xref: /linux/arch/powerpc/kvm/book3s_64_vio.c (revision a713ca234ea9d946235ac7248995c5fddfd9e523)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
5  * Copyright 2011 David Gibson, IBM Corporation <dwg@au1.ibm.com>
6  * Copyright 2016 Alexey Kardashevskiy, IBM Corporation <aik@au1.ibm.com>
7  */
8 
9 #include <linux/types.h>
10 #include <linux/string.h>
11 #include <linux/kvm.h>
12 #include <linux/kvm_host.h>
13 #include <linux/highmem.h>
14 #include <linux/gfp.h>
15 #include <linux/slab.h>
16 #include <linux/sched/signal.h>
17 #include <linux/hugetlb.h>
18 #include <linux/list.h>
19 #include <linux/anon_inodes.h>
20 #include <linux/iommu.h>
21 #include <linux/file.h>
22 #include <linux/mm.h>
23 
24 #include <asm/kvm_ppc.h>
25 #include <asm/kvm_book3s.h>
26 #include <asm/book3s/64/mmu-hash.h>
27 #include <asm/hvcall.h>
28 #include <asm/synch.h>
29 #include <asm/ppc-opcode.h>
30 #include <asm/udbg.h>
31 #include <asm/iommu.h>
32 #include <asm/tce.h>
33 #include <asm/mmu_context.h>
34 
35 static unsigned long kvmppc_tce_pages(unsigned long iommu_pages)
36 {
37 	return ALIGN(iommu_pages * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
38 }
39 
40 static unsigned long kvmppc_stt_pages(unsigned long tce_pages)
41 {
42 	unsigned long stt_bytes = sizeof(struct kvmppc_spapr_tce_table) +
43 			(tce_pages * sizeof(struct page *));
44 
45 	return tce_pages + ALIGN(stt_bytes, PAGE_SIZE) / PAGE_SIZE;
46 }
47 
48 static void kvm_spapr_tce_iommu_table_free(struct rcu_head *head)
49 {
50 	struct kvmppc_spapr_tce_iommu_table *stit = container_of(head,
51 			struct kvmppc_spapr_tce_iommu_table, rcu);
52 
53 	iommu_tce_table_put(stit->tbl);
54 
55 	kfree(stit);
56 }
57 
58 static void kvm_spapr_tce_liobn_put(struct kref *kref)
59 {
60 	struct kvmppc_spapr_tce_iommu_table *stit = container_of(kref,
61 			struct kvmppc_spapr_tce_iommu_table, kref);
62 
63 	list_del_rcu(&stit->next);
64 
65 	call_rcu(&stit->rcu, kvm_spapr_tce_iommu_table_free);
66 }
67 
68 extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
69 		struct iommu_group *grp)
70 {
71 	int i;
72 	struct kvmppc_spapr_tce_table *stt;
73 	struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
74 	struct iommu_table_group *table_group = NULL;
75 
76 	rcu_read_lock();
77 	list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
78 
79 		table_group = iommu_group_get_iommudata(grp);
80 		if (WARN_ON(!table_group))
81 			continue;
82 
83 		list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
84 			for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
85 				if (table_group->tables[i] != stit->tbl)
86 					continue;
87 
88 				kref_put(&stit->kref, kvm_spapr_tce_liobn_put);
89 			}
90 		}
91 		cond_resched_rcu();
92 	}
93 	rcu_read_unlock();
94 }
95 
96 extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd,
97 		struct iommu_group *grp)
98 {
99 	struct kvmppc_spapr_tce_table *stt = NULL;
100 	bool found = false;
101 	struct iommu_table *tbl = NULL;
102 	struct iommu_table_group *table_group;
103 	long i;
104 	struct kvmppc_spapr_tce_iommu_table *stit;
105 	struct fd f;
106 
107 	f = fdget(tablefd);
108 	if (!f.file)
109 		return -EBADF;
110 
111 	rcu_read_lock();
112 	list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
113 		if (stt == f.file->private_data) {
114 			found = true;
115 			break;
116 		}
117 	}
118 	rcu_read_unlock();
119 
120 	fdput(f);
121 
122 	if (!found)
123 		return -EINVAL;
124 
125 	table_group = iommu_group_get_iommudata(grp);
126 	if (WARN_ON(!table_group))
127 		return -EFAULT;
128 
129 	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
130 		struct iommu_table *tbltmp = table_group->tables[i];
131 
132 		if (!tbltmp)
133 			continue;
134 		/* Make sure hardware table parameters are compatible */
135 		if ((tbltmp->it_page_shift <= stt->page_shift) &&
136 				(tbltmp->it_offset << tbltmp->it_page_shift ==
137 				 stt->offset << stt->page_shift) &&
138 				(tbltmp->it_size << tbltmp->it_page_shift >=
139 				 stt->size << stt->page_shift)) {
140 			/*
141 			 * Reference the table to avoid races with
142 			 * add/remove DMA windows.
143 			 */
144 			tbl = iommu_tce_table_get(tbltmp);
145 			break;
146 		}
147 	}
148 	if (!tbl)
149 		return -EINVAL;
150 
151 	rcu_read_lock();
152 	list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
153 		if (tbl != stit->tbl)
154 			continue;
155 
156 		if (!kref_get_unless_zero(&stit->kref)) {
157 			/* stit is being destroyed */
158 			iommu_tce_table_put(tbl);
159 			rcu_read_unlock();
160 			return -ENOTTY;
161 		}
162 		/*
163 		 * The table is already known to this KVM, we just increased
164 		 * its KVM reference counter and can return.
165 		 */
166 		rcu_read_unlock();
167 		return 0;
168 	}
169 	rcu_read_unlock();
170 
171 	stit = kzalloc(sizeof(*stit), GFP_KERNEL);
172 	if (!stit) {
173 		iommu_tce_table_put(tbl);
174 		return -ENOMEM;
175 	}
176 
177 	stit->tbl = tbl;
178 	kref_init(&stit->kref);
179 
180 	list_add_rcu(&stit->next, &stt->iommu_tables);
181 
182 	return 0;
183 }
184 
185 static void release_spapr_tce_table(struct rcu_head *head)
186 {
187 	struct kvmppc_spapr_tce_table *stt = container_of(head,
188 			struct kvmppc_spapr_tce_table, rcu);
189 	unsigned long i, npages = kvmppc_tce_pages(stt->size);
190 
191 	for (i = 0; i < npages; i++)
192 		if (stt->pages[i])
193 			__free_page(stt->pages[i]);
194 
195 	kfree(stt);
196 }
197 
198 static struct page *kvm_spapr_get_tce_page(struct kvmppc_spapr_tce_table *stt,
199 		unsigned long sttpage)
200 {
201 	struct page *page = stt->pages[sttpage];
202 
203 	if (page)
204 		return page;
205 
206 	mutex_lock(&stt->alloc_lock);
207 	page = stt->pages[sttpage];
208 	if (!page) {
209 		page = alloc_page(GFP_KERNEL | __GFP_ZERO);
210 		WARN_ON_ONCE(!page);
211 		if (page)
212 			stt->pages[sttpage] = page;
213 	}
214 	mutex_unlock(&stt->alloc_lock);
215 
216 	return page;
217 }
218 
219 static vm_fault_t kvm_spapr_tce_fault(struct vm_fault *vmf)
220 {
221 	struct kvmppc_spapr_tce_table *stt = vmf->vma->vm_file->private_data;
222 	struct page *page;
223 
224 	if (vmf->pgoff >= kvmppc_tce_pages(stt->size))
225 		return VM_FAULT_SIGBUS;
226 
227 	page = kvm_spapr_get_tce_page(stt, vmf->pgoff);
228 	if (!page)
229 		return VM_FAULT_OOM;
230 
231 	get_page(page);
232 	vmf->page = page;
233 	return 0;
234 }
235 
236 static const struct vm_operations_struct kvm_spapr_tce_vm_ops = {
237 	.fault = kvm_spapr_tce_fault,
238 };
239 
240 static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma)
241 {
242 	vma->vm_ops = &kvm_spapr_tce_vm_ops;
243 	return 0;
244 }
245 
246 static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
247 {
248 	struct kvmppc_spapr_tce_table *stt = filp->private_data;
249 	struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
250 	struct kvm *kvm = stt->kvm;
251 
252 	mutex_lock(&kvm->lock);
253 	list_del_rcu(&stt->list);
254 	mutex_unlock(&kvm->lock);
255 
256 	list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
257 		WARN_ON(!kref_read(&stit->kref));
258 		while (1) {
259 			if (kref_put(&stit->kref, kvm_spapr_tce_liobn_put))
260 				break;
261 		}
262 	}
263 
264 	account_locked_vm(kvm->mm,
265 		kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);
266 
267 	kvm_put_kvm(stt->kvm);
268 
269 	call_rcu(&stt->rcu, release_spapr_tce_table);
270 
271 	return 0;
272 }
273 
274 static const struct file_operations kvm_spapr_tce_fops = {
275 	.mmap           = kvm_spapr_tce_mmap,
276 	.release	= kvm_spapr_tce_release,
277 };
278 
279 long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
280 				   struct kvm_create_spapr_tce_64 *args)
281 {
282 	struct kvmppc_spapr_tce_table *stt = NULL;
283 	struct kvmppc_spapr_tce_table *siter;
284 	struct mm_struct *mm = kvm->mm;
285 	unsigned long npages, size = args->size;
286 	int ret;
287 
288 	if (!args->size || args->page_shift < 12 || args->page_shift > 34 ||
289 		(args->offset + args->size > (ULLONG_MAX >> args->page_shift)))
290 		return -EINVAL;
291 
292 	npages = kvmppc_tce_pages(size);
293 	ret = account_locked_vm(mm, kvmppc_stt_pages(npages), true);
294 	if (ret)
295 		return ret;
296 
297 	ret = -ENOMEM;
298 	stt = kzalloc(struct_size(stt, pages, npages), GFP_KERNEL);
299 	if (!stt)
300 		goto fail_acct;
301 
302 	stt->liobn = args->liobn;
303 	stt->page_shift = args->page_shift;
304 	stt->offset = args->offset;
305 	stt->size = size;
306 	stt->kvm = kvm;
307 	mutex_init(&stt->alloc_lock);
308 	INIT_LIST_HEAD_RCU(&stt->iommu_tables);
309 
310 	mutex_lock(&kvm->lock);
311 
312 	/* Check this LIOBN hasn't been previously allocated */
313 	ret = 0;
314 	list_for_each_entry(siter, &kvm->arch.spapr_tce_tables, list) {
315 		if (siter->liobn == args->liobn) {
316 			ret = -EBUSY;
317 			break;
318 		}
319 	}
320 
321 	kvm_get_kvm(kvm);
322 	if (!ret)
323 		ret = anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
324 				       stt, O_RDWR | O_CLOEXEC);
325 
326 	if (ret >= 0)
327 		list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables);
328 	else
329 		kvm_put_kvm_no_destroy(kvm);
330 
331 	mutex_unlock(&kvm->lock);
332 
333 	if (ret >= 0)
334 		return ret;
335 
336 	kfree(stt);
337  fail_acct:
338 	account_locked_vm(mm, kvmppc_stt_pages(npages), false);
339 	return ret;
340 }
341 
342 static long kvmppc_tce_to_ua(struct kvm *kvm, unsigned long tce,
343 		unsigned long *ua)
344 {
345 	unsigned long gfn = tce >> PAGE_SHIFT;
346 	struct kvm_memory_slot *memslot;
347 
348 	memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
349 	if (!memslot)
350 		return -EINVAL;
351 
352 	*ua = __gfn_to_hva_memslot(memslot, gfn) |
353 		(tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));
354 
355 	return 0;
356 }
357 
358 static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt,
359 		unsigned long tce)
360 {
361 	unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
362 	enum dma_data_direction dir = iommu_tce_direction(tce);
363 	struct kvmppc_spapr_tce_iommu_table *stit;
364 	unsigned long ua = 0;
365 
366 	/* Allow userspace to poison TCE table */
367 	if (dir == DMA_NONE)
368 		return H_SUCCESS;
369 
370 	if (iommu_tce_check_gpa(stt->page_shift, gpa))
371 		return H_TOO_HARD;
372 
373 	if (kvmppc_tce_to_ua(stt->kvm, tce, &ua))
374 		return H_TOO_HARD;
375 
376 	rcu_read_lock();
377 	list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
378 		unsigned long hpa = 0;
379 		struct mm_iommu_table_group_mem_t *mem;
380 		long shift = stit->tbl->it_page_shift;
381 
382 		mem = mm_iommu_lookup(stt->kvm->mm, ua, 1ULL << shift);
383 		if (!mem || mm_iommu_ua_to_hpa(mem, ua, shift, &hpa)) {
384 			rcu_read_unlock();
385 			return H_TOO_HARD;
386 		}
387 	}
388 	rcu_read_unlock();
389 
390 	return H_SUCCESS;
391 }
392 
393 /*
394  * Handles TCE requests for emulated devices.
395  * Puts guest TCE values to the table and expects user space to convert them.
396  * Cannot fail so kvmppc_tce_validate must be called before it.
397  */
398 static void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
399 		unsigned long idx, unsigned long tce)
400 {
401 	struct page *page;
402 	u64 *tbl;
403 	unsigned long sttpage;
404 
405 	idx -= stt->offset;
406 	sttpage = idx / TCES_PER_PAGE;
407 	page = stt->pages[sttpage];
408 
409 	if (!page) {
410 		/* We allow any TCE, not just with read|write permissions */
411 		if (!tce)
412 			return;
413 
414 		page = kvm_spapr_get_tce_page(stt, sttpage);
415 		if (!page)
416 			return;
417 	}
418 	tbl = page_to_virt(page);
419 
420 	tbl[idx % TCES_PER_PAGE] = tce;
421 }
422 
423 static void kvmppc_clear_tce(struct mm_struct *mm, struct iommu_table *tbl,
424 		unsigned long entry)
425 {
426 	unsigned long hpa = 0;
427 	enum dma_data_direction dir = DMA_NONE;
428 
429 	iommu_tce_xchg_no_kill(mm, tbl, entry, &hpa, &dir);
430 }
431 
432 static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm,
433 		struct iommu_table *tbl, unsigned long entry)
434 {
435 	struct mm_iommu_table_group_mem_t *mem = NULL;
436 	const unsigned long pgsize = 1ULL << tbl->it_page_shift;
437 	__be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY_RO(tbl, entry);
438 
439 	if (!pua)
440 		return H_SUCCESS;
441 
442 	mem = mm_iommu_lookup(kvm->mm, be64_to_cpu(*pua), pgsize);
443 	if (!mem)
444 		return H_TOO_HARD;
445 
446 	mm_iommu_mapped_dec(mem);
447 
448 	*pua = cpu_to_be64(0);
449 
450 	return H_SUCCESS;
451 }
452 
453 static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
454 		struct iommu_table *tbl, unsigned long entry)
455 {
456 	enum dma_data_direction dir = DMA_NONE;
457 	unsigned long hpa = 0;
458 	long ret;
459 
460 	if (WARN_ON_ONCE(iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa,
461 					&dir)))
462 		return H_TOO_HARD;
463 
464 	if (dir == DMA_NONE)
465 		return H_SUCCESS;
466 
467 	ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
468 	if (ret != H_SUCCESS)
469 		iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
470 
471 	return ret;
472 }
473 
474 static long kvmppc_tce_iommu_unmap(struct kvm *kvm,
475 		struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
476 		unsigned long entry)
477 {
478 	unsigned long i, ret = H_SUCCESS;
479 	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
480 	unsigned long io_entry = entry * subpages;
481 
482 	for (i = 0; i < subpages; ++i) {
483 		ret = kvmppc_tce_iommu_do_unmap(kvm, tbl, io_entry + i);
484 		if (ret != H_SUCCESS)
485 			break;
486 	}
487 
488 	return ret;
489 }
490 
491 static long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
492 		unsigned long entry, unsigned long ua,
493 		enum dma_data_direction dir)
494 {
495 	long ret;
496 	unsigned long hpa;
497 	__be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
498 	struct mm_iommu_table_group_mem_t *mem;
499 
500 	if (!pua)
501 		/* it_userspace allocation might be delayed */
502 		return H_TOO_HARD;
503 
504 	mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
505 	if (!mem)
506 		/* This only handles v2 IOMMU type, v1 is handled via ioctl() */
507 		return H_TOO_HARD;
508 
509 	if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
510 		return H_TOO_HARD;
511 
512 	if (mm_iommu_mapped_inc(mem))
513 		return H_TOO_HARD;
514 
515 	ret = iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
516 	if (WARN_ON_ONCE(ret)) {
517 		mm_iommu_mapped_dec(mem);
518 		return H_TOO_HARD;
519 	}
520 
521 	if (dir != DMA_NONE)
522 		kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
523 
524 	*pua = cpu_to_be64(ua);
525 
526 	return 0;
527 }
528 
529 static long kvmppc_tce_iommu_map(struct kvm *kvm,
530 		struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
531 		unsigned long entry, unsigned long ua,
532 		enum dma_data_direction dir)
533 {
534 	unsigned long i, pgoff, ret = H_SUCCESS;
535 	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
536 	unsigned long io_entry = entry * subpages;
537 
538 	for (i = 0, pgoff = 0; i < subpages;
539 			++i, pgoff += IOMMU_PAGE_SIZE(tbl)) {
540 
541 		ret = kvmppc_tce_iommu_do_map(kvm, tbl,
542 				io_entry + i, ua + pgoff, dir);
543 		if (ret != H_SUCCESS)
544 			break;
545 	}
546 
547 	return ret;
548 }
549 
550 long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
551 		      unsigned long ioba, unsigned long tce)
552 {
553 	struct kvmppc_spapr_tce_table *stt;
554 	long ret, idx;
555 	struct kvmppc_spapr_tce_iommu_table *stit;
556 	unsigned long entry, ua = 0;
557 	enum dma_data_direction dir;
558 
559 	/* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
560 	/* 	    liobn, ioba, tce); */
561 
562 	stt = kvmppc_find_table(vcpu->kvm, liobn);
563 	if (!stt)
564 		return H_TOO_HARD;
565 
566 	ret = kvmppc_ioba_validate(stt, ioba, 1);
567 	if (ret != H_SUCCESS)
568 		return ret;
569 
570 	idx = srcu_read_lock(&vcpu->kvm->srcu);
571 
572 	ret = kvmppc_tce_validate(stt, tce);
573 	if (ret != H_SUCCESS)
574 		goto unlock_exit;
575 
576 	dir = iommu_tce_direction(tce);
577 
578 	if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
579 		ret = H_PARAMETER;
580 		goto unlock_exit;
581 	}
582 
583 	entry = ioba >> stt->page_shift;
584 
585 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
586 		if (dir == DMA_NONE)
587 			ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
588 					stit->tbl, entry);
589 		else
590 			ret = kvmppc_tce_iommu_map(vcpu->kvm, stt, stit->tbl,
591 					entry, ua, dir);
592 
593 		iommu_tce_kill(stit->tbl, entry, 1);
594 
595 		if (ret != H_SUCCESS) {
596 			kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl, entry);
597 			goto unlock_exit;
598 		}
599 	}
600 
601 	kvmppc_tce_put(stt, entry, tce);
602 
603 unlock_exit:
604 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
605 
606 	return ret;
607 }
608 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
609 
610 long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
611 		unsigned long liobn, unsigned long ioba,
612 		unsigned long tce_list, unsigned long npages)
613 {
614 	struct kvmppc_spapr_tce_table *stt;
615 	long i, ret = H_SUCCESS, idx;
616 	unsigned long entry, ua = 0;
617 	u64 __user *tces;
618 	u64 tce;
619 	struct kvmppc_spapr_tce_iommu_table *stit;
620 
621 	stt = kvmppc_find_table(vcpu->kvm, liobn);
622 	if (!stt)
623 		return H_TOO_HARD;
624 
625 	entry = ioba >> stt->page_shift;
626 	/*
627 	 * SPAPR spec says that the maximum size of the list is 512 TCEs
628 	 * so the whole table fits in 4K page
629 	 */
630 	if (npages > 512)
631 		return H_PARAMETER;
632 
633 	if (tce_list & (SZ_4K - 1))
634 		return H_PARAMETER;
635 
636 	ret = kvmppc_ioba_validate(stt, ioba, npages);
637 	if (ret != H_SUCCESS)
638 		return ret;
639 
640 	idx = srcu_read_lock(&vcpu->kvm->srcu);
641 	if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua)) {
642 		ret = H_TOO_HARD;
643 		goto unlock_exit;
644 	}
645 	tces = (u64 __user *) ua;
646 
647 	for (i = 0; i < npages; ++i) {
648 		if (get_user(tce, tces + i)) {
649 			ret = H_TOO_HARD;
650 			goto unlock_exit;
651 		}
652 		tce = be64_to_cpu(tce);
653 
654 		ret = kvmppc_tce_validate(stt, tce);
655 		if (ret != H_SUCCESS)
656 			goto unlock_exit;
657 	}
658 
659 	for (i = 0; i < npages; ++i) {
660 		/*
661 		 * This looks unsafe, because we validate, then regrab
662 		 * the TCE from userspace which could have been changed by
663 		 * another thread.
664 		 *
665 		 * But it actually is safe, because the relevant checks will be
666 		 * re-executed in the following code.  If userspace tries to
667 		 * change this dodgily it will result in a messier failure mode
668 		 * but won't threaten the host.
669 		 */
670 		if (get_user(tce, tces + i)) {
671 			ret = H_TOO_HARD;
672 			goto invalidate_exit;
673 		}
674 		tce = be64_to_cpu(tce);
675 
676 		if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
677 			ret = H_PARAMETER;
678 			goto invalidate_exit;
679 		}
680 
681 		list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
682 			ret = kvmppc_tce_iommu_map(vcpu->kvm, stt,
683 					stit->tbl, entry + i, ua,
684 					iommu_tce_direction(tce));
685 
686 			if (ret != H_SUCCESS) {
687 				kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl,
688 						entry);
689 				goto invalidate_exit;
690 			}
691 		}
692 
693 		kvmppc_tce_put(stt, entry + i, tce);
694 	}
695 
696 invalidate_exit:
697 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next)
698 		iommu_tce_kill(stit->tbl, entry, npages);
699 
700 unlock_exit:
701 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
702 
703 	return ret;
704 }
705 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce_indirect);
706 
707 long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
708 		unsigned long liobn, unsigned long ioba,
709 		unsigned long tce_value, unsigned long npages)
710 {
711 	struct kvmppc_spapr_tce_table *stt;
712 	long i, ret;
713 	struct kvmppc_spapr_tce_iommu_table *stit;
714 
715 	stt = kvmppc_find_table(vcpu->kvm, liobn);
716 	if (!stt)
717 		return H_TOO_HARD;
718 
719 	ret = kvmppc_ioba_validate(stt, ioba, npages);
720 	if (ret != H_SUCCESS)
721 		return ret;
722 
723 	/* Check permission bits only to allow userspace poison TCE for debug */
724 	if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
725 		return H_PARAMETER;
726 
727 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
728 		unsigned long entry = ioba >> stt->page_shift;
729 
730 		for (i = 0; i < npages; ++i) {
731 			ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
732 					stit->tbl, entry + i);
733 
734 			if (ret == H_SUCCESS)
735 				continue;
736 
737 			if (ret == H_TOO_HARD)
738 				goto invalidate_exit;
739 
740 			WARN_ON_ONCE(1);
741 			kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl, entry);
742 		}
743 	}
744 
745 	for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
746 		kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
747 
748 invalidate_exit:
749 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next)
750 		iommu_tce_kill(stit->tbl, ioba >> stt->page_shift, npages);
751 
752 	return ret;
753 }
754 EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);
755