xref: /openbmc/qemu/hw/block/xen-block.c (revision b11a093c)
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     char *str, *p;
407     const char *end;
408 
409     if (dev->realized) {
410         qdev_prop_set_after_realize(dev, name, errp);
411         return;
412     }
413 
414     if (!visit_type_str(v, name, &str, errp)) {
415         return;
416     }
417 
418     p = strchr(str, 'd');
419     if (!p) {
420         goto invalid;
421     }
422 
423     *p++ = '\0';
424     if (*str == '\0') {
425         vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
426     } else if (strcmp(str, "xv") == 0) {
427         vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
428     } else if (strcmp(str, "h") == 0) {
429         vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
430     } else if (strcmp(str, "s") == 0) {
431         vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
432     } else {
433         goto invalid;
434     }
435 
436     if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
437         if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
438             goto invalid;
439         }
440 
441         if (*end == 'p') {
442             if (*(++end) == '\0') {
443                 goto invalid;
444             }
445         }
446     } else {
447         if (vbd_name_to_disk(p, &end, &vdev->disk)) {
448             goto invalid;
449         }
450     }
451 
452     if (*end != '\0') {
453         p = (char *)end;
454 
455         if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
456             goto invalid;
457         }
458 
459         if (*end != '\0') {
460             goto invalid;
461         }
462     } else {
463         vdev->partition = 0;
464     }
465 
466     switch (vdev->type) {
467     case XEN_BLOCK_VDEV_TYPE_DP:
468     case XEN_BLOCK_VDEV_TYPE_XVD:
469         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
470             vdev->number = (202 << 8) | (vdev->disk << 4) |
471                 vdev->partition;
472         } else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
473             vdev->number = (1 << 28) | (vdev->disk << 8) |
474                 vdev->partition;
475         } else {
476             goto invalid;
477         }
478         break;
479 
480     case XEN_BLOCK_VDEV_TYPE_HD:
481         if ((vdev->disk == 0 || vdev->disk == 1) &&
482             vdev->partition < (1 << 6)) {
483             vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
484         } else if ((vdev->disk == 2 || vdev->disk == 3) &&
485                    vdev->partition < (1 << 6)) {
486             vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
487                 vdev->partition;
488         } else {
489             goto invalid;
490         }
491         break;
492 
493     case XEN_BLOCK_VDEV_TYPE_SD:
494         if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
495             vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
496         } else {
497             goto invalid;
498         }
499         break;
500 
501     default:
502         goto invalid;
503     }
504 
505     g_free(str);
506     return;
507 
508 invalid:
509     error_setg(errp, "invalid virtual disk specifier");
510 
511     vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
512     g_free(str);
513 }
514 
515 /*
516  * This property deals with 'vdev' names adhering to the Xen VBD naming
517  * scheme described in:
518  *
519  * https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
520  */
521 const PropertyInfo xen_block_prop_vdev = {
522     .name  = "str",
523     .description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
524     .get = xen_block_get_vdev,
525     .set = xen_block_set_vdev,
526 };
527 
528 static Property xen_block_props[] = {
529     DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
530                 xen_block_prop_vdev, XenBlockVdev),
531     DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
532     DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
533                        props.max_ring_page_order, 4),
534     DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
535                      TYPE_IOTHREAD, IOThread *),
536     DEFINE_PROP_END_OF_LIST()
537 };
538 
539 static void xen_block_class_init(ObjectClass *class, void *data)
540 {
541     DeviceClass *dev_class = DEVICE_CLASS(class);
542     XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
543 
544     xendev_class->backend = "qdisk";
545     xendev_class->device = "vbd";
546     xendev_class->get_name = xen_block_get_name;
547     xendev_class->realize = xen_block_realize;
548     xendev_class->frontend_changed = xen_block_frontend_changed;
549     xendev_class->unrealize = xen_block_unrealize;
550 
551     device_class_set_props(dev_class, xen_block_props);
552 }
553 
554 static const TypeInfo xen_block_type_info = {
555     .name = TYPE_XEN_BLOCK_DEVICE,
556     .parent = TYPE_XEN_DEVICE,
557     .instance_size = sizeof(XenBlockDevice),
558     .abstract = true,
559     .class_size = sizeof(XenBlockDeviceClass),
560     .class_init = xen_block_class_init,
561 };
562 
563 static void xen_disk_unrealize(XenBlockDevice *blockdev)
564 {
565     trace_xen_disk_unrealize();
566 }
567 
568 static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
569 {
570     BlockConf *conf = &blockdev->props.conf;
571 
572     trace_xen_disk_realize();
573 
574     blockdev->device_type = "disk";
575 
576     if (!conf->blk) {
577         error_setg(errp, "drive property not set");
578         return;
579     }
580 
581     blockdev->info = blk_is_read_only(conf->blk) ? VDISK_READONLY : 0;
582 }
583 
584 static void xen_disk_class_init(ObjectClass *class, void *data)
585 {
586     DeviceClass *dev_class = DEVICE_CLASS(class);
587     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
588 
589     blockdev_class->realize = xen_disk_realize;
590     blockdev_class->unrealize = xen_disk_unrealize;
591 
592     dev_class->desc = "Xen Disk Device";
593 }
594 
595 static const TypeInfo xen_disk_type_info = {
596     .name = TYPE_XEN_DISK_DEVICE,
597     .parent = TYPE_XEN_BLOCK_DEVICE,
598     .instance_size = sizeof(XenDiskDevice),
599     .class_init = xen_disk_class_init,
600 };
601 
602 static void xen_cdrom_unrealize(XenBlockDevice *blockdev)
603 {
604     trace_xen_cdrom_unrealize();
605 }
606 
607 static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
608 {
609     BlockConf *conf = &blockdev->props.conf;
610 
611     trace_xen_cdrom_realize();
612 
613     blockdev->device_type = "cdrom";
614 
615     if (!conf->blk) {
616         int rc;
617 
618         /* Set up an empty drive */
619         conf->blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
620 
621         rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
622         if (!rc) {
623             error_setg_errno(errp, -rc, "failed to create drive");
624             return;
625         }
626     }
627 
628     blockdev->info = VDISK_READONLY | VDISK_CDROM;
629 }
630 
631 static void xen_cdrom_class_init(ObjectClass *class, void *data)
632 {
633     DeviceClass *dev_class = DEVICE_CLASS(class);
634     XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
635 
636     blockdev_class->realize = xen_cdrom_realize;
637     blockdev_class->unrealize = xen_cdrom_unrealize;
638 
639     dev_class->desc = "Xen CD-ROM Device";
640 }
641 
642 static const TypeInfo xen_cdrom_type_info = {
643     .name = TYPE_XEN_CDROM_DEVICE,
644     .parent = TYPE_XEN_BLOCK_DEVICE,
645     .instance_size = sizeof(XenCDRomDevice),
646     .class_init = xen_cdrom_class_init,
647 };
648 
649 static void xen_block_register_types(void)
650 {
651     type_register_static(&xen_block_type_info);
652     type_register_static(&xen_disk_type_info);
653     type_register_static(&xen_cdrom_type_info);
654 }
655 
656 type_init(xen_block_register_types)
657 
658 static void xen_block_blockdev_del(const char *node_name, Error **errp)
659 {
660     trace_xen_block_blockdev_del(node_name);
661 
662     qmp_blockdev_del(node_name, errp);
663 }
664 
665 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
666                                     Error **errp)
667 {
668     const char *driver = qdict_get_try_str(qdict, "driver");
669     BlockdevOptions *options = NULL;
670     Error *local_err = NULL;
671     char *node_name;
672     Visitor *v;
673 
674     if (!driver) {
675         error_setg(errp, "no 'driver' parameter");
676         return NULL;
677     }
678 
679     node_name = g_strdup_printf("%s-%s", id, driver);
680     qdict_put_str(qdict, "node-name", node_name);
681 
682     trace_xen_block_blockdev_add(node_name);
683 
684     v = qobject_input_visitor_new(QOBJECT(qdict));
685     visit_type_BlockdevOptions(v, NULL, &options, errp);
686     visit_free(v);
687     if (!options) {
688         goto fail;
689     }
690 
691     qmp_blockdev_add(options, &local_err);
692 
693     if (local_err) {
694         error_propagate(errp, local_err);
695         goto fail;
696     }
697 
698     qapi_free_BlockdevOptions(options);
699 
700     return node_name;
701 
702 fail:
703     if (options) {
704         qapi_free_BlockdevOptions(options);
705     }
706     g_free(node_name);
707 
708     return NULL;
709 }
710 
711 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
712 {
713     char *node_name = drive->node_name;
714 
715     if (node_name) {
716         Error *local_err = NULL;
717 
718         xen_block_blockdev_del(node_name, &local_err);
719         if (local_err) {
720             error_propagate(errp, local_err);
721             return;
722         }
723         g_free(node_name);
724         drive->node_name = NULL;
725     }
726     g_free(drive->id);
727     g_free(drive);
728 }
729 
730 static XenBlockDrive *xen_block_drive_create(const char *id,
731                                              const char *device_type,
732                                              QDict *opts, Error **errp)
733 {
734     const char *params = qdict_get_try_str(opts, "params");
735     const char *mode = qdict_get_try_str(opts, "mode");
736     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
737     const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
738     char *driver = NULL;
739     char *filename = NULL;
740     XenBlockDrive *drive = NULL;
741     Error *local_err = NULL;
742     QDict *file_layer;
743     QDict *driver_layer;
744 
745     if (params) {
746         char **v = g_strsplit(params, ":", 2);
747 
748         if (v[1] == NULL) {
749             filename = g_strdup(v[0]);
750             driver = g_strdup("raw");
751         } else {
752             if (strcmp(v[0], "aio") == 0) {
753                 driver = g_strdup("raw");
754             } else if (strcmp(v[0], "vhd") == 0) {
755                 driver = g_strdup("vpc");
756             } else {
757                 driver = g_strdup(v[0]);
758             }
759             filename = g_strdup(v[1]);
760         }
761 
762         g_strfreev(v);
763     } else {
764         error_setg(errp, "no params");
765         goto done;
766     }
767 
768     assert(filename);
769     assert(driver);
770 
771     drive = g_new0(XenBlockDrive, 1);
772     drive->id = g_strdup(id);
773 
774     file_layer = qdict_new();
775     driver_layer = qdict_new();
776 
777     qdict_put_str(file_layer, "driver", "file");
778     qdict_put_str(file_layer, "filename", filename);
779     g_free(filename);
780 
781     if (mode && *mode != 'w') {
782         qdict_put_bool(file_layer, "read-only", true);
783     }
784 
785     if (direct_io_safe) {
786         unsigned long value;
787 
788         if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
789             QDict *cache_qdict = qdict_new();
790 
791             qdict_put_bool(cache_qdict, "direct", true);
792             qdict_put(file_layer, "cache", cache_qdict);
793 
794             qdict_put_str(file_layer, "aio", "native");
795         }
796     }
797 
798     if (discard_enable) {
799         unsigned long value;
800 
801         if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
802             qdict_put_str(file_layer, "discard", "unmap");
803             qdict_put_str(driver_layer, "discard", "unmap");
804         }
805     }
806 
807     /*
808      * It is necessary to turn file locking off as an emulated device
809      * may have already opened the same image file.
810      */
811     qdict_put_str(file_layer, "locking", "off");
812 
813     qdict_put_str(driver_layer, "driver", driver);
814     g_free(driver);
815 
816     qdict_put(driver_layer, "file", file_layer);
817 
818     g_assert(!drive->node_name);
819     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
820                                               &local_err);
821 
822     qobject_unref(driver_layer);
823 
824 done:
825     if (local_err) {
826         error_propagate(errp, local_err);
827         xen_block_drive_destroy(drive, NULL);
828         return NULL;
829     }
830 
831     return drive;
832 }
833 
834 static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
835 {
836     return drive->node_name ? drive->node_name : "";
837 }
838 
839 static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
840                                        Error **errp)
841 {
842     qmp_object_del(iothread->id, errp);
843 
844     g_free(iothread->id);
845     g_free(iothread);
846 }
847 
848 static XenBlockIOThread *xen_block_iothread_create(const char *id,
849                                                    Error **errp)
850 {
851     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
852     Error *local_err = NULL;
853     QDict *opts;
854     QObject *ret_data = NULL;
855 
856     iothread->id = g_strdup(id);
857 
858     opts = qdict_new();
859     qdict_put_str(opts, "qom-type", TYPE_IOTHREAD);
860     qdict_put_str(opts, "id", id);
861     qmp_object_add(opts, &ret_data, &local_err);
862     qobject_unref(opts);
863     qobject_unref(ret_data);
864 
865     if (local_err) {
866         error_propagate(errp, local_err);
867 
868         g_free(iothread->id);
869         g_free(iothread);
870         return NULL;
871     }
872 
873     return iothread;
874 }
875 
876 static void xen_block_device_create(XenBackendInstance *backend,
877                                     QDict *opts, Error **errp)
878 {
879     XenBus *xenbus = xen_backend_get_bus(backend);
880     const char *name = xen_backend_get_name(backend);
881     unsigned long number;
882     const char *vdev, *device_type;
883     XenBlockDrive *drive = NULL;
884     XenBlockIOThread *iothread = NULL;
885     XenDevice *xendev = NULL;
886     Error *local_err = NULL;
887     const char *type;
888     XenBlockDevice *blockdev;
889 
890     if (qemu_strtoul(name, NULL, 10, &number)) {
891         error_setg(errp, "failed to parse name '%s'", name);
892         goto fail;
893     }
894 
895     trace_xen_block_device_create(number);
896 
897     vdev = qdict_get_try_str(opts, "dev");
898     if (!vdev) {
899         error_setg(errp, "no dev parameter");
900         goto fail;
901     }
902 
903     device_type = qdict_get_try_str(opts, "device-type");
904     if (!device_type) {
905         error_setg(errp, "no device-type parameter");
906         goto fail;
907     }
908 
909     if (!strcmp(device_type, "disk")) {
910         type = TYPE_XEN_DISK_DEVICE;
911     } else if (!strcmp(device_type, "cdrom")) {
912         type = TYPE_XEN_CDROM_DEVICE;
913     } else {
914         error_setg(errp, "invalid device-type parameter '%s'", device_type);
915         goto fail;
916     }
917 
918     drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
919     if (!drive) {
920         error_propagate_prepend(errp, local_err, "failed to create drive: ");
921         goto fail;
922     }
923 
924     iothread = xen_block_iothread_create(vdev, &local_err);
925     if (local_err) {
926         error_propagate_prepend(errp, local_err,
927                                 "failed to create iothread: ");
928         goto fail;
929     }
930 
931     xendev = XEN_DEVICE(qdev_new(type));
932     blockdev = XEN_BLOCK_DEVICE(xendev);
933 
934     if (!object_property_set_str(OBJECT(xendev), "vdev", vdev,
935                                  &local_err)) {
936         error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
937         goto fail;
938     }
939 
940     if (!object_property_set_str(OBJECT(xendev), "drive",
941                                  xen_block_drive_get_node_name(drive),
942                                  &local_err)) {
943         error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
944         goto fail;
945     }
946 
947     if (!object_property_set_str(OBJECT(xendev), "iothread", iothread->id,
948                                  &local_err)) {
949         error_propagate_prepend(errp, local_err,
950                                 "failed to set 'iothread': ");
951         goto fail;
952     }
953 
954     blockdev->iothread = iothread;
955     blockdev->drive = drive;
956 
957     if (!qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), &local_err)) {
958         error_propagate_prepend(errp, local_err,
959                                 "realization of device %s failed: ",
960                                 type);
961         goto fail;
962     }
963 
964     xen_backend_set_device(backend, xendev);
965     return;
966 
967 fail:
968     if (xendev) {
969         object_unparent(OBJECT(xendev));
970     }
971 
972     if (iothread) {
973         xen_block_iothread_destroy(iothread, NULL);
974     }
975 
976     if (drive) {
977         xen_block_drive_destroy(drive, NULL);
978     }
979 }
980 
981 static void xen_block_device_destroy(XenBackendInstance *backend,
982                                      Error **errp)
983 {
984     XenDevice *xendev = xen_backend_get_device(backend);
985     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
986     XenBlockVdev *vdev = &blockdev->props.vdev;
987     XenBlockDrive *drive = blockdev->drive;
988     XenBlockIOThread *iothread = blockdev->iothread;
989     Error *local_err = NULL;
990 
991     trace_xen_block_device_destroy(vdev->number);
992 
993     object_unparent(OBJECT(xendev));
994 
995     if (iothread) {
996         xen_block_iothread_destroy(iothread, &local_err);
997         if (local_err) {
998             error_propagate_prepend(errp, local_err,
999                                     "failed to destroy iothread: ");
1000             return;
1001         }
1002     }
1003 
1004     if (drive) {
1005         xen_block_drive_destroy(drive, &local_err);
1006         if (local_err) {
1007             error_propagate_prepend(errp, local_err,
1008                                     "failed to destroy drive: ");
1009             return;
1010         }
1011     }
1012 }
1013 
1014 static const XenBackendInfo xen_block_backend_info = {
1015     .type = "qdisk",
1016     .create = xen_block_device_create,
1017     .destroy = xen_block_device_destroy,
1018 };
1019 
1020 static void xen_block_register_backend(void)
1021 {
1022     xen_backend_register(&xen_block_backend_info);
1023 }
1024 
1025 xen_backend_init(xen_block_register_backend);
1026