1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * NUMA emulation
4 */
5 #include <linux/kernel.h>
6 #include <linux/errno.h>
7 #include <linux/topology.h>
8 #include <linux/memblock.h>
9 #include <linux/numa_memblks.h>
10 #include <asm/numa.h>
11
12 #define FAKE_NODE_MIN_SIZE ((u64)32 << 20)
13 #define FAKE_NODE_MIN_HASH_MASK (~(FAKE_NODE_MIN_SIZE - 1UL))
14
15 static int emu_nid_to_phys[MAX_NUMNODES];
16 static char *emu_cmdline __initdata;
17
18 int __init numa_emu_cmdline(char *str)
19 {
20 emu_cmdline = str;
21 return 0;
22 }
23
24 static int __init emu_find_memblk_by_nid(int nid, const struct numa_meminfo *mi)
25 {
26 int i;
27
28 for (i = 0; i < mi->nr_blks; i++)
29 if (mi->blk[i].nid == nid)
30 return i;
31 return -ENOENT;
32 }
33
34 static u64 __init mem_hole_size(u64 start, u64 end)
35 {
36 unsigned long start_pfn = PFN_UP(start);
37 unsigned long end_pfn = PFN_DOWN(end);
38
39 if (start_pfn < end_pfn)
40 return PFN_PHYS(absent_pages_in_range(start_pfn, end_pfn));
41 return 0;
42 }
43
44 /*
45 * Sets up nid to range from @start to @end. The return value is -errno if
46 * something went wrong, 0 otherwise.
47 */
48 static int __init emu_setup_memblk(struct numa_meminfo *ei,
49 struct numa_meminfo *pi,
50 int nid, int phys_blk, u64 size)
51 {
52 struct numa_memblk *eb = &ei->blk[ei->nr_blks];
53 struct numa_memblk *pb = &pi->blk[phys_blk];
54
55 if (ei->nr_blks >= NR_NODE_MEMBLKS) {
56 pr_err("NUMA: Too many emulated memblks, failing emulation\n");
57 return -EINVAL;
58 }
59
60 ei->nr_blks++;
61 eb->start = pb->start;
62 eb->end = pb->start + size;
63 eb->nid = nid;
64
65 if (emu_nid_to_phys[nid] == NUMA_NO_NODE)
66 emu_nid_to_phys[nid] = pb->nid;
67
68 pb->start += size;
69 if (pb->start >= pb->end) {
70 WARN_ON_ONCE(pb->start > pb->end);
71 numa_remove_memblk_from(phys_blk, pi);
72 }
73
74 printk(KERN_INFO "Faking node %d at [mem %#018Lx-%#018Lx] (%LuMB)\n",
75 nid, eb->start, eb->end - 1, (eb->end - eb->start) >> 20);
76 return 0;
77 }
78
79 /*
80 * Sets up nr_nodes fake nodes interleaved over physical nodes ranging from addr
81 * to max_addr.
82 *
83 * Returns zero on success or negative on error.
84 */
85 static int __init split_nodes_interleave(struct numa_meminfo *ei,
86 struct numa_meminfo *pi,
87 u64 addr, u64 max_addr, int nr_nodes)
88 {
89 nodemask_t physnode_mask = numa_nodes_parsed;
90 u64 size;
91 int big;
92 int nid = 0;
93 int i, ret;
94
95 if (nr_nodes <= 0)
96 return -1;
97 if (nr_nodes > MAX_NUMNODES) {
98 pr_info("numa=fake=%d too large, reducing to %d\n",
99 nr_nodes, MAX_NUMNODES);
100 nr_nodes = MAX_NUMNODES;
101 }
102
103 /*
104 * Calculate target node size. x86_32 freaks on __udivdi3() so do
105 * the division in ulong number of pages and convert back.
106 */
107 size = max_addr - addr - mem_hole_size(addr, max_addr);
108 size = PFN_PHYS((unsigned long)(size >> PAGE_SHIFT) / nr_nodes);
109
110 /*
111 * Calculate the number of big nodes that can be allocated as a result
112 * of consolidating the remainder.
113 */
114 big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
115 FAKE_NODE_MIN_SIZE;
116
117 size &= FAKE_NODE_MIN_HASH_MASK;
118 if (!size) {
119 pr_err("Not enough memory for each node. "
120 "NUMA emulation disabled.\n");
121 return -1;
122 }
123
124 /*
125 * Continue to fill physical nodes with fake nodes until there is no
126 * memory left on any of them.
127 */
128 while (!nodes_empty(physnode_mask)) {
129 for_each_node_mask(i, physnode_mask) {
130 u64 dma32_end = numa_emu_dma_end();
131 u64 start, limit, end;
132 int phys_blk;
133
134 phys_blk = emu_find_memblk_by_nid(i, pi);
135 if (phys_blk < 0) {
136 node_clear(i, physnode_mask);
137 continue;
138 }
139 start = pi->blk[phys_blk].start;
140 limit = pi->blk[phys_blk].end;
141 end = start + size;
142
143 if (nid < big)
144 end += FAKE_NODE_MIN_SIZE;
145
146 /*
147 * Continue to add memory to this fake node if its
148 * non-reserved memory is less than the per-node size.
149 */
150 while (end - start - mem_hole_size(start, end) < size) {
151 end += FAKE_NODE_MIN_SIZE;
152 if (end > limit) {
153 end = limit;
154 break;
155 }
156 }
157
158 /*
159 * If there won't be at least FAKE_NODE_MIN_SIZE of
160 * non-reserved memory in ZONE_DMA32 for the next node,
161 * this one must extend to the boundary.
162 */
163 if (end < dma32_end && dma32_end - end -
164 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
165 end = dma32_end;
166
167 /*
168 * If there won't be enough non-reserved memory for the
169 * next node, this one must extend to the end of the
170 * physical node.
171 */
172 if (limit - end - mem_hole_size(end, limit) < size)
173 end = limit;
174
175 ret = emu_setup_memblk(ei, pi, nid++ % nr_nodes,
176 phys_blk,
177 min(end, limit) - start);
178 if (ret < 0)
179 return ret;
180 }
181 }
182 return 0;
183 }
184
185 /*
186 * Returns the end address of a node so that there is at least `size' amount of
187 * non-reserved memory or `max_addr' is reached.
188 */
189 static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
190 {
191 u64 end = start + size;
192
193 while (end - start - mem_hole_size(start, end) < size) {
194 end += FAKE_NODE_MIN_SIZE;
195 if (end > max_addr) {
196 end = max_addr;
197 break;
198 }
199 }
200 return end;
201 }
202
203 static u64 uniform_size(u64 max_addr, u64 base, u64 hole, int nr_nodes)
204 {
205 unsigned long max_pfn = PHYS_PFN(max_addr);
206 unsigned long base_pfn = PHYS_PFN(base);
207 unsigned long hole_pfns = PHYS_PFN(hole);
208
209 return PFN_PHYS((max_pfn - base_pfn - hole_pfns) / nr_nodes);
210 }
211
212 /*
213 * Sets up fake nodes of `size' interleaved over physical nodes ranging from
214 * `addr' to `max_addr'.
215 *
216 * Returns zero on success or negative on error.
217 */
218 static int __init split_nodes_size_interleave_uniform(struct numa_meminfo *ei,
219 struct numa_meminfo *pi,
220 u64 addr, u64 max_addr, u64 size,
221 int nr_nodes, struct numa_memblk *pblk,
222 int nid)
223 {
224 nodemask_t physnode_mask = numa_nodes_parsed;
225 int i, ret, uniform = 0;
226 u64 min_size;
227
228 if ((!size && !nr_nodes) || (nr_nodes && !pblk))
229 return -1;
230
231 /*
232 * In the 'uniform' case split the passed in physical node by
233 * nr_nodes, in the non-uniform case, ignore the passed in
234 * physical block and try to create nodes of at least size
235 * @size.
236 *
237 * In the uniform case, split the nodes strictly by physical
238 * capacity, i.e. ignore holes. In the non-uniform case account
239 * for holes and treat @size as a minimum floor.
240 */
241 if (!nr_nodes)
242 nr_nodes = MAX_NUMNODES;
243 else {
244 nodes_clear(physnode_mask);
245 node_set(pblk->nid, physnode_mask);
246 uniform = 1;
247 }
248
249 if (uniform) {
250 min_size = uniform_size(max_addr, addr, 0, nr_nodes);
251 size = min_size;
252 } else {
253 /*
254 * The limit on emulated nodes is MAX_NUMNODES, so the
255 * size per node is increased accordingly if the
256 * requested size is too small. This creates a uniform
257 * distribution of node sizes across the entire machine
258 * (but not necessarily over physical nodes).
259 */
260 min_size = uniform_size(max_addr, addr,
261 mem_hole_size(addr, max_addr), nr_nodes);
262 }
263 min_size = ALIGN(max(min_size, FAKE_NODE_MIN_SIZE), FAKE_NODE_MIN_SIZE);
264 if (size < min_size) {
265 pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
266 size >> 20, min_size >> 20);
267 size = min_size;
268 }
269 size = ALIGN_DOWN(size, FAKE_NODE_MIN_SIZE);
270
271 /*
272 * Fill physical nodes with fake nodes of size until there is no memory
273 * left on any of them.
274 */
275 while (!nodes_empty(physnode_mask)) {
276 for_each_node_mask(i, physnode_mask) {
277 u64 dma32_end = numa_emu_dma_end();
278 u64 start, limit, end;
279 int phys_blk;
280
281 phys_blk = emu_find_memblk_by_nid(i, pi);
282 if (phys_blk < 0) {
283 node_clear(i, physnode_mask);
284 continue;
285 }
286
287 start = pi->blk[phys_blk].start;
288 limit = pi->blk[phys_blk].end;
289
290 if (uniform)
291 end = start + size;
292 else
293 end = find_end_of_node(start, limit, size);
294 /*
295 * If there won't be at least FAKE_NODE_MIN_SIZE of
296 * non-reserved memory in ZONE_DMA32 for the next node,
297 * this one must extend to the boundary.
298 */
299 if (end < dma32_end && dma32_end - end -
300 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
301 end = dma32_end;
302
303 /*
304 * If there won't be enough non-reserved memory for the
305 * next node, this one must extend to the end of the
306 * physical node.
307 */
308 if ((limit - end - mem_hole_size(end, limit) < size)
309 && !uniform)
310 end = limit;
311
312 ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
313 phys_blk,
314 min(end, limit) - start);
315 if (ret < 0)
316 return ret;
317 }
318 }
319 return nid;
320 }
321
322 static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
323 struct numa_meminfo *pi,
324 u64 addr, u64 max_addr, u64 size)
325 {
326 return split_nodes_size_interleave_uniform(ei, pi, addr, max_addr, size,
327 0, NULL, 0);
328 }
329
330 static int __init setup_emu2phys_nid(int *dfl_phys_nid)
331 {
332 int i, max_emu_nid = 0;
333
334 *dfl_phys_nid = NUMA_NO_NODE;
335 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {
336 if (emu_nid_to_phys[i] != NUMA_NO_NODE) {
337 max_emu_nid = i;
338 if (*dfl_phys_nid == NUMA_NO_NODE)
339 *dfl_phys_nid = emu_nid_to_phys[i];
340 }
341 }
342
343 return max_emu_nid;
344 }
345
346 /**
347 * numa_emulation - Emulate NUMA nodes
348 * @numa_meminfo: NUMA configuration to massage
349 * @numa_dist_cnt: The size of the physical NUMA distance table
350 *
351 * Emulate NUMA nodes according to the numa=fake kernel parameter.
352 * @numa_meminfo contains the physical memory configuration and is modified
353 * to reflect the emulated configuration on success. @numa_dist_cnt is
354 * used to determine the size of the physical distance table.
355 *
356 * On success, the following modifications are made.
357 *
358 * - @numa_meminfo is updated to reflect the emulated nodes.
359 *
360 * - __apicid_to_node[] is updated such that APIC IDs are mapped to the
361 * emulated nodes.
362 *
363 * - NUMA distance table is rebuilt to represent distances between emulated
364 * nodes. The distances are determined considering how emulated nodes
365 * are mapped to physical nodes and match the actual distances.
366 *
367 * - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical
368 * nodes. This is used by numa_add_cpu() and numa_remove_cpu().
369 *
370 * If emulation is not enabled or fails, emu_nid_to_phys[] is filled with
371 * identity mapping and no other modification is made.
372 */
373 void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
374 {
375 static struct numa_meminfo ei __initdata;
376 static struct numa_meminfo pi __initdata;
377 const u64 max_addr = PFN_PHYS(max_pfn);
378 u8 *phys_dist = NULL;
379 size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
380 int max_emu_nid, dfl_phys_nid;
381 int i, j, ret;
382
383 if (!emu_cmdline)
384 goto no_emu;
385
386 memset(&ei, 0, sizeof(ei));
387 pi = *numa_meminfo;
388
389 for (i = 0; i < MAX_NUMNODES; i++)
390 emu_nid_to_phys[i] = NUMA_NO_NODE;
391
392 /*
393 * If the numa=fake command-line contains a 'M' or 'G', it represents
394 * the fixed node size. Otherwise, if it is just a single number N,
395 * split the system RAM into N fake nodes.
396 */
397 if (strchr(emu_cmdline, 'U')) {
398 nodemask_t physnode_mask = numa_nodes_parsed;
399 unsigned long n;
400 int nid = 0;
401
402 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
403 ret = -1;
404 for_each_node_mask(i, physnode_mask) {
405 /*
406 * The reason we pass in blk[0] is due to
407 * numa_remove_memblk_from() called by
408 * emu_setup_memblk() will delete entry 0
409 * and then move everything else up in the pi.blk
410 * array. Therefore we should always be looking
411 * at blk[0].
412 */
413 ret = split_nodes_size_interleave_uniform(&ei, &pi,
414 pi.blk[0].start, pi.blk[0].end, 0,
415 n, &pi.blk[0], nid);
416 if (ret < 0)
417 break;
418 if (ret < n) {
419 pr_info("%s: phys: %d only got %d of %ld nodes, failing\n",
420 __func__, i, ret, n);
421 ret = -1;
422 break;
423 }
424 nid = ret;
425 }
426 } else if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
427 u64 size;
428
429 size = memparse(emu_cmdline, &emu_cmdline);
430 ret = split_nodes_size_interleave(&ei, &pi, 0, max_addr, size);
431 } else {
432 unsigned long n;
433
434 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
435 ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
436 }
437 if (*emu_cmdline == ':')
438 emu_cmdline++;
439
440 if (ret < 0)
441 goto no_emu;
442
443 if (numa_cleanup_meminfo(&ei) < 0) {
444 pr_warn("NUMA: Warning: constructed meminfo invalid, disabling emulation\n");
445 goto no_emu;
446 }
447
448 /* copy the physical distance table */
449 if (numa_dist_cnt) {
450 phys_dist = memblock_alloc(phys_size, PAGE_SIZE);
451 if (!phys_dist) {
452 pr_warn("NUMA: Warning: can't allocate copy of distance table, disabling emulation\n");
453 goto no_emu;
454 }
455
456 for (i = 0; i < numa_dist_cnt; i++)
457 for (j = 0; j < numa_dist_cnt; j++)
458 phys_dist[i * numa_dist_cnt + j] =
459 node_distance(i, j);
460 }
461
462 /*
463 * Determine the max emulated nid and the default phys nid to use
464 * for unmapped nodes.
465 */
466 max_emu_nid = setup_emu2phys_nid(&dfl_phys_nid);
467
468 /* commit */
469 *numa_meminfo = ei;
470
471 /* Make sure numa_nodes_parsed only contains emulated nodes */
472 nodes_clear(numa_nodes_parsed);
473 for (i = 0; i < ARRAY_SIZE(ei.blk); i++)
474 if (ei.blk[i].start != ei.blk[i].end &&
475 ei.blk[i].nid != NUMA_NO_NODE)
476 node_set(ei.blk[i].nid, numa_nodes_parsed);
477
478 numa_emu_update_cpu_to_node(emu_nid_to_phys, ARRAY_SIZE(emu_nid_to_phys));
479
480 /* make sure all emulated nodes are mapped to a physical node */
481 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
482 if (emu_nid_to_phys[i] == NUMA_NO_NODE)
483 emu_nid_to_phys[i] = dfl_phys_nid;
484
485 /* transform distance table */
486 numa_reset_distance();
487 for (i = 0; i < max_emu_nid + 1; i++) {
488 for (j = 0; j < max_emu_nid + 1; j++) {
489 int physi = emu_nid_to_phys[i];
490 int physj = emu_nid_to_phys[j];
491 int dist;
492
493 if (get_option(&emu_cmdline, &dist) == 2)
494 ;
495 else if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
496 dist = physi == physj ?
497 LOCAL_DISTANCE : REMOTE_DISTANCE;
498 else
499 dist = phys_dist[physi * numa_dist_cnt + physj];
500
501 numa_set_distance(i, j, dist);
502 }
503 }
504
505 /* free the copied physical distance table */
506 memblock_free(phys_dist, phys_size);
507 return;
508
509 no_emu:
510 /* No emulation. Build identity emu_nid_to_phys[] for numa_add_cpu() */
511 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
512 emu_nid_to_phys[i] = i;
513 }
514
515 #ifndef CONFIG_DEBUG_PER_CPU_MAPS
516 void numa_add_cpu(unsigned int cpu)
517 {
518 int physnid, nid;
519
520 nid = early_cpu_to_node(cpu);
521 BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));
522
523 physnid = emu_nid_to_phys[nid];
524
525 /*
526 * Map the cpu to each emulated node that is allocated on the physical
527 * node of the cpu's apic id.
528 */
529 for_each_online_node(nid)
530 if (emu_nid_to_phys[nid] == physnid)
531 cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
532 }
533
534 void numa_remove_cpu(unsigned int cpu)
535 {
536 int i;
537
538 for_each_online_node(i)
539 cpumask_clear_cpu(cpu, node_to_cpumask_map[i]);
540 }
541 #else /* !CONFIG_DEBUG_PER_CPU_MAPS */
542 static void numa_set_cpumask(unsigned int cpu, bool enable)
543 {
544 int nid, physnid;
545
546 nid = early_cpu_to_node(cpu);
547 if (nid == NUMA_NO_NODE) {
548 /* early_cpu_to_node() already emits a warning and trace */
549 return;
550 }
551
552 physnid = emu_nid_to_phys[nid];
553
554 for_each_online_node(nid) {
555 if (emu_nid_to_phys[nid] != physnid)
556 continue;
557
558 debug_cpumask_set_cpu(cpu, nid, enable);
559 }
560 }
561
562 void numa_add_cpu(unsigned int cpu)
563 {
564 numa_set_cpumask(cpu, true);
565 }
566
567 void numa_remove_cpu(unsigned int cpu)
568 {
569 numa_set_cpumask(cpu, false);
570 }
571 #endif /* !CONFIG_DEBUG_PER_CPU_MAPS */
572
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