xref: /openbmc/qemu/hw/block/xen-block.c (revision 135b03cb)
1 /*
2  * Copyright (c) 2018  Citrix Systems Inc.
3  *
4  * This work is licensed under the terms of the GNU GPL, version 2 or later.
5  * See the COPYING file in the top-level directory.
6  */
7 
8 #include "qemu/osdep.h"
9 #include "qemu/cutils.h"
10 #include "qemu/main-loop.h"
11 #include "qemu/module.h"
12 #include "qemu/option.h"
13 #include "qapi/error.h"
14 #include "qapi/qapi-commands-block-core.h"
15 #include "qapi/qapi-commands-qom.h"
16 #include "qapi/qapi-visit-block-core.h"
17 #include "qapi/qobject-input-visitor.h"
18 #include "qapi/visitor.h"
19 #include "qapi/qmp/qdict.h"
20 #include "qapi/qmp/qstring.h"
21 #include "hw/xen/xen_common.h"
22 #include "hw/block/xen_blkif.h"
23 #include "hw/qdev-properties.h"
24 #include "hw/xen/xen-block.h"
25 #include "hw/xen/xen-backend.h"
26 #include "sysemu/blockdev.h"
27 #include "sysemu/block-backend.h"
28 #include "sysemu/iothread.h"
29 #include "dataplane/xen-block.h"
30 #include "trace.h"
31 
32 static char *xen_block_get_name(XenDevice *xendev, Error **errp)
33 {
34     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
35     XenBlockVdev *vdev = &blockdev->props.vdev;
36 
37     return g_strdup_printf("%lu", vdev->number);
38 }
39 
40 static void xen_block_disconnect(XenDevice *xendev, Error **errp)
41 {
42     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
43     const char *type = object_get_typename(OBJECT(blockdev));
44     XenBlockVdev *vdev = &blockdev->props.vdev;
45 
46     trace_xen_block_disconnect(type, vdev->disk, vdev->partition);
47 
48     xen_block_dataplane_stop(blockdev->dataplane);
49 }
50 
51 static void xen_block_connect(XenDevice *xendev, Error **errp)
52 {
53     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
54     const char *type = object_get_typename(OBJECT(blockdev));
55     XenBlockVdev *vdev = &blockdev->props.vdev;
56     BlockConf *conf = &blockdev->props.conf;
57     unsigned int feature_large_sector_size;
58     unsigned int order, nr_ring_ref, *ring_ref, event_channel, protocol;
59     char *str;
60 
61     trace_xen_block_connect(type, vdev->disk, vdev->partition);
62 
63     if (xen_device_frontend_scanf(xendev, "feature-large-sector-size", "%u",
64                                   &feature_large_sector_size) != 1) {
65         feature_large_sector_size = 0;
66     }
67 
68     if (feature_large_sector_size != 1 &&
69         conf->logical_block_size != XEN_BLKIF_SECTOR_SIZE) {
70         error_setg(errp, "logical_block_size != %u not supported by frontend",
71                    XEN_BLKIF_SECTOR_SIZE);
72         return;
73     }
74 
75     if (xen_device_frontend_scanf(xendev, "ring-page-order", "%u",
76                                   &order) != 1) {
77         nr_ring_ref = 1;
78         ring_ref = g_new(unsigned int, nr_ring_ref);
79 
80         if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
81                                       &ring_ref[0]) != 1) {
82             error_setg(errp, "failed to read ring-ref");
83             g_free(ring_ref);
84             return;
85         }
86     } else if (order <= blockdev->props.max_ring_page_order) {
87         unsigned int i;
88 
89         nr_ring_ref = 1 << order;
90         ring_ref = g_new(unsigned int, nr_ring_ref);
91 
92         for (i = 0; i < nr_ring_ref; i++) {
93             const char *key = g_strdup_printf("ring-ref%u", i);
94 
95             if (xen_device_frontend_scanf(xendev, key, "%u",
96                                           &ring_ref[i]) != 1) {
97                 error_setg(errp, "failed to read %s", key);
98                 g_free((gpointer)key);
99                 g_free(ring_ref);
100                 return;
101             }
102 
103             g_free((gpointer)key);
104         }
105     } else {
106         error_setg(errp, "invalid ring-page-order (%d)", order);
107         return;
108     }
109 
110     if (xen_device_frontend_scanf(xendev, "event-channel", "%u",
111                                   &event_channel) != 1) {
112         error_setg(errp, "failed to read event-channel");
113         g_free(ring_ref);
114         return;
115     }
116 
117     if (xen_device_frontend_scanf(xendev, "protocol", "%ms",
118                                   &str) != 1) {
119         protocol = BLKIF_PROTOCOL_NATIVE;
120     } else {
121         if (strcmp(str, XEN_IO_PROTO_ABI_X86_32) == 0) {
122             protocol = BLKIF_PROTOCOL_X86_32;
123         } else if (strcmp(str, XEN_IO_PROTO_ABI_X86_64) == 0) {
124             protocol = BLKIF_PROTOCOL_X86_64;
125         } else {
126             protocol = BLKIF_PROTOCOL_NATIVE;
127         }
128 
129         free(str);
130     }
131 
132     xen_block_dataplane_start(blockdev->dataplane, ring_ref, nr_ring_ref,
133                               event_channel, protocol, errp);
134 
135     g_free(ring_ref);
136 }
137 
138 static void xen_block_unrealize(XenDevice *xendev, Error **errp)
139 {
140     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
141     XenBlockDeviceClass *blockdev_class =
142         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
143     const char *type = object_get_typename(OBJECT(blockdev));
144     XenBlockVdev *vdev = &blockdev->props.vdev;
145 
146     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
147         return;
148     }
149 
150     trace_xen_block_unrealize(type, vdev->disk, vdev->partition);
151 
152     /* Disconnect from the frontend in case this has not already happened */
153     xen_block_disconnect(xendev, NULL);
154 
155     xen_block_dataplane_destroy(blockdev->dataplane);
156     blockdev->dataplane = NULL;
157 
158     if (blockdev_class->unrealize) {
159         blockdev_class->unrealize(blockdev, errp);
160     }
161 }
162 
163 static void xen_block_set_size(XenBlockDevice *blockdev)
164 {
165     const char *type = object_get_typename(OBJECT(blockdev));
166     XenBlockVdev *vdev = &blockdev->props.vdev;
167     BlockConf *conf = &blockdev->props.conf;
168     int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size;
169     XenDevice *xendev = XEN_DEVICE(blockdev);
170 
171     trace_xen_block_size(type, vdev->disk, vdev->partition, sectors);
172 
173     xen_device_backend_printf(xendev, "sectors", "%"PRIi64, sectors);
174 }
175 
176 static void xen_block_resize_cb(void *opaque)
177 {
178     XenBlockDevice *blockdev = opaque;
179     XenDevice *xendev = XEN_DEVICE(blockdev);
180     enum xenbus_state state = xen_device_backend_get_state(xendev);
181 
182     xen_block_set_size(blockdev);
183 
184     /*
185      * Mimic the behaviour of Linux xen-blkback and re-write the state
186      * to trigger the frontend watch.
187      */
188     xen_device_backend_printf(xendev, "state", "%u", state);
189 }
190 
191 static const BlockDevOps xen_block_dev_ops = {
192     .resize_cb = xen_block_resize_cb,
193 };
194 
195 static void xen_block_realize(XenDevice *xendev, Error **errp)
196 {
197     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
198     XenBlockDeviceClass *blockdev_class =
199         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
200     const char *type = object_get_typename(OBJECT(blockdev));
201     XenBlockVdev *vdev = &blockdev->props.vdev;
202     BlockConf *conf = &blockdev->props.conf;
203     BlockBackend *blk = conf->blk;
204     Error *local_err = NULL;
205 
206     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
207         error_setg(errp, "vdev property not set");
208         return;
209     }
210 
211     trace_xen_block_realize(type, vdev->disk, vdev->partition);
212 
213     if (blockdev_class->realize) {
214         blockdev_class->realize(blockdev, &local_err);
215         if (local_err) {
216             error_propagate(errp, local_err);
217             return;
218         }
219     }
220 
221     /*
222      * The blkif protocol does not deal with removable media, so it must
223      * always be present, even for CDRom devices.
224      */
225     assert(blk);
226     if (!blk_is_inserted(blk)) {
227         error_setg(errp, "device needs media, but drive is empty");
228         return;
229     }
230 
231     if (!blkconf_apply_backend_options(conf, blockdev->info & VDISK_READONLY,
232                                        true, errp)) {
233         return;
234     }
235 
236     if (!(blockdev->info & VDISK_CDROM) &&
237         !blkconf_geometry(conf, NULL, 65535, 255, 255, errp)) {
238         return;
239     }
240 
241     blkconf_blocksizes(conf);
242 
243     if (conf->logical_block_size > conf->physical_block_size) {
244         error_setg(
245             errp, "logical_block_size > physical_block_size not supported");
246         return;
247     }
248 
249     blk_set_dev_ops(blk, &xen_block_dev_ops, blockdev);
250     blk_set_guest_block_size(blk, conf->logical_block_size);
251 
252     if (conf->discard_granularity == -1) {
253         conf->discard_granularity = conf->physical_block_size;
254     }
255 
256     if (blk_get_flags(blk) & BDRV_O_UNMAP) {
257         xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
258         xen_device_backend_printf(xendev, "discard-granularity", "%u",
259                                   conf->discard_granularity);
260     }
261 
262     xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
263     xen_device_backend_printf(xendev, "max-ring-page-order", "%u",
264                               blockdev->props.max_ring_page_order);
265     xen_device_backend_printf(xendev, "info", "%u", blockdev->info);
266 
267     xen_device_frontend_printf(xendev, "virtual-device", "%lu",
268                                vdev->number);
269     xen_device_frontend_printf(xendev, "device-type", "%s",
270                                blockdev->device_type);
271 
272     xen_device_backend_printf(xendev, "sector-size", "%u",
273                               conf->logical_block_size);
274 
275     xen_block_set_size(blockdev);
276 
277     blockdev->dataplane =
278         xen_block_dataplane_create(xendev, blk, conf->logical_block_size,
279                                    blockdev->props.iothread);
280 }
281 
282 static void xen_block_frontend_changed(XenDevice *xendev,
283                                        enum xenbus_state frontend_state,
284                                        Error **errp)
285 {
286     enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
287     Error *local_err = NULL;
288 
289     switch (frontend_state) {
290     case XenbusStateInitialised:
291     case XenbusStateConnected:
292         if (backend_state == XenbusStateConnected) {
293             break;
294         }
295 
296         xen_block_disconnect(xendev, &local_err);
297         if (local_err) {
298             error_propagate(errp, local_err);
299             break;
300         }
301 
302         xen_block_connect(xendev, &local_err);
303         if (local_err) {
304             error_propagate(errp, local_err);
305             break;
306         }
307 
308         xen_device_backend_set_state(xendev, XenbusStateConnected);
309         break;
310 
311     case XenbusStateClosing:
312         xen_device_backend_set_state(xendev, XenbusStateClosing);
313         break;
314 
315     case XenbusStateClosed:
316         xen_block_disconnect(xendev, &local_err);
317         if (local_err) {
318             error_propagate(errp, local_err);
319             break;
320         }
321 
322         xen_device_backend_set_state(xendev, XenbusStateClosed);
323         break;
324 
325     default:
326         break;
327     }
328 }
329 
330 static char *disk_to_vbd_name(unsigned int disk)
331 {
332     char *name, *prefix = (disk >= 26) ?
333         disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
334 
335     name = g_strdup_printf("%s%c", prefix, 'a' + disk % 26);
336     g_free(prefix);
337 
338     return name;
339 }
340 
341 static void xen_block_get_vdev(Object *obj, Visitor *v, const char *name,
342                                void *opaque, Error **errp)
343 {
344     DeviceState *dev = DEVICE(obj);
345     Property *prop = opaque;
346     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
347     char *str;
348 
349     switch (vdev->type) {
350     case XEN_BLOCK_VDEV_TYPE_DP:
351         str = g_strdup_printf("d%lup%lu", vdev->disk, vdev->partition);
352         break;
353 
354     case XEN_BLOCK_VDEV_TYPE_XVD:
355     case XEN_BLOCK_VDEV_TYPE_HD:
356     case XEN_BLOCK_VDEV_TYPE_SD: {
357         char *name = disk_to_vbd_name(vdev->disk);
358 
359         str = g_strdup_printf("%s%s%lu",
360                               (vdev->type == XEN_BLOCK_VDEV_TYPE_XVD) ?
361                               "xvd" :
362                               (vdev->type == XEN_BLOCK_VDEV_TYPE_HD) ?
363                               "hd" :
364                               "sd",
365                               name, vdev->partition);
366         g_free(name);
367         break;
368     }
369     default:
370         error_setg(errp, "invalid vdev type");
371         return;
372     }
373 
374     visit_type_str(v, name, &str, errp);
375     g_free(str);
376 }
377 
378 static int vbd_name_to_disk(const char *name, const char **endp,
379                             unsigned long *disk)
380 {
381     unsigned int n = 0;
382 
383     while (*name != '\0') {
384         if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
385             break;
386         }
387 
388         n *= 26;
389         n += *name++ - 'a' + 1;
390     }
391     *endp = name;
392 
393     if (!n) {
394         return -1;
395     }
396 
397     *disk = n - 1;
398 
399     return 0;
400 }
401 
402 static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
403                                void *opaque, Error **errp)
404 {
405     DeviceState *dev = DEVICE(obj);
406     Property *prop = opaque;
407     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
408     Error *local_err = NULL;
409     char *str, *p;
410     const char *end;
411 
412     if (dev->realized) {
413         qdev_prop_set_after_realize(dev, name, errp);
414         return;
415     }
416 
417     visit_type_str(v, name, &str, &local_err);
418     if (local_err) {
419         error_propagate(errp, local_err);
420         return;
421     }
422 
423     p = strchr(str, 'd');
424     if (!p) {
425         goto invalid;
426     }
427 
428     *p++ = '\0';
429     if (*str == '\0') {
430         vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
431     } else if (strcmp(str, "xv") == 0) {
432         vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
433     } else if (strcmp(str, "h") == 0) {
434         vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
435     } else if (strcmp(str, "s") == 0) {
436         vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
437     } else {
438         goto invalid;
439     }
440 
441     if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
442         if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
443             goto invalid;
444         }
445 
446         if (*end == 'p') {
447             if (*(++end) == '\0') {
448                 goto invalid;
449             }
450         }
451     } else {
452         if (vbd_name_to_disk(p, &end, &vdev->disk)) {
453             goto invalid;
454         }
455     }
456 
457     if (*end != '\0') {
458         p = (char *)end;
459 
460         if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
461             goto invalid;
462         }
463 
464         if (*end != '\0') {
465             goto invalid;
466         }
467     } else {
468         vdev->partition = 0;
469     }
470 
471     switch (vdev->type) {
472     case XEN_BLOCK_VDEV_TYPE_DP:
473     case XEN_BLOCK_VDEV_TYPE_XVD:
474         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
475             vdev->number = (202 << 8) | (vdev->disk << 4) |
476                 vdev->partition;
477         } else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
478             vdev->number = (1 << 28) | (vdev->disk << 8) |
479                 vdev->partition;
480         } else {
481             goto invalid;
482         }
483         break;
484 
485     case XEN_BLOCK_VDEV_TYPE_HD:
486         if ((vdev->disk == 0 || vdev->disk == 1) &&
487             vdev->partition < (1 << 6)) {
488             vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
489         } else if ((vdev->disk == 2 || vdev->disk == 3) &&
490                    vdev->partition < (1 << 6)) {
491             vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
492                 vdev->partition;
493         } else {
494             goto invalid;
495         }
496         break;
497 
498     case XEN_BLOCK_VDEV_TYPE_SD:
499         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
500             vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
501         } else {
502             goto invalid;
503         }
504         break;
505 
506     default:
507         goto invalid;
508     }
509 
510     g_free(str);
511     return;
512 
513 invalid:
514     error_setg(errp, "invalid virtual disk specifier");
515 
516     vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
517     g_free(str);
518 }
519 
520 /*
521  * This property deals with 'vdev' names adhering to the Xen VBD naming
522  * scheme described in:
523  *
524  * https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
525  */
526 const PropertyInfo xen_block_prop_vdev = {
527     .name  = "str",
528     .description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
529     .get = xen_block_get_vdev,
530     .set = xen_block_set_vdev,
531 };
532 
533 static Property xen_block_props[] = {
534     DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
535                 xen_block_prop_vdev, XenBlockVdev),
536     DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
537     DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
538                        props.max_ring_page_order, 4),
539     DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
540                      TYPE_IOTHREAD, IOThread *),
541     DEFINE_PROP_END_OF_LIST()
542 };
543 
544 static void xen_block_class_init(ObjectClass *class, void *data)
545 {
546     DeviceClass *dev_class = DEVICE_CLASS(class);
547     XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
548 
549     xendev_class->backend = "qdisk";
550     xendev_class->device = "vbd";
551     xendev_class->get_name = xen_block_get_name;
552     xendev_class->realize = xen_block_realize;
553     xendev_class->frontend_changed = xen_block_frontend_changed;
554     xendev_class->unrealize = xen_block_unrealize;
555 
556     dev_class->props = xen_block_props;
557 }
558 
559 static const TypeInfo xen_block_type_info = {
560     .name = TYPE_XEN_BLOCK_DEVICE,
561     .parent = TYPE_XEN_DEVICE,
562     .instance_size = sizeof(XenBlockDevice),
563     .abstract = true,
564     .class_size = sizeof(XenBlockDeviceClass),
565     .class_init = xen_block_class_init,
566 };
567 
568 static void xen_disk_unrealize(XenBlockDevice *blockdev, Error **errp)
569 {
570     trace_xen_disk_unrealize();
571 }
572 
573 static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
574 {
575     BlockConf *conf = &blockdev->props.conf;
576 
577     trace_xen_disk_realize();
578 
579     blockdev->device_type = "disk";
580 
581     if (!conf->blk) {
582         error_setg(errp, "drive property not set");
583         return;
584     }
585 
586     blockdev->info = blk_is_read_only(conf->blk) ? VDISK_READONLY : 0;
587 }
588 
589 static void xen_disk_class_init(ObjectClass *class, void *data)
590 {
591     DeviceClass *dev_class = DEVICE_CLASS(class);
592     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
593 
594     blockdev_class->realize = xen_disk_realize;
595     blockdev_class->unrealize = xen_disk_unrealize;
596 
597     dev_class->desc = "Xen Disk Device";
598 }
599 
600 static const TypeInfo xen_disk_type_info = {
601     .name = TYPE_XEN_DISK_DEVICE,
602     .parent = TYPE_XEN_BLOCK_DEVICE,
603     .instance_size = sizeof(XenDiskDevice),
604     .class_init = xen_disk_class_init,
605 };
606 
607 static void xen_cdrom_unrealize(XenBlockDevice *blockdev, Error **errp)
608 {
609     trace_xen_cdrom_unrealize();
610 }
611 
612 static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
613 {
614     BlockConf *conf = &blockdev->props.conf;
615 
616     trace_xen_cdrom_realize();
617 
618     blockdev->device_type = "cdrom";
619 
620     if (!conf->blk) {
621         int rc;
622 
623         /* Set up an empty drive */
624         conf->blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
625 
626         rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
627         if (!rc) {
628             error_setg_errno(errp, -rc, "failed to create drive");
629             return;
630         }
631     }
632 
633     blockdev->info = VDISK_READONLY | VDISK_CDROM;
634 }
635 
636 static void xen_cdrom_class_init(ObjectClass *class, void *data)
637 {
638     DeviceClass *dev_class = DEVICE_CLASS(class);
639     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
640 
641     blockdev_class->realize = xen_cdrom_realize;
642     blockdev_class->unrealize = xen_cdrom_unrealize;
643 
644     dev_class->desc = "Xen CD-ROM Device";
645 }
646 
647 static const TypeInfo xen_cdrom_type_info = {
648     .name = TYPE_XEN_CDROM_DEVICE,
649     .parent = TYPE_XEN_BLOCK_DEVICE,
650     .instance_size = sizeof(XenCDRomDevice),
651     .class_init = xen_cdrom_class_init,
652 };
653 
654 static void xen_block_register_types(void)
655 {
656     type_register_static(&xen_block_type_info);
657     type_register_static(&xen_disk_type_info);
658     type_register_static(&xen_cdrom_type_info);
659 }
660 
661 type_init(xen_block_register_types)
662 
663 static void xen_block_blockdev_del(const char *node_name, Error **errp)
664 {
665     trace_xen_block_blockdev_del(node_name);
666 
667     qmp_blockdev_del(node_name, errp);
668 }
669 
670 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
671                                     Error **errp)
672 {
673     const char *driver = qdict_get_try_str(qdict, "driver");
674     BlockdevOptions *options = NULL;
675     Error *local_err = NULL;
676     char *node_name;
677     Visitor *v;
678 
679     if (!driver) {
680         error_setg(errp, "no 'driver' parameter");
681         return NULL;
682     }
683 
684     node_name = g_strdup_printf("%s-%s", id, driver);
685     qdict_put_str(qdict, "node-name", node_name);
686 
687     trace_xen_block_blockdev_add(node_name);
688 
689     v = qobject_input_visitor_new(QOBJECT(qdict));
690     visit_type_BlockdevOptions(v, NULL, &options, &local_err);
691     visit_free(v);
692 
693     if (local_err) {
694         error_propagate(errp, local_err);
695         goto fail;
696     }
697 
698     qmp_blockdev_add(options, &local_err);
699 
700     if (local_err) {
701         error_propagate(errp, local_err);
702         goto fail;
703     }
704 
705     qapi_free_BlockdevOptions(options);
706 
707     return node_name;
708 
709 fail:
710     if (options) {
711         qapi_free_BlockdevOptions(options);
712     }
713     g_free(node_name);
714 
715     return NULL;
716 }
717 
718 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
719 {
720     char *node_name = drive->node_name;
721 
722     if (node_name) {
723         Error *local_err = NULL;
724 
725         xen_block_blockdev_del(node_name, &local_err);
726         if (local_err) {
727             error_propagate(errp, local_err);
728             return;
729         }
730         g_free(node_name);
731         drive->node_name = NULL;
732     }
733     g_free(drive->id);
734     g_free(drive);
735 }
736 
737 static XenBlockDrive *xen_block_drive_create(const char *id,
738                                              const char *device_type,
739                                              QDict *opts, Error **errp)
740 {
741     const char *params = qdict_get_try_str(opts, "params");
742     const char *mode = qdict_get_try_str(opts, "mode");
743     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
744     const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
745     char *driver = NULL;
746     char *filename = NULL;
747     XenBlockDrive *drive = NULL;
748     Error *local_err = NULL;
749     QDict *file_layer;
750     QDict *driver_layer;
751 
752     if (params) {
753         char **v = g_strsplit(params, ":", 2);
754 
755         if (v[1] == NULL) {
756             filename = g_strdup(v[0]);
757             driver = g_strdup("raw");
758         } else {
759             if (strcmp(v[0], "aio") == 0) {
760                 driver = g_strdup("raw");
761             } else if (strcmp(v[0], "vhd") == 0) {
762                 driver = g_strdup("vpc");
763             } else {
764                 driver = g_strdup(v[0]);
765             }
766             filename = g_strdup(v[1]);
767         }
768 
769         g_strfreev(v);
770     } else {
771         error_setg(errp, "no params");
772         goto done;
773     }
774 
775     assert(filename);
776     assert(driver);
777 
778     drive = g_new0(XenBlockDrive, 1);
779     drive->id = g_strdup(id);
780 
781     file_layer = qdict_new();
782     driver_layer = qdict_new();
783 
784     qdict_put_str(file_layer, "driver", "file");
785     qdict_put_str(file_layer, "filename", filename);
786     g_free(filename);
787 
788     if (mode && *mode != 'w') {
789         qdict_put_bool(file_layer, "read-only", true);
790     }
791 
792     if (direct_io_safe) {
793         unsigned long value;
794 
795         if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
796             QDict *cache_qdict = qdict_new();
797 
798             qdict_put_bool(cache_qdict, "direct", true);
799             qdict_put(file_layer, "cache", cache_qdict);
800 
801             qdict_put_str(file_layer, "aio", "native");
802         }
803     }
804 
805     if (discard_enable) {
806         unsigned long value;
807 
808         if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
809             qdict_put_str(file_layer, "discard", "unmap");
810             qdict_put_str(driver_layer, "discard", "unmap");
811         }
812     }
813 
814     /*
815      * It is necessary to turn file locking off as an emulated device
816      * may have already opened the same image file.
817      */
818     qdict_put_str(file_layer, "locking", "off");
819 
820     qdict_put_str(driver_layer, "driver", driver);
821     g_free(driver);
822 
823     qdict_put(driver_layer, "file", file_layer);
824 
825     g_assert(!drive->node_name);
826     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
827                                               &local_err);
828 
829     qobject_unref(driver_layer);
830 
831 done:
832     if (local_err) {
833         error_propagate(errp, local_err);
834         xen_block_drive_destroy(drive, NULL);
835         return NULL;
836     }
837 
838     return drive;
839 }
840 
841 static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
842 {
843     return drive->node_name ? drive->node_name : "";
844 }
845 
846 static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
847                                        Error **errp)
848 {
849     qmp_object_del(iothread->id, errp);
850 
851     g_free(iothread->id);
852     g_free(iothread);
853 }
854 
855 static XenBlockIOThread *xen_block_iothread_create(const char *id,
856                                                    Error **errp)
857 {
858     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
859     Error *local_err = NULL;
860 
861     iothread->id = g_strdup(id);
862 
863     qmp_object_add(TYPE_IOTHREAD, id, false, NULL, &local_err);
864     if (local_err) {
865         error_propagate(errp, local_err);
866 
867         g_free(iothread->id);
868         g_free(iothread);
869         return NULL;
870     }
871 
872     return iothread;
873 }
874 
875 static void xen_block_device_create(XenBackendInstance *backend,
876                                     QDict *opts, Error **errp)
877 {
878     XenBus *xenbus = xen_backend_get_bus(backend);
879     const char *name = xen_backend_get_name(backend);
880     unsigned long number;
881     const char *vdev, *device_type;
882     XenBlockDrive *drive = NULL;
883     XenBlockIOThread *iothread = NULL;
884     XenDevice *xendev = NULL;
885     Error *local_err = NULL;
886     const char *type;
887     XenBlockDevice *blockdev;
888 
889     if (qemu_strtoul(name, NULL, 10, &number)) {
890         error_setg(errp, "failed to parse name '%s'", name);
891         goto fail;
892     }
893 
894     trace_xen_block_device_create(number);
895 
896     vdev = qdict_get_try_str(opts, "dev");
897     if (!vdev) {
898         error_setg(errp, "no dev parameter");
899         goto fail;
900     }
901 
902     device_type = qdict_get_try_str(opts, "device-type");
903     if (!device_type) {
904         error_setg(errp, "no device-type parameter");
905         goto fail;
906     }
907 
908     if (!strcmp(device_type, "disk")) {
909         type = TYPE_XEN_DISK_DEVICE;
910     } else if (!strcmp(device_type, "cdrom")) {
911         type = TYPE_XEN_CDROM_DEVICE;
912     } else {
913         error_setg(errp, "invalid device-type parameter '%s'", device_type);
914         goto fail;
915     }
916 
917     drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
918     if (!drive) {
919         error_propagate_prepend(errp, local_err, "failed to create drive: ");
920         goto fail;
921     }
922 
923     iothread = xen_block_iothread_create(vdev, &local_err);
924     if (local_err) {
925         error_propagate_prepend(errp, local_err,
926                                 "failed to create iothread: ");
927         goto fail;
928     }
929 
930     xendev = XEN_DEVICE(qdev_create(BUS(xenbus), type));
931     blockdev = XEN_BLOCK_DEVICE(xendev);
932 
933     object_property_set_str(OBJECT(xendev), vdev, "vdev", &local_err);
934     if (local_err) {
935         error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
936         goto fail;
937     }
938 
939     object_property_set_str(OBJECT(xendev),
940                             xen_block_drive_get_node_name(drive), "drive",
941                             &local_err);
942     if (local_err) {
943         error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
944         goto fail;
945     }
946 
947     object_property_set_str(OBJECT(xendev), iothread->id, "iothread",
948                             &local_err);
949     if (local_err) {
950         error_propagate_prepend(errp, local_err,
951                                 "failed to set 'iothread': ");
952         goto fail;
953     }
954 
955     blockdev->iothread = iothread;
956     blockdev->drive = drive;
957 
958     object_property_set_bool(OBJECT(xendev), true, "realized", &local_err);
959     if (local_err) {
960         error_propagate_prepend(errp, local_err,
961                                 "realization of device %s failed: ",
962                                 type);
963         goto fail;
964     }
965 
966     xen_backend_set_device(backend, xendev);
967     return;
968 
969 fail:
970     if (xendev) {
971         object_unparent(OBJECT(xendev));
972     }
973 
974     if (iothread) {
975         xen_block_iothread_destroy(iothread, NULL);
976     }
977 
978     if (drive) {
979         xen_block_drive_destroy(drive, NULL);
980     }
981 }
982 
983 static void xen_block_device_destroy(XenBackendInstance *backend,
984                                      Error **errp)
985 {
986     XenDevice *xendev = xen_backend_get_device(backend);
987     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
988     XenBlockVdev *vdev = &blockdev->props.vdev;
989     XenBlockDrive *drive = blockdev->drive;
990     XenBlockIOThread *iothread = blockdev->iothread;
991 
992     trace_xen_block_device_destroy(vdev->number);
993 
994     object_unparent(OBJECT(xendev));
995 
996     if (iothread) {
997         Error *local_err = NULL;
998 
999         xen_block_iothread_destroy(iothread, &local_err);
1000         if (local_err) {
1001             error_propagate_prepend(errp, local_err,
1002                                 "failed to destroy iothread: ");
1003             return;
1004         }
1005     }
1006 
1007     if (drive) {
1008         Error *local_err = NULL;
1009 
1010         xen_block_drive_destroy(drive, &local_err);
1011         if (local_err) {
1012             error_propagate_prepend(errp, local_err,
1013                                 "failed to destroy drive: ");
1014         }
1015     }
1016 }
1017 
1018 static const XenBackendInfo xen_block_backend_info = {
1019     .type = "qdisk",
1020     .create = xen_block_device_create,
1021     .destroy = xen_block_device_destroy,
1022 };
1023 
1024 static void xen_block_register_backend(void)
1025 {
1026     xen_backend_register(&xen_block_backend_info);
1027 }
1028 
1029 xen_backend_init(xen_block_register_backend);
1030