xref: /openbmc/qemu/hw/block/xen-block.c (revision b097ba37)
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/option.h"
11 #include "qapi/error.h"
12 #include "qapi/qapi-commands-block-core.h"
13 #include "qapi/qapi-commands-misc.h"
14 #include "qapi/qapi-visit-block-core.h"
15 #include "qapi/qobject-input-visitor.h"
16 #include "qapi/visitor.h"
17 #include "qapi/qmp/qdict.h"
18 #include "qapi/qmp/qstring.h"
19 #include "hw/hw.h"
20 #include "hw/xen/xen_common.h"
21 #include "hw/block/xen_blkif.h"
22 #include "hw/xen/xen-block.h"
23 #include "hw/xen/xen-backend.h"
24 #include "sysemu/blockdev.h"
25 #include "sysemu/block-backend.h"
26 #include "sysemu/iothread.h"
27 #include "dataplane/xen-block.h"
28 #include "trace.h"
29 
30 static char *xen_block_get_name(XenDevice *xendev, Error **errp)
31 {
32     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
33     XenBlockVdev *vdev = &blockdev->props.vdev;
34 
35     return g_strdup_printf("%lu", vdev->number);
36 }
37 
38 static void xen_block_disconnect(XenDevice *xendev, Error **errp)
39 {
40     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
41     const char *type = object_get_typename(OBJECT(blockdev));
42     XenBlockVdev *vdev = &blockdev->props.vdev;
43 
44     trace_xen_block_disconnect(type, vdev->disk, vdev->partition);
45 
46     xen_block_dataplane_stop(blockdev->dataplane);
47 }
48 
49 static void xen_block_connect(XenDevice *xendev, Error **errp)
50 {
51     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
52     const char *type = object_get_typename(OBJECT(blockdev));
53     XenBlockVdev *vdev = &blockdev->props.vdev;
54     unsigned int order, nr_ring_ref, *ring_ref, event_channel, protocol;
55     char *str;
56 
57     trace_xen_block_connect(type, vdev->disk, vdev->partition);
58 
59     if (xen_device_frontend_scanf(xendev, "ring-page-order", "%u",
60                                   &order) != 1) {
61         nr_ring_ref = 1;
62         ring_ref = g_new(unsigned int, nr_ring_ref);
63 
64         if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
65                                       &ring_ref[0]) != 1) {
66             error_setg(errp, "failed to read ring-ref");
67             g_free(ring_ref);
68             return;
69         }
70     } else if (order <= blockdev->props.max_ring_page_order) {
71         unsigned int i;
72 
73         nr_ring_ref = 1 << order;
74         ring_ref = g_new(unsigned int, nr_ring_ref);
75 
76         for (i = 0; i < nr_ring_ref; i++) {
77             const char *key = g_strdup_printf("ring-ref%u", i);
78 
79             if (xen_device_frontend_scanf(xendev, key, "%u",
80                                           &ring_ref[i]) != 1) {
81                 error_setg(errp, "failed to read %s", key);
82                 g_free((gpointer)key);
83                 g_free(ring_ref);
84                 return;
85             }
86 
87             g_free((gpointer)key);
88         }
89     } else {
90         error_setg(errp, "invalid ring-page-order (%d)", order);
91         return;
92     }
93 
94     if (xen_device_frontend_scanf(xendev, "event-channel", "%u",
95                                   &event_channel) != 1) {
96         error_setg(errp, "failed to read event-channel");
97         g_free(ring_ref);
98         return;
99     }
100 
101     if (xen_device_frontend_scanf(xendev, "protocol", "%ms",
102                                   &str) != 1) {
103         protocol = BLKIF_PROTOCOL_NATIVE;
104     } else {
105         if (strcmp(str, XEN_IO_PROTO_ABI_X86_32) == 0) {
106             protocol = BLKIF_PROTOCOL_X86_32;
107         } else if (strcmp(str, XEN_IO_PROTO_ABI_X86_64) == 0) {
108             protocol = BLKIF_PROTOCOL_X86_64;
109         } else {
110             protocol = BLKIF_PROTOCOL_NATIVE;
111         }
112 
113         free(str);
114     }
115 
116     xen_block_dataplane_start(blockdev->dataplane, ring_ref, nr_ring_ref,
117                               event_channel, protocol, errp);
118 
119     g_free(ring_ref);
120 }
121 
122 static void xen_block_unrealize(XenDevice *xendev, Error **errp)
123 {
124     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
125     XenBlockDeviceClass *blockdev_class =
126         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
127     const char *type = object_get_typename(OBJECT(blockdev));
128     XenBlockVdev *vdev = &blockdev->props.vdev;
129 
130     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
131         return;
132     }
133 
134     trace_xen_block_unrealize(type, vdev->disk, vdev->partition);
135 
136     /* Disconnect from the frontend in case this has not already happened */
137     xen_block_disconnect(xendev, NULL);
138 
139     xen_block_dataplane_destroy(blockdev->dataplane);
140     blockdev->dataplane = NULL;
141 
142     if (blockdev_class->unrealize) {
143         blockdev_class->unrealize(blockdev, errp);
144     }
145 }
146 
147 static void xen_block_set_size(XenBlockDevice *blockdev)
148 {
149     const char *type = object_get_typename(OBJECT(blockdev));
150     XenBlockVdev *vdev = &blockdev->props.vdev;
151     BlockConf *conf = &blockdev->props.conf;
152     int64_t sectors = blk_getlength(conf->blk) / XEN_BLKIF_SECTOR_SIZE;
153     XenDevice *xendev = XEN_DEVICE(blockdev);
154 
155     trace_xen_block_size(type, vdev->disk, vdev->partition, sectors);
156 
157     xen_device_backend_printf(xendev, "sectors", "%"PRIi64, sectors);
158 }
159 
160 static void xen_block_resize_cb(void *opaque)
161 {
162     XenBlockDevice *blockdev = opaque;
163     XenDevice *xendev = XEN_DEVICE(blockdev);
164     enum xenbus_state state = xen_device_backend_get_state(xendev);
165 
166     xen_block_set_size(blockdev);
167 
168     /*
169      * Mimic the behaviour of Linux xen-blkback and re-write the state
170      * to trigger the frontend watch.
171      */
172     xen_device_backend_printf(xendev, "state", "%u", state);
173 }
174 
175 static const BlockDevOps xen_block_dev_ops = {
176     .resize_cb = xen_block_resize_cb,
177 };
178 
179 static void xen_block_realize(XenDevice *xendev, Error **errp)
180 {
181     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
182     XenBlockDeviceClass *blockdev_class =
183         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
184     const char *type = object_get_typename(OBJECT(blockdev));
185     XenBlockVdev *vdev = &blockdev->props.vdev;
186     BlockConf *conf = &blockdev->props.conf;
187     Error *local_err = NULL;
188 
189     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
190         error_setg(errp, "vdev property not set");
191         return;
192     }
193 
194     trace_xen_block_realize(type, vdev->disk, vdev->partition);
195 
196     if (blockdev_class->realize) {
197         blockdev_class->realize(blockdev, &local_err);
198         if (local_err) {
199             error_propagate(errp, local_err);
200             return;
201         }
202     }
203 
204     /*
205      * The blkif protocol does not deal with removable media, so it must
206      * always be present, even for CDRom devices.
207      */
208     assert(conf->blk);
209     if (!blk_is_inserted(conf->blk)) {
210         error_setg(errp, "device needs media, but drive is empty");
211         return;
212     }
213 
214     if (!blkconf_apply_backend_options(conf, blockdev->info & VDISK_READONLY,
215                                        true, errp)) {
216         return;
217     }
218 
219     if (!(blockdev->info & VDISK_CDROM) &&
220         !blkconf_geometry(conf, NULL, 65535, 255, 255, errp)) {
221         return;
222     }
223 
224     blkconf_blocksizes(conf);
225 
226     if (conf->logical_block_size != XEN_BLKIF_SECTOR_SIZE) {
227         error_setg(errp, "logical_block_size != %u not supported",
228                    XEN_BLKIF_SECTOR_SIZE);
229         return;
230     }
231 
232     if (conf->logical_block_size > conf->physical_block_size) {
233         error_setg(
234             errp, "logical_block_size > physical_block_size not supported");
235         return;
236     }
237 
238     blk_set_dev_ops(conf->blk, &xen_block_dev_ops, blockdev);
239     blk_set_guest_block_size(conf->blk, conf->logical_block_size);
240 
241     if (conf->discard_granularity == -1) {
242         conf->discard_granularity = conf->physical_block_size;
243     }
244 
245     if (blk_get_flags(conf->blk) & BDRV_O_UNMAP) {
246         xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
247         xen_device_backend_printf(xendev, "discard-granularity", "%u",
248                                   conf->discard_granularity);
249     }
250 
251     xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
252     xen_device_backend_printf(xendev, "max-ring-page-order", "%u",
253                               blockdev->props.max_ring_page_order);
254     xen_device_backend_printf(xendev, "info", "%u", blockdev->info);
255 
256     xen_device_frontend_printf(xendev, "virtual-device", "%lu",
257                                vdev->number);
258     xen_device_frontend_printf(xendev, "device-type", "%s",
259                                blockdev->device_type);
260 
261     xen_device_backend_printf(xendev, "sector-size", "%u",
262                               XEN_BLKIF_SECTOR_SIZE);
263 
264     xen_block_set_size(blockdev);
265 
266     blockdev->dataplane =
267         xen_block_dataplane_create(xendev, conf, blockdev->props.iothread);
268 }
269 
270 static void xen_block_frontend_changed(XenDevice *xendev,
271                                        enum xenbus_state frontend_state,
272                                        Error **errp)
273 {
274     enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
275     Error *local_err = NULL;
276 
277     switch (frontend_state) {
278     case XenbusStateInitialised:
279     case XenbusStateConnected:
280         if (backend_state == XenbusStateConnected) {
281             break;
282         }
283 
284         xen_block_disconnect(xendev, &local_err);
285         if (local_err) {
286             error_propagate(errp, local_err);
287             break;
288         }
289 
290         xen_block_connect(xendev, &local_err);
291         if (local_err) {
292             error_propagate(errp, local_err);
293             break;
294         }
295 
296         xen_device_backend_set_state(xendev, XenbusStateConnected);
297         break;
298 
299     case XenbusStateClosing:
300         xen_device_backend_set_state(xendev, XenbusStateClosing);
301         break;
302 
303     case XenbusStateClosed:
304         xen_block_disconnect(xendev, &local_err);
305         if (local_err) {
306             error_propagate(errp, local_err);
307             break;
308         }
309 
310         xen_device_backend_set_state(xendev, XenbusStateClosed);
311         break;
312 
313     default:
314         break;
315     }
316 }
317 
318 static char *disk_to_vbd_name(unsigned int disk)
319 {
320     char *name, *prefix = (disk >= 26) ?
321         disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
322 
323     name = g_strdup_printf("%s%c", prefix, 'a' + disk % 26);
324     g_free(prefix);
325 
326     return name;
327 }
328 
329 static void xen_block_get_vdev(Object *obj, Visitor *v, const char *name,
330                                void *opaque, Error **errp)
331 {
332     DeviceState *dev = DEVICE(obj);
333     Property *prop = opaque;
334     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
335     char *str;
336 
337     switch (vdev->type) {
338     case XEN_BLOCK_VDEV_TYPE_DP:
339         str = g_strdup_printf("d%lup%lu", vdev->disk, vdev->partition);
340         break;
341 
342     case XEN_BLOCK_VDEV_TYPE_XVD:
343     case XEN_BLOCK_VDEV_TYPE_HD:
344     case XEN_BLOCK_VDEV_TYPE_SD: {
345         char *name = disk_to_vbd_name(vdev->disk);
346 
347         str = g_strdup_printf("%s%s%lu",
348                               (vdev->type == XEN_BLOCK_VDEV_TYPE_XVD) ?
349                               "xvd" :
350                               (vdev->type == XEN_BLOCK_VDEV_TYPE_HD) ?
351                               "hd" :
352                               "sd",
353                               name, vdev->partition);
354         g_free(name);
355         break;
356     }
357     default:
358         error_setg(errp, "invalid vdev type");
359         return;
360     }
361 
362     visit_type_str(v, name, &str, errp);
363     g_free(str);
364 }
365 
366 static int vbd_name_to_disk(const char *name, const char **endp,
367                             unsigned long *disk)
368 {
369     unsigned int n = 0;
370 
371     while (*name != '\0') {
372         if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
373             break;
374         }
375 
376         n *= 26;
377         n += *name++ - 'a' + 1;
378     }
379     *endp = name;
380 
381     if (!n) {
382         return -1;
383     }
384 
385     *disk = n - 1;
386 
387     return 0;
388 }
389 
390 static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
391                                void *opaque, Error **errp)
392 {
393     DeviceState *dev = DEVICE(obj);
394     Property *prop = opaque;
395     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
396     Error *local_err = NULL;
397     char *str, *p;
398     const char *end;
399 
400     if (dev->realized) {
401         qdev_prop_set_after_realize(dev, name, errp);
402         return;
403     }
404 
405     visit_type_str(v, name, &str, &local_err);
406     if (local_err) {
407         error_propagate(errp, local_err);
408         return;
409     }
410 
411     p = strchr(str, 'd');
412     if (!p) {
413         goto invalid;
414     }
415 
416     *p++ = '\0';
417     if (*str == '\0') {
418         vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
419     } else if (strcmp(str, "xv") == 0) {
420         vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
421     } else if (strcmp(str, "h") == 0) {
422         vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
423     } else if (strcmp(str, "s") == 0) {
424         vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
425     } else {
426         goto invalid;
427     }
428 
429     if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
430         if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
431             goto invalid;
432         }
433 
434         if (*end == 'p') {
435             if (*(++end) == '\0') {
436                 goto invalid;
437             }
438         }
439     } else {
440         if (vbd_name_to_disk(p, &end, &vdev->disk)) {
441             goto invalid;
442         }
443     }
444 
445     if (*end != '\0') {
446         p = (char *)end;
447 
448         if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
449             goto invalid;
450         }
451 
452         if (*end != '\0') {
453             goto invalid;
454         }
455     } else {
456         vdev->partition = 0;
457     }
458 
459     switch (vdev->type) {
460     case XEN_BLOCK_VDEV_TYPE_DP:
461     case XEN_BLOCK_VDEV_TYPE_XVD:
462         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
463             vdev->number = (202 << 8) | (vdev->disk << 4) |
464                 vdev->partition;
465         } else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
466             vdev->number = (1 << 28) | (vdev->disk << 8) |
467                 vdev->partition;
468         } else {
469             goto invalid;
470         }
471         break;
472 
473     case XEN_BLOCK_VDEV_TYPE_HD:
474         if ((vdev->disk == 0 || vdev->disk == 1) &&
475             vdev->partition < (1 << 6)) {
476             vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
477         } else if ((vdev->disk == 2 || vdev->disk == 3) &&
478                    vdev->partition < (1 << 6)) {
479             vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
480                 vdev->partition;
481         } else {
482             goto invalid;
483         }
484         break;
485 
486     case XEN_BLOCK_VDEV_TYPE_SD:
487         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
488             vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
489         } else {
490             goto invalid;
491         }
492         break;
493 
494     default:
495         goto invalid;
496     }
497 
498     g_free(str);
499     return;
500 
501 invalid:
502     error_setg(errp, "invalid virtual disk specifier");
503 
504     vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
505     g_free(str);
506 }
507 
508 /*
509  * This property deals with 'vdev' names adhering to the Xen VBD naming
510  * scheme described in:
511  *
512  * https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
513  */
514 const PropertyInfo xen_block_prop_vdev = {
515     .name  = "str",
516     .description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
517     .get = xen_block_get_vdev,
518     .set = xen_block_set_vdev,
519 };
520 
521 static Property xen_block_props[] = {
522     DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
523                 xen_block_prop_vdev, XenBlockVdev),
524     DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
525     DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
526                        props.max_ring_page_order, 4),
527     DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
528                      TYPE_IOTHREAD, IOThread *),
529     DEFINE_PROP_END_OF_LIST()
530 };
531 
532 static void xen_block_class_init(ObjectClass *class, void *data)
533 {
534     DeviceClass *dev_class = DEVICE_CLASS(class);
535     XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
536 
537     xendev_class->backend = "qdisk";
538     xendev_class->device = "vbd";
539     xendev_class->get_name = xen_block_get_name;
540     xendev_class->realize = xen_block_realize;
541     xendev_class->frontend_changed = xen_block_frontend_changed;
542     xendev_class->unrealize = xen_block_unrealize;
543 
544     dev_class->props = xen_block_props;
545 }
546 
547 static const TypeInfo xen_block_type_info = {
548     .name = TYPE_XEN_BLOCK_DEVICE,
549     .parent = TYPE_XEN_DEVICE,
550     .instance_size = sizeof(XenBlockDevice),
551     .abstract = true,
552     .class_size = sizeof(XenBlockDeviceClass),
553     .class_init = xen_block_class_init,
554 };
555 
556 static void xen_disk_unrealize(XenBlockDevice *blockdev, Error **errp)
557 {
558     trace_xen_disk_unrealize();
559 }
560 
561 static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
562 {
563     BlockConf *conf = &blockdev->props.conf;
564 
565     trace_xen_disk_realize();
566 
567     blockdev->device_type = "disk";
568 
569     if (!conf->blk) {
570         error_setg(errp, "drive property not set");
571         return;
572     }
573 
574     blockdev->info = blk_is_read_only(conf->blk) ? VDISK_READONLY : 0;
575 }
576 
577 static void xen_disk_class_init(ObjectClass *class, void *data)
578 {
579     DeviceClass *dev_class = DEVICE_CLASS(class);
580     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
581 
582     blockdev_class->realize = xen_disk_realize;
583     blockdev_class->unrealize = xen_disk_unrealize;
584 
585     dev_class->desc = "Xen Disk Device";
586 }
587 
588 static const TypeInfo xen_disk_type_info = {
589     .name = TYPE_XEN_DISK_DEVICE,
590     .parent = TYPE_XEN_BLOCK_DEVICE,
591     .instance_size = sizeof(XenDiskDevice),
592     .class_init = xen_disk_class_init,
593 };
594 
595 static void xen_cdrom_unrealize(XenBlockDevice *blockdev, Error **errp)
596 {
597     trace_xen_cdrom_unrealize();
598 }
599 
600 static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
601 {
602     BlockConf *conf = &blockdev->props.conf;
603 
604     trace_xen_cdrom_realize();
605 
606     blockdev->device_type = "cdrom";
607 
608     if (!conf->blk) {
609         int rc;
610 
611         /* Set up an empty drive */
612         conf->blk = blk_new(0, BLK_PERM_ALL);
613 
614         rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
615         if (!rc) {
616             error_setg_errno(errp, -rc, "failed to create drive");
617             return;
618         }
619     }
620 
621     blockdev->info = VDISK_READONLY | VDISK_CDROM;
622 }
623 
624 static void xen_cdrom_class_init(ObjectClass *class, void *data)
625 {
626     DeviceClass *dev_class = DEVICE_CLASS(class);
627     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
628 
629     blockdev_class->realize = xen_cdrom_realize;
630     blockdev_class->unrealize = xen_cdrom_unrealize;
631 
632     dev_class->desc = "Xen CD-ROM Device";
633 }
634 
635 static const TypeInfo xen_cdrom_type_info = {
636     .name = TYPE_XEN_CDROM_DEVICE,
637     .parent = TYPE_XEN_BLOCK_DEVICE,
638     .instance_size = sizeof(XenCDRomDevice),
639     .class_init = xen_cdrom_class_init,
640 };
641 
642 static void xen_block_register_types(void)
643 {
644     type_register_static(&xen_block_type_info);
645     type_register_static(&xen_disk_type_info);
646     type_register_static(&xen_cdrom_type_info);
647 }
648 
649 type_init(xen_block_register_types)
650 
651 static void xen_block_blockdev_del(const char *node_name, Error **errp)
652 {
653     trace_xen_block_blockdev_del(node_name);
654 
655     qmp_blockdev_del(node_name, errp);
656 }
657 
658 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
659                                     Error **errp)
660 {
661     const char *driver = qdict_get_try_str(qdict, "driver");
662     BlockdevOptions *options = NULL;
663     Error *local_err = NULL;
664     char *node_name;
665     Visitor *v;
666 
667     if (!driver) {
668         error_setg(errp, "no 'driver' parameter");
669         return NULL;
670     }
671 
672     node_name = g_strdup_printf("%s-%s", id, driver);
673     qdict_put_str(qdict, "node-name", node_name);
674 
675     trace_xen_block_blockdev_add(node_name);
676 
677     v = qobject_input_visitor_new(QOBJECT(qdict));
678     visit_type_BlockdevOptions(v, NULL, &options, &local_err);
679     visit_free(v);
680 
681     if (local_err) {
682         error_propagate(errp, local_err);
683         goto fail;
684     }
685 
686     qmp_blockdev_add(options, &local_err);
687 
688     if (local_err) {
689         error_propagate(errp, local_err);
690         goto fail;
691     }
692 
693     qapi_free_BlockdevOptions(options);
694 
695     return node_name;
696 
697 fail:
698     if (options) {
699         qapi_free_BlockdevOptions(options);
700     }
701     g_free(node_name);
702 
703     return NULL;
704 }
705 
706 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
707 {
708     char *node_name = drive->node_name;
709 
710     if (node_name) {
711         Error *local_err = NULL;
712 
713         xen_block_blockdev_del(node_name, &local_err);
714         if (local_err) {
715             error_propagate(errp, local_err);
716             return;
717         }
718         g_free(node_name);
719         drive->node_name = NULL;
720     }
721     g_free(drive->id);
722     g_free(drive);
723 }
724 
725 static XenBlockDrive *xen_block_drive_create(const char *id,
726                                              const char *device_type,
727                                              QDict *opts, Error **errp)
728 {
729     const char *params = qdict_get_try_str(opts, "params");
730     const char *mode = qdict_get_try_str(opts, "mode");
731     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
732     const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
733     char *driver = NULL;
734     char *filename = NULL;
735     XenBlockDrive *drive = NULL;
736     Error *local_err = NULL;
737     QDict *file_layer;
738     QDict *driver_layer;
739 
740     if (params) {
741         char **v = g_strsplit(params, ":", 2);
742 
743         if (v[1] == NULL) {
744             filename = g_strdup(v[0]);
745             driver = g_strdup("raw");
746         } else {
747             if (strcmp(v[0], "aio") == 0) {
748                 driver = g_strdup("raw");
749             } else if (strcmp(v[0], "vhd") == 0) {
750                 driver = g_strdup("vpc");
751             } else {
752                 driver = g_strdup(v[0]);
753             }
754             filename = g_strdup(v[1]);
755         }
756 
757         g_strfreev(v);
758     } else {
759         error_setg(errp, "no params");
760         goto done;
761     }
762 
763     assert(filename);
764     assert(driver);
765 
766     drive = g_new0(XenBlockDrive, 1);
767     drive->id = g_strdup(id);
768 
769     file_layer = qdict_new();
770     driver_layer = qdict_new();
771 
772     qdict_put_str(file_layer, "driver", "file");
773     qdict_put_str(file_layer, "filename", filename);
774     g_free(filename);
775 
776     if (mode && *mode != 'w') {
777         qdict_put_bool(file_layer, "read-only", true);
778     }
779 
780     if (direct_io_safe) {
781         unsigned long value;
782 
783         if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
784             QDict *cache_qdict = qdict_new();
785 
786             qdict_put_bool(cache_qdict, "direct", true);
787             qdict_put(file_layer, "cache", cache_qdict);
788 
789             qdict_put_str(file_layer, "aio", "native");
790         }
791     }
792 
793     if (discard_enable) {
794         unsigned long value;
795 
796         if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
797             qdict_put_str(file_layer, "discard", "unmap");
798             qdict_put_str(driver_layer, "discard", "unmap");
799         }
800     }
801 
802     /*
803      * It is necessary to turn file locking off as an emulated device
804      * may have already opened the same image file.
805      */
806     qdict_put_str(file_layer, "locking", "off");
807 
808     qdict_put_str(driver_layer, "driver", driver);
809     g_free(driver);
810 
811     qdict_put(driver_layer, "file", file_layer);
812 
813     g_assert(!drive->node_name);
814     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
815                                               &local_err);
816 
817     qobject_unref(driver_layer);
818 
819 done:
820     if (local_err) {
821         error_propagate(errp, local_err);
822         xen_block_drive_destroy(drive, NULL);
823         return NULL;
824     }
825 
826     return drive;
827 }
828 
829 static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
830 {
831     return drive->node_name ? drive->node_name : "";
832 }
833 
834 static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
835                                        Error **errp)
836 {
837     qmp_object_del(iothread->id, errp);
838 
839     g_free(iothread->id);
840     g_free(iothread);
841 }
842 
843 static XenBlockIOThread *xen_block_iothread_create(const char *id,
844                                                    Error **errp)
845 {
846     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
847     Error *local_err = NULL;
848 
849     iothread->id = g_strdup(id);
850 
851     qmp_object_add(TYPE_IOTHREAD, id, false, NULL, &local_err);
852     if (local_err) {
853         error_propagate(errp, local_err);
854 
855         g_free(iothread->id);
856         g_free(iothread);
857         return NULL;
858     }
859 
860     return iothread;
861 }
862 
863 static void xen_block_device_create(XenBackendInstance *backend,
864                                     QDict *opts, Error **errp)
865 {
866     XenBus *xenbus = xen_backend_get_bus(backend);
867     const char *name = xen_backend_get_name(backend);
868     unsigned long number;
869     const char *vdev, *device_type;
870     XenBlockDrive *drive = NULL;
871     XenBlockIOThread *iothread = NULL;
872     XenDevice *xendev = NULL;
873     Error *local_err = NULL;
874     const char *type;
875     XenBlockDevice *blockdev;
876 
877     if (qemu_strtoul(name, NULL, 10, &number)) {
878         error_setg(errp, "failed to parse name '%s'", name);
879         goto fail;
880     }
881 
882     trace_xen_block_device_create(number);
883 
884     vdev = qdict_get_try_str(opts, "dev");
885     if (!vdev) {
886         error_setg(errp, "no dev parameter");
887         goto fail;
888     }
889 
890     device_type = qdict_get_try_str(opts, "device-type");
891     if (!device_type) {
892         error_setg(errp, "no device-type parameter");
893         goto fail;
894     }
895 
896     if (!strcmp(device_type, "disk")) {
897         type = TYPE_XEN_DISK_DEVICE;
898     } else if (!strcmp(device_type, "cdrom")) {
899         type = TYPE_XEN_CDROM_DEVICE;
900     } else {
901         error_setg(errp, "invalid device-type parameter '%s'", device_type);
902         goto fail;
903     }
904 
905     drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
906     if (!drive) {
907         error_propagate_prepend(errp, local_err, "failed to create drive: ");
908         goto fail;
909     }
910 
911     iothread = xen_block_iothread_create(vdev, &local_err);
912     if (local_err) {
913         error_propagate_prepend(errp, local_err,
914                                 "failed to create iothread: ");
915         goto fail;
916     }
917 
918     xendev = XEN_DEVICE(qdev_create(BUS(xenbus), type));
919     blockdev = XEN_BLOCK_DEVICE(xendev);
920 
921     object_property_set_str(OBJECT(xendev), vdev, "vdev", &local_err);
922     if (local_err) {
923         error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
924         goto fail;
925     }
926 
927     object_property_set_str(OBJECT(xendev),
928                             xen_block_drive_get_node_name(drive), "drive",
929                             &local_err);
930     if (local_err) {
931         error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
932         goto fail;
933     }
934 
935     object_property_set_str(OBJECT(xendev), iothread->id, "iothread",
936                             &local_err);
937     if (local_err) {
938         error_propagate_prepend(errp, local_err,
939                                 "failed to set 'iothread': ");
940         goto fail;
941     }
942 
943     blockdev->iothread = iothread;
944     blockdev->drive = drive;
945 
946     object_property_set_bool(OBJECT(xendev), true, "realized", &local_err);
947     if (local_err) {
948         error_propagate_prepend(errp, local_err,
949                                 "realization of device %s failed: ",
950                                 type);
951         goto fail;
952     }
953 
954     xen_backend_set_device(backend, xendev);
955     return;
956 
957 fail:
958     if (xendev) {
959         object_unparent(OBJECT(xendev));
960     }
961 
962     if (iothread) {
963         xen_block_iothread_destroy(iothread, NULL);
964     }
965 
966     if (drive) {
967         xen_block_drive_destroy(drive, NULL);
968     }
969 }
970 
971 static void xen_block_device_destroy(XenBackendInstance *backend,
972                                      Error **errp)
973 {
974     XenDevice *xendev = xen_backend_get_device(backend);
975     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
976     XenBlockVdev *vdev = &blockdev->props.vdev;
977     XenBlockDrive *drive = blockdev->drive;
978     XenBlockIOThread *iothread = blockdev->iothread;
979 
980     trace_xen_block_device_destroy(vdev->number);
981 
982     object_unparent(OBJECT(xendev));
983 
984     if (iothread) {
985         Error *local_err = NULL;
986 
987         xen_block_iothread_destroy(iothread, &local_err);
988         if (local_err) {
989             error_propagate_prepend(errp, local_err,
990                                 "failed to destroy iothread: ");
991             return;
992         }
993     }
994 
995     if (drive) {
996         Error *local_err = NULL;
997 
998         xen_block_drive_destroy(drive, &local_err);
999         if (local_err) {
1000             error_propagate_prepend(errp, local_err,
1001                                 "failed to destroy drive: ");
1002         }
1003     }
1004 }
1005 
1006 static const XenBackendInfo xen_block_backend_info = {
1007     .type = "qdisk",
1008     .create = xen_block_device_create,
1009     .destroy = xen_block_device_destroy,
1010 };
1011 
1012 static void xen_block_register_backend(void)
1013 {
1014     xen_backend_register(&xen_block_backend_info);
1015 }
1016 
1017 xen_backend_init(xen_block_register_backend);
1018