xref: /openbmc/linux/arch/powerpc/kvm/book3s_64_vio.c (revision fbb6b31a)
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 kvmppc_spapr_tce_table *stt,
424 		struct iommu_table *tbl, unsigned long entry)
425 {
426 	unsigned long i;
427 	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
428 	unsigned long io_entry = entry << (stt->page_shift - tbl->it_page_shift);
429 
430 	for (i = 0; i < subpages; ++i) {
431 		unsigned long hpa = 0;
432 		enum dma_data_direction dir = DMA_NONE;
433 
434 		iommu_tce_xchg_no_kill(mm, tbl, io_entry + i, &hpa, &dir);
435 	}
436 }
437 
438 static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm,
439 		struct iommu_table *tbl, unsigned long entry)
440 {
441 	struct mm_iommu_table_group_mem_t *mem = NULL;
442 	const unsigned long pgsize = 1ULL << tbl->it_page_shift;
443 	__be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY_RO(tbl, entry);
444 
445 	if (!pua)
446 		return H_SUCCESS;
447 
448 	mem = mm_iommu_lookup(kvm->mm, be64_to_cpu(*pua), pgsize);
449 	if (!mem)
450 		return H_TOO_HARD;
451 
452 	mm_iommu_mapped_dec(mem);
453 
454 	*pua = cpu_to_be64(0);
455 
456 	return H_SUCCESS;
457 }
458 
459 static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
460 		struct iommu_table *tbl, unsigned long entry)
461 {
462 	enum dma_data_direction dir = DMA_NONE;
463 	unsigned long hpa = 0;
464 	long ret;
465 
466 	if (WARN_ON_ONCE(iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa,
467 					&dir)))
468 		return H_TOO_HARD;
469 
470 	if (dir == DMA_NONE)
471 		return H_SUCCESS;
472 
473 	ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
474 	if (ret != H_SUCCESS)
475 		iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
476 
477 	return ret;
478 }
479 
480 static long kvmppc_tce_iommu_unmap(struct kvm *kvm,
481 		struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
482 		unsigned long entry)
483 {
484 	unsigned long i, ret = H_SUCCESS;
485 	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
486 	unsigned long io_entry = entry * subpages;
487 
488 	for (i = 0; i < subpages; ++i) {
489 		ret = kvmppc_tce_iommu_do_unmap(kvm, tbl, io_entry + i);
490 		if (ret != H_SUCCESS)
491 			break;
492 	}
493 
494 	iommu_tce_kill(tbl, io_entry, subpages);
495 
496 	return ret;
497 }
498 
499 static long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
500 		unsigned long entry, unsigned long ua,
501 		enum dma_data_direction dir)
502 {
503 	long ret;
504 	unsigned long hpa;
505 	__be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
506 	struct mm_iommu_table_group_mem_t *mem;
507 
508 	if (!pua)
509 		/* it_userspace allocation might be delayed */
510 		return H_TOO_HARD;
511 
512 	mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
513 	if (!mem)
514 		/* This only handles v2 IOMMU type, v1 is handled via ioctl() */
515 		return H_TOO_HARD;
516 
517 	if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
518 		return H_TOO_HARD;
519 
520 	if (mm_iommu_mapped_inc(mem))
521 		return H_TOO_HARD;
522 
523 	ret = iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
524 	if (WARN_ON_ONCE(ret)) {
525 		mm_iommu_mapped_dec(mem);
526 		return H_TOO_HARD;
527 	}
528 
529 	if (dir != DMA_NONE)
530 		kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
531 
532 	*pua = cpu_to_be64(ua);
533 
534 	return 0;
535 }
536 
537 static long kvmppc_tce_iommu_map(struct kvm *kvm,
538 		struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
539 		unsigned long entry, unsigned long ua,
540 		enum dma_data_direction dir)
541 {
542 	unsigned long i, pgoff, ret = H_SUCCESS;
543 	unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
544 	unsigned long io_entry = entry * subpages;
545 
546 	for (i = 0, pgoff = 0; i < subpages;
547 			++i, pgoff += IOMMU_PAGE_SIZE(tbl)) {
548 
549 		ret = kvmppc_tce_iommu_do_map(kvm, tbl,
550 				io_entry + i, ua + pgoff, dir);
551 		if (ret != H_SUCCESS)
552 			break;
553 	}
554 
555 	iommu_tce_kill(tbl, io_entry, subpages);
556 
557 	return ret;
558 }
559 
560 long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
561 		      unsigned long ioba, unsigned long tce)
562 {
563 	struct kvmppc_spapr_tce_table *stt;
564 	long ret, idx;
565 	struct kvmppc_spapr_tce_iommu_table *stit;
566 	unsigned long entry, ua = 0;
567 	enum dma_data_direction dir;
568 
569 	/* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
570 	/* 	    liobn, ioba, tce); */
571 
572 	stt = kvmppc_find_table(vcpu->kvm, liobn);
573 	if (!stt)
574 		return H_TOO_HARD;
575 
576 	ret = kvmppc_ioba_validate(stt, ioba, 1);
577 	if (ret != H_SUCCESS)
578 		return ret;
579 
580 	idx = srcu_read_lock(&vcpu->kvm->srcu);
581 
582 	ret = kvmppc_tce_validate(stt, tce);
583 	if (ret != H_SUCCESS)
584 		goto unlock_exit;
585 
586 	dir = iommu_tce_direction(tce);
587 
588 	if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
589 		ret = H_PARAMETER;
590 		goto unlock_exit;
591 	}
592 
593 	entry = ioba >> stt->page_shift;
594 
595 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
596 		if (dir == DMA_NONE)
597 			ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
598 					stit->tbl, entry);
599 		else
600 			ret = kvmppc_tce_iommu_map(vcpu->kvm, stt, stit->tbl,
601 					entry, ua, dir);
602 
603 
604 		if (ret != H_SUCCESS) {
605 			kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl, entry);
606 			goto unlock_exit;
607 		}
608 	}
609 
610 	kvmppc_tce_put(stt, entry, tce);
611 
612 unlock_exit:
613 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
614 
615 	return ret;
616 }
617 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
618 
619 long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
620 		unsigned long liobn, unsigned long ioba,
621 		unsigned long tce_list, unsigned long npages)
622 {
623 	struct kvmppc_spapr_tce_table *stt;
624 	long i, ret = H_SUCCESS, idx;
625 	unsigned long entry, ua = 0;
626 	u64 __user *tces;
627 	u64 tce;
628 	struct kvmppc_spapr_tce_iommu_table *stit;
629 
630 	stt = kvmppc_find_table(vcpu->kvm, liobn);
631 	if (!stt)
632 		return H_TOO_HARD;
633 
634 	entry = ioba >> stt->page_shift;
635 	/*
636 	 * SPAPR spec says that the maximum size of the list is 512 TCEs
637 	 * so the whole table fits in 4K page
638 	 */
639 	if (npages > 512)
640 		return H_PARAMETER;
641 
642 	if (tce_list & (SZ_4K - 1))
643 		return H_PARAMETER;
644 
645 	ret = kvmppc_ioba_validate(stt, ioba, npages);
646 	if (ret != H_SUCCESS)
647 		return ret;
648 
649 	idx = srcu_read_lock(&vcpu->kvm->srcu);
650 	if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua)) {
651 		ret = H_TOO_HARD;
652 		goto unlock_exit;
653 	}
654 	tces = (u64 __user *) ua;
655 
656 	for (i = 0; i < npages; ++i) {
657 		if (get_user(tce, tces + i)) {
658 			ret = H_TOO_HARD;
659 			goto unlock_exit;
660 		}
661 		tce = be64_to_cpu(tce);
662 
663 		ret = kvmppc_tce_validate(stt, tce);
664 		if (ret != H_SUCCESS)
665 			goto unlock_exit;
666 	}
667 
668 	for (i = 0; i < npages; ++i) {
669 		/*
670 		 * This looks unsafe, because we validate, then regrab
671 		 * the TCE from userspace which could have been changed by
672 		 * another thread.
673 		 *
674 		 * But it actually is safe, because the relevant checks will be
675 		 * re-executed in the following code.  If userspace tries to
676 		 * change this dodgily it will result in a messier failure mode
677 		 * but won't threaten the host.
678 		 */
679 		if (get_user(tce, tces + i)) {
680 			ret = H_TOO_HARD;
681 			goto unlock_exit;
682 		}
683 		tce = be64_to_cpu(tce);
684 
685 		if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
686 			ret = H_PARAMETER;
687 			goto unlock_exit;
688 		}
689 
690 		list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
691 			ret = kvmppc_tce_iommu_map(vcpu->kvm, stt,
692 					stit->tbl, entry + i, ua,
693 					iommu_tce_direction(tce));
694 
695 			if (ret != H_SUCCESS) {
696 				kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl,
697 						 entry + i);
698 				goto unlock_exit;
699 			}
700 		}
701 
702 		kvmppc_tce_put(stt, entry + i, tce);
703 	}
704 
705 unlock_exit:
706 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
707 
708 	return ret;
709 }
710 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce_indirect);
711 
712 long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
713 		unsigned long liobn, unsigned long ioba,
714 		unsigned long tce_value, unsigned long npages)
715 {
716 	struct kvmppc_spapr_tce_table *stt;
717 	long i, ret;
718 	struct kvmppc_spapr_tce_iommu_table *stit;
719 
720 	stt = kvmppc_find_table(vcpu->kvm, liobn);
721 	if (!stt)
722 		return H_TOO_HARD;
723 
724 	ret = kvmppc_ioba_validate(stt, ioba, npages);
725 	if (ret != H_SUCCESS)
726 		return ret;
727 
728 	/* Check permission bits only to allow userspace poison TCE for debug */
729 	if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
730 		return H_PARAMETER;
731 
732 	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
733 		unsigned long entry = ioba >> stt->page_shift;
734 
735 		for (i = 0; i < npages; ++i) {
736 			ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
737 					stit->tbl, entry + i);
738 
739 			if (ret == H_SUCCESS)
740 				continue;
741 
742 			if (ret == H_TOO_HARD)
743 				return ret;
744 
745 			WARN_ON_ONCE(1);
746 			kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl, entry + i);
747 		}
748 	}
749 
750 	for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
751 		kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
752 
753 	return ret;
754 }
755 EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);
756