xref: /openbmc/qemu/hw/acpi/cpu.c (revision 80e5db30)
1 #include "qemu/osdep.h"
2 #include "hw/boards.h"
3 #include "hw/acpi/cpu.h"
4 #include "qapi/error.h"
5 #include "qapi-event.h"
6 #include "trace.h"
7 #include "sysemu/numa.h"
8 
9 #define ACPI_CPU_HOTPLUG_REG_LEN 12
10 #define ACPI_CPU_SELECTOR_OFFSET_WR 0
11 #define ACPI_CPU_FLAGS_OFFSET_RW 4
12 #define ACPI_CPU_CMD_OFFSET_WR 5
13 #define ACPI_CPU_CMD_DATA_OFFSET_RW 8
14 
15 enum {
16     CPHP_GET_NEXT_CPU_WITH_EVENT_CMD = 0,
17     CPHP_OST_EVENT_CMD = 1,
18     CPHP_OST_STATUS_CMD = 2,
19     CPHP_CMD_MAX
20 };
21 
22 static ACPIOSTInfo *acpi_cpu_device_status(int idx, AcpiCpuStatus *cdev)
23 {
24     ACPIOSTInfo *info = g_new0(ACPIOSTInfo, 1);
25 
26     info->slot_type = ACPI_SLOT_TYPE_CPU;
27     info->slot = g_strdup_printf("%d", idx);
28     info->source = cdev->ost_event;
29     info->status = cdev->ost_status;
30     if (cdev->cpu) {
31         DeviceState *dev = DEVICE(cdev->cpu);
32         if (dev->id) {
33             info->device = g_strdup(dev->id);
34             info->has_device = true;
35         }
36     }
37     return info;
38 }
39 
40 void acpi_cpu_ospm_status(CPUHotplugState *cpu_st, ACPIOSTInfoList ***list)
41 {
42     int i;
43 
44     for (i = 0; i < cpu_st->dev_count; i++) {
45         ACPIOSTInfoList *elem = g_new0(ACPIOSTInfoList, 1);
46         elem->value = acpi_cpu_device_status(i, &cpu_st->devs[i]);
47         elem->next = NULL;
48         **list = elem;
49         *list = &elem->next;
50     }
51 }
52 
53 static uint64_t cpu_hotplug_rd(void *opaque, hwaddr addr, unsigned size)
54 {
55     uint64_t val = 0;
56     CPUHotplugState *cpu_st = opaque;
57     AcpiCpuStatus *cdev;
58 
59     if (cpu_st->selector >= cpu_st->dev_count) {
60         return val;
61     }
62 
63     cdev = &cpu_st->devs[cpu_st->selector];
64     switch (addr) {
65     case ACPI_CPU_FLAGS_OFFSET_RW: /* pack and return is_* fields */
66         val |= cdev->cpu ? 1 : 0;
67         val |= cdev->is_inserting ? 2 : 0;
68         val |= cdev->is_removing  ? 4 : 0;
69         trace_cpuhp_acpi_read_flags(cpu_st->selector, val);
70         break;
71     case ACPI_CPU_CMD_DATA_OFFSET_RW:
72         switch (cpu_st->command) {
73         case CPHP_GET_NEXT_CPU_WITH_EVENT_CMD:
74            val = cpu_st->selector;
75            break;
76         default:
77            break;
78         }
79         trace_cpuhp_acpi_read_cmd_data(cpu_st->selector, val);
80         break;
81     default:
82         break;
83     }
84     return val;
85 }
86 
87 static void cpu_hotplug_wr(void *opaque, hwaddr addr, uint64_t data,
88                            unsigned int size)
89 {
90     CPUHotplugState *cpu_st = opaque;
91     AcpiCpuStatus *cdev;
92     ACPIOSTInfo *info;
93 
94     assert(cpu_st->dev_count);
95 
96     if (addr) {
97         if (cpu_st->selector >= cpu_st->dev_count) {
98             trace_cpuhp_acpi_invalid_idx_selected(cpu_st->selector);
99             return;
100         }
101     }
102 
103     switch (addr) {
104     case ACPI_CPU_SELECTOR_OFFSET_WR: /* current CPU selector */
105         cpu_st->selector = data;
106         trace_cpuhp_acpi_write_idx(cpu_st->selector);
107         break;
108     case ACPI_CPU_FLAGS_OFFSET_RW: /* set is_* fields  */
109         cdev = &cpu_st->devs[cpu_st->selector];
110         if (data & 2) { /* clear insert event */
111             cdev->is_inserting = false;
112             trace_cpuhp_acpi_clear_inserting_evt(cpu_st->selector);
113         } else if (data & 4) { /* clear remove event */
114             cdev->is_removing = false;
115             trace_cpuhp_acpi_clear_remove_evt(cpu_st->selector);
116         } else if (data & 8) {
117             DeviceState *dev = NULL;
118             HotplugHandler *hotplug_ctrl = NULL;
119 
120             if (!cdev->cpu) {
121                 trace_cpuhp_acpi_ejecting_invalid_cpu(cpu_st->selector);
122                 break;
123             }
124 
125             trace_cpuhp_acpi_ejecting_cpu(cpu_st->selector);
126             dev = DEVICE(cdev->cpu);
127             hotplug_ctrl = qdev_get_hotplug_handler(dev);
128             hotplug_handler_unplug(hotplug_ctrl, dev, NULL);
129         }
130         break;
131     case ACPI_CPU_CMD_OFFSET_WR:
132         trace_cpuhp_acpi_write_cmd(cpu_st->selector, data);
133         if (data < CPHP_CMD_MAX) {
134             cpu_st->command = data;
135             if (cpu_st->command == CPHP_GET_NEXT_CPU_WITH_EVENT_CMD) {
136                 uint32_t iter = cpu_st->selector;
137 
138                 do {
139                     cdev = &cpu_st->devs[iter];
140                     if (cdev->is_inserting || cdev->is_removing) {
141                         cpu_st->selector = iter;
142                         trace_cpuhp_acpi_cpu_has_events(cpu_st->selector,
143                             cdev->is_inserting, cdev->is_removing);
144                         break;
145                     }
146                     iter = iter + 1 < cpu_st->dev_count ? iter + 1 : 0;
147                 } while (iter != cpu_st->selector);
148             }
149         }
150         break;
151     case ACPI_CPU_CMD_DATA_OFFSET_RW:
152         switch (cpu_st->command) {
153         case CPHP_OST_EVENT_CMD: {
154            cdev = &cpu_st->devs[cpu_st->selector];
155            cdev->ost_event = data;
156            trace_cpuhp_acpi_write_ost_ev(cpu_st->selector, cdev->ost_event);
157            break;
158         }
159         case CPHP_OST_STATUS_CMD: {
160            cdev = &cpu_st->devs[cpu_st->selector];
161            cdev->ost_status = data;
162            info = acpi_cpu_device_status(cpu_st->selector, cdev);
163            qapi_event_send_acpi_device_ost(info, &error_abort);
164            qapi_free_ACPIOSTInfo(info);
165            trace_cpuhp_acpi_write_ost_status(cpu_st->selector,
166                                              cdev->ost_status);
167            break;
168         }
169         default:
170            break;
171         }
172         break;
173     default:
174         break;
175     }
176 }
177 
178 static const MemoryRegionOps cpu_hotplug_ops = {
179     .read = cpu_hotplug_rd,
180     .write = cpu_hotplug_wr,
181     .endianness = DEVICE_LITTLE_ENDIAN,
182     .valid = {
183         .min_access_size = 1,
184         .max_access_size = 4,
185     },
186 };
187 
188 void cpu_hotplug_hw_init(MemoryRegion *as, Object *owner,
189                          CPUHotplugState *state, hwaddr base_addr)
190 {
191     MachineState *machine = MACHINE(qdev_get_machine());
192     MachineClass *mc = MACHINE_GET_CLASS(machine);
193     const CPUArchIdList *id_list;
194     int i;
195 
196     assert(mc->possible_cpu_arch_ids);
197     id_list = mc->possible_cpu_arch_ids(machine);
198     state->dev_count = id_list->len;
199     state->devs = g_new0(typeof(*state->devs), state->dev_count);
200     for (i = 0; i < id_list->len; i++) {
201         state->devs[i].cpu =  id_list->cpus[i].cpu;
202         state->devs[i].arch_id = id_list->cpus[i].arch_id;
203     }
204     memory_region_init_io(&state->ctrl_reg, owner, &cpu_hotplug_ops, state,
205                           "acpi-mem-hotplug", ACPI_CPU_HOTPLUG_REG_LEN);
206     memory_region_add_subregion(as, base_addr, &state->ctrl_reg);
207 }
208 
209 static AcpiCpuStatus *get_cpu_status(CPUHotplugState *cpu_st, DeviceState *dev)
210 {
211     CPUClass *k = CPU_GET_CLASS(dev);
212     uint64_t cpu_arch_id = k->get_arch_id(CPU(dev));
213     int i;
214 
215     for (i = 0; i < cpu_st->dev_count; i++) {
216         if (cpu_arch_id == cpu_st->devs[i].arch_id) {
217             return &cpu_st->devs[i];
218         }
219     }
220     return NULL;
221 }
222 
223 void acpi_cpu_plug_cb(HotplugHandler *hotplug_dev,
224                       CPUHotplugState *cpu_st, DeviceState *dev, Error **errp)
225 {
226     AcpiCpuStatus *cdev;
227 
228     cdev = get_cpu_status(cpu_st, dev);
229     if (!cdev) {
230         return;
231     }
232 
233     cdev->cpu = CPU(dev);
234     if (dev->hotplugged) {
235         cdev->is_inserting = true;
236         acpi_send_event(DEVICE(hotplug_dev), ACPI_CPU_HOTPLUG_STATUS);
237     }
238 }
239 
240 void acpi_cpu_unplug_request_cb(HotplugHandler *hotplug_dev,
241                                 CPUHotplugState *cpu_st,
242                                 DeviceState *dev, Error **errp)
243 {
244     AcpiCpuStatus *cdev;
245 
246     cdev = get_cpu_status(cpu_st, dev);
247     if (!cdev) {
248         return;
249     }
250 
251     cdev->is_removing = true;
252     acpi_send_event(DEVICE(hotplug_dev), ACPI_CPU_HOTPLUG_STATUS);
253 }
254 
255 void acpi_cpu_unplug_cb(CPUHotplugState *cpu_st,
256                         DeviceState *dev, Error **errp)
257 {
258     AcpiCpuStatus *cdev;
259 
260     cdev = get_cpu_status(cpu_st, dev);
261     if (!cdev) {
262         return;
263     }
264 
265     cdev->cpu = NULL;
266 }
267 
268 static const VMStateDescription vmstate_cpuhp_sts = {
269     .name = "CPU hotplug device state",
270     .version_id = 1,
271     .minimum_version_id = 1,
272     .minimum_version_id_old = 1,
273     .fields      = (VMStateField[]) {
274         VMSTATE_BOOL(is_inserting, AcpiCpuStatus),
275         VMSTATE_BOOL(is_removing, AcpiCpuStatus),
276         VMSTATE_UINT32(ost_event, AcpiCpuStatus),
277         VMSTATE_UINT32(ost_status, AcpiCpuStatus),
278         VMSTATE_END_OF_LIST()
279     }
280 };
281 
282 const VMStateDescription vmstate_cpu_hotplug = {
283     .name = "CPU hotplug state",
284     .version_id = 1,
285     .minimum_version_id = 1,
286     .minimum_version_id_old = 1,
287     .fields      = (VMStateField[]) {
288         VMSTATE_UINT32(selector, CPUHotplugState),
289         VMSTATE_UINT8(command, CPUHotplugState),
290         VMSTATE_STRUCT_VARRAY_POINTER_UINT32(devs, CPUHotplugState, dev_count,
291                                              vmstate_cpuhp_sts, AcpiCpuStatus),
292         VMSTATE_END_OF_LIST()
293     }
294 };
295 
296 #define CPU_NAME_FMT      "C%.03X"
297 #define CPUHP_RES_DEVICE  "PRES"
298 #define CPU_LOCK          "CPLK"
299 #define CPU_STS_METHOD    "CSTA"
300 #define CPU_SCAN_METHOD   "CSCN"
301 #define CPU_NOTIFY_METHOD "CTFY"
302 #define CPU_EJECT_METHOD  "CEJ0"
303 #define CPU_OST_METHOD    "COST"
304 
305 #define CPU_ENABLED       "CPEN"
306 #define CPU_SELECTOR      "CSEL"
307 #define CPU_COMMAND       "CCMD"
308 #define CPU_DATA          "CDAT"
309 #define CPU_INSERT_EVENT  "CINS"
310 #define CPU_REMOVE_EVENT  "CRMV"
311 #define CPU_EJECT_EVENT   "CEJ0"
312 
313 void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts,
314                     hwaddr io_base,
315                     const char *res_root,
316                     const char *event_handler_method)
317 {
318     Aml *ifctx;
319     Aml *field;
320     Aml *method;
321     Aml *cpu_ctrl_dev;
322     Aml *cpus_dev;
323     Aml *zero = aml_int(0);
324     Aml *one = aml_int(1);
325     Aml *sb_scope = aml_scope("_SB");
326     MachineClass *mc = MACHINE_GET_CLASS(machine);
327     const CPUArchIdList *arch_ids = mc->possible_cpu_arch_ids(machine);
328     char *cphp_res_path = g_strdup_printf("%s." CPUHP_RES_DEVICE, res_root);
329     Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
330     AcpiDeviceIfClass *adevc = ACPI_DEVICE_IF_GET_CLASS(obj);
331     AcpiDeviceIf *adev = ACPI_DEVICE_IF(obj);
332 
333     cpu_ctrl_dev = aml_device("%s", cphp_res_path);
334     {
335         Aml *crs;
336 
337         aml_append(cpu_ctrl_dev,
338             aml_name_decl("_HID", aml_eisaid("PNP0A06")));
339         aml_append(cpu_ctrl_dev,
340             aml_name_decl("_UID", aml_string("CPU Hotplug resources")));
341         aml_append(cpu_ctrl_dev, aml_mutex(CPU_LOCK, 0));
342 
343         crs = aml_resource_template();
344         aml_append(crs, aml_io(AML_DECODE16, io_base, io_base, 1,
345                                ACPI_CPU_HOTPLUG_REG_LEN));
346         aml_append(cpu_ctrl_dev, aml_name_decl("_CRS", crs));
347 
348         /* declare CPU hotplug MMIO region with related access fields */
349         aml_append(cpu_ctrl_dev,
350             aml_operation_region("PRST", AML_SYSTEM_IO, aml_int(io_base),
351                                  ACPI_CPU_HOTPLUG_REG_LEN));
352 
353         field = aml_field("PRST", AML_BYTE_ACC, AML_NOLOCK,
354                           AML_WRITE_AS_ZEROS);
355         aml_append(field, aml_reserved_field(ACPI_CPU_FLAGS_OFFSET_RW * 8));
356         /* 1 if enabled, read only */
357         aml_append(field, aml_named_field(CPU_ENABLED, 1));
358         /* (read) 1 if has a insert event. (write) 1 to clear event */
359         aml_append(field, aml_named_field(CPU_INSERT_EVENT, 1));
360         /* (read) 1 if has a remove event. (write) 1 to clear event */
361         aml_append(field, aml_named_field(CPU_REMOVE_EVENT, 1));
362         /* initiates device eject, write only */
363         aml_append(field, aml_named_field(CPU_EJECT_EVENT, 1));
364         aml_append(field, aml_reserved_field(4));
365         aml_append(field, aml_named_field(CPU_COMMAND, 8));
366         aml_append(cpu_ctrl_dev, field);
367 
368         field = aml_field("PRST", AML_DWORD_ACC, AML_NOLOCK, AML_PRESERVE);
369         /* CPU selector, write only */
370         aml_append(field, aml_named_field(CPU_SELECTOR, 32));
371         /* flags + cmd + 2byte align */
372         aml_append(field, aml_reserved_field(4 * 8));
373         aml_append(field, aml_named_field(CPU_DATA, 32));
374         aml_append(cpu_ctrl_dev, field);
375 
376         if (opts.has_legacy_cphp) {
377             method = aml_method("_INI", 0, AML_SERIALIZED);
378             /* switch off legacy CPU hotplug HW and use new one,
379              * on reboot system is in new mode and writing 0
380              * in CPU_SELECTOR selects BSP, which is NOP at
381              * the time _INI is called */
382             aml_append(method, aml_store(zero, aml_name(CPU_SELECTOR)));
383             aml_append(cpu_ctrl_dev, method);
384         }
385     }
386     aml_append(sb_scope, cpu_ctrl_dev);
387 
388     cpus_dev = aml_device("\\_SB.CPUS");
389     {
390         int i;
391         Aml *ctrl_lock = aml_name("%s.%s", cphp_res_path, CPU_LOCK);
392         Aml *cpu_selector = aml_name("%s.%s", cphp_res_path, CPU_SELECTOR);
393         Aml *is_enabled = aml_name("%s.%s", cphp_res_path, CPU_ENABLED);
394         Aml *cpu_cmd = aml_name("%s.%s", cphp_res_path, CPU_COMMAND);
395         Aml *cpu_data = aml_name("%s.%s", cphp_res_path, CPU_DATA);
396         Aml *ins_evt = aml_name("%s.%s", cphp_res_path, CPU_INSERT_EVENT);
397         Aml *rm_evt = aml_name("%s.%s", cphp_res_path, CPU_REMOVE_EVENT);
398         Aml *ej_evt = aml_name("%s.%s", cphp_res_path, CPU_EJECT_EVENT);
399 
400         aml_append(cpus_dev, aml_name_decl("_HID", aml_string("ACPI0010")));
401         aml_append(cpus_dev, aml_name_decl("_CID", aml_eisaid("PNP0A05")));
402 
403         method = aml_method(CPU_NOTIFY_METHOD, 2, AML_NOTSERIALIZED);
404         for (i = 0; i < arch_ids->len; i++) {
405             Aml *cpu = aml_name(CPU_NAME_FMT, i);
406             Aml *uid = aml_arg(0);
407             Aml *event = aml_arg(1);
408 
409             ifctx = aml_if(aml_equal(uid, aml_int(i)));
410             {
411                 aml_append(ifctx, aml_notify(cpu, event));
412             }
413             aml_append(method, ifctx);
414         }
415         aml_append(cpus_dev, method);
416 
417         method = aml_method(CPU_STS_METHOD, 1, AML_SERIALIZED);
418         {
419             Aml *idx = aml_arg(0);
420             Aml *sta = aml_local(0);
421 
422             aml_append(method, aml_acquire(ctrl_lock, 0xFFFF));
423             aml_append(method, aml_store(idx, cpu_selector));
424             aml_append(method, aml_store(zero, sta));
425             ifctx = aml_if(aml_equal(is_enabled, one));
426             {
427                 aml_append(ifctx, aml_store(aml_int(0xF), sta));
428             }
429             aml_append(method, ifctx);
430             aml_append(method, aml_release(ctrl_lock));
431             aml_append(method, aml_return(sta));
432         }
433         aml_append(cpus_dev, method);
434 
435         method = aml_method(CPU_EJECT_METHOD, 1, AML_SERIALIZED);
436         {
437             Aml *idx = aml_arg(0);
438 
439             aml_append(method, aml_acquire(ctrl_lock, 0xFFFF));
440             aml_append(method, aml_store(idx, cpu_selector));
441             aml_append(method, aml_store(one, ej_evt));
442             aml_append(method, aml_release(ctrl_lock));
443         }
444         aml_append(cpus_dev, method);
445 
446         method = aml_method(CPU_SCAN_METHOD, 0, AML_SERIALIZED);
447         {
448             Aml *else_ctx;
449             Aml *while_ctx;
450             Aml *has_event = aml_local(0);
451             Aml *dev_chk = aml_int(1);
452             Aml *eject_req = aml_int(3);
453             Aml *next_cpu_cmd = aml_int(CPHP_GET_NEXT_CPU_WITH_EVENT_CMD);
454 
455             aml_append(method, aml_acquire(ctrl_lock, 0xFFFF));
456             aml_append(method, aml_store(one, has_event));
457             while_ctx = aml_while(aml_equal(has_event, one));
458             {
459                  /* clear loop exit condition, ins_evt/rm_evt checks
460                   * will set it to 1 while next_cpu_cmd returns a CPU
461                   * with events */
462                  aml_append(while_ctx, aml_store(zero, has_event));
463                  aml_append(while_ctx, aml_store(next_cpu_cmd, cpu_cmd));
464                  ifctx = aml_if(aml_equal(ins_evt, one));
465                  {
466                      aml_append(ifctx,
467                          aml_call2(CPU_NOTIFY_METHOD, cpu_data, dev_chk));
468                      aml_append(ifctx, aml_store(one, ins_evt));
469                      aml_append(ifctx, aml_store(one, has_event));
470                  }
471                  aml_append(while_ctx, ifctx);
472                  else_ctx = aml_else();
473                  ifctx = aml_if(aml_equal(rm_evt, one));
474                  {
475                      aml_append(ifctx,
476                          aml_call2(CPU_NOTIFY_METHOD, cpu_data, eject_req));
477                      aml_append(ifctx, aml_store(one, rm_evt));
478                      aml_append(ifctx, aml_store(one, has_event));
479                  }
480                  aml_append(else_ctx, ifctx);
481                  aml_append(while_ctx, else_ctx);
482             }
483             aml_append(method, while_ctx);
484             aml_append(method, aml_release(ctrl_lock));
485         }
486         aml_append(cpus_dev, method);
487 
488         method = aml_method(CPU_OST_METHOD, 4, AML_SERIALIZED);
489         {
490             Aml *uid = aml_arg(0);
491             Aml *ev_cmd = aml_int(CPHP_OST_EVENT_CMD);
492             Aml *st_cmd = aml_int(CPHP_OST_STATUS_CMD);
493 
494             aml_append(method, aml_acquire(ctrl_lock, 0xFFFF));
495             aml_append(method, aml_store(uid, cpu_selector));
496             aml_append(method, aml_store(ev_cmd, cpu_cmd));
497             aml_append(method, aml_store(aml_arg(1), cpu_data));
498             aml_append(method, aml_store(st_cmd, cpu_cmd));
499             aml_append(method, aml_store(aml_arg(2), cpu_data));
500             aml_append(method, aml_release(ctrl_lock));
501         }
502         aml_append(cpus_dev, method);
503 
504         /* build Processor object for each processor */
505         for (i = 0; i < arch_ids->len; i++) {
506             int j;
507             Aml *dev;
508             Aml *uid = aml_int(i);
509             GArray *madt_buf = g_array_new(0, 1, 1);
510             int arch_id = arch_ids->cpus[i].arch_id;
511 
512             if (opts.apci_1_compatible && arch_id < 255) {
513                 dev = aml_processor(i, 0, 0, CPU_NAME_FMT, i);
514             } else {
515                 dev = aml_device(CPU_NAME_FMT, i);
516                 aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0007")));
517                 aml_append(dev, aml_name_decl("_UID", uid));
518             }
519 
520             method = aml_method("_STA", 0, AML_SERIALIZED);
521             aml_append(method, aml_return(aml_call1(CPU_STS_METHOD, uid)));
522             aml_append(dev, method);
523 
524             /* build _MAT object */
525             assert(adevc && adevc->madt_cpu);
526             adevc->madt_cpu(adev, i, arch_ids, madt_buf);
527             switch (madt_buf->data[0]) {
528             case ACPI_APIC_PROCESSOR: {
529                 AcpiMadtProcessorApic *apic = (void *)madt_buf->data;
530                 apic->flags = cpu_to_le32(1);
531                 break;
532             }
533             case ACPI_APIC_LOCAL_X2APIC: {
534                 AcpiMadtProcessorX2Apic *apic = (void *)madt_buf->data;
535                 apic->flags = cpu_to_le32(1);
536                 break;
537             }
538             default:
539                 assert(0);
540             }
541             aml_append(dev, aml_name_decl("_MAT",
542                 aml_buffer(madt_buf->len, (uint8_t *)madt_buf->data)));
543             g_array_free(madt_buf, true);
544 
545             method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
546             aml_append(method, aml_call1(CPU_EJECT_METHOD, uid));
547             aml_append(dev, method);
548 
549             method = aml_method("_OST", 3, AML_SERIALIZED);
550             aml_append(method,
551                 aml_call4(CPU_OST_METHOD, uid, aml_arg(0),
552                           aml_arg(1), aml_arg(2))
553             );
554             aml_append(dev, method);
555 
556             /* Linux guests discard SRAT info for non-present CPUs
557              * as a result _PXM is required for all CPUs which might
558              * be hot-plugged. For simplicity, add it for all CPUs.
559              */
560             j = numa_get_node_for_cpu(i);
561             if (j < nb_numa_nodes) {
562                 aml_append(dev, aml_name_decl("_PXM", aml_int(j)));
563             }
564 
565             aml_append(cpus_dev, dev);
566         }
567     }
568     aml_append(sb_scope, cpus_dev);
569     aml_append(table, sb_scope);
570 
571     method = aml_method(event_handler_method, 0, AML_NOTSERIALIZED);
572     aml_append(method, aml_call0("\\_SB.CPUS." CPU_SCAN_METHOD));
573     aml_append(table, method);
574 
575     g_free(cphp_res_path);
576 }
577