xref: /freebsd/sys/dev/acpica/acpi_pxm.c (revision 3c4ba5f55438f7afd4f4b0b56f88f2bb505fd6a6)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2010 Hudson River Trading LLC
5  * Written by: John H. Baldwin <jhb@FreeBSD.org>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include "opt_vm.h"
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/bus.h>
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/mutex.h>
41 #include <sys/smp.h>
42 #include <sys/vmmeter.h>
43 #include <vm/vm.h>
44 #include <vm/pmap.h>
45 #include <vm/vm_param.h>
46 #include <vm/vm_page.h>
47 #include <vm/vm_phys.h>
48 
49 #include <contrib/dev/acpica/include/acpi.h>
50 #include <contrib/dev/acpica/include/aclocal.h>
51 #include <contrib/dev/acpica/include/actables.h>
52 
53 #include <machine/md_var.h>
54 
55 #include <dev/acpica/acpivar.h>
56 
57 #if MAXMEMDOM > 1
58 static struct cpu_info {
59 	int enabled:1;
60 	int has_memory:1;
61 	int domain;
62 	int id;
63 } *cpus;
64 
65 static int max_cpus;
66 static int last_cpu;
67 
68 struct mem_affinity mem_info[VM_PHYSSEG_MAX + 1];
69 int num_mem;
70 
71 static ACPI_TABLE_SRAT *srat;
72 static vm_paddr_t srat_physaddr;
73 
74 static int domain_pxm[MAXMEMDOM];
75 static int ndomain;
76 static vm_paddr_t maxphyaddr;
77 
78 static ACPI_TABLE_SLIT *slit;
79 static vm_paddr_t slit_physaddr;
80 static int vm_locality_table[MAXMEMDOM * MAXMEMDOM];
81 
82 static void	srat_walk_table(acpi_subtable_handler *handler, void *arg);
83 
84 /*
85  * SLIT parsing.
86  */
87 
88 static void
89 slit_parse_table(ACPI_TABLE_SLIT *s)
90 {
91 	int i, j;
92 	int i_domain, j_domain;
93 	int offset = 0;
94 	uint8_t e;
95 
96 	/*
97 	 * This maps the SLIT data into the VM-domain centric view.
98 	 * There may be sparse entries in the PXM namespace, so
99 	 * remap them to a VM-domain ID and if it doesn't exist,
100 	 * skip it.
101 	 *
102 	 * It should result in a packed 2d array of VM-domain
103 	 * locality information entries.
104 	 */
105 
106 	if (bootverbose)
107 		printf("SLIT.Localities: %d\n", (int) s->LocalityCount);
108 	for (i = 0; i < s->LocalityCount; i++) {
109 		i_domain = acpi_map_pxm_to_vm_domainid(i);
110 		if (i_domain < 0)
111 			continue;
112 
113 		if (bootverbose)
114 			printf("%d: ", i);
115 		for (j = 0; j < s->LocalityCount; j++) {
116 			j_domain = acpi_map_pxm_to_vm_domainid(j);
117 			if (j_domain < 0)
118 				continue;
119 			e = s->Entry[i * s->LocalityCount + j];
120 			if (bootverbose)
121 				printf("%d ", (int) e);
122 			/* 255 == "no locality information" */
123 			if (e == 255)
124 				vm_locality_table[offset] = -1;
125 			else
126 				vm_locality_table[offset] = e;
127 			offset++;
128 		}
129 		if (bootverbose)
130 			printf("\n");
131 	}
132 }
133 
134 /*
135  * Look for an ACPI System Locality Distance Information Table ("SLIT")
136  */
137 static int
138 parse_slit(void)
139 {
140 
141 	if (resource_disabled("slit", 0)) {
142 		return (-1);
143 	}
144 
145 	slit_physaddr = acpi_find_table(ACPI_SIG_SLIT);
146 	if (slit_physaddr == 0) {
147 		return (-1);
148 	}
149 
150 	/*
151 	 * Make a pass over the table to populate the cpus[] and
152 	 * mem_info[] tables.
153 	 */
154 	slit = acpi_map_table(slit_physaddr, ACPI_SIG_SLIT);
155 	slit_parse_table(slit);
156 	acpi_unmap_table(slit);
157 	slit = NULL;
158 
159 	return (0);
160 }
161 
162 /*
163  * SRAT parsing.
164  */
165 
166 /*
167  * Returns true if a memory range overlaps with at least one range in
168  * phys_avail[].
169  */
170 static int
171 overlaps_phys_avail(vm_paddr_t start, vm_paddr_t end)
172 {
173 	int i;
174 
175 	for (i = 0; phys_avail[i] != 0 && phys_avail[i + 1] != 0; i += 2) {
176 		if (phys_avail[i + 1] <= start)
177 			continue;
178 		if (phys_avail[i] < end)
179 			return (1);
180 		break;
181 	}
182 	return (0);
183 }
184 
185 /*
186  * On x86 we can use the cpuid to index the cpus array, but on arm64
187  * we have an ACPI Processor UID with a larger range.
188  *
189  * Use this variable to indicate if the cpus can be stored by index.
190  */
191 #ifdef __aarch64__
192 static const int cpus_use_indexing = 0;
193 #else
194 static const int cpus_use_indexing = 1;
195 #endif
196 
197 /*
198  * Find CPU by processor ID (APIC ID on x86, Processor UID on arm64)
199  */
200 static struct cpu_info *
201 cpu_find(int cpuid)
202 {
203 	int i;
204 
205 	if (cpus_use_indexing) {
206 		if (cpuid <= last_cpu && cpus[cpuid].enabled)
207 			return (&cpus[cpuid]);
208 	} else {
209 		for (i = 0; i <= last_cpu; i++)
210 			if (cpus[i].id == cpuid)
211 				return (&cpus[i]);
212 	}
213 	return (NULL);
214 }
215 
216 /*
217  * Find CPU by pcpu pointer.
218  */
219 static struct cpu_info *
220 cpu_get_info(struct pcpu *pc)
221 {
222 	struct cpu_info *cpup;
223 	int id;
224 
225 #ifdef __aarch64__
226 	id = pc->pc_acpi_id;
227 #else
228 	id = pc->pc_apic_id;
229 #endif
230 	cpup = cpu_find(id);
231 	if (cpup == NULL)
232 		panic("SRAT: CPU with ID %u is not known", id);
233 	return (cpup);
234 }
235 
236 /*
237  * Add proximity information for a new CPU.
238  */
239 static struct cpu_info *
240 cpu_add(int cpuid, int domain)
241 {
242 	struct cpu_info *cpup;
243 
244 	if (cpus_use_indexing) {
245 		if (cpuid >= max_cpus)
246 			return (NULL);
247 		last_cpu = imax(last_cpu, cpuid);
248 		cpup = &cpus[cpuid];
249 	} else {
250 		if (last_cpu >= max_cpus - 1)
251 			return (NULL);
252 		cpup = &cpus[++last_cpu];
253 	}
254 	cpup->domain = domain;
255 	cpup->id = cpuid;
256 	cpup->enabled = 1;
257 	return (cpup);
258 }
259 
260 static void
261 srat_parse_entry(ACPI_SUBTABLE_HEADER *entry, void *arg)
262 {
263 	ACPI_SRAT_CPU_AFFINITY *cpu;
264 	ACPI_SRAT_X2APIC_CPU_AFFINITY *x2apic;
265 	ACPI_SRAT_MEM_AFFINITY *mem;
266 	ACPI_SRAT_GICC_AFFINITY *gicc;
267 	static struct cpu_info *cpup;
268 	uint64_t base, length;
269 	int domain, i, slot;
270 
271 	switch (entry->Type) {
272 	case ACPI_SRAT_TYPE_CPU_AFFINITY:
273 		cpu = (ACPI_SRAT_CPU_AFFINITY *)entry;
274 		domain = cpu->ProximityDomainLo |
275 		    cpu->ProximityDomainHi[0] << 8 |
276 		    cpu->ProximityDomainHi[1] << 16 |
277 		    cpu->ProximityDomainHi[2] << 24;
278 		if (bootverbose)
279 			printf("SRAT: Found CPU APIC ID %u domain %d: %s\n",
280 			    cpu->ApicId, domain,
281 			    (cpu->Flags & ACPI_SRAT_CPU_ENABLED) ?
282 			    "enabled" : "disabled");
283 		if (!(cpu->Flags & ACPI_SRAT_CPU_ENABLED))
284 			break;
285 		cpup = cpu_find(cpu->ApicId);
286 		if (cpup != NULL) {
287 			printf("SRAT: Duplicate local APIC ID %u\n",
288 			    cpu->ApicId);
289 			*(int *)arg = ENXIO;
290 			break;
291 		}
292 		cpup = cpu_add(cpu->ApicId, domain);
293 		if (cpup == NULL)
294 			printf("SRAT: Ignoring local APIC ID %u (too high)\n",
295 			    cpu->ApicId);
296 		break;
297 	case ACPI_SRAT_TYPE_X2APIC_CPU_AFFINITY:
298 		x2apic = (ACPI_SRAT_X2APIC_CPU_AFFINITY *)entry;
299 		if (bootverbose)
300 			printf("SRAT: Found CPU APIC ID %u domain %d: %s\n",
301 			    x2apic->ApicId, x2apic->ProximityDomain,
302 			    (x2apic->Flags & ACPI_SRAT_CPU_ENABLED) ?
303 			    "enabled" : "disabled");
304 		if (!(x2apic->Flags & ACPI_SRAT_CPU_ENABLED))
305 			break;
306 		KASSERT(cpu_find(x2apic->ApicId) == NULL,
307 		    ("Duplicate local APIC ID %u", x2apic->ApicId));
308 		cpup = cpu_add(x2apic->ApicId, x2apic->ProximityDomain);
309 		if (cpup == NULL)
310 			printf("SRAT: Ignoring local APIC ID %u (too high)\n",
311 			    x2apic->ApicId);
312 		break;
313 	case ACPI_SRAT_TYPE_GICC_AFFINITY:
314 		gicc = (ACPI_SRAT_GICC_AFFINITY *)entry;
315 		if (bootverbose)
316 			printf("SRAT: Found CPU UID %u domain %d: %s\n",
317 			    gicc->AcpiProcessorUid, gicc->ProximityDomain,
318 			    (gicc->Flags & ACPI_SRAT_GICC_ENABLED) ?
319 			    "enabled" : "disabled");
320 		if (!(gicc->Flags & ACPI_SRAT_GICC_ENABLED))
321 			break;
322 		KASSERT(cpu_find(gicc->AcpiProcessorUid) == NULL,
323 		    ("Duplicate CPU UID %u", gicc->AcpiProcessorUid));
324 		cpup = cpu_add(gicc->AcpiProcessorUid, gicc->ProximityDomain);
325 		if (cpup == NULL)
326 			printf("SRAT: Ignoring CPU UID %u (too high)\n",
327 			    gicc->AcpiProcessorUid);
328 		break;
329 	case ACPI_SRAT_TYPE_MEMORY_AFFINITY:
330 		mem = (ACPI_SRAT_MEM_AFFINITY *)entry;
331 		base = mem->BaseAddress;
332 		length = mem->Length;
333 		domain = mem->ProximityDomain;
334 
335 		if (bootverbose)
336 			printf(
337 		    "SRAT: Found memory domain %d addr 0x%jx len 0x%jx: %s\n",
338 			    domain, (uintmax_t)base, (uintmax_t)length,
339 			    (mem->Flags & ACPI_SRAT_MEM_ENABLED) ?
340 			    "enabled" : "disabled");
341 		if (!(mem->Flags & ACPI_SRAT_MEM_ENABLED))
342 			break;
343 		if (base >= maxphyaddr ||
344 		    !overlaps_phys_avail(base, base + length)) {
345 			printf("SRAT: Ignoring memory at addr 0x%jx\n",
346 			    (uintmax_t)base);
347 			break;
348 		}
349 		if (num_mem == VM_PHYSSEG_MAX) {
350 			printf("SRAT: Too many memory regions\n");
351 			*(int *)arg = ENXIO;
352 			break;
353 		}
354 		slot = num_mem;
355 		for (i = 0; i < num_mem; i++) {
356 			if (mem_info[i].domain == domain) {
357 				/* Try to extend an existing segment. */
358 				if (base == mem_info[i].end) {
359 					mem_info[i].end += length;
360 					return;
361 				}
362 				if (base + length == mem_info[i].start) {
363 					mem_info[i].start -= length;
364 					return;
365 				}
366 			}
367 			if (mem_info[i].end <= base)
368 				continue;
369 			if (mem_info[i].start < base + length) {
370 				printf("SRAT: Overlapping memory entries\n");
371 				*(int *)arg = ENXIO;
372 				return;
373 			}
374 			slot = i;
375 		}
376 		for (i = num_mem; i > slot; i--)
377 			mem_info[i] = mem_info[i - 1];
378 		mem_info[slot].start = base;
379 		mem_info[slot].end = base + length;
380 		mem_info[slot].domain = domain;
381 		num_mem++;
382 		break;
383 	}
384 }
385 
386 /*
387  * Ensure each memory domain has at least one CPU and that each CPU
388  * has at least one memory domain.
389  */
390 static int
391 check_domains(void)
392 {
393 	int found, i, j;
394 
395 	for (i = 0; i < num_mem; i++) {
396 		found = 0;
397 		for (j = 0; j <= last_cpu; j++)
398 			if (cpus[j].enabled &&
399 			    cpus[j].domain == mem_info[i].domain) {
400 				cpus[j].has_memory = 1;
401 				found++;
402 			}
403 		if (!found) {
404 			printf("SRAT: No CPU found for memory domain %d\n",
405 			    mem_info[i].domain);
406 			return (ENXIO);
407 		}
408 	}
409 	for (i = 0; i <= last_cpu; i++)
410 		if (cpus[i].enabled && !cpus[i].has_memory) {
411 			found = 0;
412 			for (j = 0; j < num_mem && !found; j++) {
413 				if (mem_info[j].domain == cpus[i].domain)
414 					found = 1;
415 			}
416 			if (!found) {
417 				if (bootverbose)
418 					printf("SRAT: mem dom %d is empty\n",
419 					    cpus[i].domain);
420 				mem_info[num_mem].start = 0;
421 				mem_info[num_mem].end = 0;
422 				mem_info[num_mem].domain = cpus[i].domain;
423 				num_mem++;
424 			}
425 		}
426 	return (0);
427 }
428 
429 /*
430  * Check that the SRAT memory regions cover all of the regions in
431  * phys_avail[].
432  */
433 static int
434 check_phys_avail(void)
435 {
436 	vm_paddr_t address;
437 	int i, j;
438 
439 	/* j is the current offset into phys_avail[]. */
440 	address = phys_avail[0];
441 	j = 0;
442 	for (i = 0; i < num_mem; i++) {
443 		/*
444 		 * Consume as many phys_avail[] entries as fit in this
445 		 * region.
446 		 */
447 		while (address >= mem_info[i].start &&
448 		    address <= mem_info[i].end) {
449 			/*
450 			 * If we cover the rest of this phys_avail[] entry,
451 			 * advance to the next entry.
452 			 */
453 			if (phys_avail[j + 1] <= mem_info[i].end) {
454 				j += 2;
455 				if (phys_avail[j] == 0 &&
456 				    phys_avail[j + 1] == 0) {
457 					return (0);
458 				}
459 				address = phys_avail[j];
460 			} else
461 				address = mem_info[i].end + 1;
462 		}
463 	}
464 	printf("SRAT: No memory region found for 0x%jx - 0x%jx\n",
465 	    (uintmax_t)phys_avail[j], (uintmax_t)phys_avail[j + 1]);
466 	return (ENXIO);
467 }
468 
469 /*
470  * Renumber the memory domains to be compact and zero-based if not
471  * already.  Returns an error if there are too many domains.
472  */
473 static int
474 renumber_domains(void)
475 {
476 	int i, j, slot;
477 
478 	/* Enumerate all the domains. */
479 	ndomain = 0;
480 	for (i = 0; i < num_mem; i++) {
481 		/* See if this domain is already known. */
482 		for (j = 0; j < ndomain; j++) {
483 			if (domain_pxm[j] >= mem_info[i].domain)
484 				break;
485 		}
486 		if (j < ndomain && domain_pxm[j] == mem_info[i].domain)
487 			continue;
488 
489 		if (ndomain >= MAXMEMDOM) {
490 			ndomain = 1;
491 			printf("SRAT: Too many memory domains\n");
492 			return (EFBIG);
493 		}
494 
495 		/* Insert the new domain at slot 'j'. */
496 		slot = j;
497 		for (j = ndomain; j > slot; j--)
498 			domain_pxm[j] = domain_pxm[j - 1];
499 		domain_pxm[slot] = mem_info[i].domain;
500 		ndomain++;
501 	}
502 
503 	/* Renumber each domain to its index in the sorted 'domain_pxm' list. */
504 	for (i = 0; i < ndomain; i++) {
505 		/*
506 		 * If the domain is already the right value, no need
507 		 * to renumber.
508 		 */
509 		if (domain_pxm[i] == i)
510 			continue;
511 
512 		/* Walk the cpu[] and mem_info[] arrays to renumber. */
513 		for (j = 0; j < num_mem; j++)
514 			if (mem_info[j].domain == domain_pxm[i])
515 				mem_info[j].domain = i;
516 		for (j = 0; j <= last_cpu; j++)
517 			if (cpus[j].enabled && cpus[j].domain == domain_pxm[i])
518 				cpus[j].domain = i;
519 	}
520 
521 	return (0);
522 }
523 
524 /*
525  * Look for an ACPI System Resource Affinity Table ("SRAT"),
526  * allocate space for cpu information, and initialize globals.
527  */
528 int
529 acpi_pxm_init(int ncpus, vm_paddr_t maxphys)
530 {
531 	unsigned int idx, size;
532 	vm_paddr_t addr;
533 
534 	if (resource_disabled("srat", 0))
535 		return (-1);
536 
537 	max_cpus = ncpus;
538 	last_cpu = -1;
539 	maxphyaddr = maxphys;
540 	srat_physaddr = acpi_find_table(ACPI_SIG_SRAT);
541 	if (srat_physaddr == 0)
542 		return (-1);
543 
544 	/*
545 	 * Allocate data structure:
546 	 *
547 	 * Find the last physical memory region and steal some memory from
548 	 * it. This is done because at this point in the boot process
549 	 * malloc is still not usable.
550 	 */
551 	for (idx = 0; phys_avail[idx + 1] != 0; idx += 2);
552 	KASSERT(idx != 0, ("phys_avail is empty!"));
553 	idx -= 2;
554 
555 	size =  sizeof(*cpus) * max_cpus;
556 	addr = trunc_page(phys_avail[idx + 1] - size);
557 	KASSERT(addr >= phys_avail[idx],
558 	    ("Not enough memory for SRAT table items"));
559 	phys_avail[idx + 1] = addr - 1;
560 
561 	/*
562 	 * We cannot rely on PHYS_TO_DMAP because this code is also used in
563 	 * i386, so use pmap_mapbios to map the memory, this will end up using
564 	 * the default memory attribute (WB), and the DMAP when available.
565 	 */
566 	cpus = (struct cpu_info *)pmap_mapbios(addr, size);
567 	bzero(cpus, size);
568 	return (0);
569 }
570 
571 static int
572 parse_srat(void)
573 {
574 	int error;
575 
576 	/*
577 	 * Make a pass over the table to populate the cpus[] and
578 	 * mem_info[] tables.
579 	 */
580 	srat = acpi_map_table(srat_physaddr, ACPI_SIG_SRAT);
581 	error = 0;
582 	srat_walk_table(srat_parse_entry, &error);
583 	acpi_unmap_table(srat);
584 	srat = NULL;
585 	if (error || check_domains() != 0 || check_phys_avail() != 0 ||
586 	    renumber_domains() != 0) {
587 		srat_physaddr = 0;
588 		return (-1);
589 	}
590 
591 	return (0);
592 }
593 
594 static void
595 init_mem_locality(void)
596 {
597 	int i;
598 
599 	/*
600 	 * For now, assume -1 == "no locality information for
601 	 * this pairing.
602 	 */
603 	for (i = 0; i < MAXMEMDOM * MAXMEMDOM; i++)
604 		vm_locality_table[i] = -1;
605 }
606 
607 /*
608  * Parse SRAT and SLIT to save proximity info. Don't do
609  * anything if SRAT is not available.
610  */
611 void
612 acpi_pxm_parse_tables(void)
613 {
614 
615 	if (srat_physaddr == 0)
616 		return;
617 	if (parse_srat() < 0)
618 		return;
619 	init_mem_locality();
620 	(void)parse_slit();
621 }
622 
623 /*
624  * Use saved data from SRAT/SLIT to update memory locality.
625  */
626 void
627 acpi_pxm_set_mem_locality(void)
628 {
629 
630 	if (srat_physaddr == 0)
631 		return;
632 	vm_phys_register_domains(ndomain, mem_info, vm_locality_table);
633 }
634 
635 static void
636 srat_walk_table(acpi_subtable_handler *handler, void *arg)
637 {
638 
639 	acpi_walk_subtables(srat + 1, (char *)srat + srat->Header.Length,
640 	    handler, arg);
641 }
642 
643 /*
644  * Set up per-CPU domain IDs from information saved in 'cpus' and tear down data
645  * structures allocated by acpi_pxm_init().
646  */
647 void
648 acpi_pxm_set_cpu_locality(void)
649 {
650 	struct cpu_info *cpu;
651 	struct pcpu *pc;
652 	u_int i;
653 
654 	if (srat_physaddr == 0)
655 		return;
656 	for (i = 0; i < MAXCPU; i++) {
657 		if (CPU_ABSENT(i))
658 			continue;
659 		pc = pcpu_find(i);
660 		KASSERT(pc != NULL, ("no pcpu data for CPU %u", i));
661 		cpu = cpu_get_info(pc);
662 		pc->pc_domain = vm_ndomains > 1 ? cpu->domain : 0;
663 		CPU_SET(i, &cpuset_domain[pc->pc_domain]);
664 		if (bootverbose)
665 			printf("SRAT: CPU %u has memory domain %d\n", i,
666 			    pc->pc_domain);
667 	}
668 	/* XXXMJ the page is leaked. */
669 	pmap_unmapbios(cpus, sizeof(*cpus) * max_cpus);
670 	srat_physaddr = 0;
671 	cpus = NULL;
672 }
673 
674 int
675 acpi_pxm_get_cpu_locality(int apic_id)
676 {
677 	struct cpu_info *cpu;
678 
679 	cpu = cpu_find(apic_id);
680 	if (cpu == NULL)
681 		panic("SRAT: CPU with ID %u is not known", apic_id);
682 	return (cpu->domain);
683 }
684 
685 /*
686  * Map a _PXM value to a VM domain ID.
687  *
688  * Returns the domain ID, or -1 if no domain ID was found.
689  */
690 int
691 acpi_map_pxm_to_vm_domainid(int pxm)
692 {
693 	int i;
694 
695 	for (i = 0; i < ndomain; i++) {
696 		if (domain_pxm[i] == pxm)
697 			return (vm_ndomains > 1 ? i : 0);
698 	}
699 
700 	return (-1);
701 }
702 
703 #else /* MAXMEMDOM == 1 */
704 
705 int
706 acpi_map_pxm_to_vm_domainid(int pxm)
707 {
708 
709 	return (-1);
710 }
711 
712 #endif /* MAXMEMDOM > 1 */
713