xref: /qemu/contrib/vhost-user-scsi/vhost-user-scsi.c (revision 422a26872e4c14292ad2adc1411d6eb2032255e9) 
1 /*
2  * vhost-user-scsi sample application
3  *
4  * Copyright (c) 2016 Nutanix Inc. All rights reserved.
5  *
6  * Author:
7  *  Felipe Franciosi <felipe@nutanix.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 only.
10  * See the COPYING file in the top-level directory.
11  */
12 
13 #include "qemu/osdep.h"
14 #include "contrib/libvhost-user/libvhost-user.h"
15 #include "standard-headers/linux/virtio_scsi.h"
16 #include "iscsi/iscsi.h"
17 #include "iscsi/scsi-lowlevel.h"
18 
19 #include <glib.h>
20 
21 #define VUS_ISCSI_INITIATOR "iqn.2016-11.com.nutanix:vhost-user-scsi"
22 
23 typedef struct VusIscsiLun {
24     struct iscsi_context *iscsi_ctx;
25     int iscsi_lun;
26 } VusIscsiLun;
27 
28 typedef struct VusDev {
29     VuDev vu_dev;
30     int server_sock;
31     GMainLoop *loop;
32     GHashTable *fdmap;   /* fd -> gsource */
33     VusIscsiLun lun;
34 } VusDev;
35 
36 /** glib event loop integration for libvhost-user and misc callbacks **/
37 
38 QEMU_BUILD_BUG_ON((int)G_IO_IN != (int)VU_WATCH_IN);
39 QEMU_BUILD_BUG_ON((int)G_IO_OUT != (int)VU_WATCH_OUT);
40 QEMU_BUILD_BUG_ON((int)G_IO_PRI != (int)VU_WATCH_PRI);
41 QEMU_BUILD_BUG_ON((int)G_IO_ERR != (int)VU_WATCH_ERR);
42 QEMU_BUILD_BUG_ON((int)G_IO_HUP != (int)VU_WATCH_HUP);
43 
44 typedef struct vus_gsrc {
45     GSource parent;
46     VusDev *vdev_scsi;
47     GPollFD gfd;
48 } vus_gsrc_t;
49 
50 static gboolean vus_gsrc_prepare(GSource *src, gint *timeout)
51 {
52     assert(timeout);
53 
54     *timeout = -1;
55     return FALSE;
56 }
57 
58 static gboolean vus_gsrc_check(GSource *src)
59 {
60     vus_gsrc_t *vus_src = (vus_gsrc_t *)src;
61 
62     assert(vus_src);
63 
64     return vus_src->gfd.revents & vus_src->gfd.events;
65 }
66 
67 static gboolean vus_gsrc_dispatch(GSource *src, GSourceFunc cb, gpointer data)
68 {
69     VusDev *vdev_scsi;
70     vus_gsrc_t *vus_src = (vus_gsrc_t *)src;
71 
72     assert(vus_src);
73 
74     vdev_scsi = vus_src->vdev_scsi;
75 
76     assert(vdev_scsi);
77 
78     ((vu_watch_cb)cb)(&vdev_scsi->vu_dev, vus_src->gfd.revents, data);
79 
80     return G_SOURCE_CONTINUE;
81 }
82 
83 static GSourceFuncs vus_gsrc_funcs = {
84     vus_gsrc_prepare,
85     vus_gsrc_check,
86     vus_gsrc_dispatch,
87     NULL
88 };
89 
90 static GSource *vus_gsrc_new(VusDev *vdev_scsi, int fd, GIOCondition cond,
91                              vu_watch_cb vu_cb, GSourceFunc gsrc_cb, gpointer data)
92 {
93     GSource *vus_gsrc;
94     vus_gsrc_t *vus_src;
95     guint id;
96 
97     assert(vdev_scsi);
98     assert(fd >= 0);
99     assert(vu_cb || gsrc_cb);
100     assert(!(vu_cb && gsrc_cb));
101 
102     vus_gsrc = g_source_new(&vus_gsrc_funcs, sizeof(vus_gsrc_t));
103     g_source_set_callback(vus_gsrc, (GSourceFunc) vu_cb, data, NULL);
104     vus_src = (vus_gsrc_t *)vus_gsrc;
105     vus_src->vdev_scsi = vdev_scsi;
106     vus_src->gfd.fd = fd;
107     vus_src->gfd.events = cond;
108 
109     g_source_add_poll(vus_gsrc, &vus_src->gfd);
110     g_source_set_callback(vus_gsrc, gsrc_cb, data, NULL);
111     id = g_source_attach(vus_gsrc, NULL);
112     assert(id);
113     g_source_unref(vus_gsrc);
114 
115     return vus_gsrc;
116 }
117 
118 /** libiscsi integration **/
119 
120 typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
121 typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
122 
123 static int vus_iscsi_add_lun(VusIscsiLun *lun, char *iscsi_uri)
124 {
125     struct iscsi_url *iscsi_url;
126     struct iscsi_context *iscsi_ctx;
127     int ret = 0;
128 
129     assert(lun);
130     assert(iscsi_uri);
131     assert(!lun->iscsi_ctx);
132 
133     iscsi_ctx = iscsi_create_context(VUS_ISCSI_INITIATOR);
134     if (!iscsi_ctx) {
135         g_warning("Unable to create iSCSI context");
136         return -1;
137     }
138 
139     iscsi_url = iscsi_parse_full_url(iscsi_ctx, iscsi_uri);
140     if (!iscsi_url) {
141         g_warning("Unable to parse iSCSI URL: %s", iscsi_get_error(iscsi_ctx));
142         goto fail;
143     }
144 
145     iscsi_set_session_type(iscsi_ctx, ISCSI_SESSION_NORMAL);
146     iscsi_set_header_digest(iscsi_ctx, ISCSI_HEADER_DIGEST_NONE_CRC32C);
147     if (iscsi_full_connect_sync(iscsi_ctx, iscsi_url->portal, iscsi_url->lun)) {
148         g_warning("Unable to login to iSCSI portal: %s",
149                   iscsi_get_error(iscsi_ctx));
150         goto fail;
151     }
152 
153     lun->iscsi_ctx = iscsi_ctx;
154     lun->iscsi_lun = iscsi_url->lun;
155 
156     g_debug("Context %p created for lun 0: %s", iscsi_ctx, iscsi_uri);
157 
158 out:
159     if (iscsi_url) {
160         iscsi_destroy_url(iscsi_url);
161     }
162     return ret;
163 
164 fail:
165     (void)iscsi_destroy_context(iscsi_ctx);
166     ret = -1;
167     goto out;
168 }
169 
170 static struct scsi_task *scsi_task_new(int cdb_len, uint8_t *cdb, int dir,
171                                        int xfer_len)
172 {
173     struct scsi_task *task;
174 
175     assert(cdb_len > 0);
176     assert(cdb);
177 
178     task = g_new0(struct scsi_task, 1);
179     memcpy(task->cdb, cdb, cdb_len);
180     task->cdb_size = cdb_len;
181     task->xfer_dir = dir;
182     task->expxferlen = xfer_len;
183 
184     return task;
185 }
186 
187 static int get_cdb_len(uint8_t *cdb)
188 {
189     assert(cdb);
190 
191     switch (cdb[0] >> 5) {
192     case 0: return 6;
193     case 1: /* fall through */
194     case 2: return 10;
195     case 4: return 16;
196     case 5: return 12;
197     }
198     g_warning("Unable to determine cdb len (0x%02hhX)", cdb[0] >> 5);
199     return -1;
200 }
201 
202 static int handle_cmd_sync(struct iscsi_context *ctx,
203                            VirtIOSCSICmdReq *req,
204                            struct iovec *out, unsigned int out_len,
205                            VirtIOSCSICmdResp *rsp,
206                            struct iovec *in, unsigned int in_len)
207 {
208     struct scsi_task *task;
209     uint32_t dir;
210     uint32_t len;
211     int cdb_len;
212     int i;
213 
214     assert(ctx);
215     assert(req);
216     assert(rsp);
217 
218     if (!(!req->lun[1] && req->lun[2] == 0x40 && !req->lun[3])) {
219         /* Ignore anything different than target=0, lun=0 */
220         g_debug("Ignoring unconnected lun (0x%hhX, 0x%hhX)",
221              req->lun[1], req->lun[3]);
222         rsp->status = SCSI_STATUS_CHECK_CONDITION;
223         memset(rsp->sense, 0, sizeof(rsp->sense));
224         rsp->sense_len = 18;
225         rsp->sense[0] = 0x70;
226         rsp->sense[2] = SCSI_SENSE_ILLEGAL_REQUEST;
227         rsp->sense[7] = 10;
228         rsp->sense[12] = 0x24;
229 
230         return 0;
231     }
232 
233     cdb_len = get_cdb_len(req->cdb);
234     if (cdb_len == -1) {
235         return -1;
236     }
237 
238     len = 0;
239     if (!out_len && !in_len) {
240         dir = SCSI_XFER_NONE;
241     } else if (out_len) {
242         dir = SCSI_XFER_WRITE;
243         for (i = 0; i < out_len; i++) {
244             len += out[i].iov_len;
245         }
246     } else {
247         dir = SCSI_XFER_READ;
248         for (i = 0; i < in_len; i++) {
249             len += in[i].iov_len;
250         }
251     }
252 
253     task = scsi_task_new(cdb_len, req->cdb, dir, len);
254 
255     if (dir == SCSI_XFER_WRITE) {
256         task->iovector_out.iov = (struct scsi_iovec *)out;
257         task->iovector_out.niov = out_len;
258     } else if (dir == SCSI_XFER_READ) {
259         task->iovector_in.iov = (struct scsi_iovec *)in;
260         task->iovector_in.niov = in_len;
261     }
262 
263     g_debug("Sending iscsi cmd (cdb_len=%d, dir=%d, task=%p)",
264          cdb_len, dir, task);
265     if (!iscsi_scsi_command_sync(ctx, 0, task, NULL)) {
266         g_warning("Error serving SCSI command");
267         g_free(task);
268         return -1;
269     }
270 
271     memset(rsp, 0, sizeof(*rsp));
272 
273     rsp->status = task->status;
274     rsp->resid  = task->residual;
275 
276     if (task->status == SCSI_STATUS_CHECK_CONDITION) {
277         rsp->response = VIRTIO_SCSI_S_FAILURE;
278         rsp->sense_len = task->datain.size - 2;
279         memcpy(rsp->sense, &task->datain.data[2], rsp->sense_len);
280     }
281 
282     g_free(task);
283 
284     g_debug("Filled in rsp: status=%hhX, resid=%u, response=%hhX, sense_len=%u",
285          rsp->status, rsp->resid, rsp->response, rsp->sense_len);
286 
287     return 0;
288 }
289 
290 /** libvhost-user callbacks **/
291 
292 static void vus_panic_cb(VuDev *vu_dev, const char *buf)
293 {
294     VusDev *vdev_scsi;
295 
296     assert(vu_dev);
297 
298     vdev_scsi = container_of(vu_dev, VusDev, vu_dev);
299     if (buf) {
300         g_warning("vu_panic: %s", buf);
301     }
302 
303     g_main_loop_quit(vdev_scsi->loop);
304 }
305 
306 static void vus_add_watch_cb(VuDev *vu_dev, int fd, int vu_evt, vu_watch_cb cb,
307                              void *pvt)
308 {
309     GSource *src;
310     VusDev *vdev_scsi;
311 
312     assert(vu_dev);
313     assert(fd >= 0);
314     assert(cb);
315 
316     vdev_scsi = container_of(vu_dev, VusDev, vu_dev);
317     src = vus_gsrc_new(vdev_scsi, fd, vu_evt, cb, NULL, pvt);
318     g_hash_table_replace(vdev_scsi->fdmap, GINT_TO_POINTER(fd), src);
319 }
320 
321 static void vus_del_watch_cb(VuDev *vu_dev, int fd)
322 {
323     VusDev *vdev_scsi;
324 
325     assert(vu_dev);
326     assert(fd >= 0);
327 
328     vdev_scsi = container_of(vu_dev, VusDev, vu_dev);
329     g_hash_table_remove(vdev_scsi->fdmap, GINT_TO_POINTER(fd));
330 }
331 
332 static void vus_proc_req(VuDev *vu_dev, int idx)
333 {
334     VusDev *vdev_scsi;
335     VuVirtq *vq;
336 
337     assert(vu_dev);
338 
339     vdev_scsi = container_of(vu_dev, VusDev, vu_dev);
340     if (idx < 0 || idx >= VHOST_MAX_NR_VIRTQUEUE) {
341         g_warning("VQ Index out of range: %d", idx);
342         vus_panic_cb(vu_dev, NULL);
343         return;
344     }
345 
346     vq = vu_get_queue(vu_dev, idx);
347     if (!vq) {
348         g_warning("Error fetching VQ (dev=%p, idx=%d)", vu_dev, idx);
349         vus_panic_cb(vu_dev, NULL);
350         return;
351     }
352 
353     g_debug("Got kicked on vq[%d]@%p", idx, vq);
354 
355     while (1) {
356         VuVirtqElement *elem;
357         VirtIOSCSICmdReq *req;
358         VirtIOSCSICmdResp *rsp;
359 
360         elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement));
361         if (!elem) {
362             g_debug("No more elements pending on vq[%d]@%p", idx, vq);
363             break;
364         }
365         g_debug("Popped elem@%p", elem);
366 
367         assert(!(elem->out_num > 1 && elem->in_num > 1));
368         assert(elem->out_num > 0 && elem->in_num > 0);
369 
370         if (elem->out_sg[0].iov_len < sizeof(VirtIOSCSICmdReq)) {
371             g_warning("Invalid virtio-scsi req header");
372             vus_panic_cb(vu_dev, NULL);
373             break;
374         }
375         req = (VirtIOSCSICmdReq *)elem->out_sg[0].iov_base;
376 
377         if (elem->in_sg[0].iov_len < sizeof(VirtIOSCSICmdResp)) {
378             g_warning("Invalid virtio-scsi rsp header");
379             vus_panic_cb(vu_dev, NULL);
380             break;
381         }
382         rsp = (VirtIOSCSICmdResp *)elem->in_sg[0].iov_base;
383 
384         if (handle_cmd_sync(vdev_scsi->lun.iscsi_ctx,
385                             req, &elem->out_sg[1], elem->out_num - 1,
386                             rsp, &elem->in_sg[1], elem->in_num - 1) != 0) {
387             vus_panic_cb(vu_dev, NULL);
388             break;
389         }
390 
391         vu_queue_push(vu_dev, vq, elem, 0);
392         vu_queue_notify(vu_dev, vq);
393 
394         free(elem);
395     }
396 }
397 
398 static void vus_queue_set_started(VuDev *vu_dev, int idx, bool started)
399 {
400     VuVirtq *vq;
401 
402     assert(vu_dev);
403 
404     if (idx < 0 || idx >= VHOST_MAX_NR_VIRTQUEUE) {
405         g_warning("VQ Index out of range: %d", idx);
406         vus_panic_cb(vu_dev, NULL);
407         return;
408     }
409 
410     vq = vu_get_queue(vu_dev, idx);
411 
412     if (idx == 0 || idx == 1) {
413         g_debug("queue %d unimplemented", idx);
414     } else {
415         vu_set_queue_handler(vu_dev, vq, started ? vus_proc_req : NULL);
416     }
417 }
418 
419 static const VuDevIface vus_iface = {
420     .queue_set_started = vus_queue_set_started,
421 };
422 
423 static gboolean vus_vhost_cb(gpointer data)
424 {
425     VuDev *vu_dev = (VuDev *)data;
426 
427     assert(vu_dev);
428 
429     if (!vu_dispatch(vu_dev) != 0) {
430         g_warning("Error processing vhost message");
431         vus_panic_cb(vu_dev, NULL);
432         return G_SOURCE_REMOVE;
433     }
434 
435     return G_SOURCE_CONTINUE;
436 }
437 
438 /** misc helpers **/
439 
440 static int unix_sock_new(char *unix_fn)
441 {
442     int sock;
443     struct sockaddr_un un;
444     size_t len;
445 
446     assert(unix_fn);
447 
448     sock = socket(AF_UNIX, SOCK_STREAM, 0);
449     if (sock <= 0) {
450         perror("socket");
451         return -1;
452     }
453 
454     un.sun_family = AF_UNIX;
455     (void)snprintf(un.sun_path, sizeof(un.sun_path), "%s", unix_fn);
456     len = sizeof(un.sun_family) + strlen(un.sun_path);
457 
458     (void)unlink(unix_fn);
459     if (bind(sock, (struct sockaddr *)&un, len) < 0) {
460         perror("bind");
461         goto fail;
462     }
463 
464     if (listen(sock, 1) < 0) {
465         perror("listen");
466         goto fail;
467     }
468 
469     return sock;
470 
471 fail:
472     (void)close(sock);
473 
474     return -1;
475 }
476 
477 /** vhost-user-scsi **/
478 
479 static void vdev_scsi_free(VusDev *vdev_scsi)
480 {
481     if (vdev_scsi->server_sock >= 0) {
482         close(vdev_scsi->server_sock);
483     }
484     g_main_loop_unref(vdev_scsi->loop);
485     g_hash_table_unref(vdev_scsi->fdmap);
486     g_free(vdev_scsi);
487 }
488 
489 static VusDev *vdev_scsi_new(int server_sock)
490 {
491     VusDev *vdev_scsi;
492 
493     vdev_scsi = g_new0(VusDev, 1);
494     vdev_scsi->server_sock = server_sock;
495     vdev_scsi->loop = g_main_loop_new(NULL, FALSE);
496     vdev_scsi->fdmap =
497         g_hash_table_new_full(NULL, NULL, NULL,
498                               (GDestroyNotify) g_source_destroy);
499 
500     return vdev_scsi;
501 }
502 
503 static int vdev_scsi_run(VusDev *vdev_scsi)
504 {
505     int cli_sock;
506     int ret = 0;
507 
508     assert(vdev_scsi);
509     assert(vdev_scsi->server_sock >= 0);
510     assert(vdev_scsi->loop);
511 
512     cli_sock = accept(vdev_scsi->server_sock, NULL, NULL);
513     if (cli_sock < 0) {
514         perror("accept");
515         return -1;
516     }
517 
518     vu_init(&vdev_scsi->vu_dev,
519             cli_sock,
520             vus_panic_cb,
521             vus_add_watch_cb,
522             vus_del_watch_cb,
523             &vus_iface);
524 
525     vus_gsrc_new(vdev_scsi, cli_sock, G_IO_IN, NULL, vus_vhost_cb,
526                  &vdev_scsi->vu_dev);
527 
528     g_main_loop_run(vdev_scsi->loop);
529 
530     vu_deinit(&vdev_scsi->vu_dev);
531 
532     return ret;
533 }
534 
535 int main(int argc, char **argv)
536 {
537     VusDev *vdev_scsi = NULL;
538     char *unix_fn = NULL;
539     char *iscsi_uri = NULL;
540     int sock, opt, err = EXIT_SUCCESS;
541 
542     while ((opt = getopt(argc, argv, "u:i:")) != -1) {
543         switch (opt) {
544         case 'h':
545             goto help;
546         case 'u':
547             unix_fn = g_strdup(optarg);
548             break;
549         case 'i':
550             iscsi_uri = g_strdup(optarg);
551             break;
552         default:
553             goto help;
554         }
555     }
556     if (!unix_fn || !iscsi_uri) {
557         goto help;
558     }
559 
560     sock = unix_sock_new(unix_fn);
561     if (sock < 0) {
562         goto err;
563     }
564     vdev_scsi = vdev_scsi_new(sock);
565 
566     if (vus_iscsi_add_lun(&vdev_scsi->lun, iscsi_uri) != 0) {
567         goto err;
568     }
569 
570     if (vdev_scsi_run(vdev_scsi) != 0) {
571         goto err;
572     }
573 
574 out:
575     if (vdev_scsi) {
576         vdev_scsi_free(vdev_scsi);
577         unlink(unix_fn);
578     }
579     g_free(unix_fn);
580     g_free(iscsi_uri);
581 
582     return err;
583 
584 err:
585     err = EXIT_FAILURE;
586     goto out;
587 
588 help:
589     fprintf(stderr, "Usage: %s [ -u unix_sock_path -i iscsi_uri ] | [ -h ]\n",
590             argv[0]);
591     fprintf(stderr, "          -u path to unix socket\n");
592     fprintf(stderr, "          -i iscsi uri for lun 0\n");
593     fprintf(stderr, "          -h print help and quit\n");
594 
595     goto err;
596 }
597