1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Support for Partition Mobility/Migration
4  *
5  * Copyright (C) 2010 Nathan Fontenot
6  * Copyright (C) 2010 IBM Corporation
7  */
8 
9 
10 #define pr_fmt(fmt) "mobility: " fmt
11 
12 #include <linux/cpu.h>
13 #include <linux/kernel.h>
14 #include <linux/kobject.h>
15 #include <linux/nmi.h>
16 #include <linux/sched.h>
17 #include <linux/smp.h>
18 #include <linux/stat.h>
19 #include <linux/stop_machine.h>
20 #include <linux/completion.h>
21 #include <linux/device.h>
22 #include <linux/delay.h>
23 #include <linux/slab.h>
24 #include <linux/stringify.h>
25 
26 #include <asm/machdep.h>
27 #include <asm/rtas.h>
28 #include "pseries.h"
29 #include "vas.h"	/* vas_migration_handler() */
30 #include "../../kernel/cacheinfo.h"
31 
32 static struct kobject *mobility_kobj;
33 
34 struct update_props_workarea {
35 	__be32 phandle;
36 	__be32 state;
37 	__be64 reserved;
38 	__be32 nprops;
39 } __packed;
40 
41 #define NODE_ACTION_MASK	0xff000000
42 #define NODE_COUNT_MASK		0x00ffffff
43 
44 #define DELETE_DT_NODE	0x01000000
45 #define UPDATE_DT_NODE	0x02000000
46 #define ADD_DT_NODE	0x03000000
47 
48 #define MIGRATION_SCOPE	(1)
49 #define PRRN_SCOPE -2
50 
51 #ifdef CONFIG_PPC_WATCHDOG
52 static unsigned int nmi_wd_lpm_factor = 200;
53 
54 #ifdef CONFIG_SYSCTL
55 static struct ctl_table nmi_wd_lpm_factor_ctl_table[] = {
56 	{
57 		.procname	= "nmi_wd_lpm_factor",
58 		.data		= &nmi_wd_lpm_factor,
59 		.maxlen		= sizeof(int),
60 		.mode		= 0644,
61 		.proc_handler	= proc_douintvec_minmax,
62 	},
63 	{}
64 };
65 
66 static int __init register_nmi_wd_lpm_factor_sysctl(void)
67 {
68 	register_sysctl("kernel", nmi_wd_lpm_factor_ctl_table);
69 
70 	return 0;
71 }
72 device_initcall(register_nmi_wd_lpm_factor_sysctl);
73 #endif /* CONFIG_SYSCTL */
74 #endif /* CONFIG_PPC_WATCHDOG */
75 
76 static int mobility_rtas_call(int token, char *buf, s32 scope)
77 {
78 	int rc;
79 
80 	spin_lock(&rtas_data_buf_lock);
81 
82 	memcpy(rtas_data_buf, buf, RTAS_DATA_BUF_SIZE);
83 	rc = rtas_call(token, 2, 1, NULL, rtas_data_buf, scope);
84 	memcpy(buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);
85 
86 	spin_unlock(&rtas_data_buf_lock);
87 	return rc;
88 }
89 
90 static int delete_dt_node(struct device_node *dn)
91 {
92 	struct device_node *pdn;
93 	bool is_platfac;
94 
95 	pdn = of_get_parent(dn);
96 	is_platfac = of_node_is_type(dn, "ibm,platform-facilities") ||
97 		     of_node_is_type(pdn, "ibm,platform-facilities");
98 	of_node_put(pdn);
99 
100 	/*
101 	 * The drivers that bind to nodes in the platform-facilities
102 	 * hierarchy don't support node removal, and the removal directive
103 	 * from firmware is always followed by an add of an equivalent
104 	 * node. The capability (e.g. RNG, encryption, compression)
105 	 * represented by the node is never interrupted by the migration.
106 	 * So ignore changes to this part of the tree.
107 	 */
108 	if (is_platfac) {
109 		pr_notice("ignoring remove operation for %pOFfp\n", dn);
110 		return 0;
111 	}
112 
113 	pr_debug("removing node %pOFfp\n", dn);
114 	dlpar_detach_node(dn);
115 	return 0;
116 }
117 
118 static int update_dt_property(struct device_node *dn, struct property **prop,
119 			      const char *name, u32 vd, char *value)
120 {
121 	struct property *new_prop = *prop;
122 	int more = 0;
123 
124 	/* A negative 'vd' value indicates that only part of the new property
125 	 * value is contained in the buffer and we need to call
126 	 * ibm,update-properties again to get the rest of the value.
127 	 *
128 	 * A negative value is also the two's compliment of the actual value.
129 	 */
130 	if (vd & 0x80000000) {
131 		vd = ~vd + 1;
132 		more = 1;
133 	}
134 
135 	if (new_prop) {
136 		/* partial property fixup */
137 		char *new_data = kzalloc(new_prop->length + vd, GFP_KERNEL);
138 		if (!new_data)
139 			return -ENOMEM;
140 
141 		memcpy(new_data, new_prop->value, new_prop->length);
142 		memcpy(new_data + new_prop->length, value, vd);
143 
144 		kfree(new_prop->value);
145 		new_prop->value = new_data;
146 		new_prop->length += vd;
147 	} else {
148 		new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
149 		if (!new_prop)
150 			return -ENOMEM;
151 
152 		new_prop->name = kstrdup(name, GFP_KERNEL);
153 		if (!new_prop->name) {
154 			kfree(new_prop);
155 			return -ENOMEM;
156 		}
157 
158 		new_prop->length = vd;
159 		new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
160 		if (!new_prop->value) {
161 			kfree(new_prop->name);
162 			kfree(new_prop);
163 			return -ENOMEM;
164 		}
165 
166 		memcpy(new_prop->value, value, vd);
167 		*prop = new_prop;
168 	}
169 
170 	if (!more) {
171 		pr_debug("updating node %pOF property %s\n", dn, name);
172 		of_update_property(dn, new_prop);
173 		*prop = NULL;
174 	}
175 
176 	return 0;
177 }
178 
179 static int update_dt_node(struct device_node *dn, s32 scope)
180 {
181 	struct update_props_workarea *upwa;
182 	struct property *prop = NULL;
183 	int i, rc, rtas_rc;
184 	char *prop_data;
185 	char *rtas_buf;
186 	int update_properties_token;
187 	u32 nprops;
188 	u32 vd;
189 
190 	update_properties_token = rtas_function_token(RTAS_FN_IBM_UPDATE_PROPERTIES);
191 	if (update_properties_token == RTAS_UNKNOWN_SERVICE)
192 		return -EINVAL;
193 
194 	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
195 	if (!rtas_buf)
196 		return -ENOMEM;
197 
198 	upwa = (struct update_props_workarea *)&rtas_buf[0];
199 	upwa->phandle = cpu_to_be32(dn->phandle);
200 
201 	do {
202 		rtas_rc = mobility_rtas_call(update_properties_token, rtas_buf,
203 					scope);
204 		if (rtas_rc < 0)
205 			break;
206 
207 		prop_data = rtas_buf + sizeof(*upwa);
208 		nprops = be32_to_cpu(upwa->nprops);
209 
210 		/* On the first call to ibm,update-properties for a node the
211 		 * first property value descriptor contains an empty
212 		 * property name, the property value length encoded as u32,
213 		 * and the property value is the node path being updated.
214 		 */
215 		if (*prop_data == 0) {
216 			prop_data++;
217 			vd = be32_to_cpu(*(__be32 *)prop_data);
218 			prop_data += vd + sizeof(vd);
219 			nprops--;
220 		}
221 
222 		for (i = 0; i < nprops; i++) {
223 			char *prop_name;
224 
225 			prop_name = prop_data;
226 			prop_data += strlen(prop_name) + 1;
227 			vd = be32_to_cpu(*(__be32 *)prop_data);
228 			prop_data += sizeof(vd);
229 
230 			switch (vd) {
231 			case 0x00000000:
232 				/* name only property, nothing to do */
233 				break;
234 
235 			case 0x80000000:
236 				of_remove_property(dn, of_find_property(dn,
237 							prop_name, NULL));
238 				prop = NULL;
239 				break;
240 
241 			default:
242 				rc = update_dt_property(dn, &prop, prop_name,
243 							vd, prop_data);
244 				if (rc) {
245 					pr_err("updating %s property failed: %d\n",
246 					       prop_name, rc);
247 				}
248 
249 				prop_data += vd;
250 				break;
251 			}
252 
253 			cond_resched();
254 		}
255 
256 		cond_resched();
257 	} while (rtas_rc == 1);
258 
259 	kfree(rtas_buf);
260 	return 0;
261 }
262 
263 static int add_dt_node(struct device_node *parent_dn, __be32 drc_index)
264 {
265 	struct device_node *dn;
266 	int rc;
267 
268 	dn = dlpar_configure_connector(drc_index, parent_dn);
269 	if (!dn)
270 		return -ENOENT;
271 
272 	/*
273 	 * Since delete_dt_node() ignores this node type, this is the
274 	 * necessary counterpart. We also know that a platform-facilities
275 	 * node returned from dlpar_configure_connector() has children
276 	 * attached, and dlpar_attach_node() only adds the parent, leaking
277 	 * the children. So ignore these on the add side for now.
278 	 */
279 	if (of_node_is_type(dn, "ibm,platform-facilities")) {
280 		pr_notice("ignoring add operation for %pOF\n", dn);
281 		dlpar_free_cc_nodes(dn);
282 		return 0;
283 	}
284 
285 	rc = dlpar_attach_node(dn, parent_dn);
286 	if (rc)
287 		dlpar_free_cc_nodes(dn);
288 
289 	pr_debug("added node %pOFfp\n", dn);
290 
291 	return rc;
292 }
293 
294 static int pseries_devicetree_update(s32 scope)
295 {
296 	char *rtas_buf;
297 	__be32 *data;
298 	int update_nodes_token;
299 	int rc;
300 
301 	update_nodes_token = rtas_function_token(RTAS_FN_IBM_UPDATE_NODES);
302 	if (update_nodes_token == RTAS_UNKNOWN_SERVICE)
303 		return 0;
304 
305 	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
306 	if (!rtas_buf)
307 		return -ENOMEM;
308 
309 	do {
310 		rc = mobility_rtas_call(update_nodes_token, rtas_buf, scope);
311 		if (rc && rc != 1)
312 			break;
313 
314 		data = (__be32 *)rtas_buf + 4;
315 		while (be32_to_cpu(*data) & NODE_ACTION_MASK) {
316 			int i;
317 			u32 action = be32_to_cpu(*data) & NODE_ACTION_MASK;
318 			u32 node_count = be32_to_cpu(*data) & NODE_COUNT_MASK;
319 
320 			data++;
321 
322 			for (i = 0; i < node_count; i++) {
323 				struct device_node *np;
324 				__be32 phandle = *data++;
325 				__be32 drc_index;
326 
327 				np = of_find_node_by_phandle(be32_to_cpu(phandle));
328 				if (!np) {
329 					pr_warn("Failed lookup: phandle 0x%x for action 0x%x\n",
330 						be32_to_cpu(phandle), action);
331 					continue;
332 				}
333 
334 				switch (action) {
335 				case DELETE_DT_NODE:
336 					delete_dt_node(np);
337 					break;
338 				case UPDATE_DT_NODE:
339 					update_dt_node(np, scope);
340 					break;
341 				case ADD_DT_NODE:
342 					drc_index = *data++;
343 					add_dt_node(np, drc_index);
344 					break;
345 				}
346 
347 				of_node_put(np);
348 				cond_resched();
349 			}
350 		}
351 
352 		cond_resched();
353 	} while (rc == 1);
354 
355 	kfree(rtas_buf);
356 	return rc;
357 }
358 
359 void post_mobility_fixup(void)
360 {
361 	int rc;
362 
363 	rtas_activate_firmware();
364 
365 	/*
366 	 * We don't want CPUs to go online/offline while the device
367 	 * tree is being updated.
368 	 */
369 	cpus_read_lock();
370 
371 	/*
372 	 * It's common for the destination firmware to replace cache
373 	 * nodes.  Release all of the cacheinfo hierarchy's references
374 	 * before updating the device tree.
375 	 */
376 	cacheinfo_teardown();
377 
378 	rc = pseries_devicetree_update(MIGRATION_SCOPE);
379 	if (rc)
380 		pr_err("device tree update failed: %d\n", rc);
381 
382 	cacheinfo_rebuild();
383 
384 	cpus_read_unlock();
385 
386 	/* Possibly switch to a new L1 flush type */
387 	pseries_setup_security_mitigations();
388 
389 	/* Reinitialise system information for hv-24x7 */
390 	read_24x7_sys_info();
391 
392 	return;
393 }
394 
395 static int poll_vasi_state(u64 handle, unsigned long *res)
396 {
397 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
398 	long hvrc;
399 	int ret;
400 
401 	hvrc = plpar_hcall(H_VASI_STATE, retbuf, handle);
402 	switch (hvrc) {
403 	case H_SUCCESS:
404 		ret = 0;
405 		*res = retbuf[0];
406 		break;
407 	case H_PARAMETER:
408 		ret = -EINVAL;
409 		break;
410 	case H_FUNCTION:
411 		ret = -EOPNOTSUPP;
412 		break;
413 	case H_HARDWARE:
414 	default:
415 		pr_err("unexpected H_VASI_STATE result %ld\n", hvrc);
416 		ret = -EIO;
417 		break;
418 	}
419 	return ret;
420 }
421 
422 static int wait_for_vasi_session_suspending(u64 handle)
423 {
424 	unsigned long state;
425 	int ret;
426 
427 	/*
428 	 * Wait for transition from H_VASI_ENABLED to
429 	 * H_VASI_SUSPENDING. Treat anything else as an error.
430 	 */
431 	while (true) {
432 		ret = poll_vasi_state(handle, &state);
433 
434 		if (ret != 0 || state == H_VASI_SUSPENDING) {
435 			break;
436 		} else if (state == H_VASI_ENABLED) {
437 			ssleep(1);
438 		} else {
439 			pr_err("unexpected H_VASI_STATE result %lu\n", state);
440 			ret = -EIO;
441 			break;
442 		}
443 	}
444 
445 	/*
446 	 * Proceed even if H_VASI_STATE is unavailable. If H_JOIN or
447 	 * ibm,suspend-me are also unimplemented, we'll recover then.
448 	 */
449 	if (ret == -EOPNOTSUPP)
450 		ret = 0;
451 
452 	return ret;
453 }
454 
455 static void wait_for_vasi_session_completed(u64 handle)
456 {
457 	unsigned long state = 0;
458 	int ret;
459 
460 	pr_info("waiting for memory transfer to complete...\n");
461 
462 	/*
463 	 * Wait for transition from H_VASI_RESUMED to H_VASI_COMPLETED.
464 	 */
465 	while (true) {
466 		ret = poll_vasi_state(handle, &state);
467 
468 		/*
469 		 * If the memory transfer is already complete and the migration
470 		 * has been cleaned up by the hypervisor, H_PARAMETER is return,
471 		 * which is translate in EINVAL by poll_vasi_state().
472 		 */
473 		if (ret == -EINVAL || (!ret && state == H_VASI_COMPLETED)) {
474 			pr_info("memory transfer completed.\n");
475 			break;
476 		}
477 
478 		if (ret) {
479 			pr_err("H_VASI_STATE return error (%d)\n", ret);
480 			break;
481 		}
482 
483 		if (state != H_VASI_RESUMED) {
484 			pr_err("unexpected H_VASI_STATE result %lu\n", state);
485 			break;
486 		}
487 
488 		msleep(500);
489 	}
490 }
491 
492 static void prod_single(unsigned int target_cpu)
493 {
494 	long hvrc;
495 	int hwid;
496 
497 	hwid = get_hard_smp_processor_id(target_cpu);
498 	hvrc = plpar_hcall_norets(H_PROD, hwid);
499 	if (hvrc == H_SUCCESS)
500 		return;
501 	pr_err_ratelimited("H_PROD of CPU %u (hwid %d) error: %ld\n",
502 			   target_cpu, hwid, hvrc);
503 }
504 
505 static void prod_others(void)
506 {
507 	unsigned int cpu;
508 
509 	for_each_online_cpu(cpu) {
510 		if (cpu != smp_processor_id())
511 			prod_single(cpu);
512 	}
513 }
514 
515 static u16 clamp_slb_size(void)
516 {
517 #ifdef CONFIG_PPC_64S_HASH_MMU
518 	u16 prev = mmu_slb_size;
519 
520 	slb_set_size(SLB_MIN_SIZE);
521 
522 	return prev;
523 #else
524 	return 0;
525 #endif
526 }
527 
528 static int do_suspend(void)
529 {
530 	u16 saved_slb_size;
531 	int status;
532 	int ret;
533 
534 	pr_info("calling ibm,suspend-me on CPU %i\n", smp_processor_id());
535 
536 	/*
537 	 * The destination processor model may have fewer SLB entries
538 	 * than the source. We reduce mmu_slb_size to a safe minimum
539 	 * before suspending in order to minimize the possibility of
540 	 * programming non-existent entries on the destination. If
541 	 * suspend fails, we restore it before returning. On success
542 	 * the OF reconfig path will update it from the new device
543 	 * tree after resuming on the destination.
544 	 */
545 	saved_slb_size = clamp_slb_size();
546 
547 	ret = rtas_ibm_suspend_me(&status);
548 	if (ret != 0) {
549 		pr_err("ibm,suspend-me error: %d\n", status);
550 		slb_set_size(saved_slb_size);
551 	}
552 
553 	return ret;
554 }
555 
556 /**
557  * struct pseries_suspend_info - State shared between CPUs for join/suspend.
558  * @counter: Threads are to increment this upon resuming from suspend
559  *           or if an error is received from H_JOIN. The thread which performs
560  *           the first increment (i.e. sets it to 1) is responsible for
561  *           waking the other threads.
562  * @done: False if join/suspend is in progress. True if the operation is
563  *        complete (successful or not).
564  */
565 struct pseries_suspend_info {
566 	atomic_t counter;
567 	bool done;
568 };
569 
570 static int do_join(void *arg)
571 {
572 	struct pseries_suspend_info *info = arg;
573 	atomic_t *counter = &info->counter;
574 	long hvrc;
575 	int ret;
576 
577 retry:
578 	/* Must ensure MSR.EE off for H_JOIN. */
579 	hard_irq_disable();
580 	hvrc = plpar_hcall_norets(H_JOIN);
581 
582 	switch (hvrc) {
583 	case H_CONTINUE:
584 		/*
585 		 * All other CPUs are offline or in H_JOIN. This CPU
586 		 * attempts the suspend.
587 		 */
588 		ret = do_suspend();
589 		break;
590 	case H_SUCCESS:
591 		/*
592 		 * The suspend is complete and this cpu has received a
593 		 * prod, or we've received a stray prod from unrelated
594 		 * code (e.g. paravirt spinlocks) and we need to join
595 		 * again.
596 		 *
597 		 * This barrier orders the return from H_JOIN above vs
598 		 * the load of info->done. It pairs with the barrier
599 		 * in the wakeup/prod path below.
600 		 */
601 		smp_mb();
602 		if (READ_ONCE(info->done) == false) {
603 			pr_info_ratelimited("premature return from H_JOIN on CPU %i, retrying",
604 					    smp_processor_id());
605 			goto retry;
606 		}
607 		ret = 0;
608 		break;
609 	case H_BAD_MODE:
610 	case H_HARDWARE:
611 	default:
612 		ret = -EIO;
613 		pr_err_ratelimited("H_JOIN error %ld on CPU %i\n",
614 				   hvrc, smp_processor_id());
615 		break;
616 	}
617 
618 	if (atomic_inc_return(counter) == 1) {
619 		pr_info("CPU %u waking all threads\n", smp_processor_id());
620 		WRITE_ONCE(info->done, true);
621 		/*
622 		 * This barrier orders the store to info->done vs subsequent
623 		 * H_PRODs to wake the other CPUs. It pairs with the barrier
624 		 * in the H_SUCCESS case above.
625 		 */
626 		smp_mb();
627 		prod_others();
628 	}
629 	/*
630 	 * Execution may have been suspended for several seconds, so reset
631 	 * the watchdogs. touch_nmi_watchdog() also touches the soft lockup
632 	 * watchdog.
633 	 */
634 	rcu_cpu_stall_reset();
635 	touch_nmi_watchdog();
636 
637 	return ret;
638 }
639 
640 /*
641  * Abort reason code byte 0. We use only the 'Migrating partition' value.
642  */
643 enum vasi_aborting_entity {
644 	ORCHESTRATOR        = 1,
645 	VSP_SOURCE          = 2,
646 	PARTITION_FIRMWARE  = 3,
647 	PLATFORM_FIRMWARE   = 4,
648 	VSP_TARGET          = 5,
649 	MIGRATING_PARTITION = 6,
650 };
651 
652 static void pseries_cancel_migration(u64 handle, int err)
653 {
654 	u32 reason_code;
655 	u32 detail;
656 	u8 entity;
657 	long hvrc;
658 
659 	entity = MIGRATING_PARTITION;
660 	detail = abs(err) & 0xffffff;
661 	reason_code = (entity << 24) | detail;
662 
663 	hvrc = plpar_hcall_norets(H_VASI_SIGNAL, handle,
664 				  H_VASI_SIGNAL_CANCEL, reason_code);
665 	if (hvrc)
666 		pr_err("H_VASI_SIGNAL error: %ld\n", hvrc);
667 }
668 
669 static int pseries_suspend(u64 handle)
670 {
671 	const unsigned int max_attempts = 5;
672 	unsigned int retry_interval_ms = 1;
673 	unsigned int attempt = 1;
674 	int ret;
675 
676 	while (true) {
677 		struct pseries_suspend_info info;
678 		unsigned long vasi_state;
679 		int vasi_err;
680 
681 		info = (struct pseries_suspend_info) {
682 			.counter = ATOMIC_INIT(0),
683 			.done = false,
684 		};
685 
686 		ret = stop_machine(do_join, &info, cpu_online_mask);
687 		if (ret == 0)
688 			break;
689 		/*
690 		 * Encountered an error. If the VASI stream is still
691 		 * in Suspending state, it's likely a transient
692 		 * condition related to some device in the partition
693 		 * and we can retry in the hope that the cause has
694 		 * cleared after some delay.
695 		 *
696 		 * A better design would allow drivers etc to prepare
697 		 * for the suspend and avoid conditions which prevent
698 		 * the suspend from succeeding. For now, we have this
699 		 * mitigation.
700 		 */
701 		pr_notice("Partition suspend attempt %u of %u error: %d\n",
702 			  attempt, max_attempts, ret);
703 
704 		if (attempt == max_attempts)
705 			break;
706 
707 		vasi_err = poll_vasi_state(handle, &vasi_state);
708 		if (vasi_err == 0) {
709 			if (vasi_state != H_VASI_SUSPENDING) {
710 				pr_notice("VASI state %lu after failed suspend\n",
711 					  vasi_state);
712 				break;
713 			}
714 		} else if (vasi_err != -EOPNOTSUPP) {
715 			pr_err("VASI state poll error: %d", vasi_err);
716 			break;
717 		}
718 
719 		pr_notice("Will retry partition suspend after %u ms\n",
720 			  retry_interval_ms);
721 
722 		msleep(retry_interval_ms);
723 		retry_interval_ms *= 10;
724 		attempt++;
725 	}
726 
727 	return ret;
728 }
729 
730 static int pseries_migrate_partition(u64 handle)
731 {
732 	int ret;
733 	unsigned int factor = 0;
734 
735 #ifdef CONFIG_PPC_WATCHDOG
736 	factor = nmi_wd_lpm_factor;
737 #endif
738 	/*
739 	 * When the migration is initiated, the hypervisor changes VAS
740 	 * mappings to prepare before OS gets the notification and
741 	 * closes all VAS windows. NX generates continuous faults during
742 	 * this time and the user space can not differentiate these
743 	 * faults from the migration event. So reduce this time window
744 	 * by closing VAS windows at the beginning of this function.
745 	 */
746 	vas_migration_handler(VAS_SUSPEND);
747 
748 	ret = wait_for_vasi_session_suspending(handle);
749 	if (ret)
750 		goto out;
751 
752 	if (factor)
753 		watchdog_nmi_set_timeout_pct(factor);
754 
755 	ret = pseries_suspend(handle);
756 	if (ret == 0) {
757 		post_mobility_fixup();
758 		/*
759 		 * Wait until the memory transfer is complete, so that the user
760 		 * space process returns from the syscall after the transfer is
761 		 * complete. This allows the user hooks to be executed at the
762 		 * right time.
763 		 */
764 		wait_for_vasi_session_completed(handle);
765 	} else
766 		pseries_cancel_migration(handle, ret);
767 
768 	if (factor)
769 		watchdog_nmi_set_timeout_pct(0);
770 
771 out:
772 	vas_migration_handler(VAS_RESUME);
773 
774 	return ret;
775 }
776 
777 int rtas_syscall_dispatch_ibm_suspend_me(u64 handle)
778 {
779 	return pseries_migrate_partition(handle);
780 }
781 
782 static ssize_t migration_store(const struct class *class,
783 			       const struct class_attribute *attr, const char *buf,
784 			       size_t count)
785 {
786 	u64 streamid;
787 	int rc;
788 
789 	rc = kstrtou64(buf, 0, &streamid);
790 	if (rc)
791 		return rc;
792 
793 	rc = pseries_migrate_partition(streamid);
794 	if (rc)
795 		return rc;
796 
797 	return count;
798 }
799 
800 /*
801  * Used by drmgr to determine the kernel behavior of the migration interface.
802  *
803  * Version 1: Performs all PAPR requirements for migration including
804  *	firmware activation and device tree update.
805  */
806 #define MIGRATION_API_VERSION	1
807 
808 static CLASS_ATTR_WO(migration);
809 static CLASS_ATTR_STRING(api_version, 0444, __stringify(MIGRATION_API_VERSION));
810 
811 static int __init mobility_sysfs_init(void)
812 {
813 	int rc;
814 
815 	mobility_kobj = kobject_create_and_add("mobility", kernel_kobj);
816 	if (!mobility_kobj)
817 		return -ENOMEM;
818 
819 	rc = sysfs_create_file(mobility_kobj, &class_attr_migration.attr);
820 	if (rc)
821 		pr_err("unable to create migration sysfs file (%d)\n", rc);
822 
823 	rc = sysfs_create_file(mobility_kobj, &class_attr_api_version.attr.attr);
824 	if (rc)
825 		pr_err("unable to create api_version sysfs file (%d)\n", rc);
826 
827 	return 0;
828 }
829 machine_device_initcall(pseries, mobility_sysfs_init);
830