xref: /openbmc/qemu/hw/ppc/spapr_vio.c (revision 9c5ce8db2e5c2769ed2fd3d91928dd1853b5ce7c)
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 "hw/hw.h"
26 #include "qemu/log.h"
27 #include "sysemu/sysemu.h"
28 #include "hw/boards.h"
29 #include "hw/loader.h"
30 #include "elf.h"
31 #include "hw/sysbus.h"
32 #include "sysemu/kvm.h"
33 #include "sysemu/device_tree.h"
34 #include "kvm_ppc.h"
35 
36 #include "hw/ppc/spapr.h"
37 #include "hw/ppc/spapr_vio.h"
38 #include "hw/ppc/xics.h"
39 
40 #include <libfdt.h>
41 
42 /* #define DEBUG_SPAPR */
43 
44 #ifdef DEBUG_SPAPR
45 #define DPRINTF(fmt, ...) \
46     do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
47 #else
48 #define DPRINTF(fmt, ...) \
49     do { } while (0)
50 #endif
51 
52 static Property spapr_vio_props[] = {
53     DEFINE_PROP_UINT32("irq", VIOsPAPRDevice, irq, 0), \
54     DEFINE_PROP_END_OF_LIST(),
55 };
56 
57 static char *spapr_vio_get_dev_name(DeviceState *qdev)
58 {
59     VIOsPAPRDevice *dev = VIO_SPAPR_DEVICE(qdev);
60     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
61 
62     /* Device tree style name device@reg */
63     return g_strdup_printf("%s@%x", pc->dt_name, dev->reg);
64 }
65 
66 static void spapr_vio_bus_class_init(ObjectClass *klass, void *data)
67 {
68     BusClass *k = BUS_CLASS(klass);
69 
70     k->get_dev_path = spapr_vio_get_dev_name;
71     k->get_fw_dev_path = spapr_vio_get_dev_name;
72 }
73 
74 static const TypeInfo spapr_vio_bus_info = {
75     .name = TYPE_SPAPR_VIO_BUS,
76     .parent = TYPE_BUS,
77     .class_init = spapr_vio_bus_class_init,
78     .instance_size = sizeof(VIOsPAPRBus),
79 };
80 
81 VIOsPAPRDevice *spapr_vio_find_by_reg(VIOsPAPRBus *bus, uint32_t reg)
82 {
83     BusChild *kid;
84     VIOsPAPRDevice *dev = NULL;
85 
86     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
87         dev = (VIOsPAPRDevice *)kid->child;
88         if (dev->reg == reg) {
89             return dev;
90         }
91     }
92 
93     return NULL;
94 }
95 
96 static int vio_make_devnode(VIOsPAPRDevice *dev,
97                             void *fdt)
98 {
99     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
100     int vdevice_off, node_off, ret;
101     char *dt_name;
102 
103     vdevice_off = fdt_path_offset(fdt, "/vdevice");
104     if (vdevice_off < 0) {
105         return vdevice_off;
106     }
107 
108     dt_name = spapr_vio_get_dev_name(DEVICE(dev));
109     node_off = fdt_add_subnode(fdt, vdevice_off, dt_name);
110     g_free(dt_name);
111     if (node_off < 0) {
112         return node_off;
113     }
114 
115     ret = fdt_setprop_cell(fdt, node_off, "reg", dev->reg);
116     if (ret < 0) {
117         return ret;
118     }
119 
120     if (pc->dt_type) {
121         ret = fdt_setprop_string(fdt, node_off, "device_type",
122                                  pc->dt_type);
123         if (ret < 0) {
124             return ret;
125         }
126     }
127 
128     if (pc->dt_compatible) {
129         ret = fdt_setprop_string(fdt, node_off, "compatible",
130                                  pc->dt_compatible);
131         if (ret < 0) {
132             return ret;
133         }
134     }
135 
136     if (dev->irq) {
137         uint32_t ints_prop[] = {cpu_to_be32(dev->irq), 0};
138 
139         ret = fdt_setprop(fdt, node_off, "interrupts", ints_prop,
140                           sizeof(ints_prop));
141         if (ret < 0) {
142             return ret;
143         }
144     }
145 
146     ret = spapr_tcet_dma_dt(fdt, node_off, "ibm,my-dma-window", dev->tcet);
147     if (ret < 0) {
148         return ret;
149     }
150 
151     if (pc->devnode) {
152         ret = (pc->devnode)(dev, fdt, node_off);
153         if (ret < 0) {
154             return ret;
155         }
156     }
157 
158     return node_off;
159 }
160 
161 /*
162  * CRQ handling
163  */
164 static target_ulong h_reg_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
165                               target_ulong opcode, target_ulong *args)
166 {
167     target_ulong reg = args[0];
168     target_ulong queue_addr = args[1];
169     target_ulong queue_len = args[2];
170     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
171 
172     if (!dev) {
173         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
174         return H_PARAMETER;
175     }
176 
177     /* We can't grok a queue size bigger than 256M for now */
178     if (queue_len < 0x1000 || queue_len > 0x10000000) {
179         hcall_dprintf("Queue size too small or too big (0x" TARGET_FMT_lx
180                       ")\n", queue_len);
181         return H_PARAMETER;
182     }
183 
184     /* Check queue alignment */
185     if (queue_addr & 0xfff) {
186         hcall_dprintf("Queue not aligned (0x" TARGET_FMT_lx ")\n", queue_addr);
187         return H_PARAMETER;
188     }
189 
190     /* Check if device supports CRQs */
191     if (!dev->crq.SendFunc) {
192         hcall_dprintf("Device does not support CRQ\n");
193         return H_NOT_FOUND;
194     }
195 
196     /* Already a queue ? */
197     if (dev->crq.qsize) {
198         hcall_dprintf("CRQ already registered\n");
199         return H_RESOURCE;
200     }
201     dev->crq.qladdr = queue_addr;
202     dev->crq.qsize = queue_len;
203     dev->crq.qnext = 0;
204 
205     DPRINTF("CRQ for dev 0x" TARGET_FMT_lx " registered at 0x"
206             TARGET_FMT_lx "/0x" TARGET_FMT_lx "\n",
207             reg, queue_addr, queue_len);
208     return H_SUCCESS;
209 }
210 
211 static target_ulong free_crq(VIOsPAPRDevice *dev)
212 {
213     dev->crq.qladdr = 0;
214     dev->crq.qsize = 0;
215     dev->crq.qnext = 0;
216 
217     DPRINTF("CRQ for dev 0x%" PRIx32 " freed\n", dev->reg);
218 
219     return H_SUCCESS;
220 }
221 
222 static target_ulong h_free_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
223                                target_ulong opcode, target_ulong *args)
224 {
225     target_ulong reg = args[0];
226     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
227 
228     if (!dev) {
229         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
230         return H_PARAMETER;
231     }
232 
233     return free_crq(dev);
234 }
235 
236 static target_ulong h_send_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
237                                target_ulong opcode, target_ulong *args)
238 {
239     target_ulong reg = args[0];
240     target_ulong msg_hi = args[1];
241     target_ulong msg_lo = args[2];
242     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
243     uint64_t crq_mangle[2];
244 
245     if (!dev) {
246         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
247         return H_PARAMETER;
248     }
249     crq_mangle[0] = cpu_to_be64(msg_hi);
250     crq_mangle[1] = cpu_to_be64(msg_lo);
251 
252     if (dev->crq.SendFunc) {
253         return dev->crq.SendFunc(dev, (uint8_t *)crq_mangle);
254     }
255 
256     return H_HARDWARE;
257 }
258 
259 static target_ulong h_enable_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
260                                  target_ulong opcode, target_ulong *args)
261 {
262     target_ulong reg = args[0];
263     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
264 
265     if (!dev) {
266         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
267         return H_PARAMETER;
268     }
269 
270     return 0;
271 }
272 
273 /* Returns negative error, 0 success, or positive: queue full */
274 int spapr_vio_send_crq(VIOsPAPRDevice *dev, uint8_t *crq)
275 {
276     int rc;
277     uint8_t byte;
278 
279     if (!dev->crq.qsize) {
280         error_report("spapr_vio_send_creq on uninitialized queue");
281         return -1;
282     }
283 
284     /* Maybe do a fast path for KVM just writing to the pages */
285     rc = spapr_vio_dma_read(dev, dev->crq.qladdr + dev->crq.qnext, &byte, 1);
286     if (rc) {
287         return rc;
288     }
289     if (byte != 0) {
290         return 1;
291     }
292 
293     rc = spapr_vio_dma_write(dev, dev->crq.qladdr + dev->crq.qnext + 8,
294                              &crq[8], 8);
295     if (rc) {
296         return rc;
297     }
298 
299     kvmppc_eieio();
300 
301     rc = spapr_vio_dma_write(dev, dev->crq.qladdr + dev->crq.qnext, crq, 8);
302     if (rc) {
303         return rc;
304     }
305 
306     dev->crq.qnext = (dev->crq.qnext + 16) % dev->crq.qsize;
307 
308     if (dev->signal_state & 1) {
309         qemu_irq_pulse(spapr_vio_qirq(dev));
310     }
311 
312     return 0;
313 }
314 
315 /* "quiesce" handling */
316 
317 static void spapr_vio_quiesce_one(VIOsPAPRDevice *dev)
318 {
319     if (dev->tcet) {
320         device_reset(DEVICE(dev->tcet));
321     }
322     free_crq(dev);
323 }
324 
325 void spapr_vio_set_bypass(VIOsPAPRDevice *dev, bool bypass)
326 {
327     if (!dev->tcet) {
328         return;
329     }
330 
331     memory_region_set_enabled(&dev->mrbypass, bypass);
332     memory_region_set_enabled(spapr_tce_get_iommu(dev->tcet), !bypass);
333 
334     dev->tcet->bypass = bypass;
335 }
336 
337 static void rtas_set_tce_bypass(PowerPCCPU *cpu, sPAPRMachineState *spapr,
338                                 uint32_t token,
339                                 uint32_t nargs, target_ulong args,
340                                 uint32_t nret, target_ulong rets)
341 {
342     VIOsPAPRBus *bus = spapr->vio_bus;
343     VIOsPAPRDevice *dev;
344     uint32_t unit, enable;
345 
346     if (nargs != 2) {
347         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
348         return;
349     }
350     unit = rtas_ld(args, 0);
351     enable = rtas_ld(args, 1);
352     dev = spapr_vio_find_by_reg(bus, unit);
353     if (!dev) {
354         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
355         return;
356     }
357 
358     if (!dev->tcet) {
359         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
360         return;
361     }
362 
363     spapr_vio_set_bypass(dev, !!enable);
364 
365     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
366 }
367 
368 static void rtas_quiesce(PowerPCCPU *cpu, sPAPRMachineState *spapr,
369                          uint32_t token,
370                          uint32_t nargs, target_ulong args,
371                          uint32_t nret, target_ulong rets)
372 {
373     VIOsPAPRBus *bus = spapr->vio_bus;
374     BusChild *kid;
375     VIOsPAPRDevice *dev = NULL;
376 
377     if (nargs != 0) {
378         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
379         return;
380     }
381 
382     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
383         dev = (VIOsPAPRDevice *)kid->child;
384         spapr_vio_quiesce_one(dev);
385     }
386 
387     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
388 }
389 
390 static VIOsPAPRDevice *reg_conflict(VIOsPAPRDevice *dev)
391 {
392     VIOsPAPRBus *bus = SPAPR_VIO_BUS(dev->qdev.parent_bus);
393     BusChild *kid;
394     VIOsPAPRDevice *other;
395 
396     /*
397      * Check for a device other than the given one which is already
398      * using the requested address. We have to open code this because
399      * the given dev might already be in the list.
400      */
401     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
402         other = VIO_SPAPR_DEVICE(kid->child);
403 
404         if (other != dev && other->reg == dev->reg) {
405             return other;
406         }
407     }
408 
409     return 0;
410 }
411 
412 static void spapr_vio_busdev_reset(DeviceState *qdev)
413 {
414     VIOsPAPRDevice *dev = VIO_SPAPR_DEVICE(qdev);
415     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
416 
417     /* Shut down the request queue and TCEs if necessary */
418     spapr_vio_quiesce_one(dev);
419 
420     dev->signal_state = 0;
421 
422     spapr_vio_set_bypass(dev, false);
423     if (pc->reset) {
424         pc->reset(dev);
425     }
426 }
427 
428 static void spapr_vio_busdev_realize(DeviceState *qdev, Error **errp)
429 {
430     sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
431     VIOsPAPRDevice *dev = (VIOsPAPRDevice *)qdev;
432     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
433     char *id;
434     Error *local_err = NULL;
435 
436     if (dev->reg != -1) {
437         /*
438          * Explicitly assigned address, just verify that no-one else
439          * is using it.  other mechanism). We have to open code this
440          * rather than using spapr_vio_find_by_reg() because sdev
441          * itself is already in the list.
442          */
443         VIOsPAPRDevice *other = reg_conflict(dev);
444 
445         if (other) {
446             error_setg(errp, "%s and %s devices conflict at address %#x",
447                        object_get_typename(OBJECT(qdev)),
448                        object_get_typename(OBJECT(&other->qdev)),
449                        dev->reg);
450             return;
451         }
452     } else {
453         /* Need to assign an address */
454         VIOsPAPRBus *bus = SPAPR_VIO_BUS(dev->qdev.parent_bus);
455 
456         do {
457             dev->reg = bus->next_reg++;
458         } while (reg_conflict(dev));
459     }
460 
461     /* Don't overwrite ids assigned on the command line */
462     if (!dev->qdev.id) {
463         id = spapr_vio_get_dev_name(DEVICE(dev));
464         dev->qdev.id = id;
465     }
466 
467     dev->irq = xics_spapr_alloc(spapr->xics, 0, dev->irq, false, &local_err);
468     if (local_err) {
469         error_propagate(errp, local_err);
470         return;
471     }
472 
473     if (pc->rtce_window_size) {
474         uint32_t liobn = SPAPR_VIO_LIOBN(dev->reg);
475 
476         memory_region_init(&dev->mrroot, OBJECT(dev), "iommu-spapr-root",
477                            ram_size);
478         memory_region_init_alias(&dev->mrbypass, OBJECT(dev),
479                                  "iommu-spapr-bypass", get_system_memory(),
480                                  0, ram_size);
481         memory_region_add_subregion_overlap(&dev->mrroot, 0, &dev->mrbypass, 1);
482         address_space_init(&dev->as, &dev->mrroot, qdev->id);
483 
484         dev->tcet = spapr_tce_new_table(qdev, liobn);
485         spapr_tce_table_enable(dev->tcet, SPAPR_TCE_PAGE_SHIFT, 0,
486                                pc->rtce_window_size >> SPAPR_TCE_PAGE_SHIFT);
487         dev->tcet->vdev = dev;
488         memory_region_add_subregion_overlap(&dev->mrroot, 0,
489                                             spapr_tce_get_iommu(dev->tcet), 2);
490     }
491 
492     pc->realize(dev, errp);
493 }
494 
495 static target_ulong h_vio_signal(PowerPCCPU *cpu, sPAPRMachineState *spapr,
496                                  target_ulong opcode,
497                                  target_ulong *args)
498 {
499     target_ulong reg = args[0];
500     target_ulong mode = args[1];
501     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
502     VIOsPAPRDeviceClass *pc;
503 
504     if (!dev) {
505         return H_PARAMETER;
506     }
507 
508     pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
509 
510     if (mode & ~pc->signal_mask) {
511         return H_PARAMETER;
512     }
513 
514     dev->signal_state = mode;
515 
516     return H_SUCCESS;
517 }
518 
519 VIOsPAPRBus *spapr_vio_bus_init(void)
520 {
521     VIOsPAPRBus *bus;
522     BusState *qbus;
523     DeviceState *dev;
524 
525     /* Create bridge device */
526     dev = qdev_create(NULL, TYPE_SPAPR_VIO_BRIDGE);
527     qdev_init_nofail(dev);
528 
529     /* Create bus on bridge device */
530     qbus = qbus_create(TYPE_SPAPR_VIO_BUS, dev, "spapr-vio");
531     bus = SPAPR_VIO_BUS(qbus);
532     bus->next_reg = 0x71000000;
533 
534     /* hcall-vio */
535     spapr_register_hypercall(H_VIO_SIGNAL, h_vio_signal);
536 
537     /* hcall-crq */
538     spapr_register_hypercall(H_REG_CRQ, h_reg_crq);
539     spapr_register_hypercall(H_FREE_CRQ, h_free_crq);
540     spapr_register_hypercall(H_SEND_CRQ, h_send_crq);
541     spapr_register_hypercall(H_ENABLE_CRQ, h_enable_crq);
542 
543     /* RTAS calls */
544     spapr_rtas_register(RTAS_IBM_SET_TCE_BYPASS, "ibm,set-tce-bypass",
545                         rtas_set_tce_bypass);
546     spapr_rtas_register(RTAS_QUIESCE, "quiesce", rtas_quiesce);
547 
548     return bus;
549 }
550 
551 /* Represents sPAPR hcall VIO devices */
552 
553 static int spapr_vio_bridge_init(SysBusDevice *dev)
554 {
555     /* nothing */
556     return 0;
557 }
558 
559 static void spapr_vio_bridge_class_init(ObjectClass *klass, void *data)
560 {
561     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
562     DeviceClass *dc = DEVICE_CLASS(klass);
563 
564     dc->fw_name = "vdevice";
565     k->init = spapr_vio_bridge_init;
566 }
567 
568 static const TypeInfo spapr_vio_bridge_info = {
569     .name          = TYPE_SPAPR_VIO_BRIDGE,
570     .parent        = TYPE_SYS_BUS_DEVICE,
571     .class_init    = spapr_vio_bridge_class_init,
572 };
573 
574 const VMStateDescription vmstate_spapr_vio = {
575     .name = "spapr_vio",
576     .version_id = 1,
577     .minimum_version_id = 1,
578     .fields = (VMStateField[]) {
579         /* Sanity check */
580         VMSTATE_UINT32_EQUAL(reg, VIOsPAPRDevice),
581         VMSTATE_UINT32_EQUAL(irq, VIOsPAPRDevice),
582 
583         /* General VIO device state */
584         VMSTATE_UINT64(signal_state, VIOsPAPRDevice),
585         VMSTATE_UINT64(crq.qladdr, VIOsPAPRDevice),
586         VMSTATE_UINT32(crq.qsize, VIOsPAPRDevice),
587         VMSTATE_UINT32(crq.qnext, VIOsPAPRDevice),
588 
589         VMSTATE_END_OF_LIST()
590     },
591 };
592 
593 static void vio_spapr_device_class_init(ObjectClass *klass, void *data)
594 {
595     DeviceClass *k = DEVICE_CLASS(klass);
596     k->realize = spapr_vio_busdev_realize;
597     k->reset = spapr_vio_busdev_reset;
598     k->bus_type = TYPE_SPAPR_VIO_BUS;
599     k->props = spapr_vio_props;
600 }
601 
602 static const TypeInfo spapr_vio_type_info = {
603     .name = TYPE_VIO_SPAPR_DEVICE,
604     .parent = TYPE_DEVICE,
605     .instance_size = sizeof(VIOsPAPRDevice),
606     .abstract = true,
607     .class_size = sizeof(VIOsPAPRDeviceClass),
608     .class_init = vio_spapr_device_class_init,
609 };
610 
611 static void spapr_vio_register_types(void)
612 {
613     type_register_static(&spapr_vio_bus_info);
614     type_register_static(&spapr_vio_bridge_info);
615     type_register_static(&spapr_vio_type_info);
616 }
617 
618 type_init(spapr_vio_register_types)
619 
620 static int compare_reg(const void *p1, const void *p2)
621 {
622     VIOsPAPRDevice const *dev1, *dev2;
623 
624     dev1 = (VIOsPAPRDevice *)*(DeviceState **)p1;
625     dev2 = (VIOsPAPRDevice *)*(DeviceState **)p2;
626 
627     if (dev1->reg < dev2->reg) {
628         return -1;
629     }
630     if (dev1->reg == dev2->reg) {
631         return 0;
632     }
633 
634     /* dev1->reg > dev2->reg */
635     return 1;
636 }
637 
638 int spapr_populate_vdevice(VIOsPAPRBus *bus, void *fdt)
639 {
640     DeviceState *qdev, **qdevs;
641     BusChild *kid;
642     int i, num, ret = 0;
643 
644     /* Count qdevs on the bus list */
645     num = 0;
646     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
647         num++;
648     }
649 
650     /* Copy out into an array of pointers */
651     qdevs = g_malloc(sizeof(qdev) * num);
652     num = 0;
653     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
654         qdevs[num++] = kid->child;
655     }
656 
657     /* Sort the array */
658     qsort(qdevs, num, sizeof(qdev), compare_reg);
659 
660     /* Hack alert. Give the devices to libfdt in reverse order, we happen
661      * to know that will mean they are in forward order in the tree. */
662     for (i = num - 1; i >= 0; i--) {
663         VIOsPAPRDevice *dev = (VIOsPAPRDevice *)(qdevs[i]);
664 
665         ret = vio_make_devnode(dev, fdt);
666 
667         if (ret < 0) {
668             goto out;
669         }
670     }
671 
672     ret = 0;
673 out:
674     g_free(qdevs);
675 
676     return ret;
677 }
678 
679 int spapr_populate_chosen_stdout(void *fdt, VIOsPAPRBus *bus)
680 {
681     VIOsPAPRDevice *dev;
682     char *name, *path;
683     int ret, offset;
684 
685     dev = spapr_vty_get_default(bus);
686     if (!dev)
687         return 0;
688 
689     offset = fdt_path_offset(fdt, "/chosen");
690     if (offset < 0) {
691         return offset;
692     }
693 
694     name = spapr_vio_get_dev_name(DEVICE(dev));
695     path = g_strdup_printf("/vdevice/%s", name);
696 
697     ret = fdt_setprop_string(fdt, offset, "linux,stdout-path", path);
698 
699     g_free(name);
700     g_free(path);
701 
702     return ret;
703 }
704