summaryrefslogtreecommitdiff
path: root/arch/powerpc/kvm/book3s_64_vio.c
blob: b569ebaa590e2d263be0db24196b6498f5f12135 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
 * Copyright 2011 David Gibson, IBM Corporation <dwg@au1.ibm.com>
 * Copyright 2016 Alexey Kardashevskiy, IBM Corporation <aik@au1.ibm.com>
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/hugetlb.h>
#include <linux/list.h>
#include <linux/anon_inodes.h>
#include <linux/iommu.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/rcupdate_wait.h>

#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/book3s/64/mmu-hash.h>
#include <asm/hvcall.h>
#include <asm/synch.h>
#include <asm/ppc-opcode.h>
#include <asm/udbg.h>
#include <asm/iommu.h>
#include <asm/tce.h>
#include <asm/mmu_context.h>

static struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm,
	unsigned long liobn)
{
	struct kvmppc_spapr_tce_table *stt;

	list_for_each_entry_lockless(stt, &kvm->arch.spapr_tce_tables, list)
		if (stt->liobn == liobn)
			return stt;

	return NULL;
}

static unsigned long kvmppc_tce_pages(unsigned long iommu_pages)
{
	return ALIGN(iommu_pages * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
}

static unsigned long kvmppc_stt_pages(unsigned long tce_pages)
{
	unsigned long stt_bytes = sizeof(struct kvmppc_spapr_tce_table) +
			(tce_pages * sizeof(struct page *));

	return tce_pages + ALIGN(stt_bytes, PAGE_SIZE) / PAGE_SIZE;
}

static void kvm_spapr_tce_iommu_table_free(struct rcu_head *head)
{
	struct kvmppc_spapr_tce_iommu_table *stit = container_of(head,
			struct kvmppc_spapr_tce_iommu_table, rcu);

	iommu_tce_table_put(stit->tbl);

	kfree(stit);
}

static void kvm_spapr_tce_liobn_put(struct kref *kref)
{
	struct kvmppc_spapr_tce_iommu_table *stit = container_of(kref,
			struct kvmppc_spapr_tce_iommu_table, kref);

	list_del_rcu(&stit->next);

	call_rcu(&stit->rcu, kvm_spapr_tce_iommu_table_free);
}

void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
				       struct iommu_group *grp)
{
	int i;
	struct kvmppc_spapr_tce_table *stt;
	struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
	struct iommu_table_group *table_group = NULL;

	rcu_read_lock();
	list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {

		table_group = iommu_group_get_iommudata(grp);
		if (WARN_ON(!table_group))
			continue;

		list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
			for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
				if (table_group->tables[i] != stit->tbl)
					continue;

				kref_put(&stit->kref, kvm_spapr_tce_liobn_put);
			}
		}
		cond_resched_rcu();
	}
	rcu_read_unlock();
}

long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd,
				      struct iommu_group *grp)
{
	struct kvmppc_spapr_tce_table *stt = NULL;
	bool found = false;
	struct iommu_table *tbl = NULL;
	struct iommu_table_group *table_group;
	long i;
	struct kvmppc_spapr_tce_iommu_table *stit;
	struct fd f;

	f = fdget(tablefd);
	if (!f.file)
		return -EBADF;

	rcu_read_lock();
	list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
		if (stt == f.file->private_data) {
			found = true;
			break;
		}
	}
	rcu_read_unlock();

	fdput(f);

	if (!found)
		return -EINVAL;

	table_group = iommu_group_get_iommudata(grp);
	if (WARN_ON(!table_group))
		return -EFAULT;

	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
		struct iommu_table *tbltmp = table_group->tables[i];

		if (!tbltmp)
			continue;
		/* Make sure hardware table parameters are compatible */
		if ((tbltmp->it_page_shift <= stt->page_shift) &&
				(tbltmp->it_offset << tbltmp->it_page_shift ==
				 stt->offset << stt->page_shift) &&
				(tbltmp->it_size << tbltmp->it_page_shift >=
				 stt->size << stt->page_shift)) {
			/*
			 * Reference the table to avoid races with
			 * add/remove DMA windows.
			 */
			tbl = iommu_tce_table_get(tbltmp);
			break;
		}
	}
	if (!tbl)
		return -EINVAL;

	rcu_read_lock();
	list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
		if (tbl != stit->tbl)
			continue;

		if (!kref_get_unless_zero(&stit->kref)) {
			/* stit is being destroyed */
			iommu_tce_table_put(tbl);
			rcu_read_unlock();
			return -ENOTTY;
		}
		/*
		 * The table is already known to this KVM, we just increased
		 * its KVM reference counter and can return.
		 */
		rcu_read_unlock();
		return 0;
	}
	rcu_read_unlock();

	stit = kzalloc(sizeof(*stit), GFP_KERNEL);
	if (!stit) {
		iommu_tce_table_put(tbl);
		return -ENOMEM;
	}

	stit->tbl = tbl;
	kref_init(&stit->kref);

	list_add_rcu(&stit->next, &stt->iommu_tables);

	return 0;
}

static void release_spapr_tce_table(struct rcu_head *head)
{
	struct kvmppc_spapr_tce_table *stt = container_of(head,
			struct kvmppc_spapr_tce_table, rcu);
	unsigned long i, npages = kvmppc_tce_pages(stt->size);

	for (i = 0; i < npages; i++)
		if (stt->pages[i])
			__free_page(stt->pages[i]);

	kfree(stt);
}

static struct page *kvm_spapr_get_tce_page(struct kvmppc_spapr_tce_table *stt,
		unsigned long sttpage)
{
	struct page *page = stt->pages[sttpage];

	if (page)
		return page;

	mutex_lock(&stt->alloc_lock);
	page = stt->pages[sttpage];
	if (!page) {
		page = alloc_page(GFP_KERNEL | __GFP_ZERO);
		WARN_ON_ONCE(!page);
		if (page)
			stt->pages[sttpage] = page;
	}
	mutex_unlock(&stt->alloc_lock);

	return page;
}

static vm_fault_t kvm_spapr_tce_fault(struct vm_fault *vmf)
{
	struct kvmppc_spapr_tce_table *stt = vmf->vma->vm_file->private_data;
	struct page *page;

	if (vmf->pgoff >= kvmppc_tce_pages(stt->size))
		return VM_FAULT_SIGBUS;

	page = kvm_spapr_get_tce_page(stt, vmf->pgoff);
	if (!page)
		return VM_FAULT_OOM;

	get_page(page);
	vmf->page = page;
	return 0;
}

static const struct vm_operations_struct kvm_spapr_tce_vm_ops = {
	.fault = kvm_spapr_tce_fault,
};

static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma)
{
	vma->vm_ops = &kvm_spapr_tce_vm_ops;
	return 0;
}

static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
{
	struct kvmppc_spapr_tce_table *stt = filp->private_data;
	struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
	struct kvm *kvm = stt->kvm;

	mutex_lock(&kvm->lock);
	list_del_rcu(&stt->list);
	mutex_unlock(&kvm->lock);

	list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
		WARN_ON(!kref_read(&stit->kref));
		while (1) {
			if (kref_put(&stit->kref, kvm_spapr_tce_liobn_put))
				break;
		}
	}

	account_locked_vm(kvm->mm,
		kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);

	kvm_put_kvm(stt->kvm);

	call_rcu(&stt->rcu, release_spapr_tce_table);

	return 0;
}

static const struct file_operations kvm_spapr_tce_fops = {
	.mmap           = kvm_spapr_tce_mmap,
	.release	= kvm_spapr_tce_release,
};

int kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
				  struct kvm_create_spapr_tce_64 *args)
{
	struct kvmppc_spapr_tce_table *stt = NULL;
	struct kvmppc_spapr_tce_table *siter;
	struct mm_struct *mm = kvm->mm;
	unsigned long npages;
	int ret;

	if (!args->size || args->page_shift < 12 || args->page_shift > 34 ||
		(args->offset + args->size > (ULLONG_MAX >> args->page_shift)))
		return -EINVAL;

	npages = kvmppc_tce_pages(args->size);
	ret = account_locked_vm(mm, kvmppc_stt_pages(npages), true);
	if (ret)
		return ret;

	ret = -ENOMEM;
	stt = kzalloc(struct_size(stt, pages, npages), GFP_KERNEL | __GFP_NOWARN);
	if (!stt)
		goto fail_acct;

	stt->liobn = args->liobn;
	stt->page_shift = args->page_shift;
	stt->offset = args->offset;
	stt->size = args->size;
	stt->kvm = kvm;
	mutex_init(&stt->alloc_lock);
	INIT_LIST_HEAD_RCU(&stt->iommu_tables);

	mutex_lock(&kvm->lock);

	/* Check this LIOBN hasn't been previously allocated */
	ret = 0;
	list_for_each_entry(siter, &kvm->arch.spapr_tce_tables, list) {
		if (siter->liobn == args->liobn) {
			ret = -EBUSY;
			break;
		}
	}

	kvm_get_kvm(kvm);
	if (!ret)
		ret = anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
				       stt, O_RDWR | O_CLOEXEC);

	if (ret >= 0)
		list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables);
	else
		kvm_put_kvm_no_destroy(kvm);

	mutex_unlock(&kvm->lock);

	if (ret >= 0)
		return ret;

	kfree(stt);
 fail_acct:
	account_locked_vm(mm, kvmppc_stt_pages(npages), false);
	return ret;
}

static long kvmppc_tce_to_ua(struct kvm *kvm, unsigned long tce,
		unsigned long *ua)
{
	unsigned long gfn = tce >> PAGE_SHIFT;
	struct kvm_memory_slot *memslot;

	memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
	if (!memslot)
		return -EINVAL;

	*ua = __gfn_to_hva_memslot(memslot, gfn) |
		(tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));

	return 0;
}

static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt,
		unsigned long tce)
{
	unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
	enum dma_data_direction dir = iommu_tce_direction(tce);
	struct kvmppc_spapr_tce_iommu_table *stit;
	unsigned long ua = 0;

	/* Allow userspace to poison TCE table */
	if (dir == DMA_NONE)
		return H_SUCCESS;

	if (iommu_tce_check_gpa(stt->page_shift, gpa))
		return H_TOO_HARD;

	if (kvmppc_tce_to_ua(stt->kvm, tce, &ua))
		return H_TOO_HARD;

	rcu_read_lock();
	list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
		unsigned long hpa = 0;
		struct mm_iommu_table_group_mem_t *mem;
		long shift = stit->tbl->it_page_shift;

		mem = mm_iommu_lookup(stt->kvm->mm, ua, 1ULL << shift);
		if (!mem || mm_iommu_ua_to_hpa(mem, ua, shift, &hpa)) {
			rcu_read_unlock();
			return H_TOO_HARD;
		}
	}
	rcu_read_unlock();

	return H_SUCCESS;
}

/*
 * Handles TCE requests for emulated devices.
 * Puts guest TCE values to the table and expects user space to convert them.
 * Cannot fail so kvmppc_tce_validate must be called before it.
 */
static void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
		unsigned long idx, unsigned long tce)
{
	struct page *page;
	u64 *tbl;
	unsigned long sttpage;

	idx -= stt->offset;
	sttpage = idx / TCES_PER_PAGE;
	page = stt->pages[sttpage];

	if (!page) {
		/* We allow any TCE, not just with read|write permissions */
		if (!tce)
			return;

		page = kvm_spapr_get_tce_page(stt, sttpage);
		if (!page)
			return;
	}
	tbl = page_to_virt(page);

	tbl[idx % TCES_PER_PAGE] = tce;
}

static void kvmppc_clear_tce(struct mm_struct *mm, struct kvmppc_spapr_tce_table *stt,
		struct iommu_table *tbl, unsigned long entry)
{
	unsigned long i;
	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
	unsigned long io_entry = entry << (stt->page_shift - tbl->it_page_shift);

	for (i = 0; i < subpages; ++i) {
		unsigned long hpa = 0;
		enum dma_data_direction dir = DMA_NONE;

		iommu_tce_xchg_no_kill(mm, tbl, io_entry + i, &hpa, &dir);
	}
}

static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm,
		struct iommu_table *tbl, unsigned long entry)
{
	struct mm_iommu_table_group_mem_t *mem = NULL;
	const unsigned long pgsize = 1ULL << tbl->it_page_shift;
	__be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY_RO(tbl, entry);

	if (!pua)
		return H_SUCCESS;

	mem = mm_iommu_lookup(kvm->mm, be64_to_cpu(*pua), pgsize);
	if (!mem)
		return H_TOO_HARD;

	mm_iommu_mapped_dec(mem);

	*pua = cpu_to_be64(0);

	return H_SUCCESS;
}

static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
		struct iommu_table *tbl, unsigned long entry)
{
	enum dma_data_direction dir = DMA_NONE;
	unsigned long hpa = 0;
	long ret;

	if (WARN_ON_ONCE(iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa,
					&dir)))
		return H_TOO_HARD;

	if (dir == DMA_NONE)
		return H_SUCCESS;

	ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
	if (ret != H_SUCCESS)
		iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);

	return ret;
}

static long kvmppc_tce_iommu_unmap(struct kvm *kvm,
		struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
		unsigned long entry)
{
	unsigned long i, ret = H_SUCCESS;
	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
	unsigned long io_entry = entry * subpages;

	for (i = 0; i < subpages; ++i) {
		ret = kvmppc_tce_iommu_do_unmap(kvm, tbl, io_entry + i);
		if (ret != H_SUCCESS)
			break;
	}

	iommu_tce_kill(tbl, io_entry, subpages);

	return ret;
}

static long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
		unsigned long entry, unsigned long ua,
		enum dma_data_direction dir)
{
	long ret;
	unsigned long hpa;
	__be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
	struct mm_iommu_table_group_mem_t *mem;

	if (!pua)
		/* it_userspace allocation might be delayed */
		return H_TOO_HARD;

	mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
	if (!mem)
		/* This only handles v2 IOMMU type, v1 is handled via ioctl() */
		return H_TOO_HARD;

	if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
		return H_TOO_HARD;

	if (mm_iommu_mapped_inc(mem))
		return H_TOO_HARD;

	ret = iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
	if (WARN_ON_ONCE(ret)) {
		mm_iommu_mapped_dec(mem);
		return H_TOO_HARD;
	}

	if (dir != DMA_NONE)
		kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);

	*pua = cpu_to_be64(ua);

	return 0;
}

static long kvmppc_tce_iommu_map(struct kvm *kvm,
		struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
		unsigned long entry, unsigned long ua,
		enum dma_data_direction dir)
{
	unsigned long i, pgoff, ret = H_SUCCESS;
	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
	unsigned long io_entry = entry * subpages;

	for (i = 0, pgoff = 0; i < subpages;
			++i, pgoff += IOMMU_PAGE_SIZE(tbl)) {

		ret = kvmppc_tce_iommu_do_map(kvm, tbl,
				io_entry + i, ua + pgoff, dir);
		if (ret != H_SUCCESS)
			break;
	}

	iommu_tce_kill(tbl, io_entry, subpages);

	return ret;
}

long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
		      unsigned long ioba, unsigned long tce)
{
	struct kvmppc_spapr_tce_table *stt;
	long ret, idx;
	struct kvmppc_spapr_tce_iommu_table *stit;
	unsigned long entry, ua = 0;
	enum dma_data_direction dir;

	/* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
	/* 	    liobn, ioba, tce); */

	stt = kvmppc_find_table(vcpu->kvm, liobn);
	if (!stt)
		return H_TOO_HARD;

	ret = kvmppc_ioba_validate(stt, ioba, 1);
	if (ret != H_SUCCESS)
		return ret;

	idx = srcu_read_lock(&vcpu->kvm->srcu);

	ret = kvmppc_tce_validate(stt, tce);
	if (ret != H_SUCCESS)
		goto unlock_exit;

	dir = iommu_tce_direction(tce);

	if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
		ret = H_PARAMETER;
		goto unlock_exit;
	}

	entry = ioba >> stt->page_shift;

	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
		if (dir == DMA_NONE)
			ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
					stit->tbl, entry);
		else
			ret = kvmppc_tce_iommu_map(vcpu->kvm, stt, stit->tbl,
					entry, ua, dir);


		if (ret != H_SUCCESS) {
			kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl, entry);
			goto unlock_exit;
		}
	}

	kvmppc_tce_put(stt, entry, tce);

unlock_exit:
	srcu_read_unlock(&vcpu->kvm->srcu, idx);

	return ret;
}
EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);

long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
		unsigned long liobn, unsigned long ioba,
		unsigned long tce_list, unsigned long npages)
{
	struct kvmppc_spapr_tce_table *stt;
	long i, ret = H_SUCCESS, idx;
	unsigned long entry, ua = 0;
	u64 __user *tces;
	u64 tce;
	struct kvmppc_spapr_tce_iommu_table *stit;

	stt = kvmppc_find_table(vcpu->kvm, liobn);
	if (!stt)
		return H_TOO_HARD;

	entry = ioba >> stt->page_shift;
	/*
	 * SPAPR spec says that the maximum size of the list is 512 TCEs
	 * so the whole table fits in 4K page
	 */
	if (npages > 512)
		return H_PARAMETER;

	if (tce_list & (SZ_4K - 1))
		return H_PARAMETER;

	ret = kvmppc_ioba_validate(stt, ioba, npages);
	if (ret != H_SUCCESS)
		return ret;

	idx = srcu_read_lock(&vcpu->kvm->srcu);
	if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua)) {
		ret = H_TOO_HARD;
		goto unlock_exit;
	}
	tces = (u64 __user *) ua;

	for (i = 0; i < npages; ++i) {
		if (get_user(tce, tces + i)) {
			ret = H_TOO_HARD;
			goto unlock_exit;
		}
		tce = be64_to_cpu(tce);

		ret = kvmppc_tce_validate(stt, tce);
		if (ret != H_SUCCESS)
			goto unlock_exit;
	}

	for (i = 0; i < npages; ++i) {
		/*
		 * This looks unsafe, because we validate, then regrab
		 * the TCE from userspace which could have been changed by
		 * another thread.
		 *
		 * But it actually is safe, because the relevant checks will be
		 * re-executed in the following code.  If userspace tries to
		 * change this dodgily it will result in a messier failure mode
		 * but won't threaten the host.
		 */
		if (get_user(tce, tces + i)) {
			ret = H_TOO_HARD;
			goto unlock_exit;
		}
		tce = be64_to_cpu(tce);

		if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
			ret = H_PARAMETER;
			goto unlock_exit;
		}

		list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
			ret = kvmppc_tce_iommu_map(vcpu->kvm, stt,
					stit->tbl, entry + i, ua,
					iommu_tce_direction(tce));

			if (ret != H_SUCCESS) {
				kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl,
						 entry + i);
				goto unlock_exit;
			}
		}

		kvmppc_tce_put(stt, entry + i, tce);
	}

unlock_exit:
	srcu_read_unlock(&vcpu->kvm->srcu, idx);

	return ret;
}
EXPORT_SYMBOL_GPL(kvmppc_h_put_tce_indirect);

long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
		unsigned long liobn, unsigned long ioba,
		unsigned long tce_value, unsigned long npages)
{
	struct kvmppc_spapr_tce_table *stt;
	long i, ret;
	struct kvmppc_spapr_tce_iommu_table *stit;

	stt = kvmppc_find_table(vcpu->kvm, liobn);
	if (!stt)
		return H_TOO_HARD;

	ret = kvmppc_ioba_validate(stt, ioba, npages);
	if (ret != H_SUCCESS)
		return ret;

	/* Check permission bits only to allow userspace poison TCE for debug */
	if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
		return H_PARAMETER;

	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
		unsigned long entry = ioba >> stt->page_shift;

		for (i = 0; i < npages; ++i) {
			ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
					stit->tbl, entry + i);

			if (ret == H_SUCCESS)
				continue;

			if (ret == H_TOO_HARD)
				return ret;

			WARN_ON_ONCE(1);
			kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl, entry + i);
		}
	}

	for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
		kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);

	return ret;
}
EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);

long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
		      unsigned long ioba)
{
	struct kvmppc_spapr_tce_table *stt;
	long ret;
	unsigned long idx;
	struct page *page;
	u64 *tbl;

	stt = kvmppc_find_table(vcpu->kvm, liobn);
	if (!stt)
		return H_TOO_HARD;

	ret = kvmppc_ioba_validate(stt, ioba, 1);
	if (ret != H_SUCCESS)
		return ret;

	idx = (ioba >> stt->page_shift) - stt->offset;
	page = stt->pages[idx / TCES_PER_PAGE];
	if (!page) {
		kvmppc_set_gpr(vcpu, 4, 0);
		return H_SUCCESS;
	}
	tbl = (u64 *)page_address(page);

	kvmppc_set_gpr(vcpu, 4, tbl[idx % TCES_PER_PAGE]);

	return H_SUCCESS;
}
EXPORT_SYMBOL_GPL(kvmppc_h_get_tce);