xref: /openbmc/qemu/hw/block/xen-block.c (revision 778a2dc5)
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 "qom/object_interfaces.h"
22 #include "hw/xen/xen_common.h"
23 #include "hw/block/xen_blkif.h"
24 #include "hw/qdev-properties.h"
25 #include "hw/xen/xen-block.h"
26 #include "hw/xen/xen-backend.h"
27 #include "sysemu/blockdev.h"
28 #include "sysemu/block-backend.h"
29 #include "sysemu/iothread.h"
30 #include "dataplane/xen-block.h"
31 #include "trace.h"
32 
33 static char *xen_block_get_name(XenDevice *xendev, Error **errp)
34 {
35     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
36     XenBlockVdev *vdev = &blockdev->props.vdev;
37 
38     return g_strdup_printf("%lu", vdev->number);
39 }
40 
41 static void xen_block_disconnect(XenDevice *xendev, Error **errp)
42 {
43     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
44     const char *type = object_get_typename(OBJECT(blockdev));
45     XenBlockVdev *vdev = &blockdev->props.vdev;
46 
47     trace_xen_block_disconnect(type, vdev->disk, vdev->partition);
48 
49     xen_block_dataplane_stop(blockdev->dataplane);
50 }
51 
52 static void xen_block_connect(XenDevice *xendev, Error **errp)
53 {
54     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
55     const char *type = object_get_typename(OBJECT(blockdev));
56     XenBlockVdev *vdev = &blockdev->props.vdev;
57     BlockConf *conf = &blockdev->props.conf;
58     unsigned int feature_large_sector_size;
59     unsigned int order, nr_ring_ref, *ring_ref, event_channel, protocol;
60     char *str;
61 
62     trace_xen_block_connect(type, vdev->disk, vdev->partition);
63 
64     if (xen_device_frontend_scanf(xendev, "feature-large-sector-size", "%u",
65                                   &feature_large_sector_size) != 1) {
66         feature_large_sector_size = 0;
67     }
68 
69     if (feature_large_sector_size != 1 &&
70         conf->logical_block_size != XEN_BLKIF_SECTOR_SIZE) {
71         error_setg(errp, "logical_block_size != %u not supported by frontend",
72                    XEN_BLKIF_SECTOR_SIZE);
73         return;
74     }
75 
76     if (xen_device_frontend_scanf(xendev, "ring-page-order", "%u",
77                                   &order) != 1) {
78         nr_ring_ref = 1;
79         ring_ref = g_new(unsigned int, nr_ring_ref);
80 
81         if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
82                                       &ring_ref[0]) != 1) {
83             error_setg(errp, "failed to read ring-ref");
84             g_free(ring_ref);
85             return;
86         }
87     } else if (order <= blockdev->props.max_ring_page_order) {
88         unsigned int i;
89 
90         nr_ring_ref = 1 << order;
91         ring_ref = g_new(unsigned int, nr_ring_ref);
92 
93         for (i = 0; i < nr_ring_ref; i++) {
94             const char *key = g_strdup_printf("ring-ref%u", i);
95 
96             if (xen_device_frontend_scanf(xendev, key, "%u",
97                                           &ring_ref[i]) != 1) {
98                 error_setg(errp, "failed to read %s", key);
99                 g_free((gpointer)key);
100                 g_free(ring_ref);
101                 return;
102             }
103 
104             g_free((gpointer)key);
105         }
106     } else {
107         error_setg(errp, "invalid ring-page-order (%d)", order);
108         return;
109     }
110 
111     if (xen_device_frontend_scanf(xendev, "event-channel", "%u",
112                                   &event_channel) != 1) {
113         error_setg(errp, "failed to read event-channel");
114         g_free(ring_ref);
115         return;
116     }
117 
118     if (xen_device_frontend_scanf(xendev, "protocol", "%ms",
119                                   &str) != 1) {
120         protocol = BLKIF_PROTOCOL_NATIVE;
121     } else {
122         if (strcmp(str, XEN_IO_PROTO_ABI_X86_32) == 0) {
123             protocol = BLKIF_PROTOCOL_X86_32;
124         } else if (strcmp(str, XEN_IO_PROTO_ABI_X86_64) == 0) {
125             protocol = BLKIF_PROTOCOL_X86_64;
126         } else {
127             protocol = BLKIF_PROTOCOL_NATIVE;
128         }
129 
130         free(str);
131     }
132 
133     xen_block_dataplane_start(blockdev->dataplane, ring_ref, nr_ring_ref,
134                               event_channel, protocol, errp);
135 
136     g_free(ring_ref);
137 }
138 
139 static void xen_block_unrealize(XenDevice *xendev)
140 {
141     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
142     XenBlockDeviceClass *blockdev_class =
143         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
144     const char *type = object_get_typename(OBJECT(blockdev));
145     XenBlockVdev *vdev = &blockdev->props.vdev;
146 
147     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
148         return;
149     }
150 
151     trace_xen_block_unrealize(type, vdev->disk, vdev->partition);
152 
153     /* Disconnect from the frontend in case this has not already happened */
154     xen_block_disconnect(xendev, NULL);
155 
156     xen_block_dataplane_destroy(blockdev->dataplane);
157     blockdev->dataplane = NULL;
158 
159     if (blockdev_class->unrealize) {
160         blockdev_class->unrealize(blockdev);
161     }
162 }
163 
164 static void xen_block_set_size(XenBlockDevice *blockdev)
165 {
166     const char *type = object_get_typename(OBJECT(blockdev));
167     XenBlockVdev *vdev = &blockdev->props.vdev;
168     BlockConf *conf = &blockdev->props.conf;
169     int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size;
170     XenDevice *xendev = XEN_DEVICE(blockdev);
171 
172     trace_xen_block_size(type, vdev->disk, vdev->partition, sectors);
173 
174     xen_device_backend_printf(xendev, "sectors", "%"PRIi64, sectors);
175 }
176 
177 static void xen_block_resize_cb(void *opaque)
178 {
179     XenBlockDevice *blockdev = opaque;
180     XenDevice *xendev = XEN_DEVICE(blockdev);
181     enum xenbus_state state = xen_device_backend_get_state(xendev);
182 
183     xen_block_set_size(blockdev);
184 
185     /*
186      * Mimic the behaviour of Linux xen-blkback and re-write the state
187      * to trigger the frontend watch.
188      */
189     xen_device_backend_printf(xendev, "state", "%u", state);
190 }
191 
192 static const BlockDevOps xen_block_dev_ops = {
193     .resize_cb = xen_block_resize_cb,
194 };
195 
196 static void xen_block_realize(XenDevice *xendev, Error **errp)
197 {
198     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
199     XenBlockDeviceClass *blockdev_class =
200         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
201     const char *type = object_get_typename(OBJECT(blockdev));
202     XenBlockVdev *vdev = &blockdev->props.vdev;
203     BlockConf *conf = &blockdev->props.conf;
204     BlockBackend *blk = conf->blk;
205     Error *local_err = NULL;
206 
207     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
208         error_setg(errp, "vdev property not set");
209         return;
210     }
211 
212     trace_xen_block_realize(type, vdev->disk, vdev->partition);
213 
214     if (blockdev_class->realize) {
215         blockdev_class->realize(blockdev, &local_err);
216         if (local_err) {
217             error_propagate(errp, local_err);
218             return;
219         }
220     }
221 
222     /*
223      * The blkif protocol does not deal with removable media, so it must
224      * always be present, even for CDRom devices.
225      */
226     assert(blk);
227     if (!blk_is_inserted(blk)) {
228         error_setg(errp, "device needs media, but drive is empty");
229         return;
230     }
231 
232     if (!blkconf_apply_backend_options(conf, blockdev->info & VDISK_READONLY,
233                                        true, errp)) {
234         return;
235     }
236 
237     if (!(blockdev->info & VDISK_CDROM) &&
238         !blkconf_geometry(conf, NULL, 65535, 255, 255, errp)) {
239         return;
240     }
241 
242     if (!blkconf_blocksizes(conf, errp)) {
243         return;
244     }
245 
246     blk_set_dev_ops(blk, &xen_block_dev_ops, blockdev);
247     blk_set_guest_block_size(blk, conf->logical_block_size);
248 
249     if (conf->discard_granularity == -1) {
250         conf->discard_granularity = conf->physical_block_size;
251     }
252 
253     if (blk_get_flags(blk) & BDRV_O_UNMAP) {
254         xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
255         xen_device_backend_printf(xendev, "discard-granularity", "%u",
256                                   conf->discard_granularity);
257     }
258 
259     xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
260     xen_device_backend_printf(xendev, "max-ring-page-order", "%u",
261                               blockdev->props.max_ring_page_order);
262     xen_device_backend_printf(xendev, "info", "%u", blockdev->info);
263 
264     xen_device_frontend_printf(xendev, "virtual-device", "%lu",
265                                vdev->number);
266     xen_device_frontend_printf(xendev, "device-type", "%s",
267                                blockdev->device_type);
268 
269     xen_device_backend_printf(xendev, "sector-size", "%u",
270                               conf->logical_block_size);
271 
272     xen_block_set_size(blockdev);
273 
274     blockdev->dataplane =
275         xen_block_dataplane_create(xendev, blk, conf->logical_block_size,
276                                    blockdev->props.iothread);
277 }
278 
279 static void xen_block_frontend_changed(XenDevice *xendev,
280                                        enum xenbus_state frontend_state,
281                                        Error **errp)
282 {
283     enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
284     Error *local_err = NULL;
285 
286     switch (frontend_state) {
287     case XenbusStateInitialised:
288     case XenbusStateConnected:
289         if (backend_state == XenbusStateConnected) {
290             break;
291         }
292 
293         xen_block_disconnect(xendev, &local_err);
294         if (local_err) {
295             error_propagate(errp, local_err);
296             break;
297         }
298 
299         xen_block_connect(xendev, &local_err);
300         if (local_err) {
301             error_propagate(errp, local_err);
302             break;
303         }
304 
305         xen_device_backend_set_state(xendev, XenbusStateConnected);
306         break;
307 
308     case XenbusStateClosing:
309         xen_device_backend_set_state(xendev, XenbusStateClosing);
310         break;
311 
312     case XenbusStateClosed:
313     case XenbusStateUnknown:
314         xen_block_disconnect(xendev, &local_err);
315         if (local_err) {
316             error_propagate(errp, local_err);
317             break;
318         }
319 
320         xen_device_backend_set_state(xendev, XenbusStateClosed);
321         break;
322 
323     default:
324         break;
325     }
326 }
327 
328 static char *disk_to_vbd_name(unsigned int disk)
329 {
330     char *name, *prefix = (disk >= 26) ?
331         disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
332 
333     name = g_strdup_printf("%s%c", prefix, 'a' + disk % 26);
334     g_free(prefix);
335 
336     return name;
337 }
338 
339 static void xen_block_get_vdev(Object *obj, Visitor *v, const char *name,
340                                void *opaque, Error **errp)
341 {
342     DeviceState *dev = DEVICE(obj);
343     Property *prop = opaque;
344     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
345     char *str;
346 
347     switch (vdev->type) {
348     case XEN_BLOCK_VDEV_TYPE_DP:
349         str = g_strdup_printf("d%lup%lu", vdev->disk, vdev->partition);
350         break;
351 
352     case XEN_BLOCK_VDEV_TYPE_XVD:
353     case XEN_BLOCK_VDEV_TYPE_HD:
354     case XEN_BLOCK_VDEV_TYPE_SD: {
355         char *name = disk_to_vbd_name(vdev->disk);
356 
357         str = g_strdup_printf("%s%s%lu",
358                               (vdev->type == XEN_BLOCK_VDEV_TYPE_XVD) ?
359                               "xvd" :
360                               (vdev->type == XEN_BLOCK_VDEV_TYPE_HD) ?
361                               "hd" :
362                               "sd",
363                               name, vdev->partition);
364         g_free(name);
365         break;
366     }
367     default:
368         error_setg(errp, "invalid vdev type");
369         return;
370     }
371 
372     visit_type_str(v, name, &str, errp);
373     g_free(str);
374 }
375 
376 static int vbd_name_to_disk(const char *name, const char **endp,
377                             unsigned long *disk)
378 {
379     unsigned int n = 0;
380 
381     while (*name != '\0') {
382         if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
383             break;
384         }
385 
386         n *= 26;
387         n += *name++ - 'a' + 1;
388     }
389     *endp = name;
390 
391     if (!n) {
392         return -1;
393     }
394 
395     *disk = n - 1;
396 
397     return 0;
398 }
399 
400 static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
401                                void *opaque, Error **errp)
402 {
403     DeviceState *dev = DEVICE(obj);
404     Property *prop = opaque;
405     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
406     Error *local_err = NULL;
407     char *str, *p;
408     const char *end;
409 
410     if (dev->realized) {
411         qdev_prop_set_after_realize(dev, name, errp);
412         return;
413     }
414 
415     if (!visit_type_str(v, name, &str, &local_err)) {
416         error_propagate(errp, local_err);
417         return;
418     }
419 
420     p = strchr(str, 'd');
421     if (!p) {
422         goto invalid;
423     }
424 
425     *p++ = '\0';
426     if (*str == '\0') {
427         vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
428     } else if (strcmp(str, "xv") == 0) {
429         vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
430     } else if (strcmp(str, "h") == 0) {
431         vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
432     } else if (strcmp(str, "s") == 0) {
433         vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
434     } else {
435         goto invalid;
436     }
437 
438     if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
439         if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
440             goto invalid;
441         }
442 
443         if (*end == 'p') {
444             if (*(++end) == '\0') {
445                 goto invalid;
446             }
447         }
448     } else {
449         if (vbd_name_to_disk(p, &end, &vdev->disk)) {
450             goto invalid;
451         }
452     }
453 
454     if (*end != '\0') {
455         p = (char *)end;
456 
457         if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
458             goto invalid;
459         }
460 
461         if (*end != '\0') {
462             goto invalid;
463         }
464     } else {
465         vdev->partition = 0;
466     }
467 
468     switch (vdev->type) {
469     case XEN_BLOCK_VDEV_TYPE_DP:
470     case XEN_BLOCK_VDEV_TYPE_XVD:
471         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
472             vdev->number = (202 << 8) | (vdev->disk << 4) |
473                 vdev->partition;
474         } else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
475             vdev->number = (1 << 28) | (vdev->disk << 8) |
476                 vdev->partition;
477         } else {
478             goto invalid;
479         }
480         break;
481 
482     case XEN_BLOCK_VDEV_TYPE_HD:
483         if ((vdev->disk == 0 || vdev->disk == 1) &&
484             vdev->partition < (1 << 6)) {
485             vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
486         } else if ((vdev->disk == 2 || vdev->disk == 3) &&
487                    vdev->partition < (1 << 6)) {
488             vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
489                 vdev->partition;
490         } else {
491             goto invalid;
492         }
493         break;
494 
495     case XEN_BLOCK_VDEV_TYPE_SD:
496         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
497             vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
498         } else {
499             goto invalid;
500         }
501         break;
502 
503     default:
504         goto invalid;
505     }
506 
507     g_free(str);
508     return;
509 
510 invalid:
511     error_setg(errp, "invalid virtual disk specifier");
512 
513     vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
514     g_free(str);
515 }
516 
517 /*
518  * This property deals with 'vdev' names adhering to the Xen VBD naming
519  * scheme described in:
520  *
521  * https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
522  */
523 const PropertyInfo xen_block_prop_vdev = {
524     .name  = "str",
525     .description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
526     .get = xen_block_get_vdev,
527     .set = xen_block_set_vdev,
528 };
529 
530 static Property xen_block_props[] = {
531     DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
532                 xen_block_prop_vdev, XenBlockVdev),
533     DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
534     DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
535                        props.max_ring_page_order, 4),
536     DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
537                      TYPE_IOTHREAD, IOThread *),
538     DEFINE_PROP_END_OF_LIST()
539 };
540 
541 static void xen_block_class_init(ObjectClass *class, void *data)
542 {
543     DeviceClass *dev_class = DEVICE_CLASS(class);
544     XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
545 
546     xendev_class->backend = "qdisk";
547     xendev_class->device = "vbd";
548     xendev_class->get_name = xen_block_get_name;
549     xendev_class->realize = xen_block_realize;
550     xendev_class->frontend_changed = xen_block_frontend_changed;
551     xendev_class->unrealize = xen_block_unrealize;
552 
553     device_class_set_props(dev_class, xen_block_props);
554 }
555 
556 static const TypeInfo xen_block_type_info = {
557     .name = TYPE_XEN_BLOCK_DEVICE,
558     .parent = TYPE_XEN_DEVICE,
559     .instance_size = sizeof(XenBlockDevice),
560     .abstract = true,
561     .class_size = sizeof(XenBlockDeviceClass),
562     .class_init = xen_block_class_init,
563 };
564 
565 static void xen_disk_unrealize(XenBlockDevice *blockdev)
566 {
567     trace_xen_disk_unrealize();
568 }
569 
570 static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
571 {
572     BlockConf *conf = &blockdev->props.conf;
573 
574     trace_xen_disk_realize();
575 
576     blockdev->device_type = "disk";
577 
578     if (!conf->blk) {
579         error_setg(errp, "drive property not set");
580         return;
581     }
582 
583     blockdev->info = blk_is_read_only(conf->blk) ? VDISK_READONLY : 0;
584 }
585 
586 static void xen_disk_class_init(ObjectClass *class, void *data)
587 {
588     DeviceClass *dev_class = DEVICE_CLASS(class);
589     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
590 
591     blockdev_class->realize = xen_disk_realize;
592     blockdev_class->unrealize = xen_disk_unrealize;
593 
594     dev_class->desc = "Xen Disk Device";
595 }
596 
597 static const TypeInfo xen_disk_type_info = {
598     .name = TYPE_XEN_DISK_DEVICE,
599     .parent = TYPE_XEN_BLOCK_DEVICE,
600     .instance_size = sizeof(XenDiskDevice),
601     .class_init = xen_disk_class_init,
602 };
603 
604 static void xen_cdrom_unrealize(XenBlockDevice *blockdev)
605 {
606     trace_xen_cdrom_unrealize();
607 }
608 
609 static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
610 {
611     BlockConf *conf = &blockdev->props.conf;
612 
613     trace_xen_cdrom_realize();
614 
615     blockdev->device_type = "cdrom";
616 
617     if (!conf->blk) {
618         int rc;
619 
620         /* Set up an empty drive */
621         conf->blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
622 
623         rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
624         if (!rc) {
625             error_setg_errno(errp, -rc, "failed to create drive");
626             return;
627         }
628     }
629 
630     blockdev->info = VDISK_READONLY | VDISK_CDROM;
631 }
632 
633 static void xen_cdrom_class_init(ObjectClass *class, void *data)
634 {
635     DeviceClass *dev_class = DEVICE_CLASS(class);
636     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
637 
638     blockdev_class->realize = xen_cdrom_realize;
639     blockdev_class->unrealize = xen_cdrom_unrealize;
640 
641     dev_class->desc = "Xen CD-ROM Device";
642 }
643 
644 static const TypeInfo xen_cdrom_type_info = {
645     .name = TYPE_XEN_CDROM_DEVICE,
646     .parent = TYPE_XEN_BLOCK_DEVICE,
647     .instance_size = sizeof(XenCDRomDevice),
648     .class_init = xen_cdrom_class_init,
649 };
650 
651 static void xen_block_register_types(void)
652 {
653     type_register_static(&xen_block_type_info);
654     type_register_static(&xen_disk_type_info);
655     type_register_static(&xen_cdrom_type_info);
656 }
657 
658 type_init(xen_block_register_types)
659 
660 static void xen_block_blockdev_del(const char *node_name, Error **errp)
661 {
662     trace_xen_block_blockdev_del(node_name);
663 
664     qmp_blockdev_del(node_name, errp);
665 }
666 
667 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
668                                     Error **errp)
669 {
670     const char *driver = qdict_get_try_str(qdict, "driver");
671     BlockdevOptions *options = NULL;
672     Error *local_err = NULL;
673     char *node_name;
674     Visitor *v;
675 
676     if (!driver) {
677         error_setg(errp, "no 'driver' parameter");
678         return NULL;
679     }
680 
681     node_name = g_strdup_printf("%s-%s", id, driver);
682     qdict_put_str(qdict, "node-name", node_name);
683 
684     trace_xen_block_blockdev_add(node_name);
685 
686     v = qobject_input_visitor_new(QOBJECT(qdict));
687     visit_type_BlockdevOptions(v, NULL, &options, &local_err);
688     visit_free(v);
689 
690     if (local_err) {
691         error_propagate(errp, local_err);
692         goto fail;
693     }
694 
695     qmp_blockdev_add(options, &local_err);
696 
697     if (local_err) {
698         error_propagate(errp, local_err);
699         goto fail;
700     }
701 
702     qapi_free_BlockdevOptions(options);
703 
704     return node_name;
705 
706 fail:
707     if (options) {
708         qapi_free_BlockdevOptions(options);
709     }
710     g_free(node_name);
711 
712     return NULL;
713 }
714 
715 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
716 {
717     char *node_name = drive->node_name;
718 
719     if (node_name) {
720         Error *local_err = NULL;
721 
722         xen_block_blockdev_del(node_name, &local_err);
723         if (local_err) {
724             error_propagate(errp, local_err);
725             return;
726         }
727         g_free(node_name);
728         drive->node_name = NULL;
729     }
730     g_free(drive->id);
731     g_free(drive);
732 }
733 
734 static XenBlockDrive *xen_block_drive_create(const char *id,
735                                              const char *device_type,
736                                              QDict *opts, Error **errp)
737 {
738     const char *params = qdict_get_try_str(opts, "params");
739     const char *mode = qdict_get_try_str(opts, "mode");
740     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
741     const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
742     char *driver = NULL;
743     char *filename = NULL;
744     XenBlockDrive *drive = NULL;
745     Error *local_err = NULL;
746     QDict *file_layer;
747     QDict *driver_layer;
748 
749     if (params) {
750         char **v = g_strsplit(params, ":", 2);
751 
752         if (v[1] == NULL) {
753             filename = g_strdup(v[0]);
754             driver = g_strdup("raw");
755         } else {
756             if (strcmp(v[0], "aio") == 0) {
757                 driver = g_strdup("raw");
758             } else if (strcmp(v[0], "vhd") == 0) {
759                 driver = g_strdup("vpc");
760             } else {
761                 driver = g_strdup(v[0]);
762             }
763             filename = g_strdup(v[1]);
764         }
765 
766         g_strfreev(v);
767     } else {
768         error_setg(errp, "no params");
769         goto done;
770     }
771 
772     assert(filename);
773     assert(driver);
774 
775     drive = g_new0(XenBlockDrive, 1);
776     drive->id = g_strdup(id);
777 
778     file_layer = qdict_new();
779     driver_layer = qdict_new();
780 
781     qdict_put_str(file_layer, "driver", "file");
782     qdict_put_str(file_layer, "filename", filename);
783     g_free(filename);
784 
785     if (mode && *mode != 'w') {
786         qdict_put_bool(file_layer, "read-only", true);
787     }
788 
789     if (direct_io_safe) {
790         unsigned long value;
791 
792         if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
793             QDict *cache_qdict = qdict_new();
794 
795             qdict_put_bool(cache_qdict, "direct", true);
796             qdict_put(file_layer, "cache", cache_qdict);
797 
798             qdict_put_str(file_layer, "aio", "native");
799         }
800     }
801 
802     if (discard_enable) {
803         unsigned long value;
804 
805         if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
806             qdict_put_str(file_layer, "discard", "unmap");
807             qdict_put_str(driver_layer, "discard", "unmap");
808         }
809     }
810 
811     /*
812      * It is necessary to turn file locking off as an emulated device
813      * may have already opened the same image file.
814      */
815     qdict_put_str(file_layer, "locking", "off");
816 
817     qdict_put_str(driver_layer, "driver", driver);
818     g_free(driver);
819 
820     qdict_put(driver_layer, "file", file_layer);
821 
822     g_assert(!drive->node_name);
823     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
824                                               &local_err);
825 
826     qobject_unref(driver_layer);
827 
828 done:
829     if (local_err) {
830         error_propagate(errp, local_err);
831         xen_block_drive_destroy(drive, NULL);
832         return NULL;
833     }
834 
835     return drive;
836 }
837 
838 static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
839 {
840     return drive->node_name ? drive->node_name : "";
841 }
842 
843 static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
844                                        Error **errp)
845 {
846     qmp_object_del(iothread->id, errp);
847 
848     g_free(iothread->id);
849     g_free(iothread);
850 }
851 
852 static XenBlockIOThread *xen_block_iothread_create(const char *id,
853                                                    Error **errp)
854 {
855     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
856     Error *local_err = NULL;
857     QDict *opts;
858     QObject *ret_data = NULL;
859 
860     iothread->id = g_strdup(id);
861 
862     opts = qdict_new();
863     qdict_put_str(opts, "qom-type", TYPE_IOTHREAD);
864     qdict_put_str(opts, "id", id);
865     qmp_object_add(opts, &ret_data, &local_err);
866     qobject_unref(opts);
867     qobject_unref(ret_data);
868 
869     if (local_err) {
870         error_propagate(errp, local_err);
871 
872         g_free(iothread->id);
873         g_free(iothread);
874         return NULL;
875     }
876 
877     return iothread;
878 }
879 
880 static void xen_block_device_create(XenBackendInstance *backend,
881                                     QDict *opts, Error **errp)
882 {
883     XenBus *xenbus = xen_backend_get_bus(backend);
884     const char *name = xen_backend_get_name(backend);
885     unsigned long number;
886     const char *vdev, *device_type;
887     XenBlockDrive *drive = NULL;
888     XenBlockIOThread *iothread = NULL;
889     XenDevice *xendev = NULL;
890     Error *local_err = NULL;
891     const char *type;
892     XenBlockDevice *blockdev;
893 
894     if (qemu_strtoul(name, NULL, 10, &number)) {
895         error_setg(errp, "failed to parse name '%s'", name);
896         goto fail;
897     }
898 
899     trace_xen_block_device_create(number);
900 
901     vdev = qdict_get_try_str(opts, "dev");
902     if (!vdev) {
903         error_setg(errp, "no dev parameter");
904         goto fail;
905     }
906 
907     device_type = qdict_get_try_str(opts, "device-type");
908     if (!device_type) {
909         error_setg(errp, "no device-type parameter");
910         goto fail;
911     }
912 
913     if (!strcmp(device_type, "disk")) {
914         type = TYPE_XEN_DISK_DEVICE;
915     } else if (!strcmp(device_type, "cdrom")) {
916         type = TYPE_XEN_CDROM_DEVICE;
917     } else {
918         error_setg(errp, "invalid device-type parameter '%s'", device_type);
919         goto fail;
920     }
921 
922     drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
923     if (!drive) {
924         error_propagate_prepend(errp, local_err, "failed to create drive: ");
925         goto fail;
926     }
927 
928     iothread = xen_block_iothread_create(vdev, &local_err);
929     if (local_err) {
930         error_propagate_prepend(errp, local_err,
931                                 "failed to create iothread: ");
932         goto fail;
933     }
934 
935     xendev = XEN_DEVICE(qdev_new(type));
936     blockdev = XEN_BLOCK_DEVICE(xendev);
937 
938     if (!object_property_set_str(OBJECT(xendev), "vdev", vdev,
939                                  &local_err)) {
940         error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
941         goto fail;
942     }
943 
944     if (!object_property_set_str(OBJECT(xendev), "drive",
945                                  xen_block_drive_get_node_name(drive),
946                                  &local_err)) {
947         error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
948         goto fail;
949     }
950 
951     if (!object_property_set_str(OBJECT(xendev), "iothread", iothread->id,
952                                  &local_err)) {
953         error_propagate_prepend(errp, local_err,
954                                 "failed to set 'iothread': ");
955         goto fail;
956     }
957 
958     blockdev->iothread = iothread;
959     blockdev->drive = drive;
960 
961     if (!qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), &local_err)) {
962         error_propagate_prepend(errp, local_err,
963                                 "realization of device %s failed: ",
964                                 type);
965         goto fail;
966     }
967 
968     xen_backend_set_device(backend, xendev);
969     return;
970 
971 fail:
972     if (xendev) {
973         object_unparent(OBJECT(xendev));
974     }
975 
976     if (iothread) {
977         xen_block_iothread_destroy(iothread, NULL);
978     }
979 
980     if (drive) {
981         xen_block_drive_destroy(drive, NULL);
982     }
983 }
984 
985 static void xen_block_device_destroy(XenBackendInstance *backend,
986                                      Error **errp)
987 {
988     XenDevice *xendev = xen_backend_get_device(backend);
989     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
990     XenBlockVdev *vdev = &blockdev->props.vdev;
991     XenBlockDrive *drive = blockdev->drive;
992     XenBlockIOThread *iothread = blockdev->iothread;
993     Error *local_err = NULL;
994 
995     trace_xen_block_device_destroy(vdev->number);
996 
997     object_unparent(OBJECT(xendev));
998 
999     if (iothread) {
1000         xen_block_iothread_destroy(iothread, &local_err);
1001         if (local_err) {
1002             error_propagate_prepend(errp, local_err,
1003                                     "failed to destroy iothread: ");
1004             return;
1005         }
1006     }
1007 
1008     if (drive) {
1009         xen_block_drive_destroy(drive, &local_err);
1010         if (local_err) {
1011             error_propagate_prepend(errp, local_err,
1012                                     "failed to destroy drive: ");
1013             return;
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