xref: /linux/arch/powerpc/kvm/book3s_64_vio.c (revision 728d90bdc9e480dc93913e59a0aa3c896c7aa697)
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/kvm_host.h>
31 #include <asm/udbg.h>
32 #include <asm/iommu.h>
33 #include <asm/tce.h>
34 #include <asm/mmu_context.h>
35 
36 static unsigned long kvmppc_tce_pages(unsigned long iommu_pages)
37 {
38 	return ALIGN(iommu_pages * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
39 }
40 
41 static unsigned long kvmppc_stt_pages(unsigned long tce_pages)
42 {
43 	unsigned long stt_bytes = sizeof(struct kvmppc_spapr_tce_table) +
44 			(tce_pages * sizeof(struct page *));
45 
46 	return tce_pages + ALIGN(stt_bytes, PAGE_SIZE) / PAGE_SIZE;
47 }
48 
49 static void kvm_spapr_tce_iommu_table_free(struct rcu_head *head)
50 {
51 	struct kvmppc_spapr_tce_iommu_table *stit = container_of(head,
52 			struct kvmppc_spapr_tce_iommu_table, rcu);
53 
54 	iommu_tce_table_put(stit->tbl);
55 
56 	kfree(stit);
57 }
58 
59 static void kvm_spapr_tce_liobn_put(struct kref *kref)
60 {
61 	struct kvmppc_spapr_tce_iommu_table *stit = container_of(kref,
62 			struct kvmppc_spapr_tce_iommu_table, kref);
63 
64 	list_del_rcu(&stit->next);
65 
66 	call_rcu(&stit->rcu, kvm_spapr_tce_iommu_table_free);
67 }
68 
69 extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
70 		struct iommu_group *grp)
71 {
72 	int i;
73 	struct kvmppc_spapr_tce_table *stt;
74 	struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
75 	struct iommu_table_group *table_group = NULL;
76 
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 	}
92 }
93 
94 extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd,
95 		struct iommu_group *grp)
96 {
97 	struct kvmppc_spapr_tce_table *stt = NULL;
98 	bool found = false;
99 	struct iommu_table *tbl = NULL;
100 	struct iommu_table_group *table_group;
101 	long i;
102 	struct kvmppc_spapr_tce_iommu_table *stit;
103 	struct fd f;
104 
105 	f = fdget(tablefd);
106 	if (!f.file)
107 		return -EBADF;
108 
109 	list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
110 		if (stt == f.file->private_data) {
111 			found = true;
112 			break;
113 		}
114 	}
115 
116 	fdput(f);
117 
118 	if (!found)
119 		return -EINVAL;
120 
121 	table_group = iommu_group_get_iommudata(grp);
122 	if (WARN_ON(!table_group))
123 		return -EFAULT;
124 
125 	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
126 		struct iommu_table *tbltmp = table_group->tables[i];
127 
128 		if (!tbltmp)
129 			continue;
130 		/* Make sure hardware table parameters are compatible */
131 		if ((tbltmp->it_page_shift <= stt->page_shift) &&
132 				(tbltmp->it_offset << tbltmp->it_page_shift ==
133 				 stt->offset << stt->page_shift) &&
134 				(tbltmp->it_size << tbltmp->it_page_shift >=
135 				 stt->size << stt->page_shift)) {
136 			/*
137 			 * Reference the table to avoid races with
138 			 * add/remove DMA windows.
139 			 */
140 			tbl = iommu_tce_table_get(tbltmp);
141 			break;
142 		}
143 	}
144 	if (!tbl)
145 		return -EINVAL;
146 
147 	list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
148 		if (tbl != stit->tbl)
149 			continue;
150 
151 		if (!kref_get_unless_zero(&stit->kref)) {
152 			/* stit is being destroyed */
153 			iommu_tce_table_put(tbl);
154 			return -ENOTTY;
155 		}
156 		/*
157 		 * The table is already known to this KVM, we just increased
158 		 * its KVM reference counter and can return.
159 		 */
160 		return 0;
161 	}
162 
163 	stit = kzalloc(sizeof(*stit), GFP_KERNEL);
164 	if (!stit) {
165 		iommu_tce_table_put(tbl);
166 		return -ENOMEM;
167 	}
168 
169 	stit->tbl = tbl;
170 	kref_init(&stit->kref);
171 
172 	list_add_rcu(&stit->next, &stt->iommu_tables);
173 
174 	return 0;
175 }
176 
177 static void release_spapr_tce_table(struct rcu_head *head)
178 {
179 	struct kvmppc_spapr_tce_table *stt = container_of(head,
180 			struct kvmppc_spapr_tce_table, rcu);
181 	unsigned long i, npages = kvmppc_tce_pages(stt->size);
182 
183 	for (i = 0; i < npages; i++)
184 		if (stt->pages[i])
185 			__free_page(stt->pages[i]);
186 
187 	kfree(stt);
188 }
189 
190 static struct page *kvm_spapr_get_tce_page(struct kvmppc_spapr_tce_table *stt,
191 		unsigned long sttpage)
192 {
193 	struct page *page = stt->pages[sttpage];
194 
195 	if (page)
196 		return page;
197 
198 	mutex_lock(&stt->alloc_lock);
199 	page = stt->pages[sttpage];
200 	if (!page) {
201 		page = alloc_page(GFP_KERNEL | __GFP_ZERO);
202 		WARN_ON_ONCE(!page);
203 		if (page)
204 			stt->pages[sttpage] = page;
205 	}
206 	mutex_unlock(&stt->alloc_lock);
207 
208 	return page;
209 }
210 
211 static vm_fault_t kvm_spapr_tce_fault(struct vm_fault *vmf)
212 {
213 	struct kvmppc_spapr_tce_table *stt = vmf->vma->vm_file->private_data;
214 	struct page *page;
215 
216 	if (vmf->pgoff >= kvmppc_tce_pages(stt->size))
217 		return VM_FAULT_SIGBUS;
218 
219 	page = kvm_spapr_get_tce_page(stt, vmf->pgoff);
220 	if (!page)
221 		return VM_FAULT_OOM;
222 
223 	get_page(page);
224 	vmf->page = page;
225 	return 0;
226 }
227 
228 static const struct vm_operations_struct kvm_spapr_tce_vm_ops = {
229 	.fault = kvm_spapr_tce_fault,
230 };
231 
232 static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma)
233 {
234 	vma->vm_ops = &kvm_spapr_tce_vm_ops;
235 	return 0;
236 }
237 
238 static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
239 {
240 	struct kvmppc_spapr_tce_table *stt = filp->private_data;
241 	struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
242 	struct kvm *kvm = stt->kvm;
243 
244 	mutex_lock(&kvm->lock);
245 	list_del_rcu(&stt->list);
246 	mutex_unlock(&kvm->lock);
247 
248 	list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
249 		WARN_ON(!kref_read(&stit->kref));
250 		while (1) {
251 			if (kref_put(&stit->kref, kvm_spapr_tce_liobn_put))
252 				break;
253 		}
254 	}
255 
256 	kvm_put_kvm(stt->kvm);
257 
258 	account_locked_vm(current->mm,
259 		kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);
260 	call_rcu(&stt->rcu, release_spapr_tce_table);
261 
262 	return 0;
263 }
264 
265 static const struct file_operations kvm_spapr_tce_fops = {
266 	.mmap           = kvm_spapr_tce_mmap,
267 	.release	= kvm_spapr_tce_release,
268 };
269 
270 long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
271 				   struct kvm_create_spapr_tce_64 *args)
272 {
273 	struct kvmppc_spapr_tce_table *stt = NULL;
274 	struct kvmppc_spapr_tce_table *siter;
275 	unsigned long npages, size = args->size;
276 	int ret = -ENOMEM;
277 
278 	if (!args->size || args->page_shift < 12 || args->page_shift > 34 ||
279 		(args->offset + args->size > (ULLONG_MAX >> args->page_shift)))
280 		return -EINVAL;
281 
282 	npages = kvmppc_tce_pages(size);
283 	ret = account_locked_vm(current->mm, kvmppc_stt_pages(npages), true);
284 	if (ret)
285 		return ret;
286 
287 	ret = -ENOMEM;
288 	stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *),
289 		      GFP_KERNEL);
290 	if (!stt)
291 		goto fail_acct;
292 
293 	stt->liobn = args->liobn;
294 	stt->page_shift = args->page_shift;
295 	stt->offset = args->offset;
296 	stt->size = size;
297 	stt->kvm = kvm;
298 	mutex_init(&stt->alloc_lock);
299 	INIT_LIST_HEAD_RCU(&stt->iommu_tables);
300 
301 	mutex_lock(&kvm->lock);
302 
303 	/* Check this LIOBN hasn't been previously allocated */
304 	ret = 0;
305 	list_for_each_entry(siter, &kvm->arch.spapr_tce_tables, list) {
306 		if (siter->liobn == args->liobn) {
307 			ret = -EBUSY;
308 			break;
309 		}
310 	}
311 
312 	kvm_get_kvm(kvm);
313 	if (!ret)
314 		ret = anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
315 				       stt, O_RDWR | O_CLOEXEC);
316 
317 	if (ret >= 0)
318 		list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables);
319 	else
320 		kvm_put_kvm(kvm);
321 
322 	mutex_unlock(&kvm->lock);
323 
324 	if (ret >= 0)
325 		return ret;
326 
327 	kfree(stt);
328  fail_acct:
329 	account_locked_vm(current->mm, kvmppc_stt_pages(npages), false);
330 	return ret;
331 }
332 
333 static long kvmppc_tce_to_ua(struct kvm *kvm, unsigned long tce,
334 		unsigned long *ua)
335 {
336 	unsigned long gfn = tce >> PAGE_SHIFT;
337 	struct kvm_memory_slot *memslot;
338 
339 	memslot = search_memslots(kvm_memslots(kvm), gfn);
340 	if (!memslot)
341 		return -EINVAL;
342 
343 	*ua = __gfn_to_hva_memslot(memslot, gfn) |
344 		(tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));
345 
346 	return 0;
347 }
348 
349 static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt,
350 		unsigned long tce)
351 {
352 	unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
353 	enum dma_data_direction dir = iommu_tce_direction(tce);
354 	struct kvmppc_spapr_tce_iommu_table *stit;
355 	unsigned long ua = 0;
356 
357 	/* Allow userspace to poison TCE table */
358 	if (dir == DMA_NONE)
359 		return H_SUCCESS;
360 
361 	if (iommu_tce_check_gpa(stt->page_shift, gpa))
362 		return H_TOO_HARD;
363 
364 	if (kvmppc_tce_to_ua(stt->kvm, tce, &ua))
365 		return H_TOO_HARD;
366 
367 	list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
368 		unsigned long hpa = 0;
369 		struct mm_iommu_table_group_mem_t *mem;
370 		long shift = stit->tbl->it_page_shift;
371 
372 		mem = mm_iommu_lookup(stt->kvm->mm, ua, 1ULL << shift);
373 		if (!mem)
374 			return H_TOO_HARD;
375 
376 		if (mm_iommu_ua_to_hpa(mem, ua, shift, &hpa))
377 			return H_TOO_HARD;
378 	}
379 
380 	return H_SUCCESS;
381 }
382 
383 /*
384  * Handles TCE requests for emulated devices.
385  * Puts guest TCE values to the table and expects user space to convert them.
386  * Cannot fail so kvmppc_tce_validate must be called before it.
387  */
388 static void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
389 		unsigned long idx, unsigned long tce)
390 {
391 	struct page *page;
392 	u64 *tbl;
393 	unsigned long sttpage;
394 
395 	idx -= stt->offset;
396 	sttpage = idx / TCES_PER_PAGE;
397 	page = stt->pages[sttpage];
398 
399 	if (!page) {
400 		/* We allow any TCE, not just with read|write permissions */
401 		if (!tce)
402 			return;
403 
404 		page = kvm_spapr_get_tce_page(stt, sttpage);
405 		if (!page)
406 			return;
407 	}
408 	tbl = page_to_virt(page);
409 
410 	tbl[idx % TCES_PER_PAGE] = tce;
411 }
412 
413 static void kvmppc_clear_tce(struct mm_struct *mm, struct iommu_table *tbl,
414 		unsigned long entry)
415 {
416 	unsigned long hpa = 0;
417 	enum dma_data_direction dir = DMA_NONE;
418 
419 	iommu_tce_xchg_no_kill(mm, tbl, entry, &hpa, &dir);
420 }
421 
422 static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm,
423 		struct iommu_table *tbl, unsigned long entry)
424 {
425 	struct mm_iommu_table_group_mem_t *mem = NULL;
426 	const unsigned long pgsize = 1ULL << tbl->it_page_shift;
427 	__be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY_RO(tbl, entry);
428 
429 	if (!pua)
430 		return H_SUCCESS;
431 
432 	mem = mm_iommu_lookup(kvm->mm, be64_to_cpu(*pua), pgsize);
433 	if (!mem)
434 		return H_TOO_HARD;
435 
436 	mm_iommu_mapped_dec(mem);
437 
438 	*pua = cpu_to_be64(0);
439 
440 	return H_SUCCESS;
441 }
442 
443 static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
444 		struct iommu_table *tbl, unsigned long entry)
445 {
446 	enum dma_data_direction dir = DMA_NONE;
447 	unsigned long hpa = 0;
448 	long ret;
449 
450 	if (WARN_ON_ONCE(iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa,
451 					&dir)))
452 		return H_TOO_HARD;
453 
454 	if (dir == DMA_NONE)
455 		return H_SUCCESS;
456 
457 	ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
458 	if (ret != H_SUCCESS)
459 		iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
460 
461 	return ret;
462 }
463 
464 static long kvmppc_tce_iommu_unmap(struct kvm *kvm,
465 		struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
466 		unsigned long entry)
467 {
468 	unsigned long i, ret = H_SUCCESS;
469 	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
470 	unsigned long io_entry = entry * subpages;
471 
472 	for (i = 0; i < subpages; ++i) {
473 		ret = kvmppc_tce_iommu_do_unmap(kvm, tbl, io_entry + i);
474 		if (ret != H_SUCCESS)
475 			break;
476 	}
477 
478 	return ret;
479 }
480 
481 long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
482 		unsigned long entry, unsigned long ua,
483 		enum dma_data_direction dir)
484 {
485 	long ret;
486 	unsigned long hpa;
487 	__be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
488 	struct mm_iommu_table_group_mem_t *mem;
489 
490 	if (!pua)
491 		/* it_userspace allocation might be delayed */
492 		return H_TOO_HARD;
493 
494 	mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
495 	if (!mem)
496 		/* This only handles v2 IOMMU type, v1 is handled via ioctl() */
497 		return H_TOO_HARD;
498 
499 	if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
500 		return H_TOO_HARD;
501 
502 	if (mm_iommu_mapped_inc(mem))
503 		return H_TOO_HARD;
504 
505 	ret = iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
506 	if (WARN_ON_ONCE(ret)) {
507 		mm_iommu_mapped_dec(mem);
508 		return H_TOO_HARD;
509 	}
510 
511 	if (dir != DMA_NONE)
512 		kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
513 
514 	*pua = cpu_to_be64(ua);
515 
516 	return 0;
517 }
518 
519 static long kvmppc_tce_iommu_map(struct kvm *kvm,
520 		struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
521 		unsigned long entry, unsigned long ua,
522 		enum dma_data_direction dir)
523 {
524 	unsigned long i, pgoff, ret = H_SUCCESS;
525 	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
526 	unsigned long io_entry = entry * subpages;
527 
528 	for (i = 0, pgoff = 0; i < subpages;
529 			++i, pgoff += IOMMU_PAGE_SIZE(tbl)) {
530 
531 		ret = kvmppc_tce_iommu_do_map(kvm, tbl,
532 				io_entry + i, ua + pgoff, dir);
533 		if (ret != H_SUCCESS)
534 			break;
535 	}
536 
537 	return ret;
538 }
539 
540 long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
541 		      unsigned long ioba, unsigned long tce)
542 {
543 	struct kvmppc_spapr_tce_table *stt;
544 	long ret, idx;
545 	struct kvmppc_spapr_tce_iommu_table *stit;
546 	unsigned long entry, ua = 0;
547 	enum dma_data_direction dir;
548 
549 	/* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
550 	/* 	    liobn, ioba, tce); */
551 
552 	stt = kvmppc_find_table(vcpu->kvm, liobn);
553 	if (!stt)
554 		return H_TOO_HARD;
555 
556 	ret = kvmppc_ioba_validate(stt, ioba, 1);
557 	if (ret != H_SUCCESS)
558 		return ret;
559 
560 	idx = srcu_read_lock(&vcpu->kvm->srcu);
561 
562 	ret = kvmppc_tce_validate(stt, tce);
563 	if (ret != H_SUCCESS)
564 		goto unlock_exit;
565 
566 	dir = iommu_tce_direction(tce);
567 
568 	if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
569 		ret = H_PARAMETER;
570 		goto unlock_exit;
571 	}
572 
573 	entry = ioba >> stt->page_shift;
574 
575 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
576 		if (dir == DMA_NONE)
577 			ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
578 					stit->tbl, entry);
579 		else
580 			ret = kvmppc_tce_iommu_map(vcpu->kvm, stt, stit->tbl,
581 					entry, ua, dir);
582 
583 		iommu_tce_kill(stit->tbl, entry, 1);
584 
585 		if (ret != H_SUCCESS) {
586 			kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl, entry);
587 			goto unlock_exit;
588 		}
589 	}
590 
591 	kvmppc_tce_put(stt, entry, tce);
592 
593 unlock_exit:
594 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
595 
596 	return ret;
597 }
598 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
599 
600 long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
601 		unsigned long liobn, unsigned long ioba,
602 		unsigned long tce_list, unsigned long npages)
603 {
604 	struct kvmppc_spapr_tce_table *stt;
605 	long i, ret = H_SUCCESS, idx;
606 	unsigned long entry, ua = 0;
607 	u64 __user *tces;
608 	u64 tce;
609 	struct kvmppc_spapr_tce_iommu_table *stit;
610 
611 	stt = kvmppc_find_table(vcpu->kvm, liobn);
612 	if (!stt)
613 		return H_TOO_HARD;
614 
615 	entry = ioba >> stt->page_shift;
616 	/*
617 	 * SPAPR spec says that the maximum size of the list is 512 TCEs
618 	 * so the whole table fits in 4K page
619 	 */
620 	if (npages > 512)
621 		return H_PARAMETER;
622 
623 	if (tce_list & (SZ_4K - 1))
624 		return H_PARAMETER;
625 
626 	ret = kvmppc_ioba_validate(stt, ioba, npages);
627 	if (ret != H_SUCCESS)
628 		return ret;
629 
630 	idx = srcu_read_lock(&vcpu->kvm->srcu);
631 	if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua)) {
632 		ret = H_TOO_HARD;
633 		goto unlock_exit;
634 	}
635 	tces = (u64 __user *) ua;
636 
637 	for (i = 0; i < npages; ++i) {
638 		if (get_user(tce, tces + i)) {
639 			ret = H_TOO_HARD;
640 			goto unlock_exit;
641 		}
642 		tce = be64_to_cpu(tce);
643 
644 		ret = kvmppc_tce_validate(stt, tce);
645 		if (ret != H_SUCCESS)
646 			goto unlock_exit;
647 	}
648 
649 	for (i = 0; i < npages; ++i) {
650 		/*
651 		 * This looks unsafe, because we validate, then regrab
652 		 * the TCE from userspace which could have been changed by
653 		 * another thread.
654 		 *
655 		 * But it actually is safe, because the relevant checks will be
656 		 * re-executed in the following code.  If userspace tries to
657 		 * change this dodgily it will result in a messier failure mode
658 		 * but won't threaten the host.
659 		 */
660 		if (get_user(tce, tces + i)) {
661 			ret = H_TOO_HARD;
662 			goto invalidate_exit;
663 		}
664 		tce = be64_to_cpu(tce);
665 
666 		if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
667 			ret = H_PARAMETER;
668 			goto invalidate_exit;
669 		}
670 
671 		list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
672 			ret = kvmppc_tce_iommu_map(vcpu->kvm, stt,
673 					stit->tbl, entry + i, ua,
674 					iommu_tce_direction(tce));
675 
676 			if (ret != H_SUCCESS) {
677 				kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl,
678 						entry);
679 				goto invalidate_exit;
680 			}
681 		}
682 
683 		kvmppc_tce_put(stt, entry + i, tce);
684 	}
685 
686 invalidate_exit:
687 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next)
688 		iommu_tce_kill(stit->tbl, entry, npages);
689 
690 unlock_exit:
691 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
692 
693 	return ret;
694 }
695 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce_indirect);
696 
697 long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
698 		unsigned long liobn, unsigned long ioba,
699 		unsigned long tce_value, unsigned long npages)
700 {
701 	struct kvmppc_spapr_tce_table *stt;
702 	long i, ret;
703 	struct kvmppc_spapr_tce_iommu_table *stit;
704 
705 	stt = kvmppc_find_table(vcpu->kvm, liobn);
706 	if (!stt)
707 		return H_TOO_HARD;
708 
709 	ret = kvmppc_ioba_validate(stt, ioba, npages);
710 	if (ret != H_SUCCESS)
711 		return ret;
712 
713 	/* Check permission bits only to allow userspace poison TCE for debug */
714 	if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
715 		return H_PARAMETER;
716 
717 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
718 		unsigned long entry = ioba >> stt->page_shift;
719 
720 		for (i = 0; i < npages; ++i) {
721 			ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
722 					stit->tbl, entry + i);
723 
724 			if (ret == H_SUCCESS)
725 				continue;
726 
727 			if (ret == H_TOO_HARD)
728 				goto invalidate_exit;
729 
730 			WARN_ON_ONCE(1);
731 			kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl, entry);
732 		}
733 	}
734 
735 	for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
736 		kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
737 
738 invalidate_exit:
739 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next)
740 		iommu_tce_kill(stit->tbl, ioba >> stt->page_shift, npages);
741 
742 	return ret;
743 }
744 EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);
745