);
157         s->chr = NULL;
158     }
159 
160     qemu_purge_queued_packets(nc);
161 }
162 
163 static bool vhost_user_has_vnet_hdr(NetClientState *nc)
164 {
165     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
166 
167     return true;
168 }
169 
170 static bool vhost_user_has_ufo(NetClientState *nc)
171 {
172     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
173 
174     return true;
175 }
176 
177 static NetClientInfo net_vhost_user_info = {
178         .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER,
179         .size = sizeof(VhostUserState),
180         .receive = vhost_user_receive,
181         .cleanup = vhost_user_cleanup,
182         .has_vnet_hdr = vhost_user_has_vnet_hdr,
183         .has_ufo = vhost_user_has_ufo,
184 };
185 
186 static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond,
187                                            void *opaque)
188 {
189     VhostUserState *s = opaque;
190     uint8_t buf[1];
191 
192     /* We don't actually want to read anything, but CHR_EVENT_CLOSED will be
193      * raised as a side-effect of the read.
194      */
195     qemu_chr_fe_read_all(s->chr, buf, sizeof(buf));
196 
197     return FALSE;
198 }
199 
200 static void net_vhost_user_event(void *opaque, int event)
201 {
202     const char *name = opaque;
203     NetClientState *ncs[MAX_QUEUE_NUM];
204     VhostUserState *s;
205     Error *err = NULL;
206     int queues;
207 
208     queues = qemu_find_net_clients_except(name, ncs,
209                                           NET_CLIENT_OPTIONS_KIND_NIC,
210                                           MAX_QUEUE_NUM);
211     assert(queues < MAX_QUEUE_NUM);
212 
213     s = DO_UPCAST(VhostUserState, nc, ncs[0]);
214     trace_vhost_user_event(s->chr->label, event);
215     switch (event) {
216     case CHR_EVENT_OPENED:
217         s->watch = qemu_chr_fe_add_watch(s->chr, G_IO_HUP,
218                                          net_vhost_user_watch, s);
219         if (vhost_user_start(queues, ncs) < 0) {
220             qemu_chr_disconnect(s->chr);
221             return;
222         }
223         qmp_set_link(name, true, &err);
224         break;
225     case CHR_EVENT_CLOSED:
226         qmp_set_link(name, false, &err);
227         vhost_user_stop(queues, ncs);
228         g_source_remove(s->watch);
229         s->watch = 0;
230         break;
231     }
232 
233     if (err) {
234         error_report_err(err);
235     }
236 }
237 
238 static int net_vhost_user_init(NetClientState *peer, const char *device,
239                                const char *name, CharDriverState *chr,
240                                int queues)
241 {
242     NetClientState *nc;
243     VhostUserState *s;
244     int i;
245 
246     assert(name);
247     assert(queues > 0);
248 
249     for (i = 0; i < queues; i++) {
250         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
251 
252         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
253                  i, chr->label);
254 
255         nc->queue_index = i;
256 
257         s = DO_UPCAST(VhostUserState, nc, nc);
258         s->chr = chr;
259     }
260 
261     qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, nc[0].name);
262 
263     return 0;
264 }
265 
266 static int net_vhost_chardev_opts(void *opaque,
267                                   const char *name, const char *value,
268                                   Error **errp)
269 {
270     VhostUserChardevProps *props = opaque;
271 
272     if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 0) {
273         props->is_socket = true;
274     } else if (strcmp(name, "path") == 0) {
275         props->is_unix = true;
276     } else if (strcmp(name, "server") == 0) {
277     } else {
278         error_setg(errp,
279                    "vhost-user does not support a chardev with option %s=%s",
280                    name, value);
281         return -1;
282     }
283     return 0;
284 }
285 
286 static CharDriverState *net_vhost_parse_chardev(
287     const NetdevVhostUserOptions *opts, Error **errp)
288 {
289     CharDriverState *chr = qemu_chr_find(opts->chardev);
290     VhostUserChardevProps props;
291 
292     if (chr == NULL) {
293         error_setg(errp, "chardev \"%s\" not found", opts->chardev);
294         return NULL;
295     }
296 
297     /* inspect chardev opts */
298     memset(&props, 0, sizeof(props));
299     if (qemu_opt_foreach(chr->opts, net_vhost_chardev_opts, &props, errp)) {
300         return NULL;
301     }
302 
303     if (!props.is_socket || !props.is_unix) {
304         error_setg(errp, "chardev \"%s\" is not a unix socket",
305                    opts->chardev);
306         return NULL;
307     }
308 
309     qemu_chr_fe_claim_no_fail(chr);
310 
311     return chr;
312 }
313 
314 static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
315 {
316     const char *name = opaque;
317     const char *driver, *netdev;
318     const char virtio_name[] = "virtio-net-";
319 
320     driver = qemu_opt_get(opts, "driver");
321     netdev = qemu_opt_get(opts, "netdev");
322 
323     if (!driver || !netdev) {
324         return 0;
325     }
326 
327     if (strcmp(netdev, name) == 0 &&
328         strncmp(driver, virtio_name, strlen(virtio_name)) != 0) {
329         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
330         return -1;
331     }
332 
333     return 0;
334 }
335 
336 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
337                         NetClientState *peer, Error **errp)
338 {
339     int queues;
340     const NetdevVhostUserOptions *vhost_user_opts;
341     CharDriverState *chr;
342 
343     assert(opts->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
344     vhost_user_opts = opts->u.vhost_user.data;
345 
346     chr = net_vhost_parse_chardev(vhost_user_opts, errp);
347     if (!chr) {
348         return -1;
349     }
350 
351     /* verify net frontend */
352     if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
353                           (char *)name, errp)) {
354         return -1;
355     }
356 
357     queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
358     if (queues < 1 || queues > MAX_QUEUE_NUM) {
359         error_setg(errp,
360                    "vhost-user number of queues must be in range [1, %d]",
361                    MAX_QUEUE_NUM);
362         return -1;
363     }
364 
365     return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
366 }
367