xref: /openbmc/qemu/hw/acpi/cpu.c (revision 7ff5920717d413d8b7c3ba13d9a0805291b9e6ec)
1  #include "qemu/osdep.h"
2  #include "hw/boards.h"
3  #include "hw/acpi/cpu.h"
4  #include "qapi/error.h"
5  #include "qapi/qapi-events-misc.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 || cdev->cpu == first_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);
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 =  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              Aml *dev;
507              Aml *uid = aml_int(i);
508              GArray *madt_buf = g_array_new(0, 1, 1);
509              int arch_id = arch_ids->cpus[i].arch_id;
510  
511              if (opts.apci_1_compatible && arch_id < 255) {
512                  dev = aml_processor(i, 0, 0, CPU_NAME_FMT, i);
513              } else {
514                  dev = aml_device(CPU_NAME_FMT, i);
515                  aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0007")));
516                  aml_append(dev, aml_name_decl("_UID", uid));
517              }
518  
519              method = aml_method("_STA", 0, AML_SERIALIZED);
520              aml_append(method, aml_return(aml_call1(CPU_STS_METHOD, uid)));
521              aml_append(dev, method);
522  
523              /* build _MAT object */
524              assert(adevc && adevc->madt_cpu);
525              adevc->madt_cpu(adev, i, arch_ids, madt_buf);
526              switch (madt_buf->data[0]) {
527              case ACPI_APIC_PROCESSOR: {
528                  AcpiMadtProcessorApic *apic = (void *)madt_buf->data;
529                  apic->flags = cpu_to_le32(1);
530                  break;
531              }
532              case ACPI_APIC_LOCAL_X2APIC: {
533                  AcpiMadtProcessorX2Apic *apic = (void *)madt_buf->data;
534                  apic->flags = cpu_to_le32(1);
535                  break;
536              }
537              default:
538                  assert(0);
539              }
540              aml_append(dev, aml_name_decl("_MAT",
541                  aml_buffer(madt_buf->len, (uint8_t *)madt_buf->data)));
542              g_array_free(madt_buf, true);
543  
544              if (CPU(arch_ids->cpus[i].cpu) != first_cpu) {
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  
550              method = aml_method("_OST", 3, AML_SERIALIZED);
551              aml_append(method,
552                  aml_call4(CPU_OST_METHOD, uid, aml_arg(0),
553                            aml_arg(1), aml_arg(2))
554              );
555              aml_append(dev, method);
556  
557              /* Linux guests discard SRAT info for non-present CPUs
558               * as a result _PXM is required for all CPUs which might
559               * be hot-plugged. For simplicity, add it for all CPUs.
560               */
561              if (arch_ids->cpus[i].props.has_node_id) {
562                  aml_append(dev, aml_name_decl("_PXM",
563                             aml_int(arch_ids->cpus[i].props.node_id)));
564              }
565  
566              aml_append(cpus_dev, dev);
567          }
568      }
569      aml_append(sb_scope, cpus_dev);
570      aml_append(table, sb_scope);
571  
572      method = aml_method(event_handler_method, 0, AML_NOTSERIALIZED);
573      aml_append(method, aml_call0("\\_SB.CPUS." CPU_SCAN_METHOD));
574      aml_append(table, method);
575  
576      g_free(cphp_res_path);
577  }
578