summaryrefslogtreecommitdiff
path: root/arch/powerpc/kvm/book3s_hv_uvmem.c
blob: b898a596db42734e3a10d92004b6f079304a7fd5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
// SPDX-License-Identifier: GPL-2.0
/*
 * Secure pages management: Migration of pages between normal and secure
 * memory of KVM guests.
 *
 * Copyright 2018 Bharata B Rao, IBM Corp. <bharata@linux.ibm.com>
 */

/*
 * A pseries guest can be run as secure guest on Ultravisor-enabled
 * POWER platforms. On such platforms, this driver will be used to manage
 * the movement of guest pages between the normal memory managed by
 * hypervisor (HV) and secure memory managed by Ultravisor (UV).
 *
 * The page-in or page-out requests from UV will come to HV as hcalls and
 * HV will call back into UV via ultracalls to satisfy these page requests.
 *
 * Private ZONE_DEVICE memory equal to the amount of secure memory
 * available in the platform for running secure guests is hotplugged.
 * Whenever a page belonging to the guest becomes secure, a page from this
 * private device memory is used to represent and track that secure page
 * on the HV side. Some pages (like virtio buffers, VPA pages etc) are
 * shared between UV and HV. However such pages aren't represented by
 * device private memory and mappings to shared memory exist in both
 * UV and HV page tables.
 */

/*
 * Notes on locking
 *
 * kvm->arch.uvmem_lock is a per-guest lock that prevents concurrent
 * page-in and page-out requests for the same GPA. Concurrent accesses
 * can either come via UV (guest vCPUs requesting for same page)
 * or when HV and guest simultaneously access the same page.
 * This mutex serializes the migration of page from HV(normal) to
 * UV(secure) and vice versa. So the serialization points are around
 * migrate_vma routines and page-in/out routines.
 *
 * Per-guest mutex comes with a cost though. Mainly it serializes the
 * fault path as page-out can occur when HV faults on accessing secure
 * guest pages. Currently UV issues page-in requests for all the guest
 * PFNs one at a time during early boot (UV_ESM uvcall), so this is
 * not a cause for concern. Also currently the number of page-outs caused
 * by HV touching secure pages is very very low. If an when UV supports
 * overcommitting, then we might see concurrent guest driven page-outs.
 *
 * Locking order
 *
 * 1. kvm->srcu - Protects KVM memslots
 * 2. kvm->mm->mmap_lock - find_vma, migrate_vma_pages and helpers, ksm_madvise
 * 3. kvm->arch.uvmem_lock - protects read/writes to uvmem slots thus acting
 *			     as sync-points for page-in/out
 */

/*
 * Notes on page size
 *
 * Currently UV uses 2MB mappings internally, but will issue H_SVM_PAGE_IN
 * and H_SVM_PAGE_OUT hcalls in PAGE_SIZE(64K) granularity. HV tracks
 * secure GPAs at 64K page size and maintains one device PFN for each
 * 64K secure GPA. UV_PAGE_IN and UV_PAGE_OUT calls by HV are also issued
 * for 64K page at a time.
 *
 * HV faulting on secure pages: When HV touches any secure page, it
 * faults and issues a UV_PAGE_OUT request with 64K page size. Currently
 * UV splits and remaps the 2MB page if necessary and copies out the
 * required 64K page contents.
 *
 * Shared pages: Whenever guest shares a secure page, UV will split and
 * remap the 2MB page if required and issue H_SVM_PAGE_IN with 64K page size.
 *
 * HV invalidating a page: When a regular page belonging to secure
 * guest gets unmapped, HV informs UV with UV_PAGE_INVAL of 64K
 * page size. Using 64K page size is correct here because any non-secure
 * page will essentially be of 64K page size. Splitting by UV during sharing
 * and page-out ensures this.
 *
 * Page fault handling: When HV handles page fault of a page belonging
 * to secure guest, it sends that to UV with a 64K UV_PAGE_IN request.
 * Using 64K size is correct here too as UV would have split the 2MB page
 * into 64k mappings and would have done page-outs earlier.
 *
 * In summary, the current secure pages handling code in HV assumes
 * 64K page size and in fact fails any page-in/page-out requests of
 * non-64K size upfront. If and when UV starts supporting multiple
 * page-sizes, we need to break this assumption.
 */

#include <linux/pagemap.h>
#include <linux/migrate.h>
#include <linux/kvm_host.h>
#include <linux/ksm.h>
#include <linux/of.h>
#include <asm/ultravisor.h>
#include <asm/mman.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s_uvmem.h>

static struct dev_pagemap kvmppc_uvmem_pgmap;
static unsigned long *kvmppc_uvmem_bitmap;
static DEFINE_SPINLOCK(kvmppc_uvmem_bitmap_lock);

/*
 * States of a GFN
 * ---------------
 * The GFN can be in one of the following states.
 *
 * (a) Secure - The GFN is secure. The GFN is associated with
 *	a Secure VM, the contents of the GFN is not accessible
 *	to the Hypervisor.  This GFN can be backed by a secure-PFN,
 *	or can be backed by a normal-PFN with contents encrypted.
 *	The former is true when the GFN is paged-in into the
 *	ultravisor. The latter is true when the GFN is paged-out
 *	of the ultravisor.
 *
 * (b) Shared - The GFN is shared. The GFN is associated with a
 *	a secure VM. The contents of the GFN is accessible to
 *	Hypervisor. This GFN is backed by a normal-PFN and its
 *	content is un-encrypted.
 *
 * (c) Normal - The GFN is a normal. The GFN is associated with
 *	a normal VM. The contents of the GFN is accesible to
 *	the Hypervisor. Its content is never encrypted.
 *
 * States of a VM.
 * ---------------
 *
 * Normal VM:  A VM whose contents are always accessible to
 *	the hypervisor.  All its GFNs are normal-GFNs.
 *
 * Secure VM: A VM whose contents are not accessible to the
 *	hypervisor without the VM's consent.  Its GFNs are
 *	either Shared-GFN or Secure-GFNs.
 *
 * Transient VM: A Normal VM that is transitioning to secure VM.
 *	The transition starts on successful return of
 *	H_SVM_INIT_START, and ends on successful return
 *	of H_SVM_INIT_DONE. This transient VM, can have GFNs
 *	in any of the three states; i.e Secure-GFN, Shared-GFN,
 *	and Normal-GFN.	The VM never executes in this state
 *	in supervisor-mode.
 *
 * Memory slot State.
 * -----------------------------
 *	The state of a memory slot mirrors the state of the
 *	VM the memory slot is associated with.
 *
 * VM State transition.
 * --------------------
 *
 *  A VM always starts in Normal Mode.
 *
 *  H_SVM_INIT_START moves the VM into transient state. During this
 *  time the Ultravisor may request some of its GFNs to be shared or
 *  secured. So its GFNs can be in one of the three GFN states.
 *
 *  H_SVM_INIT_DONE moves the VM entirely from transient state to
 *  secure-state. At this point any left-over normal-GFNs are
 *  transitioned to Secure-GFN.
 *
 *  H_SVM_INIT_ABORT moves the transient VM back to normal VM.
 *  All its GFNs are moved to Normal-GFNs.
 *
 *  UV_TERMINATE transitions the secure-VM back to normal-VM. All
 *  the secure-GFN and shared-GFNs are tranistioned to normal-GFN
 *  Note: The contents of the normal-GFN is undefined at this point.
 *
 * GFN state implementation:
 * -------------------------
 *
 * Secure GFN is associated with a secure-PFN; also called uvmem_pfn,
 * when the GFN is paged-in. Its pfn[] has KVMPPC_GFN_UVMEM_PFN flag
 * set, and contains the value of the secure-PFN.
 * It is associated with a normal-PFN; also called mem_pfn, when
 * the GFN is pagedout. Its pfn[] has KVMPPC_GFN_MEM_PFN flag set.
 * The value of the normal-PFN is not tracked.
 *
 * Shared GFN is associated with a normal-PFN. Its pfn[] has
 * KVMPPC_UVMEM_SHARED_PFN flag set. The value of the normal-PFN
 * is not tracked.
 *
 * Normal GFN is associated with normal-PFN. Its pfn[] has
 * no flag set. The value of the normal-PFN is not tracked.
 *
 * Life cycle of a GFN
 * --------------------
 *
 * --------------------------------------------------------------
 * |        |     Share  |  Unshare | SVM       |H_SVM_INIT_DONE|
 * |        |operation   |operation | abort/    |               |
 * |        |            |          | terminate |               |
 * -------------------------------------------------------------
 * |        |            |          |           |               |
 * | Secure |     Shared | Secure   |Normal     |Secure         |
 * |        |            |          |           |               |
 * | Shared |     Shared | Secure   |Normal     |Shared         |
 * |        |            |          |           |               |
 * | Normal |     Shared | Secure   |Normal     |Secure         |
 * --------------------------------------------------------------
 *
 * Life cycle of a VM
 * --------------------
 *
 * --------------------------------------------------------------------
 * |         |  start    |  H_SVM_  |H_SVM_   |H_SVM_     |UV_SVM_    |
 * |         |  VM       |INIT_START|INIT_DONE|INIT_ABORT |TERMINATE  |
 * |         |           |          |         |           |           |
 * --------- ----------------------------------------------------------
 * |         |           |          |         |           |           |
 * | Normal  | Normal    | Transient|Error    |Error      |Normal     |
 * |         |           |          |         |           |           |
 * | Secure  |   Error   | Error    |Error    |Error      |Normal     |
 * |         |           |          |         |           |           |
 * |Transient|   N/A     | Error    |Secure   |Normal     |Normal     |
 * --------------------------------------------------------------------
 */

#define KVMPPC_GFN_UVMEM_PFN	(1UL << 63)
#define KVMPPC_GFN_MEM_PFN	(1UL << 62)
#define KVMPPC_GFN_SHARED	(1UL << 61)
#define KVMPPC_GFN_SECURE	(KVMPPC_GFN_UVMEM_PFN | KVMPPC_GFN_MEM_PFN)
#define KVMPPC_GFN_FLAG_MASK	(KVMPPC_GFN_SECURE | KVMPPC_GFN_SHARED)
#define KVMPPC_GFN_PFN_MASK	(~KVMPPC_GFN_FLAG_MASK)

struct kvmppc_uvmem_slot {
	struct list_head list;
	unsigned long nr_pfns;
	unsigned long base_pfn;
	unsigned long *pfns;
};
struct kvmppc_uvmem_page_pvt {
	struct kvm *kvm;
	unsigned long gpa;
	bool skip_page_out;
	bool remove_gfn;
};

bool kvmppc_uvmem_available(void)
{
	/*
	 * If kvmppc_uvmem_bitmap != NULL, then there is an ultravisor
	 * and our data structures have been initialized successfully.
	 */
	return !!kvmppc_uvmem_bitmap;
}

int kvmppc_uvmem_slot_init(struct kvm *kvm, const struct kvm_memory_slot *slot)
{
	struct kvmppc_uvmem_slot *p;

	p = kzalloc(sizeof(*p), GFP_KERNEL);
	if (!p)
		return -ENOMEM;
	p->pfns = vzalloc(array_size(slot->npages, sizeof(*p->pfns)));
	if (!p->pfns) {
		kfree(p);
		return -ENOMEM;
	}
	p->nr_pfns = slot->npages;
	p->base_pfn = slot->base_gfn;

	mutex_lock(&kvm->arch.uvmem_lock);
	list_add(&p->list, &kvm->arch.uvmem_pfns);
	mutex_unlock(&kvm->arch.uvmem_lock);

	return 0;
}

/*
 * All device PFNs are already released by the time we come here.
 */
void kvmppc_uvmem_slot_free(struct kvm *kvm, const struct kvm_memory_slot *slot)
{
	struct kvmppc_uvmem_slot *p, *next;

	mutex_lock(&kvm->arch.uvmem_lock);
	list_for_each_entry_safe(p, next, &kvm->arch.uvmem_pfns, list) {
		if (p->base_pfn == slot->base_gfn) {
			vfree(p->pfns);
			list_del(&p->list);
			kfree(p);
			break;
		}
	}
	mutex_unlock(&kvm->arch.uvmem_lock);
}

static void kvmppc_mark_gfn(unsigned long gfn, struct kvm *kvm,
			unsigned long flag, unsigned long uvmem_pfn)
{
	struct kvmppc_uvmem_slot *p;

	list_for_each_entry(p, &kvm->arch.uvmem_pfns, list) {
		if (gfn >= p->base_pfn && gfn < p->base_pfn + p->nr_pfns) {
			unsigned long index = gfn - p->base_pfn;

			if (flag == KVMPPC_GFN_UVMEM_PFN)
				p->pfns[index] = uvmem_pfn | flag;
			else
				p->pfns[index] = flag;
			return;
		}
	}
}

/* mark the GFN as secure-GFN associated with @uvmem pfn device-PFN. */
static void kvmppc_gfn_secure_uvmem_pfn(unsigned long gfn,
			unsigned long uvmem_pfn, struct kvm *kvm)
{
	kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_UVMEM_PFN, uvmem_pfn);
}

/* mark the GFN as secure-GFN associated with a memory-PFN. */
static void kvmppc_gfn_secure_mem_pfn(unsigned long gfn, struct kvm *kvm)
{
	kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_MEM_PFN, 0);
}

/* mark the GFN as a shared GFN. */
static void kvmppc_gfn_shared(unsigned long gfn, struct kvm *kvm)
{
	kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_SHARED, 0);
}

/* mark the GFN as a non-existent GFN. */
static void kvmppc_gfn_remove(unsigned long gfn, struct kvm *kvm)
{
	kvmppc_mark_gfn(gfn, kvm, 0, 0);
}

/* return true, if the GFN is a secure-GFN backed by a secure-PFN */
static bool kvmppc_gfn_is_uvmem_pfn(unsigned long gfn, struct kvm *kvm,
				    unsigned long *uvmem_pfn)
{
	struct kvmppc_uvmem_slot *p;

	list_for_each_entry(p, &kvm->arch.uvmem_pfns, list) {
		if (gfn >= p->base_pfn && gfn < p->base_pfn + p->nr_pfns) {
			unsigned long index = gfn - p->base_pfn;

			if (p->pfns[index] & KVMPPC_GFN_UVMEM_PFN) {
				if (uvmem_pfn)
					*uvmem_pfn = p->pfns[index] &
						     KVMPPC_GFN_PFN_MASK;
				return true;
			} else
				return false;
		}
	}
	return false;
}

/*
 * starting from *gfn search for the next available GFN that is not yet
 * transitioned to a secure GFN.  return the value of that GFN in *gfn.  If a
 * GFN is found, return true, else return false
 *
 * Must be called with kvm->arch.uvmem_lock  held.
 */
static bool kvmppc_next_nontransitioned_gfn(const struct kvm_memory_slot *memslot,
		struct kvm *kvm, unsigned long *gfn)
{
	struct kvmppc_uvmem_slot *p;
	bool ret = false;
	unsigned long i;

	list_for_each_entry(p, &kvm->arch.uvmem_pfns, list)
		if (*gfn >= p->base_pfn && *gfn < p->base_pfn + p->nr_pfns)
			break;
	if (!p)
		return ret;
	/*
	 * The code below assumes, one to one correspondence between
	 * kvmppc_uvmem_slot and memslot.
	 */
	for (i = *gfn; i < p->base_pfn + p->nr_pfns; i++) {
		unsigned long index = i - p->base_pfn;

		if (!(p->pfns[index] & KVMPPC_GFN_FLAG_MASK)) {
			*gfn = i;
			ret = true;
			break;
		}
	}
	return ret;
}

static int kvmppc_memslot_page_merge(struct kvm *kvm,
		const struct kvm_memory_slot *memslot, bool merge)
{
	unsigned long gfn = memslot->base_gfn;
	unsigned long end, start = gfn_to_hva(kvm, gfn);
	int ret = 0;
	struct vm_area_struct *vma;
	int merge_flag = (merge) ? MADV_MERGEABLE : MADV_UNMERGEABLE;

	if (kvm_is_error_hva(start))
		return H_STATE;

	end = start + (memslot->npages << PAGE_SHIFT);

	mmap_write_lock(kvm->mm);
	do {
		vma = find_vma_intersection(kvm->mm, start, end);
		if (!vma) {
			ret = H_STATE;
			break;
		}
		ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
			  merge_flag, &vma->vm_flags);
		if (ret) {
			ret = H_STATE;
			break;
		}
		start = vma->vm_end;
	} while (end > vma->vm_end);

	mmap_write_unlock(kvm->mm);
	return ret;
}

static void __kvmppc_uvmem_memslot_delete(struct kvm *kvm,
		const struct kvm_memory_slot *memslot)
{
	uv_unregister_mem_slot(kvm->arch.lpid, memslot->id);
	kvmppc_uvmem_slot_free(kvm, memslot);
	kvmppc_memslot_page_merge(kvm, memslot, true);
}

static int __kvmppc_uvmem_memslot_create(struct kvm *kvm,
		const struct kvm_memory_slot *memslot)
{
	int ret = H_PARAMETER;

	if (kvmppc_memslot_page_merge(kvm, memslot, false))
		return ret;

	if (kvmppc_uvmem_slot_init(kvm, memslot))
		goto out1;

	ret = uv_register_mem_slot(kvm->arch.lpid,
				   memslot->base_gfn << PAGE_SHIFT,
				   memslot->npages * PAGE_SIZE,
				   0, memslot->id);
	if (ret < 0) {
		ret = H_PARAMETER;
		goto out;
	}
	return 0;
out:
	kvmppc_uvmem_slot_free(kvm, memslot);
out1:
	kvmppc_memslot_page_merge(kvm, memslot, true);
	return ret;
}

unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
{
	struct kvm_memslots *slots;
	struct kvm_memory_slot *memslot, *m;
	int ret = H_SUCCESS;
	int srcu_idx;

	kvm->arch.secure_guest = KVMPPC_SECURE_INIT_START;

	if (!kvmppc_uvmem_bitmap)
		return H_UNSUPPORTED;

	/* Only radix guests can be secure guests */
	if (!kvm_is_radix(kvm))
		return H_UNSUPPORTED;

	/* NAK the transition to secure if not enabled */
	if (!kvm->arch.svm_enabled)
		return H_AUTHORITY;

	srcu_idx = srcu_read_lock(&kvm->srcu);

	/* register the memslot */
	slots = kvm_memslots(kvm);
	kvm_for_each_memslot(memslot, slots) {
		ret = __kvmppc_uvmem_memslot_create(kvm, memslot);
		if (ret)
			break;
	}

	if (ret) {
		slots = kvm_memslots(kvm);
		kvm_for_each_memslot(m, slots) {
			if (m == memslot)
				break;
			__kvmppc_uvmem_memslot_delete(kvm, memslot);
		}
	}

	srcu_read_unlock(&kvm->srcu, srcu_idx);
	return ret;
}

/*
 * Provision a new page on HV side and copy over the contents
 * from secure memory using UV_PAGE_OUT uvcall.
 * Caller must held kvm->arch.uvmem_lock.
 */
static int __kvmppc_svm_page_out(struct vm_area_struct *vma,
		unsigned long start,
		unsigned long end, unsigned long page_shift,
		struct kvm *kvm, unsigned long gpa)
{
	unsigned long src_pfn, dst_pfn = 0;
	struct migrate_vma mig;
	struct page *dpage, *spage;
	struct kvmppc_uvmem_page_pvt *pvt;
	unsigned long pfn;
	int ret = U_SUCCESS;

	memset(&mig, 0, sizeof(mig));
	mig.vma = vma;
	mig.start = start;
	mig.end = end;
	mig.src = &src_pfn;
	mig.dst = &dst_pfn;
	mig.pgmap_owner = &kvmppc_uvmem_pgmap;
	mig.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;

	/* The requested page is already paged-out, nothing to do */
	if (!kvmppc_gfn_is_uvmem_pfn(gpa >> page_shift, kvm, NULL))
		return ret;

	ret = migrate_vma_setup(&mig);
	if (ret)
		return -1;

	spage = migrate_pfn_to_page(*mig.src);
	if (!spage || !(*mig.src & MIGRATE_PFN_MIGRATE))
		goto out_finalize;

	if (!is_zone_device_page(spage))
		goto out_finalize;

	dpage = alloc_page_vma(GFP_HIGHUSER, vma, start);
	if (!dpage) {
		ret = -1;
		goto out_finalize;
	}

	lock_page(dpage);
	pvt = spage->zone_device_data;
	pfn = page_to_pfn(dpage);

	/*
	 * This function is used in two cases:
	 * - When HV touches a secure page, for which we do UV_PAGE_OUT
	 * - When a secure page is converted to shared page, we *get*
	 *   the page to essentially unmap the device page. In this
	 *   case we skip page-out.
	 */
	if (!pvt->skip_page_out)
		ret = uv_page_out(kvm->arch.lpid, pfn << page_shift,
				  gpa, 0, page_shift);

	if (ret == U_SUCCESS)
		*mig.dst = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED;
	else {
		unlock_page(dpage);
		__free_page(dpage);
		goto out_finalize;
	}

	migrate_vma_pages(&mig);

out_finalize:
	migrate_vma_finalize(&mig);
	return ret;
}

static inline int kvmppc_svm_page_out(struct vm_area_struct *vma,
				      unsigned long start, unsigned long end,
				      unsigned long page_shift,
				      struct kvm *kvm, unsigned long gpa)
{
	int ret;

	mutex_lock(&kvm->arch.uvmem_lock);
	ret = __kvmppc_svm_page_out(vma, start, end, page_shift, kvm, gpa);
	mutex_unlock(&kvm->arch.uvmem_lock);

	return ret;
}

/*
 * Drop device pages that we maintain for the secure guest
 *
 * We first mark the pages to be skipped from UV_PAGE_OUT when there
 * is HV side fault on these pages. Next we *get* these pages, forcing
 * fault on them, do fault time migration to replace the device PTEs in
 * QEMU page table with normal PTEs from newly allocated pages.
 */
void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *slot,
			     struct kvm *kvm, bool skip_page_out)
{
	int i;
	struct kvmppc_uvmem_page_pvt *pvt;
	struct page *uvmem_page;
	struct vm_area_struct *vma = NULL;
	unsigned long uvmem_pfn, gfn;
	unsigned long addr;

	mmap_read_lock(kvm->mm);

	addr = slot->userspace_addr;

	gfn = slot->base_gfn;
	for (i = slot->npages; i; --i, ++gfn, addr += PAGE_SIZE) {

		/* Fetch the VMA if addr is not in the latest fetched one */
		if (!vma || addr >= vma->vm_end) {
			vma = find_vma_intersection(kvm->mm, addr, addr+1);
			if (!vma) {
				pr_err("Can't find VMA for gfn:0x%lx\n", gfn);
				break;
			}
		}

		mutex_lock(&kvm->arch.uvmem_lock);

		if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) {
			uvmem_page = pfn_to_page(uvmem_pfn);
			pvt = uvmem_page->zone_device_data;
			pvt->skip_page_out = skip_page_out;
			pvt->remove_gfn = true;

			if (__kvmppc_svm_page_out(vma, addr, addr + PAGE_SIZE,
						  PAGE_SHIFT, kvm, pvt->gpa))
				pr_err("Can't page out gpa:0x%lx addr:0x%lx\n",
				       pvt->gpa, addr);
		} else {
			/* Remove the shared flag if any */
			kvmppc_gfn_remove(gfn, kvm);
		}

		mutex_unlock(&kvm->arch.uvmem_lock);
	}

	mmap_read_unlock(kvm->mm);
}

unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
{
	int srcu_idx;
	struct kvm_memory_slot *memslot;

	/*
	 * Expect to be called only after INIT_START and before INIT_DONE.
	 * If INIT_DONE was completed, use normal VM termination sequence.
	 */
	if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
		return H_UNSUPPORTED;

	if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE)
		return H_STATE;

	srcu_idx = srcu_read_lock(&kvm->srcu);

	kvm_for_each_memslot(memslot, kvm_memslots(kvm))
		kvmppc_uvmem_drop_pages(memslot, kvm, false);

	srcu_read_unlock(&kvm->srcu, srcu_idx);

	kvm->arch.secure_guest = 0;
	uv_svm_terminate(kvm->arch.lpid);

	return H_PARAMETER;
}

/*
 * Get a free device PFN from the pool
 *
 * Called when a normal page is moved to secure memory (UV_PAGE_IN). Device
 * PFN will be used to keep track of the secure page on HV side.
 *
 * Called with kvm->arch.uvmem_lock held
 */
static struct page *kvmppc_uvmem_get_page(unsigned long gpa, struct kvm *kvm)
{
	struct page *dpage = NULL;
	unsigned long bit, uvmem_pfn;
	struct kvmppc_uvmem_page_pvt *pvt;
	unsigned long pfn_last, pfn_first;

	pfn_first = kvmppc_uvmem_pgmap.range.start >> PAGE_SHIFT;
	pfn_last = pfn_first +
		   (range_len(&kvmppc_uvmem_pgmap.range) >> PAGE_SHIFT);

	spin_lock(&kvmppc_uvmem_bitmap_lock);
	bit = find_first_zero_bit(kvmppc_uvmem_bitmap,
				  pfn_last - pfn_first);
	if (bit >= (pfn_last - pfn_first))
		goto out;
	bitmap_set(kvmppc_uvmem_bitmap, bit, 1);
	spin_unlock(&kvmppc_uvmem_bitmap_lock);

	pvt = kzalloc(sizeof(*pvt), GFP_KERNEL);
	if (!pvt)
		goto out_clear;

	uvmem_pfn = bit + pfn_first;
	kvmppc_gfn_secure_uvmem_pfn(gpa >> PAGE_SHIFT, uvmem_pfn, kvm);

	pvt->gpa = gpa;
	pvt->kvm = kvm;

	dpage = pfn_to_page(uvmem_pfn);
	dpage->zone_device_data = pvt;
	get_page(dpage);
	lock_page(dpage);
	return dpage;
out_clear:
	spin_lock(&kvmppc_uvmem_bitmap_lock);
	bitmap_clear(kvmppc_uvmem_bitmap, bit, 1);
out:
	spin_unlock(&kvmppc_uvmem_bitmap_lock);
	return NULL;
}

/*
 * Alloc a PFN from private device memory pool. If @pagein is true,
 * copy page from normal memory to secure memory using UV_PAGE_IN uvcall.
 */
static int kvmppc_svm_page_in(struct vm_area_struct *vma,
		unsigned long start,
		unsigned long end, unsigned long gpa, struct kvm *kvm,
		unsigned long page_shift,
		bool pagein)
{
	unsigned long src_pfn, dst_pfn = 0;
	struct migrate_vma mig;
	struct page *spage;
	unsigned long pfn;
	struct page *dpage;
	int ret = 0;

	memset(&mig, 0, sizeof(mig));
	mig.vma = vma;
	mig.start = start;
	mig.end = end;
	mig.src = &src_pfn;
	mig.dst = &dst_pfn;
	mig.flags = MIGRATE_VMA_SELECT_SYSTEM;

	ret = migrate_vma_setup(&mig);
	if (ret)
		return ret;

	if (!(*mig.src & MIGRATE_PFN_MIGRATE)) {
		ret = -1;
		goto out_finalize;
	}

	dpage = kvmppc_uvmem_get_page(gpa, kvm);
	if (!dpage) {
		ret = -1;
		goto out_finalize;
	}

	if (pagein) {
		pfn = *mig.src >> MIGRATE_PFN_SHIFT;
		spage = migrate_pfn_to_page(*mig.src);
		if (spage) {
			ret = uv_page_in(kvm->arch.lpid, pfn << page_shift,
					gpa, 0, page_shift);
			if (ret)
				goto out_finalize;
		}
	}

	*mig.dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
	migrate_vma_pages(&mig);
out_finalize:
	migrate_vma_finalize(&mig);
	return ret;
}

static int kvmppc_uv_migrate_mem_slot(struct kvm *kvm,
		const struct kvm_memory_slot *memslot)
{
	unsigned long gfn = memslot->base_gfn;
	struct vm_area_struct *vma;
	unsigned long start, end;
	int ret = 0;

	mmap_read_lock(kvm->mm);
	mutex_lock(&kvm->arch.uvmem_lock);
	while (kvmppc_next_nontransitioned_gfn(memslot, kvm, &gfn)) {
		ret = H_STATE;
		start = gfn_to_hva(kvm, gfn);
		if (kvm_is_error_hva(start))
			break;

		end = start + (1UL << PAGE_SHIFT);
		vma = find_vma_intersection(kvm->mm, start, end);
		if (!vma || vma->vm_start > start || vma->vm_end < end)
			break;

		ret = kvmppc_svm_page_in(vma, start, end,
				(gfn << PAGE_SHIFT), kvm, PAGE_SHIFT, false);
		if (ret) {
			ret = H_STATE;
			break;
		}

		/* relinquish the cpu if needed */
		cond_resched();
	}
	mutex_unlock(&kvm->arch.uvmem_lock);
	mmap_read_unlock(kvm->mm);
	return ret;
}

unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
{
	struct kvm_memslots *slots;
	struct kvm_memory_slot *memslot;
	int srcu_idx;
	long ret = H_SUCCESS;

	if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
		return H_UNSUPPORTED;

	/* migrate any unmoved normal pfn to device pfns*/
	srcu_idx = srcu_read_lock(&kvm->srcu);
	slots = kvm_memslots(kvm);
	kvm_for_each_memslot(memslot, slots) {
		ret = kvmppc_uv_migrate_mem_slot(kvm, memslot);
		if (ret) {
			/*
			 * The pages will remain transitioned.
			 * Its the callers responsibility to
			 * terminate the VM, which will undo
			 * all state of the VM. Till then
			 * this VM is in a erroneous state.
			 * Its KVMPPC_SECURE_INIT_DONE will
			 * remain unset.
			 */
			ret = H_STATE;
			goto out;
		}
	}

	kvm->arch.secure_guest |= KVMPPC_SECURE_INIT_DONE;
	pr_info("LPID %d went secure\n", kvm->arch.lpid);

out:
	srcu_read_unlock(&kvm->srcu, srcu_idx);
	return ret;
}

/*
 * Shares the page with HV, thus making it a normal page.
 *
 * - If the page is already secure, then provision a new page and share
 * - If the page is a normal page, share the existing page
 *
 * In the former case, uses dev_pagemap_ops.migrate_to_ram handler
 * to unmap the device page from QEMU's page tables.
 */
static unsigned long kvmppc_share_page(struct kvm *kvm, unsigned long gpa,
		unsigned long page_shift)
{

	int ret = H_PARAMETER;
	struct page *uvmem_page;
	struct kvmppc_uvmem_page_pvt *pvt;
	unsigned long pfn;
	unsigned long gfn = gpa >> page_shift;
	int srcu_idx;
	unsigned long uvmem_pfn;

	srcu_idx = srcu_read_lock(&kvm->srcu);
	mutex_lock(&kvm->arch.uvmem_lock);
	if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) {
		uvmem_page = pfn_to_page(uvmem_pfn);
		pvt = uvmem_page->zone_device_data;
		pvt->skip_page_out = true;
		/*
		 * do not drop the GFN. It is a valid GFN
		 * that is transitioned to a shared GFN.
		 */
		pvt->remove_gfn = false;
	}

retry:
	mutex_unlock(&kvm->arch.uvmem_lock);
	pfn = gfn_to_pfn(kvm, gfn);
	if (is_error_noslot_pfn(pfn))
		goto out;

	mutex_lock(&kvm->arch.uvmem_lock);
	if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) {
		uvmem_page = pfn_to_page(uvmem_pfn);
		pvt = uvmem_page->zone_device_data;
		pvt->skip_page_out = true;
		pvt->remove_gfn = false; /* it continues to be a valid GFN */
		kvm_release_pfn_clean(pfn);
		goto retry;
	}

	if (!uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0,
				page_shift)) {
		kvmppc_gfn_shared(gfn, kvm);
		ret = H_SUCCESS;
	}
	kvm_release_pfn_clean(pfn);
	mutex_unlock(&kvm->arch.uvmem_lock);
out:
	srcu_read_unlock(&kvm->srcu, srcu_idx);
	return ret;
}

/*
 * H_SVM_PAGE_IN: Move page from normal memory to secure memory.
 *
 * H_PAGE_IN_SHARED flag makes the page shared which means that the same
 * memory in is visible from both UV and HV.
 */
unsigned long kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa,
		unsigned long flags,
		unsigned long page_shift)
{
	unsigned long start, end;
	struct vm_area_struct *vma;
	int srcu_idx;
	unsigned long gfn = gpa >> page_shift;
	int ret;

	if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
		return H_UNSUPPORTED;

	if (page_shift != PAGE_SHIFT)
		return H_P3;

	if (flags & ~H_PAGE_IN_SHARED)
		return H_P2;

	if (flags & H_PAGE_IN_SHARED)
		return kvmppc_share_page(kvm, gpa, page_shift);

	ret = H_PARAMETER;
	srcu_idx = srcu_read_lock(&kvm->srcu);
	mmap_read_lock(kvm->mm);

	start = gfn_to_hva(kvm, gfn);
	if (kvm_is_error_hva(start))
		goto out;

	mutex_lock(&kvm->arch.uvmem_lock);
	/* Fail the page-in request of an already paged-in page */
	if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL))
		goto out_unlock;

	end = start + (1UL << page_shift);
	vma = find_vma_intersection(kvm->mm, start, end);
	if (!vma || vma->vm_start > start || vma->vm_end < end)
		goto out_unlock;

	if (kvmppc_svm_page_in(vma, start, end, gpa, kvm, page_shift,
				true))
		goto out_unlock;

	ret = H_SUCCESS;

out_unlock:
	mutex_unlock(&kvm->arch.uvmem_lock);
out:
	mmap_read_unlock(kvm->mm);
	srcu_read_unlock(&kvm->srcu, srcu_idx);
	return ret;
}


/*
 * Fault handler callback that gets called when HV touches any page that
 * has been moved to secure memory, we ask UV to give back the page by
 * issuing UV_PAGE_OUT uvcall.
 *
 * This eventually results in dropping of device PFN and the newly
 * provisioned page/PFN gets populated in QEMU page tables.
 */
static vm_fault_t kvmppc_uvmem_migrate_to_ram(struct vm_fault *vmf)
{
	struct kvmppc_uvmem_page_pvt *pvt = vmf->page->zone_device_data;

	if (kvmppc_svm_page_out(vmf->vma, vmf->address,
				vmf->address + PAGE_SIZE, PAGE_SHIFT,
				pvt->kvm, pvt->gpa))
		return VM_FAULT_SIGBUS;
	else
		return 0;
}

/*
 * Release the device PFN back to the pool
 *
 * Gets called when secure GFN tranistions from a secure-PFN
 * to a normal PFN during H_SVM_PAGE_OUT.
 * Gets called with kvm->arch.uvmem_lock held.
 */
static void kvmppc_uvmem_page_free(struct page *page)
{
	unsigned long pfn = page_to_pfn(page) -
			(kvmppc_uvmem_pgmap.range.start >> PAGE_SHIFT);
	struct kvmppc_uvmem_page_pvt *pvt;

	spin_lock(&kvmppc_uvmem_bitmap_lock);
	bitmap_clear(kvmppc_uvmem_bitmap, pfn, 1);
	spin_unlock(&kvmppc_uvmem_bitmap_lock);

	pvt = page->zone_device_data;
	page->zone_device_data = NULL;
	if (pvt->remove_gfn)
		kvmppc_gfn_remove(pvt->gpa >> PAGE_SHIFT, pvt->kvm);
	else
		kvmppc_gfn_secure_mem_pfn(pvt->gpa >> PAGE_SHIFT, pvt->kvm);
	kfree(pvt);
}

static const struct dev_pagemap_ops kvmppc_uvmem_ops = {
	.page_free = kvmppc_uvmem_page_free,
	.migrate_to_ram	= kvmppc_uvmem_migrate_to_ram,
};

/*
 * H_SVM_PAGE_OUT: Move page from secure memory to normal memory.
 */
unsigned long
kvmppc_h_svm_page_out(struct kvm *kvm, unsigned long gpa,
		      unsigned long flags, unsigned long page_shift)
{
	unsigned long gfn = gpa >> page_shift;
	unsigned long start, end;
	struct vm_area_struct *vma;
	int srcu_idx;
	int ret;

	if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
		return H_UNSUPPORTED;

	if (page_shift != PAGE_SHIFT)
		return H_P3;

	if (flags)
		return H_P2;

	ret = H_PARAMETER;
	srcu_idx = srcu_read_lock(&kvm->srcu);
	mmap_read_lock(kvm->mm);
	start = gfn_to_hva(kvm, gfn);
	if (kvm_is_error_hva(start))
		goto out;

	end = start + (1UL << page_shift);
	vma = find_vma_intersection(kvm->mm, start, end);
	if (!vma || vma->vm_start > start || vma->vm_end < end)
		goto out;

	if (!kvmppc_svm_page_out(vma, start, end, page_shift, kvm, gpa))
		ret = H_SUCCESS;
out:
	mmap_read_unlock(kvm->mm);
	srcu_read_unlock(&kvm->srcu, srcu_idx);
	return ret;
}

int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
{
	unsigned long pfn;
	int ret = U_SUCCESS;

	pfn = gfn_to_pfn(kvm, gfn);
	if (is_error_noslot_pfn(pfn))
		return -EFAULT;

	mutex_lock(&kvm->arch.uvmem_lock);
	if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL))
		goto out;

	ret = uv_page_in(kvm->arch.lpid, pfn << PAGE_SHIFT, gfn << PAGE_SHIFT,
			 0, PAGE_SHIFT);
out:
	kvm_release_pfn_clean(pfn);
	mutex_unlock(&kvm->arch.uvmem_lock);
	return (ret == U_SUCCESS) ? RESUME_GUEST : -EFAULT;
}

int kvmppc_uvmem_memslot_create(struct kvm *kvm, const struct kvm_memory_slot *new)
{
	int ret = __kvmppc_uvmem_memslot_create(kvm, new);

	if (!ret)
		ret = kvmppc_uv_migrate_mem_slot(kvm, new);

	return ret;
}

void kvmppc_uvmem_memslot_delete(struct kvm *kvm, const struct kvm_memory_slot *old)
{
	__kvmppc_uvmem_memslot_delete(kvm, old);
}

static u64 kvmppc_get_secmem_size(void)
{
	struct device_node *np;
	int i, len;
	const __be32 *prop;
	u64 size = 0;

	/*
	 * First try the new ibm,secure-memory nodes which supersede the
	 * secure-memory-ranges property.
	 * If we found some, no need to read the deprecated ones.
	 */
	for_each_compatible_node(np, NULL, "ibm,secure-memory") {
		prop = of_get_property(np, "reg", &len);
		if (!prop)
			continue;
		size += of_read_number(prop + 2, 2);
	}
	if (size)
		return size;

	np = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");
	if (!np)
		goto out;

	prop = of_get_property(np, "secure-memory-ranges", &len);
	if (!prop)
		goto out_put;

	for (i = 0; i < len / (sizeof(*prop) * 4); i++)
		size += of_read_number(prop + (i * 4) + 2, 2);

out_put:
	of_node_put(np);
out:
	return size;
}

int kvmppc_uvmem_init(void)
{
	int ret = 0;
	unsigned long size;
	struct resource *res;
	void *addr;
	unsigned long pfn_last, pfn_first;

	size = kvmppc_get_secmem_size();
	if (!size) {
		/*
		 * Don't fail the initialization of kvm-hv module if
		 * the platform doesn't export ibm,uv-firmware node.
		 * Let normal guests run on such PEF-disabled platform.
		 */
		pr_info("KVMPPC-UVMEM: No support for secure guests\n");
		goto out;
	}

	res = request_free_mem_region(&iomem_resource, size, "kvmppc_uvmem");
	if (IS_ERR(res)) {
		ret = PTR_ERR(res);
		goto out;
	}

	kvmppc_uvmem_pgmap.type = MEMORY_DEVICE_PRIVATE;
	kvmppc_uvmem_pgmap.range.start = res->start;
	kvmppc_uvmem_pgmap.range.end = res->end;
	kvmppc_uvmem_pgmap.nr_range = 1;
	kvmppc_uvmem_pgmap.ops = &kvmppc_uvmem_ops;
	/* just one global instance: */
	kvmppc_uvmem_pgmap.owner = &kvmppc_uvmem_pgmap;
	addr = memremap_pages(&kvmppc_uvmem_pgmap, NUMA_NO_NODE);
	if (IS_ERR(addr)) {
		ret = PTR_ERR(addr);
		goto out_free_region;
	}

	pfn_first = res->start >> PAGE_SHIFT;
	pfn_last = pfn_first + (resource_size(res) >> PAGE_SHIFT);
	kvmppc_uvmem_bitmap = kcalloc(BITS_TO_LONGS(pfn_last - pfn_first),
				      sizeof(unsigned long), GFP_KERNEL);
	if (!kvmppc_uvmem_bitmap) {
		ret = -ENOMEM;
		goto out_unmap;
	}

	pr_info("KVMPPC-UVMEM: Secure Memory size 0x%lx\n", size);
	return ret;
out_unmap:
	memunmap_pages(&kvmppc_uvmem_pgmap);
out_free_region:
	release_mem_region(res->start, size);
out:
	return ret;
}

void kvmppc_uvmem_free(void)
{
	if (!kvmppc_uvmem_bitmap)
		return;

	memunmap_pages(&kvmppc_uvmem_pgmap);
	release_mem_region(kvmppc_uvmem_pgmap.range.start,
			   range_len(&kvmppc_uvmem_pgmap.range));
	kfree(kvmppc_uvmem_bitmap);
}