xref: /qemu/hw/ppc/spapr_vio.c (revision e7b3af81) 
1 /*
2  * QEMU sPAPR VIO code
3  *
4  * Copyright (c) 2010 David Gibson, IBM Corporation <dwg@au1.ibm.com>
5  * Based on the s390 virtio bus code:
6  * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
7  *
8  * This library is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2 of the License, or (at your option) any later version.
12  *
13  * This library is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
20  */
21 
22 #include "qemu/osdep.h"
23 #include "qemu/error-report.h"
24 #include "qapi/error.h"
25 #include "qapi/visitor.h"
26 #include "hw/hw.h"
27 #include "qemu/log.h"
28 #include "sysemu/sysemu.h"
29 #include "hw/boards.h"
30 #include "hw/loader.h"
31 #include "elf.h"
32 #include "hw/sysbus.h"
33 #include "sysemu/kvm.h"
34 #include "sysemu/device_tree.h"
35 #include "kvm_ppc.h"
36 #include "sysemu/qtest.h"
37 
38 #include "hw/ppc/spapr.h"
39 #include "hw/ppc/spapr_vio.h"
40 #include "hw/ppc/xics.h"
41 #include "hw/ppc/fdt.h"
42 #include "trace.h"
43 
44 #include <libfdt.h>
45 
46 static void spapr_vio_getset_irq(Object *obj, Visitor *v, const char *name,
47                               void *opaque, Error **errp)
48 {
49     Property *prop = opaque;
50     uint32_t *ptr = qdev_get_prop_ptr(DEVICE(obj), prop);
51 
52     if (!qtest_enabled()) {
53         warn_report(TYPE_VIO_SPAPR_DEVICE " '%s' property is deprecated", name);
54     }
55     visit_type_uint32(v, name, ptr, errp);
56 }
57 
58 static const PropertyInfo spapr_vio_irq_propinfo = {
59     .name = "irq",
60     .get = spapr_vio_getset_irq,
61     .set = spapr_vio_getset_irq,
62 };
63 
64 static Property spapr_vio_props[] = {
65     DEFINE_PROP("irq", VIOsPAPRDevice, irq, spapr_vio_irq_propinfo, uint32_t),
66     DEFINE_PROP_END_OF_LIST(),
67 };
68 
69 static char *spapr_vio_get_dev_name(DeviceState *qdev)
70 {
71     VIOsPAPRDevice *dev = VIO_SPAPR_DEVICE(qdev);
72     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
73 
74     /* Device tree style name device@reg */
75     return g_strdup_printf("%s@%x", pc->dt_name, dev->reg);
76 }
77 
78 static void spapr_vio_bus_class_init(ObjectClass *klass, void *data)
79 {
80     BusClass *k = BUS_CLASS(klass);
81 
82     k->get_dev_path = spapr_vio_get_dev_name;
83     k->get_fw_dev_path = spapr_vio_get_dev_name;
84 }
85 
86 static const TypeInfo spapr_vio_bus_info = {
87     .name = TYPE_SPAPR_VIO_BUS,
88     .parent = TYPE_BUS,
89     .class_init = spapr_vio_bus_class_init,
90     .instance_size = sizeof(VIOsPAPRBus),
91 };
92 
93 VIOsPAPRDevice *spapr_vio_find_by_reg(VIOsPAPRBus *bus, uint32_t reg)
94 {
95     BusChild *kid;
96     VIOsPAPRDevice *dev = NULL;
97 
98     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
99         dev = (VIOsPAPRDevice *)kid->child;
100         if (dev->reg == reg) {
101             return dev;
102         }
103     }
104 
105     return NULL;
106 }
107 
108 static int vio_make_devnode(VIOsPAPRDevice *dev,
109                             void *fdt)
110 {
111     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
112     int vdevice_off, node_off, ret;
113     char *dt_name;
114 
115     vdevice_off = fdt_path_offset(fdt, "/vdevice");
116     if (vdevice_off < 0) {
117         return vdevice_off;
118     }
119 
120     dt_name = spapr_vio_get_dev_name(DEVICE(dev));
121     node_off = fdt_add_subnode(fdt, vdevice_off, dt_name);
122     g_free(dt_name);
123     if (node_off < 0) {
124         return node_off;
125     }
126 
127     ret = fdt_setprop_cell(fdt, node_off, "reg", dev->reg);
128     if (ret < 0) {
129         return ret;
130     }
131 
132     if (pc->dt_type) {
133         ret = fdt_setprop_string(fdt, node_off, "device_type",
134                                  pc->dt_type);
135         if (ret < 0) {
136             return ret;
137         }
138     }
139 
140     if (pc->dt_compatible) {
141         ret = fdt_setprop_string(fdt, node_off, "compatible",
142                                  pc->dt_compatible);
143         if (ret < 0) {
144             return ret;
145         }
146     }
147 
148     if (dev->irq) {
149         uint32_t ints_prop[2];
150 
151         spapr_dt_xics_irq(ints_prop, dev->irq, false);
152         ret = fdt_setprop(fdt, node_off, "interrupts", ints_prop,
153                           sizeof(ints_prop));
154         if (ret < 0) {
155             return ret;
156         }
157     }
158 
159     ret = spapr_tcet_dma_dt(fdt, node_off, "ibm,my-dma-window", dev->tcet);
160     if (ret < 0) {
161         return ret;
162     }
163 
164     if (pc->devnode) {
165         ret = (pc->devnode)(dev, fdt, node_off);
166         if (ret < 0) {
167             return ret;
168         }
169     }
170 
171     return node_off;
172 }
173 
174 /*
175  * CRQ handling
176  */
177 static target_ulong h_reg_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
178                               target_ulong opcode, target_ulong *args)
179 {
180     target_ulong reg = args[0];
181     target_ulong queue_addr = args[1];
182     target_ulong queue_len = args[2];
183     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
184 
185     if (!dev) {
186         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
187         return H_PARAMETER;
188     }
189 
190     /* We can't grok a queue size bigger than 256M for now */
191     if (queue_len < 0x1000 || queue_len > 0x10000000) {
192         hcall_dprintf("Queue size too small or too big (0x" TARGET_FMT_lx
193                       ")\n", queue_len);
194         return H_PARAMETER;
195     }
196 
197     /* Check queue alignment */
198     if (queue_addr & 0xfff) {
199         hcall_dprintf("Queue not aligned (0x" TARGET_FMT_lx ")\n", queue_addr);
200         return H_PARAMETER;
201     }
202 
203     /* Check if device supports CRQs */
204     if (!dev->crq.SendFunc) {
205         hcall_dprintf("Device does not support CRQ\n");
206         return H_NOT_FOUND;
207     }
208 
209     /* Already a queue ? */
210     if (dev->crq.qsize) {
211         hcall_dprintf("CRQ already registered\n");
212         return H_RESOURCE;
213     }
214     dev->crq.qladdr = queue_addr;
215     dev->crq.qsize = queue_len;
216     dev->crq.qnext = 0;
217 
218     trace_spapr_vio_h_reg_crq(reg, queue_addr, queue_len);
219     return H_SUCCESS;
220 }
221 
222 static target_ulong free_crq(VIOsPAPRDevice *dev)
223 {
224     dev->crq.qladdr = 0;
225     dev->crq.qsize = 0;
226     dev->crq.qnext = 0;
227 
228     trace_spapr_vio_free_crq(dev->reg);
229 
230     return H_SUCCESS;
231 }
232 
233 static target_ulong h_free_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
234                                target_ulong opcode, target_ulong *args)
235 {
236     target_ulong reg = args[0];
237     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
238 
239     if (!dev) {
240         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
241         return H_PARAMETER;
242     }
243 
244     return free_crq(dev);
245 }
246 
247 static target_ulong h_send_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
248                                target_ulong opcode, target_ulong *args)
249 {
250     target_ulong reg = args[0];
251     target_ulong msg_hi = args[1];
252     target_ulong msg_lo = args[2];
253     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
254     uint64_t crq_mangle[2];
255 
256     if (!dev) {
257         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
258         return H_PARAMETER;
259     }
260     crq_mangle[0] = cpu_to_be64(msg_hi);
261     crq_mangle[1] = cpu_to_be64(msg_lo);
262 
263     if (dev->crq.SendFunc) {
264         return dev->crq.SendFunc(dev, (uint8_t *)crq_mangle);
265     }
266 
267     return H_HARDWARE;
268 }
269 
270 static target_ulong h_enable_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
271                                  target_ulong opcode, target_ulong *args)
272 {
273     target_ulong reg = args[0];
274     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
275 
276     if (!dev) {
277         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
278         return H_PARAMETER;
279     }
280 
281     return 0;
282 }
283 
284 /* Returns negative error, 0 success, or positive: queue full */
285 int spapr_vio_send_crq(VIOsPAPRDevice *dev, uint8_t *crq)
286 {
287     int rc;
288     uint8_t byte;
289 
290     if (!dev->crq.qsize) {
291         error_report("spapr_vio_send_creq on uninitialized queue");
292         return -1;
293     }
294 
295     /* Maybe do a fast path for KVM just writing to the pages */
296     rc = spapr_vio_dma_read(dev, dev->crq.qladdr + dev->crq.qnext, &byte, 1);
297     if (rc) {
298         return rc;
299     }
300     if (byte != 0) {
301         return 1;
302     }
303 
304     rc = spapr_vio_dma_write(dev, dev->crq.qladdr + dev->crq.qnext + 8,
305                              &crq[8], 8);
306     if (rc) {
307         return rc;
308     }
309 
310     kvmppc_eieio();
311 
312     rc = spapr_vio_dma_write(dev, dev->crq.qladdr + dev->crq.qnext, crq, 8);
313     if (rc) {
314         return rc;
315     }
316 
317     dev->crq.qnext = (dev->crq.qnext + 16) % dev->crq.qsize;
318 
319     if (dev->signal_state & 1) {
320         qemu_irq_pulse(spapr_vio_qirq(dev));
321     }
322 
323     return 0;
324 }
325 
326 /* "quiesce" handling */
327 
328 static void spapr_vio_quiesce_one(VIOsPAPRDevice *dev)
329 {
330     if (dev->tcet) {
331         device_reset(DEVICE(dev->tcet));
332     }
333     free_crq(dev);
334 }
335 
336 void spapr_vio_set_bypass(VIOsPAPRDevice *dev, bool bypass)
337 {
338     if (!dev->tcet) {
339         return;
340     }
341 
342     memory_region_set_enabled(&dev->mrbypass, bypass);
343     memory_region_set_enabled(spapr_tce_get_iommu(dev->tcet), !bypass);
344 
345     dev->tcet->bypass = bypass;
346 }
347 
348 static void rtas_set_tce_bypass(PowerPCCPU *cpu, sPAPRMachineState *spapr,
349                                 uint32_t token,
350                                 uint32_t nargs, target_ulong args,
351                                 uint32_t nret, target_ulong rets)
352 {
353     VIOsPAPRBus *bus = spapr->vio_bus;
354     VIOsPAPRDevice *dev;
355     uint32_t unit, enable;
356 
357     if (nargs != 2) {
358         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
359         return;
360     }
361     unit = rtas_ld(args, 0);
362     enable = rtas_ld(args, 1);
363     dev = spapr_vio_find_by_reg(bus, unit);
364     if (!dev) {
365         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
366         return;
367     }
368 
369     if (!dev->tcet) {
370         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
371         return;
372     }
373 
374     spapr_vio_set_bypass(dev, !!enable);
375 
376     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
377 }
378 
379 static void rtas_quiesce(PowerPCCPU *cpu, sPAPRMachineState *spapr,
380                          uint32_t token,
381                          uint32_t nargs, target_ulong args,
382                          uint32_t nret, target_ulong rets)
383 {
384     VIOsPAPRBus *bus = spapr->vio_bus;
385     BusChild *kid;
386     VIOsPAPRDevice *dev = NULL;
387 
388     if (nargs != 0) {
389         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
390         return;
391     }
392 
393     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
394         dev = (VIOsPAPRDevice *)kid->child;
395         spapr_vio_quiesce_one(dev);
396     }
397 
398     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
399 }
400 
401 static VIOsPAPRDevice *reg_conflict(VIOsPAPRDevice *dev)
402 {
403     VIOsPAPRBus *bus = SPAPR_VIO_BUS(dev->qdev.parent_bus);
404     BusChild *kid;
405     VIOsPAPRDevice *other;
406 
407     /*
408      * Check for a device other than the given one which is already
409      * using the requested address. We have to open code this because
410      * the given dev might already be in the list.
411      */
412     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
413         other = VIO_SPAPR_DEVICE(kid->child);
414 
415         if (other != dev && other->reg == dev->reg) {
416             return other;
417         }
418     }
419 
420     return 0;
421 }
422 
423 static void spapr_vio_busdev_reset(DeviceState *qdev)
424 {
425     VIOsPAPRDevice *dev = VIO_SPAPR_DEVICE(qdev);
426     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
427 
428     /* Shut down the request queue and TCEs if necessary */
429     spapr_vio_quiesce_one(dev);
430 
431     dev->signal_state = 0;
432 
433     spapr_vio_set_bypass(dev, false);
434     if (pc->reset) {
435         pc->reset(dev);
436     }
437 }
438 
439 static void spapr_vio_busdev_realize(DeviceState *qdev, Error **errp)
440 {
441     sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
442     VIOsPAPRDevice *dev = (VIOsPAPRDevice *)qdev;
443     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
444     char *id;
445     Error *local_err = NULL;
446 
447     if (dev->reg != -1) {
448         /*
449          * Explicitly assigned address, just verify that no-one else
450          * is using it.  other mechanism). We have to open code this
451          * rather than using spapr_vio_find_by_reg() because sdev
452          * itself is already in the list.
453          */
454         VIOsPAPRDevice *other = reg_conflict(dev);
455 
456         if (other) {
457             error_setg(errp, "%s and %s devices conflict at address %#x",
458                        object_get_typename(OBJECT(qdev)),
459                        object_get_typename(OBJECT(&other->qdev)),
460                        dev->reg);
461             return;
462         }
463     } else {
464         /* Need to assign an address */
465         VIOsPAPRBus *bus = SPAPR_VIO_BUS(dev->qdev.parent_bus);
466 
467         do {
468             dev->reg = bus->next_reg++;
469         } while (reg_conflict(dev));
470     }
471 
472     /* Don't overwrite ids assigned on the command line */
473     if (!dev->qdev.id) {
474         id = spapr_vio_get_dev_name(DEVICE(dev));
475         dev->qdev.id = id;
476     }
477 
478     if (!dev->irq) {
479         dev->irq = spapr_irq_findone(spapr, &local_err);
480         if (local_err) {
481             error_propagate(errp, local_err);
482             return;
483         }
484     }
485 
486     spapr_irq_claim(spapr, dev->irq, false, &local_err);
487     if (local_err) {
488         error_propagate(errp, local_err);
489         return;
490     }
491 
492     if (pc->rtce_window_size) {
493         uint32_t liobn = SPAPR_VIO_LIOBN(dev->reg);
494 
495         memory_region_init(&dev->mrroot, OBJECT(dev), "iommu-spapr-root",
496                            ram_size);
497         memory_region_init_alias(&dev->mrbypass, OBJECT(dev),
498                                  "iommu-spapr-bypass", get_system_memory(),
499                                  0, ram_size);
500         memory_region_add_subregion_overlap(&dev->mrroot, 0, &dev->mrbypass, 1);
501         address_space_init(&dev->as, &dev->mrroot, qdev->id);
502 
503         dev->tcet = spapr_tce_new_table(qdev, liobn);
504         spapr_tce_table_enable(dev->tcet, SPAPR_TCE_PAGE_SHIFT, 0,
505                                pc->rtce_window_size >> SPAPR_TCE_PAGE_SHIFT);
506         dev->tcet->vdev = dev;
507         memory_region_add_subregion_overlap(&dev->mrroot, 0,
508                                             spapr_tce_get_iommu(dev->tcet), 2);
509     }
510 
511     pc->realize(dev, errp);
512 }
513 
514 static target_ulong h_vio_signal(PowerPCCPU *cpu, sPAPRMachineState *spapr,
515                                  target_ulong opcode,
516                                  target_ulong *args)
517 {
518     target_ulong reg = args[0];
519     target_ulong mode = args[1];
520     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
521     VIOsPAPRDeviceClass *pc;
522 
523     if (!dev) {
524         return H_PARAMETER;
525     }
526 
527     pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
528 
529     if (mode & ~pc->signal_mask) {
530         return H_PARAMETER;
531     }
532 
533     dev->signal_state = mode;
534 
535     return H_SUCCESS;
536 }
537 
538 VIOsPAPRBus *spapr_vio_bus_init(void)
539 {
540     VIOsPAPRBus *bus;
541     BusState *qbus;
542     DeviceState *dev;
543 
544     /* Create bridge device */
545     dev = qdev_create(NULL, TYPE_SPAPR_VIO_BRIDGE);
546     qdev_init_nofail(dev);
547 
548     /* Create bus on bridge device */
549     qbus = qbus_create(TYPE_SPAPR_VIO_BUS, dev, "spapr-vio");
550     bus = SPAPR_VIO_BUS(qbus);
551     bus->next_reg = 0x71000000;
552 
553     /* hcall-vio */
554     spapr_register_hypercall(H_VIO_SIGNAL, h_vio_signal);
555 
556     /* hcall-crq */
557     spapr_register_hypercall(H_REG_CRQ, h_reg_crq);
558     spapr_register_hypercall(H_FREE_CRQ, h_free_crq);
559     spapr_register_hypercall(H_SEND_CRQ, h_send_crq);
560     spapr_register_hypercall(H_ENABLE_CRQ, h_enable_crq);
561 
562     /* RTAS calls */
563     spapr_rtas_register(RTAS_IBM_SET_TCE_BYPASS, "ibm,set-tce-bypass",
564                         rtas_set_tce_bypass);
565     spapr_rtas_register(RTAS_QUIESCE, "quiesce", rtas_quiesce);
566 
567     return bus;
568 }
569 
570 static void spapr_vio_bridge_class_init(ObjectClass *klass, void *data)
571 {
572     DeviceClass *dc = DEVICE_CLASS(klass);
573 
574     dc->fw_name = "vdevice";
575 }
576 
577 static const TypeInfo spapr_vio_bridge_info = {
578     .name          = TYPE_SPAPR_VIO_BRIDGE,
579     .parent        = TYPE_SYS_BUS_DEVICE,
580     .class_init    = spapr_vio_bridge_class_init,
581 };
582 
583 const VMStateDescription vmstate_spapr_vio = {
584     .name = "spapr_vio",
585     .version_id = 1,
586     .minimum_version_id = 1,
587     .fields = (VMStateField[]) {
588         /* Sanity check */
589         VMSTATE_UINT32_EQUAL(reg, VIOsPAPRDevice, NULL),
590         VMSTATE_UINT32_EQUAL(irq, VIOsPAPRDevice, NULL),
591 
592         /* General VIO device state */
593         VMSTATE_UINT64(signal_state, VIOsPAPRDevice),
594         VMSTATE_UINT64(crq.qladdr, VIOsPAPRDevice),
595         VMSTATE_UINT32(crq.qsize, VIOsPAPRDevice),
596         VMSTATE_UINT32(crq.qnext, VIOsPAPRDevice),
597 
598         VMSTATE_END_OF_LIST()
599     },
600 };
601 
602 static void vio_spapr_device_class_init(ObjectClass *klass, void *data)
603 {
604     DeviceClass *k = DEVICE_CLASS(klass);
605     k->realize = spapr_vio_busdev_realize;
606     k->reset = spapr_vio_busdev_reset;
607     k->bus_type = TYPE_SPAPR_VIO_BUS;
608     k->props = spapr_vio_props;
609 }
610 
611 static const TypeInfo spapr_vio_type_info = {
612     .name = TYPE_VIO_SPAPR_DEVICE,
613     .parent = TYPE_DEVICE,
614     .instance_size = sizeof(VIOsPAPRDevice),
615     .abstract = true,
616     .class_size = sizeof(VIOsPAPRDeviceClass),
617     .class_init = vio_spapr_device_class_init,
618 };
619 
620 static void spapr_vio_register_types(void)
621 {
622     type_register_static(&spapr_vio_bus_info);
623     type_register_static(&spapr_vio_bridge_info);
624     type_register_static(&spapr_vio_type_info);
625 }
626 
627 type_init(spapr_vio_register_types)
628 
629 static int compare_reg(const void *p1, const void *p2)
630 {
631     VIOsPAPRDevice const *dev1, *dev2;
632 
633     dev1 = (VIOsPAPRDevice *)*(DeviceState **)p1;
634     dev2 = (VIOsPAPRDevice *)*(DeviceState **)p2;
635 
636     if (dev1->reg < dev2->reg) {
637         return -1;
638     }
639     if (dev1->reg == dev2->reg) {
640         return 0;
641     }
642 
643     /* dev1->reg > dev2->reg */
644     return 1;
645 }
646 
647 void spapr_dt_vdevice(VIOsPAPRBus *bus, void *fdt)
648 {
649     DeviceState *qdev, **qdevs;
650     BusChild *kid;
651     int i, num, ret = 0;
652     int node;
653 
654     _FDT(node = fdt_add_subnode(fdt, 0, "vdevice"));
655 
656     _FDT(fdt_setprop_string(fdt, node, "device_type", "vdevice"));
657     _FDT(fdt_setprop_string(fdt, node, "compatible", "IBM,vdevice"));
658     _FDT(fdt_setprop_cell(fdt, node, "#address-cells", 1));
659     _FDT(fdt_setprop_cell(fdt, node, "#size-cells", 0));
660     _FDT(fdt_setprop_cell(fdt, node, "#interrupt-cells", 2));
661     _FDT(fdt_setprop(fdt, node, "interrupt-controller", NULL, 0));
662 
663     /* Count qdevs on the bus list */
664     num = 0;
665     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
666         num++;
667     }
668 
669     /* Copy out into an array of pointers */
670     qdevs = g_malloc(sizeof(qdev) * num);
671     num = 0;
672     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
673         qdevs[num++] = kid->child;
674     }
675 
676     /* Sort the array */
677     qsort(qdevs, num, sizeof(qdev), compare_reg);
678 
679     /* Hack alert. Give the devices to libfdt in reverse order, we happen
680      * to know that will mean they are in forward order in the tree. */
681     for (i = num - 1; i >= 0; i--) {
682         VIOsPAPRDevice *dev = (VIOsPAPRDevice *)(qdevs[i]);
683         VIOsPAPRDeviceClass *vdc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
684 
685         ret = vio_make_devnode(dev, fdt);
686         if (ret < 0) {
687             error_report("Couldn't create device node /vdevice/%s@%"PRIx32,
688                          vdc->dt_name, dev->reg);
689             exit(1);
690         }
691     }
692 
693     g_free(qdevs);
694 }
695 
696 gchar *spapr_vio_stdout_path(VIOsPAPRBus *bus)
697 {
698     VIOsPAPRDevice *dev;
699     char *name, *path;
700 
701     dev = spapr_vty_get_default(bus);
702     if (!dev) {
703         return NULL;
704     }
705 
706     name = spapr_vio_get_dev_name(DEVICE(dev));
707     path = g_strdup_printf("/vdevice/%s", name);
708 
709     g_free(name);
710     return path;
711 }
712