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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * KVM guest address space mapping code
4 *
5 * Copyright IBM Corp. 2007, 2020
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 * David Hildenbrand <david@redhat.com>
8 * Janosch Frank <frankja@linux.vnet.ibm.com>
9 */
10
11#include <linux/kernel.h>
12#include <linux/pagewalk.h>
13#include <linux/swap.h>
14#include <linux/smp.h>
15#include <linux/spinlock.h>
16#include <linux/slab.h>
17#include <linux/swapops.h>
18#include <linux/ksm.h>
19#include <linux/mman.h>
20#include <linux/pgtable.h>
21
22#include <asm/pgalloc.h>
23#include <asm/gmap.h>
24#include <asm/tlb.h>
25
26#define GMAP_SHADOW_FAKE_TABLE 1ULL
27
28/**
29 * gmap_alloc - allocate and initialize a guest address space
30 * @limit: maximum address of the gmap address space
31 *
32 * Returns a guest address space structure.
33 */
34static struct gmap *gmap_alloc(unsigned long limit)
35{
36 struct gmap *gmap;
37 struct page *page;
38 unsigned long *table;
39 unsigned long etype, atype;
40
41 if (limit < _REGION3_SIZE) {
42 limit = _REGION3_SIZE - 1;
43 atype = _ASCE_TYPE_SEGMENT;
44 etype = _SEGMENT_ENTRY_EMPTY;
45 } else if (limit < _REGION2_SIZE) {
46 limit = _REGION2_SIZE - 1;
47 atype = _ASCE_TYPE_REGION3;
48 etype = _REGION3_ENTRY_EMPTY;
49 } else if (limit < _REGION1_SIZE) {
50 limit = _REGION1_SIZE - 1;
51 atype = _ASCE_TYPE_REGION2;
52 etype = _REGION2_ENTRY_EMPTY;
53 } else {
54 limit = -1UL;
55 atype = _ASCE_TYPE_REGION1;
56 etype = _REGION1_ENTRY_EMPTY;
57 }
58 gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL_ACCOUNT);
59 if (!gmap)
60 goto out;
61 INIT_LIST_HEAD(&gmap->crst_list);
62 INIT_LIST_HEAD(&gmap->children);
63 INIT_LIST_HEAD(&gmap->pt_list);
64 INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL_ACCOUNT);
65 INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC | __GFP_ACCOUNT);
66 INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC | __GFP_ACCOUNT);
67 spin_lock_init(&gmap->guest_table_lock);
68 spin_lock_init(&gmap->shadow_lock);
69 refcount_set(&gmap->ref_count, 1);
70 page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
71 if (!page)
72 goto out_free;
73 page->index = 0;
74 list_add(&page->lru, &gmap->crst_list);
75 table = page_to_virt(page);
76 crst_table_init(table, etype);
77 gmap->table = table;
78 gmap->asce = atype | _ASCE_TABLE_LENGTH |
79 _ASCE_USER_BITS | __pa(table);
80 gmap->asce_end = limit;
81 return gmap;
82
83out_free:
84 kfree(gmap);
85out:
86 return NULL;
87}
88
89/**
90 * gmap_create - create a guest address space
91 * @mm: pointer to the parent mm_struct
92 * @limit: maximum size of the gmap address space
93 *
94 * Returns a guest address space structure.
95 */
96struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit)
97{
98 struct gmap *gmap;
99 unsigned long gmap_asce;
100
101 gmap = gmap_alloc(limit);
102 if (!gmap)
103 return NULL;
104 gmap->mm = mm;
105 spin_lock(&mm->context.lock);
106 list_add_rcu(&gmap->list, &mm->context.gmap_list);
107 if (list_is_singular(&mm->context.gmap_list))
108 gmap_asce = gmap->asce;
109 else
110 gmap_asce = -1UL;
111 WRITE_ONCE(mm->context.gmap_asce, gmap_asce);
112 spin_unlock(&mm->context.lock);
113 return gmap;
114}
115EXPORT_SYMBOL_GPL(gmap_create);
116
117static void gmap_flush_tlb(struct gmap *gmap)
118{
119 if (MACHINE_HAS_IDTE)
120 __tlb_flush_idte(gmap->asce);
121 else
122 __tlb_flush_global();
123}
124
125static void gmap_radix_tree_free(struct radix_tree_root *root)
126{
127 struct radix_tree_iter iter;
128 unsigned long indices[16];
129 unsigned long index;
130 void __rcu **slot;
131 int i, nr;
132
133 /* A radix tree is freed by deleting all of its entries */
134 index = 0;
135 do {
136 nr = 0;
137 radix_tree_for_each_slot(slot, root, &iter, index) {
138 indices[nr] = iter.index;
139 if (++nr == 16)
140 break;
141 }
142 for (i = 0; i < nr; i++) {
143 index = indices[i];
144 radix_tree_delete(root, index);
145 }
146 } while (nr > 0);
147}
148
149static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
150{
151 struct gmap_rmap *rmap, *rnext, *head;
152 struct radix_tree_iter iter;
153 unsigned long indices[16];
154 unsigned long index;
155 void __rcu **slot;
156 int i, nr;
157
158 /* A radix tree is freed by deleting all of its entries */
159 index = 0;
160 do {
161 nr = 0;
162 radix_tree_for_each_slot(slot, root, &iter, index) {
163 indices[nr] = iter.index;
164 if (++nr == 16)
165 break;
166 }
167 for (i = 0; i < nr; i++) {
168 index = indices[i];
169 head = radix_tree_delete(root, index);
170 gmap_for_each_rmap_safe(rmap, rnext, head)
171 kfree(rmap);
172 }
173 } while (nr > 0);
174}
175
176/**
177 * gmap_free - free a guest address space
178 * @gmap: pointer to the guest address space structure
179 *
180 * No locks required. There are no references to this gmap anymore.
181 */
182static void gmap_free(struct gmap *gmap)
183{
184 struct page *page, *next;
185
186 /* Flush tlb of all gmaps (if not already done for shadows) */
187 if (!(gmap_is_shadow(gmap) && gmap->removed))
188 gmap_flush_tlb(gmap);
189 /* Free all segment & region tables. */
190 list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
191 __free_pages(page, CRST_ALLOC_ORDER);
192 gmap_radix_tree_free(&gmap->guest_to_host);
193 gmap_radix_tree_free(&gmap->host_to_guest);
194
195 /* Free additional data for a shadow gmap */
196 if (gmap_is_shadow(gmap)) {
197 /* Free all page tables. */
198 list_for_each_entry_safe(page, next, &gmap->pt_list, lru)
199 page_table_free_pgste(page);
200 gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
201 /* Release reference to the parent */
202 gmap_put(gmap->parent);
203 }
204
205 kfree(gmap);
206}
207
208/**
209 * gmap_get - increase reference counter for guest address space
210 * @gmap: pointer to the guest address space structure
211 *
212 * Returns the gmap pointer
213 */
214struct gmap *gmap_get(struct gmap *gmap)
215{
216 refcount_inc(&gmap->ref_count);
217 return gmap;
218}
219EXPORT_SYMBOL_GPL(gmap_get);
220
221/**
222 * gmap_put - decrease reference counter for guest address space
223 * @gmap: pointer to the guest address space structure
224 *
225 * If the reference counter reaches zero the guest address space is freed.
226 */
227void gmap_put(struct gmap *gmap)
228{
229 if (refcount_dec_and_test(&gmap->ref_count))
230 gmap_free(gmap);
231}
232EXPORT_SYMBOL_GPL(gmap_put);
233
234/**
235 * gmap_remove - remove a guest address space but do not free it yet
236 * @gmap: pointer to the guest address space structure
237 */
238void gmap_remove(struct gmap *gmap)
239{
240 struct gmap *sg, *next;
241 unsigned long gmap_asce;
242
243 /* Remove all shadow gmaps linked to this gmap */
244 if (!list_empty(&gmap->children)) {
245 spin_lock(&gmap->shadow_lock);
246 list_for_each_entry_safe(sg, next, &gmap->children, list) {
247 list_del(&sg->list);
248 gmap_put(sg);
249 }
250 spin_unlock(&gmap->shadow_lock);
251 }
252 /* Remove gmap from the pre-mm list */
253 spin_lock(&gmap->mm->context.lock);
254 list_del_rcu(&gmap->list);
255 if (list_empty(&gmap->mm->context.gmap_list))
256 gmap_asce = 0;
257 else if (list_is_singular(&gmap->mm->context.gmap_list))
258 gmap_asce = list_first_entry(&gmap->mm->context.gmap_list,
259 struct gmap, list)->asce;
260 else
261 gmap_asce = -1UL;
262 WRITE_ONCE(gmap->mm->context.gmap_asce, gmap_asce);
263 spin_unlock(&gmap->mm->context.lock);
264 synchronize_rcu();
265 /* Put reference */
266 gmap_put(gmap);
267}
268EXPORT_SYMBOL_GPL(gmap_remove);
269
270/**
271 * gmap_enable - switch primary space to the guest address space
272 * @gmap: pointer to the guest address space structure
273 */
274void gmap_enable(struct gmap *gmap)
275{
276 S390_lowcore.gmap = (unsigned long) gmap;
277}
278EXPORT_SYMBOL_GPL(gmap_enable);
279
280/**
281 * gmap_disable - switch back to the standard primary address space
282 * @gmap: pointer to the guest address space structure
283 */
284void gmap_disable(struct gmap *gmap)
285{
286 S390_lowcore.gmap = 0UL;
287}
288EXPORT_SYMBOL_GPL(gmap_disable);
289
290/**
291 * gmap_get_enabled - get a pointer to the currently enabled gmap
292 *
293 * Returns a pointer to the currently enabled gmap. 0 if none is enabled.
294 */
295struct gmap *gmap_get_enabled(void)
296{
297 return (struct gmap *) S390_lowcore.gmap;
298}
299EXPORT_SYMBOL_GPL(gmap_get_enabled);
300
301/*
302 * gmap_alloc_table is assumed to be called with mmap_lock held
303 */
304static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
305 unsigned long init, unsigned long gaddr)
306{
307 struct page *page;
308 unsigned long *new;
309
310 /* since we dont free the gmap table until gmap_free we can unlock */
311 page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
312 if (!page)
313 return -ENOMEM;
314 new = page_to_virt(page);
315 crst_table_init(new, init);
316 spin_lock(&gmap->guest_table_lock);
317 if (*table & _REGION_ENTRY_INVALID) {
318 list_add(&page->lru, &gmap->crst_list);
319 *table = __pa(new) | _REGION_ENTRY_LENGTH |
320 (*table & _REGION_ENTRY_TYPE_MASK);
321 page->index = gaddr;
322 page = NULL;
323 }
324 spin_unlock(&gmap->guest_table_lock);
325 if (page)
326 __free_pages(page, CRST_ALLOC_ORDER);
327 return 0;
328}
329
330/**
331 * __gmap_segment_gaddr - find virtual address from segment pointer
332 * @entry: pointer to a segment table entry in the guest address space
333 *
334 * Returns the virtual address in the guest address space for the segment
335 */
336static unsigned long __gmap_segment_gaddr(unsigned long *entry)
337{
338 struct page *page;
339 unsigned long offset;
340
341 offset = (unsigned long) entry / sizeof(unsigned long);
342 offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
343 page = pmd_pgtable_page((pmd_t *) entry);
344 return page->index + offset;
345}
346
347/**
348 * __gmap_unlink_by_vmaddr - unlink a single segment via a host address
349 * @gmap: pointer to the guest address space structure
350 * @vmaddr: address in the host process address space
351 *
352 * Returns 1 if a TLB flush is required
353 */
354static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr)
355{
356 unsigned long *entry;
357 int flush = 0;
358
359 BUG_ON(gmap_is_shadow(gmap));
360 spin_lock(&gmap->guest_table_lock);
361 entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
362 if (entry) {
363 flush = (*entry != _SEGMENT_ENTRY_EMPTY);
364 *entry = _SEGMENT_ENTRY_EMPTY;
365 }
366 spin_unlock(&gmap->guest_table_lock);
367 return flush;
368}
369
370/**
371 * __gmap_unmap_by_gaddr - unmap a single segment via a guest address
372 * @gmap: pointer to the guest address space structure
373 * @gaddr: address in the guest address space
374 *
375 * Returns 1 if a TLB flush is required
376 */
377static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr)
378{
379 unsigned long vmaddr;
380
381 vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host,
382 gaddr >> PMD_SHIFT);
383 return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0;
384}
385
386/**
387 * gmap_unmap_segment - unmap segment from the guest address space
388 * @gmap: pointer to the guest address space structure
389 * @to: address in the guest address space
390 * @len: length of the memory area to unmap
391 *
392 * Returns 0 if the unmap succeeded, -EINVAL if not.
393 */
394int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
395{
396 unsigned long off;
397 int flush;
398
399 BUG_ON(gmap_is_shadow(gmap));
400 if ((to | len) & (PMD_SIZE - 1))
401 return -EINVAL;
402 if (len == 0 || to + len < to)
403 return -EINVAL;
404
405 flush = 0;
406 mmap_write_lock(gmap->mm);
407 for (off = 0; off < len; off += PMD_SIZE)
408 flush |= __gmap_unmap_by_gaddr(gmap, to + off);
409 mmap_write_unlock(gmap->mm);
410 if (flush)
411 gmap_flush_tlb(gmap);
412 return 0;
413}
414EXPORT_SYMBOL_GPL(gmap_unmap_segment);
415
416/**
417 * gmap_map_segment - map a segment to the guest address space
418 * @gmap: pointer to the guest address space structure
419 * @from: source address in the parent address space
420 * @to: target address in the guest address space
421 * @len: length of the memory area to map
422 *
423 * Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not.
424 */
425int gmap_map_segment(struct gmap *gmap, unsigned long from,
426 unsigned long to, unsigned long len)
427{
428 unsigned long off;
429 int flush;
430
431 BUG_ON(gmap_is_shadow(gmap));
432 if ((from | to | len) & (PMD_SIZE - 1))
433 return -EINVAL;
434 if (len == 0 || from + len < from || to + len < to ||
435 from + len - 1 > TASK_SIZE_MAX || to + len - 1 > gmap->asce_end)
436 return -EINVAL;
437
438 flush = 0;
439 mmap_write_lock(gmap->mm);
440 for (off = 0; off < len; off += PMD_SIZE) {
441 /* Remove old translation */
442 flush |= __gmap_unmap_by_gaddr(gmap, to + off);
443 /* Store new translation */
444 if (radix_tree_insert(&gmap->guest_to_host,
445 (to + off) >> PMD_SHIFT,
446 (void *) from + off))
447 break;
448 }
449 mmap_write_unlock(gmap->mm);
450 if (flush)
451 gmap_flush_tlb(gmap);
452 if (off >= len)
453 return 0;
454 gmap_unmap_segment(gmap, to, len);
455 return -ENOMEM;
456}
457EXPORT_SYMBOL_GPL(gmap_map_segment);
458
459/**
460 * __gmap_translate - translate a guest address to a user space address
461 * @gmap: pointer to guest mapping meta data structure
462 * @gaddr: guest address
463 *
464 * Returns user space address which corresponds to the guest address or
465 * -EFAULT if no such mapping exists.
466 * This function does not establish potentially missing page table entries.
467 * The mmap_lock of the mm that belongs to the address space must be held
468 * when this function gets called.
469 *
470 * Note: Can also be called for shadow gmaps.
471 */
472unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
473{
474 unsigned long vmaddr;
475
476 vmaddr = (unsigned long)
477 radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
478 /* Note: guest_to_host is empty for a shadow gmap */
479 return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
480}
481EXPORT_SYMBOL_GPL(__gmap_translate);
482
483/**
484 * gmap_translate - translate a guest address to a user space address
485 * @gmap: pointer to guest mapping meta data structure
486 * @gaddr: guest address
487 *
488 * Returns user space address which corresponds to the guest address or
489 * -EFAULT if no such mapping exists.
490 * This function does not establish potentially missing page table entries.
491 */
492unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr)
493{
494 unsigned long rc;
495
496 mmap_read_lock(gmap->mm);
497 rc = __gmap_translate(gmap, gaddr);
498 mmap_read_unlock(gmap->mm);
499 return rc;
500}
501EXPORT_SYMBOL_GPL(gmap_translate);
502
503/**
504 * gmap_unlink - disconnect a page table from the gmap shadow tables
505 * @mm: pointer to the parent mm_struct
506 * @table: pointer to the host page table
507 * @vmaddr: vm address associated with the host page table
508 */
509void gmap_unlink(struct mm_struct *mm, unsigned long *table,
510 unsigned long vmaddr)
511{
512 struct gmap *gmap;
513 int flush;
514
515 rcu_read_lock();
516 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
517 flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
518 if (flush)
519 gmap_flush_tlb(gmap);
520 }
521 rcu_read_unlock();
522}
523
524static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *old, pmd_t new,
525 unsigned long gaddr);
526
527/**
528 * __gmap_link - set up shadow page tables to connect a host to a guest address
529 * @gmap: pointer to guest mapping meta data structure
530 * @gaddr: guest address
531 * @vmaddr: vm address
532 *
533 * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
534 * if the vm address is already mapped to a different guest segment.
535 * The mmap_lock of the mm that belongs to the address space must be held
536 * when this function gets called.
537 */
538int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
539{
540 struct mm_struct *mm;
541 unsigned long *table;
542 spinlock_t *ptl;
543 pgd_t *pgd;
544 p4d_t *p4d;
545 pud_t *pud;
546 pmd_t *pmd;
547 u64 unprot;
548 int rc;
549
550 BUG_ON(gmap_is_shadow(gmap));
551 /* Create higher level tables in the gmap page table */
552 table = gmap->table;
553 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
554 table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
555 if ((*table & _REGION_ENTRY_INVALID) &&
556 gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
557 gaddr & _REGION1_MASK))
558 return -ENOMEM;
559 table = __va(*table & _REGION_ENTRY_ORIGIN);
560 }
561 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
562 table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
563 if ((*table & _REGION_ENTRY_INVALID) &&
564 gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
565 gaddr & _REGION2_MASK))
566 return -ENOMEM;
567 table = __va(*table & _REGION_ENTRY_ORIGIN);
568 }
569 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
570 table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
571 if ((*table & _REGION_ENTRY_INVALID) &&
572 gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
573 gaddr & _REGION3_MASK))
574 return -ENOMEM;
575 table = __va(*table & _REGION_ENTRY_ORIGIN);
576 }
577 table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
578 /* Walk the parent mm page table */
579 mm = gmap->mm;
580 pgd = pgd_offset(mm, vmaddr);
581 VM_BUG_ON(pgd_none(*pgd));
582 p4d = p4d_offset(pgd, vmaddr);
583 VM_BUG_ON(p4d_none(*p4d));
584 pud = pud_offset(p4d, vmaddr);
585 VM_BUG_ON(pud_none(*pud));
586 /* large puds cannot yet be handled */
587 if (pud_large(*pud))
588 return -EFAULT;
589 pmd = pmd_offset(pud, vmaddr);
590 VM_BUG_ON(pmd_none(*pmd));
591 /* Are we allowed to use huge pages? */
592 if (pmd_large(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m)
593 return -EFAULT;
594 /* Link gmap segment table entry location to page table. */
595 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
596 if (rc)
597 return rc;
598 ptl = pmd_lock(mm, pmd);
599 spin_lock(&gmap->guest_table_lock);
600 if (*table == _SEGMENT_ENTRY_EMPTY) {
601 rc = radix_tree_insert(&gmap->host_to_guest,
602 vmaddr >> PMD_SHIFT, table);
603 if (!rc) {
604 if (pmd_large(*pmd)) {
605 *table = (pmd_val(*pmd) &
606 _SEGMENT_ENTRY_HARDWARE_BITS_LARGE)
607 | _SEGMENT_ENTRY_GMAP_UC;
608 } else
609 *table = pmd_val(*pmd) &
610 _SEGMENT_ENTRY_HARDWARE_BITS;
611 }
612 } else if (*table & _SEGMENT_ENTRY_PROTECT &&
613 !(pmd_val(*pmd) & _SEGMENT_ENTRY_PROTECT)) {
614 unprot = (u64)*table;
615 unprot &= ~_SEGMENT_ENTRY_PROTECT;
616 unprot |= _SEGMENT_ENTRY_GMAP_UC;
617 gmap_pmdp_xchg(gmap, (pmd_t *)table, __pmd(unprot), gaddr);
618 }
619 spin_unlock(&gmap->guest_table_lock);
620 spin_unlock(ptl);
621 radix_tree_preload_end();
622 return rc;
623}
624
625/**
626 * gmap_fault - resolve a fault on a guest address
627 * @gmap: pointer to guest mapping meta data structure
628 * @gaddr: guest address
629 * @fault_flags: flags to pass down to handle_mm_fault()
630 *
631 * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
632 * if the vm address is already mapped to a different guest segment.
633 */
634int gmap_fault(struct gmap *gmap, unsigned long gaddr,
635 unsigned int fault_flags)
636{
637 unsigned long vmaddr;
638 int rc;
639 bool unlocked;
640
641 mmap_read_lock(gmap->mm);
642
643retry:
644 unlocked = false;
645 vmaddr = __gmap_translate(gmap, gaddr);
646 if (IS_ERR_VALUE(vmaddr)) {
647 rc = vmaddr;
648 goto out_up;
649 }
650 if (fixup_user_fault(gmap->mm, vmaddr, fault_flags,
651 &unlocked)) {
652 rc = -EFAULT;
653 goto out_up;
654 }
655 /*
656 * In the case that fixup_user_fault unlocked the mmap_lock during
657 * faultin redo __gmap_translate to not race with a map/unmap_segment.
658 */
659 if (unlocked)
660 goto retry;
661
662 rc = __gmap_link(gmap, gaddr, vmaddr);
663out_up:
664 mmap_read_unlock(gmap->mm);
665 return rc;
666}
667EXPORT_SYMBOL_GPL(gmap_fault);
668
669/*
670 * this function is assumed to be called with mmap_lock held
671 */
672void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
673{
674 struct vm_area_struct *vma;
675 unsigned long vmaddr;
676 spinlock_t *ptl;
677 pte_t *ptep;
678
679 /* Find the vm address for the guest address */
680 vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
681 gaddr >> PMD_SHIFT);
682 if (vmaddr) {
683 vmaddr |= gaddr & ~PMD_MASK;
684
685 vma = vma_lookup(gmap->mm, vmaddr);
686 if (!vma || is_vm_hugetlb_page(vma))
687 return;
688
689 /* Get pointer to the page table entry */
690 ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
691 if (likely(ptep)) {
692 ptep_zap_unused(gmap->mm, vmaddr, ptep, 0);
693 pte_unmap_unlock(ptep, ptl);
694 }
695 }
696}
697EXPORT_SYMBOL_GPL(__gmap_zap);
698
699void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
700{
701 unsigned long gaddr, vmaddr, size;
702 struct vm_area_struct *vma;
703
704 mmap_read_lock(gmap->mm);
705 for (gaddr = from; gaddr < to;
706 gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
707 /* Find the vm address for the guest address */
708 vmaddr = (unsigned long)
709 radix_tree_lookup(&gmap->guest_to_host,
710 gaddr >> PMD_SHIFT);
711 if (!vmaddr)
712 continue;
713 vmaddr |= gaddr & ~PMD_MASK;
714 /* Find vma in the parent mm */
715 vma = find_vma(gmap->mm, vmaddr);
716 if (!vma)
717 continue;
718 /*
719 * We do not discard pages that are backed by
720 * hugetlbfs, so we don't have to refault them.
721 */
722 if (is_vm_hugetlb_page(vma))
723 continue;
724 size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
725 zap_page_range(vma, vmaddr, size);
726 }
727 mmap_read_unlock(gmap->mm);
728}
729EXPORT_SYMBOL_GPL(gmap_discard);
730
731static LIST_HEAD(gmap_notifier_list);
732static DEFINE_SPINLOCK(gmap_notifier_lock);
733
734/**
735 * gmap_register_pte_notifier - register a pte invalidation callback
736 * @nb: pointer to the gmap notifier block
737 */
738void gmap_register_pte_notifier(struct gmap_notifier *nb)
739{
740 spin_lock(&gmap_notifier_lock);
741 list_add_rcu(&nb->list, &gmap_notifier_list);
742 spin_unlock(&gmap_notifier_lock);
743}
744EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
745
746/**
747 * gmap_unregister_pte_notifier - remove a pte invalidation callback
748 * @nb: pointer to the gmap notifier block
749 */
750void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
751{
752 spin_lock(&gmap_notifier_lock);
753 list_del_rcu(&nb->list);
754 spin_unlock(&gmap_notifier_lock);
755 synchronize_rcu();
756}
757EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
758
759/**
760 * gmap_call_notifier - call all registered invalidation callbacks
761 * @gmap: pointer to guest mapping meta data structure
762 * @start: start virtual address in the guest address space
763 * @end: end virtual address in the guest address space
764 */
765static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
766 unsigned long end)
767{
768 struct gmap_notifier *nb;
769
770 list_for_each_entry(nb, &gmap_notifier_list, list)
771 nb->notifier_call(gmap, start, end);
772}
773
774/**
775 * gmap_table_walk - walk the gmap page tables
776 * @gmap: pointer to guest mapping meta data structure
777 * @gaddr: virtual address in the guest address space
778 * @level: page table level to stop at
779 *
780 * Returns a table entry pointer for the given guest address and @level
781 * @level=0 : returns a pointer to a page table table entry (or NULL)
782 * @level=1 : returns a pointer to a segment table entry (or NULL)
783 * @level=2 : returns a pointer to a region-3 table entry (or NULL)
784 * @level=3 : returns a pointer to a region-2 table entry (or NULL)
785 * @level=4 : returns a pointer to a region-1 table entry (or NULL)
786 *
787 * Returns NULL if the gmap page tables could not be walked to the
788 * requested level.
789 *
790 * Note: Can also be called for shadow gmaps.
791 */
792static inline unsigned long *gmap_table_walk(struct gmap *gmap,
793 unsigned long gaddr, int level)
794{
795 const int asce_type = gmap->asce & _ASCE_TYPE_MASK;
796 unsigned long *table = gmap->table;
797
798 if (gmap_is_shadow(gmap) && gmap->removed)
799 return NULL;
800
801 if (WARN_ON_ONCE(level > (asce_type >> 2) + 1))
802 return NULL;
803
804 if (asce_type != _ASCE_TYPE_REGION1 &&
805 gaddr & (-1UL << (31 + (asce_type >> 2) * 11)))
806 return NULL;
807
808 switch (asce_type) {
809 case _ASCE_TYPE_REGION1:
810 table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
811 if (level == 4)
812 break;
813 if (*table & _REGION_ENTRY_INVALID)
814 return NULL;
815 table = __va(*table & _REGION_ENTRY_ORIGIN);
816 fallthrough;
817 case _ASCE_TYPE_REGION2:
818 table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
819 if (level == 3)
820 break;
821 if (*table & _REGION_ENTRY_INVALID)
822 return NULL;
823 table = __va(*table & _REGION_ENTRY_ORIGIN);
824 fallthrough;
825 case _ASCE_TYPE_REGION3:
826 table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
827 if (level == 2)
828 break;
829 if (*table & _REGION_ENTRY_INVALID)
830 return NULL;
831 table = __va(*table & _REGION_ENTRY_ORIGIN);
832 fallthrough;
833 case _ASCE_TYPE_SEGMENT:
834 table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
835 if (level == 1)
836 break;
837 if (*table & _REGION_ENTRY_INVALID)
838 return NULL;
839 table = __va(*table & _SEGMENT_ENTRY_ORIGIN);
840 table += (gaddr & _PAGE_INDEX) >> _PAGE_SHIFT;
841 }
842 return table;
843}
844
845/**
846 * gmap_pte_op_walk - walk the gmap page table, get the page table lock
847 * and return the pte pointer
848 * @gmap: pointer to guest mapping meta data structure
849 * @gaddr: virtual address in the guest address space
850 * @ptl: pointer to the spinlock pointer
851 *
852 * Returns a pointer to the locked pte for a guest address, or NULL
853 */
854static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
855 spinlock_t **ptl)
856{
857 unsigned long *table;
858
859 BUG_ON(gmap_is_shadow(gmap));
860 /* Walk the gmap page table, lock and get pte pointer */
861 table = gmap_table_walk(gmap, gaddr, 1); /* get segment pointer */
862 if (!table || *table & _SEGMENT_ENTRY_INVALID)
863 return NULL;
864 return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl);
865}
866
867/**
868 * gmap_pte_op_fixup - force a page in and connect the gmap page table
869 * @gmap: pointer to guest mapping meta data structure
870 * @gaddr: virtual address in the guest address space
871 * @vmaddr: address in the host process address space
872 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
873 *
874 * Returns 0 if the caller can retry __gmap_translate (might fail again),
875 * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing
876 * up or connecting the gmap page table.
877 */
878static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
879 unsigned long vmaddr, int prot)
880{
881 struct mm_struct *mm = gmap->mm;
882 unsigned int fault_flags;
883 bool unlocked = false;
884
885 BUG_ON(gmap_is_shadow(gmap));
886 fault_flags = (prot == PROT_WRITE) ? FAULT_FLAG_WRITE : 0;
887 if (fixup_user_fault(mm, vmaddr, fault_flags, &unlocked))
888 return -EFAULT;
889 if (unlocked)
890 /* lost mmap_lock, caller has to retry __gmap_translate */
891 return 0;
892 /* Connect the page tables */
893 return __gmap_link(gmap, gaddr, vmaddr);
894}
895
896/**
897 * gmap_pte_op_end - release the page table lock
898 * @ptl: pointer to the spinlock pointer
899 */
900static void gmap_pte_op_end(spinlock_t *ptl)
901{
902 if (ptl)
903 spin_unlock(ptl);
904}
905
906/**
907 * gmap_pmd_op_walk - walk the gmap tables, get the guest table lock
908 * and return the pmd pointer
909 * @gmap: pointer to guest mapping meta data structure
910 * @gaddr: virtual address in the guest address space
911 *
912 * Returns a pointer to the pmd for a guest address, or NULL
913 */
914static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr)
915{
916 pmd_t *pmdp;
917
918 BUG_ON(gmap_is_shadow(gmap));
919 pmdp = (pmd_t *) gmap_table_walk(gmap, gaddr, 1);
920 if (!pmdp)
921 return NULL;
922
923 /* without huge pages, there is no need to take the table lock */
924 if (!gmap->mm->context.allow_gmap_hpage_1m)
925 return pmd_none(*pmdp) ? NULL : pmdp;
926
927 spin_lock(&gmap->guest_table_lock);
928 if (pmd_none(*pmdp)) {
929 spin_unlock(&gmap->guest_table_lock);
930 return NULL;
931 }
932
933 /* 4k page table entries are locked via the pte (pte_alloc_map_lock). */
934 if (!pmd_large(*pmdp))
935 spin_unlock(&gmap->guest_table_lock);
936 return pmdp;
937}
938
939/**
940 * gmap_pmd_op_end - release the guest_table_lock if needed
941 * @gmap: pointer to the guest mapping meta data structure
942 * @pmdp: pointer to the pmd
943 */
944static inline void gmap_pmd_op_end(struct gmap *gmap, pmd_t *pmdp)
945{
946 if (pmd_large(*pmdp))
947 spin_unlock(&gmap->guest_table_lock);
948}
949
950/*
951 * gmap_protect_pmd - remove access rights to memory and set pmd notification bits
952 * @pmdp: pointer to the pmd to be protected
953 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
954 * @bits: notification bits to set
955 *
956 * Returns:
957 * 0 if successfully protected
958 * -EAGAIN if a fixup is needed
959 * -EINVAL if unsupported notifier bits have been specified
960 *
961 * Expected to be called with sg->mm->mmap_lock in read and
962 * guest_table_lock held.
963 */
964static int gmap_protect_pmd(struct gmap *gmap, unsigned long gaddr,
965 pmd_t *pmdp, int prot, unsigned long bits)
966{
967 int pmd_i = pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID;
968 int pmd_p = pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT;
969 pmd_t new = *pmdp;
970
971 /* Fixup needed */
972 if ((pmd_i && (prot != PROT_NONE)) || (pmd_p && (prot == PROT_WRITE)))
973 return -EAGAIN;
974
975 if (prot == PROT_NONE && !pmd_i) {
976 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
977 gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
978 }
979
980 if (prot == PROT_READ && !pmd_p) {
981 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
982 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_PROTECT));
983 gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
984 }
985
986 if (bits & GMAP_NOTIFY_MPROT)
987 set_pmd(pmdp, set_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN)));
988
989 /* Shadow GMAP protection needs split PMDs */
990 if (bits & GMAP_NOTIFY_SHADOW)
991 return -EINVAL;
992
993 return 0;
994}
995
996/*
997 * gmap_protect_pte - remove access rights to memory and set pgste bits
998 * @gmap: pointer to guest mapping meta data structure
999 * @gaddr: virtual address in the guest address space
1000 * @pmdp: pointer to the pmd associated with the pte
1001 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1002 * @bits: notification bits to set
1003 *
1004 * Returns 0 if successfully protected, -ENOMEM if out of memory and
1005 * -EAGAIN if a fixup is needed.
1006 *
1007 * Expected to be called with sg->mm->mmap_lock in read
1008 */
1009static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
1010 pmd_t *pmdp, int prot, unsigned long bits)
1011{
1012 int rc;
1013 pte_t *ptep;
1014 spinlock_t *ptl = NULL;
1015 unsigned long pbits = 0;
1016
1017 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
1018 return -EAGAIN;
1019
1020 ptep = pte_alloc_map_lock(gmap->mm, pmdp, gaddr, &ptl);
1021 if (!ptep)
1022 return -ENOMEM;
1023
1024 pbits |= (bits & GMAP_NOTIFY_MPROT) ? PGSTE_IN_BIT : 0;
1025 pbits |= (bits & GMAP_NOTIFY_SHADOW) ? PGSTE_VSIE_BIT : 0;
1026 /* Protect and unlock. */
1027 rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits);
1028 gmap_pte_op_end(ptl);
1029 return rc;
1030}
1031
1032/*
1033 * gmap_protect_range - remove access rights to memory and set pgste bits
1034 * @gmap: pointer to guest mapping meta data structure
1035 * @gaddr: virtual address in the guest address space
1036 * @len: size of area
1037 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1038 * @bits: pgste notification bits to set
1039 *
1040 * Returns 0 if successfully protected, -ENOMEM if out of memory and
1041 * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
1042 *
1043 * Called with sg->mm->mmap_lock in read.
1044 */
1045static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
1046 unsigned long len, int prot, unsigned long bits)
1047{
1048 unsigned long vmaddr, dist;
1049 pmd_t *pmdp;
1050 int rc;
1051
1052 BUG_ON(gmap_is_shadow(gmap));
1053 while (len) {
1054 rc = -EAGAIN;
1055 pmdp = gmap_pmd_op_walk(gmap, gaddr);
1056 if (pmdp) {
1057 if (!pmd_large(*pmdp)) {
1058 rc = gmap_protect_pte(gmap, gaddr, pmdp, prot,
1059 bits);
1060 if (!rc) {
1061 len -= PAGE_SIZE;
1062 gaddr += PAGE_SIZE;
1063 }
1064 } else {
1065 rc = gmap_protect_pmd(gmap, gaddr, pmdp, prot,
1066 bits);
1067 if (!rc) {
1068 dist = HPAGE_SIZE - (gaddr & ~HPAGE_MASK);
1069 len = len < dist ? 0 : len - dist;
1070 gaddr = (gaddr & HPAGE_MASK) + HPAGE_SIZE;
1071 }
1072 }
1073 gmap_pmd_op_end(gmap, pmdp);
1074 }
1075 if (rc) {
1076 if (rc == -EINVAL)
1077 return rc;
1078
1079 /* -EAGAIN, fixup of userspace mm and gmap */
1080 vmaddr = __gmap_translate(gmap, gaddr);
1081 if (IS_ERR_VALUE(vmaddr))
1082 return vmaddr;
1083 rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot);
1084 if (rc)
1085 return rc;
1086 }
1087 }
1088 return 0;
1089}
1090
1091/**
1092 * gmap_mprotect_notify - change access rights for a range of ptes and
1093 * call the notifier if any pte changes again
1094 * @gmap: pointer to guest mapping meta data structure
1095 * @gaddr: virtual address in the guest address space
1096 * @len: size of area
1097 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1098 *
1099 * Returns 0 if for each page in the given range a gmap mapping exists,
1100 * the new access rights could be set and the notifier could be armed.
1101 * If the gmap mapping is missing for one or more pages -EFAULT is
1102 * returned. If no memory could be allocated -ENOMEM is returned.
1103 * This function establishes missing page table entries.
1104 */
1105int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
1106 unsigned long len, int prot)
1107{
1108 int rc;
1109
1110 if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
1111 return -EINVAL;
1112 if (!MACHINE_HAS_ESOP && prot == PROT_READ)
1113 return -EINVAL;
1114 mmap_read_lock(gmap->mm);
1115 rc = gmap_protect_range(gmap, gaddr, len, prot, GMAP_NOTIFY_MPROT);
1116 mmap_read_unlock(gmap->mm);
1117 return rc;
1118}
1119EXPORT_SYMBOL_GPL(gmap_mprotect_notify);
1120
1121/**
1122 * gmap_read_table - get an unsigned long value from a guest page table using
1123 * absolute addressing, without marking the page referenced.
1124 * @gmap: pointer to guest mapping meta data structure
1125 * @gaddr: virtual address in the guest address space
1126 * @val: pointer to the unsigned long value to return
1127 *
1128 * Returns 0 if the value was read, -ENOMEM if out of memory and -EFAULT
1129 * if reading using the virtual address failed. -EINVAL if called on a gmap
1130 * shadow.
1131 *
1132 * Called with gmap->mm->mmap_lock in read.
1133 */
1134int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
1135{
1136 unsigned long address, vmaddr;
1137 spinlock_t *ptl;
1138 pte_t *ptep, pte;
1139 int rc;
1140
1141 if (gmap_is_shadow(gmap))
1142 return -EINVAL;
1143
1144 while (1) {
1145 rc = -EAGAIN;
1146 ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
1147 if (ptep) {
1148 pte = *ptep;
1149 if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) {
1150 address = pte_val(pte) & PAGE_MASK;
1151 address += gaddr & ~PAGE_MASK;
1152 *val = *(unsigned long *)__va(address);
1153 set_pte(ptep, set_pte_bit(*ptep, __pgprot(_PAGE_YOUNG)));
1154 /* Do *NOT* clear the _PAGE_INVALID bit! */
1155 rc = 0;
1156 }
1157 gmap_pte_op_end(ptl);
1158 }
1159 if (!rc)
1160 break;
1161 vmaddr = __gmap_translate(gmap, gaddr);
1162 if (IS_ERR_VALUE(vmaddr)) {
1163 rc = vmaddr;
1164 break;
1165 }
1166 rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, PROT_READ);
1167 if (rc)
1168 break;
1169 }
1170 return rc;
1171}
1172EXPORT_SYMBOL_GPL(gmap_read_table);
1173
1174/**
1175 * gmap_insert_rmap - add a rmap to the host_to_rmap radix tree
1176 * @sg: pointer to the shadow guest address space structure
1177 * @vmaddr: vm address associated with the rmap
1178 * @rmap: pointer to the rmap structure
1179 *
1180 * Called with the sg->guest_table_lock
1181 */
1182static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
1183 struct gmap_rmap *rmap)
1184{
1185 struct gmap_rmap *temp;
1186 void __rcu **slot;
1187
1188 BUG_ON(!gmap_is_shadow(sg));
1189 slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
1190 if (slot) {
1191 rmap->next = radix_tree_deref_slot_protected(slot,
1192 &sg->guest_table_lock);
1193 for (temp = rmap->next; temp; temp = temp->next) {
1194 if (temp->raddr == rmap->raddr) {
1195 kfree(rmap);
1196 return;
1197 }
1198 }
1199 radix_tree_replace_slot(&sg->host_to_rmap, slot, rmap);
1200 } else {
1201 rmap->next = NULL;
1202 radix_tree_insert(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT,
1203 rmap);
1204 }
1205}
1206
1207/**
1208 * gmap_protect_rmap - restrict access rights to memory (RO) and create an rmap
1209 * @sg: pointer to the shadow guest address space structure
1210 * @raddr: rmap address in the shadow gmap
1211 * @paddr: address in the parent guest address space
1212 * @len: length of the memory area to protect
1213 *
1214 * Returns 0 if successfully protected and the rmap was created, -ENOMEM
1215 * if out of memory and -EFAULT if paddr is invalid.
1216 */
1217static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
1218 unsigned long paddr, unsigned long len)
1219{
1220 struct gmap *parent;
1221 struct gmap_rmap *rmap;
1222 unsigned long vmaddr;
1223 spinlock_t *ptl;
1224 pte_t *ptep;
1225 int rc;
1226
1227 BUG_ON(!gmap_is_shadow(sg));
1228 parent = sg->parent;
1229 while (len) {
1230 vmaddr = __gmap_translate(parent, paddr);
1231 if (IS_ERR_VALUE(vmaddr))
1232 return vmaddr;
1233 rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT);
1234 if (!rmap)
1235 return -ENOMEM;
1236 rmap->raddr = raddr;
1237 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
1238 if (rc) {
1239 kfree(rmap);
1240 return rc;
1241 }
1242 rc = -EAGAIN;
1243 ptep = gmap_pte_op_walk(parent, paddr, &ptl);
1244 if (ptep) {
1245 spin_lock(&sg->guest_table_lock);
1246 rc = ptep_force_prot(parent->mm, paddr, ptep, PROT_READ,
1247 PGSTE_VSIE_BIT);
1248 if (!rc)
1249 gmap_insert_rmap(sg, vmaddr, rmap);
1250 spin_unlock(&sg->guest_table_lock);
1251 gmap_pte_op_end(ptl);
1252 }
1253 radix_tree_preload_end();
1254 if (rc) {
1255 kfree(rmap);
1256 rc = gmap_pte_op_fixup(parent, paddr, vmaddr, PROT_READ);
1257 if (rc)
1258 return rc;
1259 continue;
1260 }
1261 paddr += PAGE_SIZE;
1262 len -= PAGE_SIZE;
1263 }
1264 return 0;
1265}
1266
1267#define _SHADOW_RMAP_MASK 0x7
1268#define _SHADOW_RMAP_REGION1 0x5
1269#define _SHADOW_RMAP_REGION2 0x4
1270#define _SHADOW_RMAP_REGION3 0x3
1271#define _SHADOW_RMAP_SEGMENT 0x2
1272#define _SHADOW_RMAP_PGTABLE 0x1
1273
1274/**
1275 * gmap_idte_one - invalidate a single region or segment table entry
1276 * @asce: region or segment table *origin* + table-type bits
1277 * @vaddr: virtual address to identify the table entry to flush
1278 *
1279 * The invalid bit of a single region or segment table entry is set
1280 * and the associated TLB entries depending on the entry are flushed.
1281 * The table-type of the @asce identifies the portion of the @vaddr
1282 * that is used as the invalidation index.
1283 */
1284static inline void gmap_idte_one(unsigned long asce, unsigned long vaddr)
1285{
1286 asm volatile(
1287 " idte %0,0,%1"
1288 : : "a" (asce), "a" (vaddr) : "cc", "memory");
1289}
1290
1291/**
1292 * gmap_unshadow_page - remove a page from a shadow page table
1293 * @sg: pointer to the shadow guest address space structure
1294 * @raddr: rmap address in the shadow guest address space
1295 *
1296 * Called with the sg->guest_table_lock
1297 */
1298static void gmap_unshadow_page(struct gmap *sg, unsigned long raddr)
1299{
1300 unsigned long *table;
1301
1302 BUG_ON(!gmap_is_shadow(sg));
1303 table = gmap_table_walk(sg, raddr, 0); /* get page table pointer */
1304 if (!table || *table & _PAGE_INVALID)
1305 return;
1306 gmap_call_notifier(sg, raddr, raddr + _PAGE_SIZE - 1);
1307 ptep_unshadow_pte(sg->mm, raddr, (pte_t *) table);
1308}
1309
1310/**
1311 * __gmap_unshadow_pgt - remove all entries from a shadow page table
1312 * @sg: pointer to the shadow guest address space structure
1313 * @raddr: rmap address in the shadow guest address space
1314 * @pgt: pointer to the start of a shadow page table
1315 *
1316 * Called with the sg->guest_table_lock
1317 */
1318static void __gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr,
1319 unsigned long *pgt)
1320{
1321 int i;
1322
1323 BUG_ON(!gmap_is_shadow(sg));
1324 for (i = 0; i < _PAGE_ENTRIES; i++, raddr += _PAGE_SIZE)
1325 pgt[i] = _PAGE_INVALID;
1326}
1327
1328/**
1329 * gmap_unshadow_pgt - remove a shadow page table from a segment entry
1330 * @sg: pointer to the shadow guest address space structure
1331 * @raddr: address in the shadow guest address space
1332 *
1333 * Called with the sg->guest_table_lock
1334 */
1335static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
1336{
1337 unsigned long *ste;
1338 phys_addr_t sto, pgt;
1339 struct page *page;
1340
1341 BUG_ON(!gmap_is_shadow(sg));
1342 ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */
1343 if (!ste || !(*ste & _SEGMENT_ENTRY_ORIGIN))
1344 return;
1345 gmap_call_notifier(sg, raddr, raddr + _SEGMENT_SIZE - 1);
1346 sto = __pa(ste - ((raddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT));
1347 gmap_idte_one(sto | _ASCE_TYPE_SEGMENT, raddr);
1348 pgt = *ste & _SEGMENT_ENTRY_ORIGIN;
1349 *ste = _SEGMENT_ENTRY_EMPTY;
1350 __gmap_unshadow_pgt(sg, raddr, __va(pgt));
1351 /* Free page table */
1352 page = phys_to_page(pgt);
1353 list_del(&page->lru);
1354 page_table_free_pgste(page);
1355}
1356
1357/**
1358 * __gmap_unshadow_sgt - remove all entries from a shadow segment table
1359 * @sg: pointer to the shadow guest address space structure
1360 * @raddr: rmap address in the shadow guest address space
1361 * @sgt: pointer to the start of a shadow segment table
1362 *
1363 * Called with the sg->guest_table_lock
1364 */
1365static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
1366 unsigned long *sgt)
1367{
1368 struct page *page;
1369 phys_addr_t pgt;
1370 int i;
1371
1372 BUG_ON(!gmap_is_shadow(sg));
1373 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _SEGMENT_SIZE) {
1374 if (!(sgt[i] & _SEGMENT_ENTRY_ORIGIN))
1375 continue;
1376 pgt = sgt[i] & _REGION_ENTRY_ORIGIN;
1377 sgt[i] = _SEGMENT_ENTRY_EMPTY;
1378 __gmap_unshadow_pgt(sg, raddr, __va(pgt));
1379 /* Free page table */
1380 page = phys_to_page(pgt);
1381 list_del(&page->lru);
1382 page_table_free_pgste(page);
1383 }
1384}
1385
1386/**
1387 * gmap_unshadow_sgt - remove a shadow segment table from a region-3 entry
1388 * @sg: pointer to the shadow guest address space structure
1389 * @raddr: rmap address in the shadow guest address space
1390 *
1391 * Called with the shadow->guest_table_lock
1392 */
1393static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
1394{
1395 unsigned long r3o, *r3e;
1396 phys_addr_t sgt;
1397 struct page *page;
1398
1399 BUG_ON(!gmap_is_shadow(sg));
1400 r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
1401 if (!r3e || !(*r3e & _REGION_ENTRY_ORIGIN))
1402 return;
1403 gmap_call_notifier(sg, raddr, raddr + _REGION3_SIZE - 1);
1404 r3o = (unsigned long) (r3e - ((raddr & _REGION3_INDEX) >> _REGION3_SHIFT));
1405 gmap_idte_one(__pa(r3o) | _ASCE_TYPE_REGION3, raddr);
1406 sgt = *r3e & _REGION_ENTRY_ORIGIN;
1407 *r3e = _REGION3_ENTRY_EMPTY;
1408 __gmap_unshadow_sgt(sg, raddr, __va(sgt));
1409 /* Free segment table */
1410 page = phys_to_page(sgt);
1411 list_del(&page->lru);
1412 __free_pages(page, CRST_ALLOC_ORDER);
1413}
1414
1415/**
1416 * __gmap_unshadow_r3t - remove all entries from a shadow region-3 table
1417 * @sg: pointer to the shadow guest address space structure
1418 * @raddr: address in the shadow guest address space
1419 * @r3t: pointer to the start of a shadow region-3 table
1420 *
1421 * Called with the sg->guest_table_lock
1422 */
1423static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
1424 unsigned long *r3t)
1425{
1426 struct page *page;
1427 phys_addr_t sgt;
1428 int i;
1429
1430 BUG_ON(!gmap_is_shadow(sg));
1431 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION3_SIZE) {
1432 if (!(r3t[i] & _REGION_ENTRY_ORIGIN))
1433 continue;
1434 sgt = r3t[i] & _REGION_ENTRY_ORIGIN;
1435 r3t[i] = _REGION3_ENTRY_EMPTY;
1436 __gmap_unshadow_sgt(sg, raddr, __va(sgt));
1437 /* Free segment table */
1438 page = phys_to_page(sgt);
1439 list_del(&page->lru);
1440 __free_pages(page, CRST_ALLOC_ORDER);
1441 }
1442}
1443
1444/**
1445 * gmap_unshadow_r3t - remove a shadow region-3 table from a region-2 entry
1446 * @sg: pointer to the shadow guest address space structure
1447 * @raddr: rmap address in the shadow guest address space
1448 *
1449 * Called with the sg->guest_table_lock
1450 */
1451static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
1452{
1453 unsigned long r2o, *r2e;
1454 phys_addr_t r3t;
1455 struct page *page;
1456
1457 BUG_ON(!gmap_is_shadow(sg));
1458 r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
1459 if (!r2e || !(*r2e & _REGION_ENTRY_ORIGIN))
1460 return;
1461 gmap_call_notifier(sg, raddr, raddr + _REGION2_SIZE - 1);
1462 r2o = (unsigned long) (r2e - ((raddr & _REGION2_INDEX) >> _REGION2_SHIFT));
1463 gmap_idte_one(__pa(r2o) | _ASCE_TYPE_REGION2, raddr);
1464 r3t = *r2e & _REGION_ENTRY_ORIGIN;
1465 *r2e = _REGION2_ENTRY_EMPTY;
1466 __gmap_unshadow_r3t(sg, raddr, __va(r3t));
1467 /* Free region 3 table */
1468 page = phys_to_page(r3t);
1469 list_del(&page->lru);
1470 __free_pages(page, CRST_ALLOC_ORDER);
1471}
1472
1473/**
1474 * __gmap_unshadow_r2t - remove all entries from a shadow region-2 table
1475 * @sg: pointer to the shadow guest address space structure
1476 * @raddr: rmap address in the shadow guest address space
1477 * @r2t: pointer to the start of a shadow region-2 table
1478 *
1479 * Called with the sg->guest_table_lock
1480 */
1481static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
1482 unsigned long *r2t)
1483{
1484 phys_addr_t r3t;
1485 struct page *page;
1486 int i;
1487
1488 BUG_ON(!gmap_is_shadow(sg));
1489 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION2_SIZE) {
1490 if (!(r2t[i] & _REGION_ENTRY_ORIGIN))
1491 continue;
1492 r3t = r2t[i] & _REGION_ENTRY_ORIGIN;
1493 r2t[i] = _REGION2_ENTRY_EMPTY;
1494 __gmap_unshadow_r3t(sg, raddr, __va(r3t));
1495 /* Free region 3 table */
1496 page = phys_to_page(r3t);
1497 list_del(&page->lru);
1498 __free_pages(page, CRST_ALLOC_ORDER);
1499 }
1500}
1501
1502/**
1503 * gmap_unshadow_r2t - remove a shadow region-2 table from a region-1 entry
1504 * @sg: pointer to the shadow guest address space structure
1505 * @raddr: rmap address in the shadow guest address space
1506 *
1507 * Called with the sg->guest_table_lock
1508 */
1509static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
1510{
1511 unsigned long r1o, *r1e;
1512 struct page *page;
1513 phys_addr_t r2t;
1514
1515 BUG_ON(!gmap_is_shadow(sg));
1516 r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */
1517 if (!r1e || !(*r1e & _REGION_ENTRY_ORIGIN))
1518 return;
1519 gmap_call_notifier(sg, raddr, raddr + _REGION1_SIZE - 1);
1520 r1o = (unsigned long) (r1e - ((raddr & _REGION1_INDEX) >> _REGION1_SHIFT));
1521 gmap_idte_one(__pa(r1o) | _ASCE_TYPE_REGION1, raddr);
1522 r2t = *r1e & _REGION_ENTRY_ORIGIN;
1523 *r1e = _REGION1_ENTRY_EMPTY;
1524 __gmap_unshadow_r2t(sg, raddr, __va(r2t));
1525 /* Free region 2 table */
1526 page = phys_to_page(r2t);
1527 list_del(&page->lru);
1528 __free_pages(page, CRST_ALLOC_ORDER);
1529}
1530
1531/**
1532 * __gmap_unshadow_r1t - remove all entries from a shadow region-1 table
1533 * @sg: pointer to the shadow guest address space structure
1534 * @raddr: rmap address in the shadow guest address space
1535 * @r1t: pointer to the start of a shadow region-1 table
1536 *
1537 * Called with the shadow->guest_table_lock
1538 */
1539static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
1540 unsigned long *r1t)
1541{
1542 unsigned long asce;
1543 struct page *page;
1544 phys_addr_t r2t;
1545 int i;
1546
1547 BUG_ON(!gmap_is_shadow(sg));
1548 asce = __pa(r1t) | _ASCE_TYPE_REGION1;
1549 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION1_SIZE) {
1550 if (!(r1t[i] & _REGION_ENTRY_ORIGIN))
1551 continue;
1552 r2t = r1t[i] & _REGION_ENTRY_ORIGIN;
1553 __gmap_unshadow_r2t(sg, raddr, __va(r2t));
1554 /* Clear entry and flush translation r1t -> r2t */
1555 gmap_idte_one(asce, raddr);
1556 r1t[i] = _REGION1_ENTRY_EMPTY;
1557 /* Free region 2 table */
1558 page = phys_to_page(r2t);
1559 list_del(&page->lru);
1560 __free_pages(page, CRST_ALLOC_ORDER);
1561 }
1562}
1563
1564/**
1565 * gmap_unshadow - remove a shadow page table completely
1566 * @sg: pointer to the shadow guest address space structure
1567 *
1568 * Called with sg->guest_table_lock
1569 */
1570static void gmap_unshadow(struct gmap *sg)
1571{
1572 unsigned long *table;
1573
1574 BUG_ON(!gmap_is_shadow(sg));
1575 if (sg->removed)
1576 return;
1577 sg->removed = 1;
1578 gmap_call_notifier(sg, 0, -1UL);
1579 gmap_flush_tlb(sg);
1580 table = __va(sg->asce & _ASCE_ORIGIN);
1581 switch (sg->asce & _ASCE_TYPE_MASK) {
1582 case _ASCE_TYPE_REGION1:
1583 __gmap_unshadow_r1t(sg, 0, table);
1584 break;
1585 case _ASCE_TYPE_REGION2:
1586 __gmap_unshadow_r2t(sg, 0, table);
1587 break;
1588 case _ASCE_TYPE_REGION3:
1589 __gmap_unshadow_r3t(sg, 0, table);
1590 break;
1591 case _ASCE_TYPE_SEGMENT:
1592 __gmap_unshadow_sgt(sg, 0, table);
1593 break;
1594 }
1595}
1596
1597/**
1598 * gmap_find_shadow - find a specific asce in the list of shadow tables
1599 * @parent: pointer to the parent gmap
1600 * @asce: ASCE for which the shadow table is created
1601 * @edat_level: edat level to be used for the shadow translation
1602 *
1603 * Returns the pointer to a gmap if a shadow table with the given asce is
1604 * already available, ERR_PTR(-EAGAIN) if another one is just being created,
1605 * otherwise NULL
1606 */
1607static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce,
1608 int edat_level)
1609{
1610 struct gmap *sg;
1611
1612 list_for_each_entry(sg, &parent->children, list) {
1613 if (sg->orig_asce != asce || sg->edat_level != edat_level ||
1614 sg->removed)
1615 continue;
1616 if (!sg->initialized)
1617 return ERR_PTR(-EAGAIN);
1618 refcount_inc(&sg->ref_count);
1619 return sg;
1620 }
1621 return NULL;
1622}
1623
1624/**
1625 * gmap_shadow_valid - check if a shadow guest address space matches the
1626 * given properties and is still valid
1627 * @sg: pointer to the shadow guest address space structure
1628 * @asce: ASCE for which the shadow table is requested
1629 * @edat_level: edat level to be used for the shadow translation
1630 *
1631 * Returns 1 if the gmap shadow is still valid and matches the given
1632 * properties, the caller can continue using it. Returns 0 otherwise, the
1633 * caller has to request a new shadow gmap in this case.
1634 *
1635 */
1636int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)
1637{
1638 if (sg->removed)
1639 return 0;
1640 return sg->orig_asce == asce && sg->edat_level == edat_level;
1641}
1642EXPORT_SYMBOL_GPL(gmap_shadow_valid);
1643
1644/**
1645 * gmap_shadow - create/find a shadow guest address space
1646 * @parent: pointer to the parent gmap
1647 * @asce: ASCE for which the shadow table is created
1648 * @edat_level: edat level to be used for the shadow translation
1649 *
1650 * The pages of the top level page table referred by the asce parameter
1651 * will be set to read-only and marked in the PGSTEs of the kvm process.
1652 * The shadow table will be removed automatically on any change to the
1653 * PTE mapping for the source table.
1654 *
1655 * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory,
1656 * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the
1657 * parent gmap table could not be protected.
1658 */
1659struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
1660 int edat_level)
1661{
1662 struct gmap *sg, *new;
1663 unsigned long limit;
1664 int rc;
1665
1666 BUG_ON(parent->mm->context.allow_gmap_hpage_1m);
1667 BUG_ON(gmap_is_shadow(parent));
1668 spin_lock(&parent->shadow_lock);
1669 sg = gmap_find_shadow(parent, asce, edat_level);
1670 spin_unlock(&parent->shadow_lock);
1671 if (sg)
1672 return sg;
1673 /* Create a new shadow gmap */
1674 limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
1675 if (asce & _ASCE_REAL_SPACE)
1676 limit = -1UL;
1677 new = gmap_alloc(limit);
1678 if (!new)
1679 return ERR_PTR(-ENOMEM);
1680 new->mm = parent->mm;
1681 new->parent = gmap_get(parent);
1682 new->orig_asce = asce;
1683 new->edat_level = edat_level;
1684 new->initialized = false;
1685 spin_lock(&parent->shadow_lock);
1686 /* Recheck if another CPU created the same shadow */
1687 sg = gmap_find_shadow(parent, asce, edat_level);
1688 if (sg) {
1689 spin_unlock(&parent->shadow_lock);
1690 gmap_free(new);
1691 return sg;
1692 }
1693 if (asce & _ASCE_REAL_SPACE) {
1694 /* only allow one real-space gmap shadow */
1695 list_for_each_entry(sg, &parent->children, list) {
1696 if (sg->orig_asce & _ASCE_REAL_SPACE) {
1697 spin_lock(&sg->guest_table_lock);
1698 gmap_unshadow(sg);
1699 spin_unlock(&sg->guest_table_lock);
1700 list_del(&sg->list);
1701 gmap_put(sg);
1702 break;
1703 }
1704 }
1705 }
1706 refcount_set(&new->ref_count, 2);
1707 list_add(&new->list, &parent->children);
1708 if (asce & _ASCE_REAL_SPACE) {
1709 /* nothing to protect, return right away */
1710 new->initialized = true;
1711 spin_unlock(&parent->shadow_lock);
1712 return new;
1713 }
1714 spin_unlock(&parent->shadow_lock);
1715 /* protect after insertion, so it will get properly invalidated */
1716 mmap_read_lock(parent->mm);
1717 rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
1718 ((asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE,
1719 PROT_READ, GMAP_NOTIFY_SHADOW);
1720 mmap_read_unlock(parent->mm);
1721 spin_lock(&parent->shadow_lock);
1722 new->initialized = true;
1723 if (rc) {
1724 list_del(&new->list);
1725 gmap_free(new);
1726 new = ERR_PTR(rc);
1727 }
1728 spin_unlock(&parent->shadow_lock);
1729 return new;
1730}
1731EXPORT_SYMBOL_GPL(gmap_shadow);
1732
1733/**
1734 * gmap_shadow_r2t - create an empty shadow region 2 table
1735 * @sg: pointer to the shadow guest address space structure
1736 * @saddr: faulting address in the shadow gmap
1737 * @r2t: parent gmap address of the region 2 table to get shadowed
1738 * @fake: r2t references contiguous guest memory block, not a r2t
1739 *
1740 * The r2t parameter specifies the address of the source table. The
1741 * four pages of the source table are made read-only in the parent gmap
1742 * address space. A write to the source table area @r2t will automatically
1743 * remove the shadow r2 table and all of its decendents.
1744 *
1745 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
1746 * shadow table structure is incomplete, -ENOMEM if out of memory and
1747 * -EFAULT if an address in the parent gmap could not be resolved.
1748 *
1749 * Called with sg->mm->mmap_lock in read.
1750 */
1751int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
1752 int fake)
1753{
1754 unsigned long raddr, origin, offset, len;
1755 unsigned long *table;
1756 phys_addr_t s_r2t;
1757 struct page *page;
1758 int rc;
1759
1760 BUG_ON(!gmap_is_shadow(sg));
1761 /* Allocate a shadow region second table */
1762 page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
1763 if (!page)
1764 return -ENOMEM;
1765 page->index = r2t & _REGION_ENTRY_ORIGIN;
1766 if (fake)
1767 page->index |= GMAP_SHADOW_FAKE_TABLE;
1768 s_r2t = page_to_phys(page);
1769 /* Install shadow region second table */
1770 spin_lock(&sg->guest_table_lock);
1771 table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
1772 if (!table) {
1773 rc = -EAGAIN; /* Race with unshadow */
1774 goto out_free;
1775 }
1776 if (!(*table & _REGION_ENTRY_INVALID)) {
1777 rc = 0; /* Already established */
1778 goto out_free;
1779 } else if (*table & _REGION_ENTRY_ORIGIN) {
1780 rc = -EAGAIN; /* Race with shadow */
1781 goto out_free;
1782 }
1783 crst_table_init(__va(s_r2t), _REGION2_ENTRY_EMPTY);
1784 /* mark as invalid as long as the parent table is not protected */
1785 *table = s_r2t | _REGION_ENTRY_LENGTH |
1786 _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
1787 if (sg->edat_level >= 1)
1788 *table |= (r2t & _REGION_ENTRY_PROTECT);
1789 list_add(&page->lru, &sg->crst_list);
1790 if (fake) {
1791 /* nothing to protect for fake tables */
1792 *table &= ~_REGION_ENTRY_INVALID;
1793 spin_unlock(&sg->guest_table_lock);
1794 return 0;
1795 }
1796 spin_unlock(&sg->guest_table_lock);
1797 /* Make r2t read-only in parent gmap page table */
1798 raddr = (saddr & _REGION1_MASK) | _SHADOW_RMAP_REGION1;
1799 origin = r2t & _REGION_ENTRY_ORIGIN;
1800 offset = ((r2t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1801 len = ((r2t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1802 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1803 spin_lock(&sg->guest_table_lock);
1804 if (!rc) {
1805 table = gmap_table_walk(sg, saddr, 4);
1806 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r2t)
1807 rc = -EAGAIN; /* Race with unshadow */
1808 else
1809 *table &= ~_REGION_ENTRY_INVALID;
1810 } else {
1811 gmap_unshadow_r2t(sg, raddr);
1812 }
1813 spin_unlock(&sg->guest_table_lock);
1814 return rc;
1815out_free:
1816 spin_unlock(&sg->guest_table_lock);
1817 __free_pages(page, CRST_ALLOC_ORDER);
1818 return rc;
1819}
1820EXPORT_SYMBOL_GPL(gmap_shadow_r2t);
1821
1822/**
1823 * gmap_shadow_r3t - create a shadow region 3 table
1824 * @sg: pointer to the shadow guest address space structure
1825 * @saddr: faulting address in the shadow gmap
1826 * @r3t: parent gmap address of the region 3 table to get shadowed
1827 * @fake: r3t references contiguous guest memory block, not a r3t
1828 *
1829 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
1830 * shadow table structure is incomplete, -ENOMEM if out of memory and
1831 * -EFAULT if an address in the parent gmap could not be resolved.
1832 *
1833 * Called with sg->mm->mmap_lock in read.
1834 */
1835int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
1836 int fake)
1837{
1838 unsigned long raddr, origin, offset, len;
1839 unsigned long *table;
1840 phys_addr_t s_r3t;
1841 struct page *page;
1842 int rc;
1843
1844 BUG_ON(!gmap_is_shadow(sg));
1845 /* Allocate a shadow region second table */
1846 page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
1847 if (!page)
1848 return -ENOMEM;
1849 page->index = r3t & _REGION_ENTRY_ORIGIN;
1850 if (fake)
1851 page->index |= GMAP_SHADOW_FAKE_TABLE;
1852 s_r3t = page_to_phys(page);
1853 /* Install shadow region second table */
1854 spin_lock(&sg->guest_table_lock);
1855 table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
1856 if (!table) {
1857 rc = -EAGAIN; /* Race with unshadow */
1858 goto out_free;
1859 }
1860 if (!(*table & _REGION_ENTRY_INVALID)) {
1861 rc = 0; /* Already established */
1862 goto out_free;
1863 } else if (*table & _REGION_ENTRY_ORIGIN) {
1864 rc = -EAGAIN; /* Race with shadow */
1865 goto out_free;
1866 }
1867 crst_table_init(__va(s_r3t), _REGION3_ENTRY_EMPTY);
1868 /* mark as invalid as long as the parent table is not protected */
1869 *table = s_r3t | _REGION_ENTRY_LENGTH |
1870 _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
1871 if (sg->edat_level >= 1)
1872 *table |= (r3t & _REGION_ENTRY_PROTECT);
1873 list_add(&page->lru, &sg->crst_list);
1874 if (fake) {
1875 /* nothing to protect for fake tables */
1876 *table &= ~_REGION_ENTRY_INVALID;
1877 spin_unlock(&sg->guest_table_lock);
1878 return 0;
1879 }
1880 spin_unlock(&sg->guest_table_lock);
1881 /* Make r3t read-only in parent gmap page table */
1882 raddr = (saddr & _REGION2_MASK) | _SHADOW_RMAP_REGION2;
1883 origin = r3t & _REGION_ENTRY_ORIGIN;
1884 offset = ((r3t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1885 len = ((r3t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1886 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1887 spin_lock(&sg->guest_table_lock);
1888 if (!rc) {
1889 table = gmap_table_walk(sg, saddr, 3);
1890 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r3t)
1891 rc = -EAGAIN; /* Race with unshadow */
1892 else
1893 *table &= ~_REGION_ENTRY_INVALID;
1894 } else {
1895 gmap_unshadow_r3t(sg, raddr);
1896 }
1897 spin_unlock(&sg->guest_table_lock);
1898 return rc;
1899out_free:
1900 spin_unlock(&sg->guest_table_lock);
1901 __free_pages(page, CRST_ALLOC_ORDER);
1902 return rc;
1903}
1904EXPORT_SYMBOL_GPL(gmap_shadow_r3t);
1905
1906/**
1907 * gmap_shadow_sgt - create a shadow segment table
1908 * @sg: pointer to the shadow guest address space structure
1909 * @saddr: faulting address in the shadow gmap
1910 * @sgt: parent gmap address of the segment table to get shadowed
1911 * @fake: sgt references contiguous guest memory block, not a sgt
1912 *
1913 * Returns: 0 if successfully shadowed or already shadowed, -EAGAIN if the
1914 * shadow table structure is incomplete, -ENOMEM if out of memory and
1915 * -EFAULT if an address in the parent gmap could not be resolved.
1916 *
1917 * Called with sg->mm->mmap_lock in read.
1918 */
1919int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
1920 int fake)
1921{
1922 unsigned long raddr, origin, offset, len;
1923 unsigned long *table;
1924 phys_addr_t s_sgt;
1925 struct page *page;
1926 int rc;
1927
1928 BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE));
1929 /* Allocate a shadow segment table */
1930 page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
1931 if (!page)
1932 return -ENOMEM;
1933 page->index = sgt & _REGION_ENTRY_ORIGIN;
1934 if (fake)
1935 page->index |= GMAP_SHADOW_FAKE_TABLE;
1936 s_sgt = page_to_phys(page);
1937 /* Install shadow region second table */
1938 spin_lock(&sg->guest_table_lock);
1939 table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
1940 if (!table) {
1941 rc = -EAGAIN; /* Race with unshadow */
1942 goto out_free;
1943 }
1944 if (!(*table & _REGION_ENTRY_INVALID)) {
1945 rc = 0; /* Already established */
1946 goto out_free;
1947 } else if (*table & _REGION_ENTRY_ORIGIN) {
1948 rc = -EAGAIN; /* Race with shadow */
1949 goto out_free;
1950 }
1951 crst_table_init(__va(s_sgt), _SEGMENT_ENTRY_EMPTY);
1952 /* mark as invalid as long as the parent table is not protected */
1953 *table = s_sgt | _REGION_ENTRY_LENGTH |
1954 _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
1955 if (sg->edat_level >= 1)
1956 *table |= sgt & _REGION_ENTRY_PROTECT;
1957 list_add(&page->lru, &sg->crst_list);
1958 if (fake) {
1959 /* nothing to protect for fake tables */
1960 *table &= ~_REGION_ENTRY_INVALID;
1961 spin_unlock(&sg->guest_table_lock);
1962 return 0;
1963 }
1964 spin_unlock(&sg->guest_table_lock);
1965 /* Make sgt read-only in parent gmap page table */
1966 raddr = (saddr & _REGION3_MASK) | _SHADOW_RMAP_REGION3;
1967 origin = sgt & _REGION_ENTRY_ORIGIN;
1968 offset = ((sgt & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1969 len = ((sgt & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1970 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1971 spin_lock(&sg->guest_table_lock);
1972 if (!rc) {
1973 table = gmap_table_walk(sg, saddr, 2);
1974 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_sgt)
1975 rc = -EAGAIN; /* Race with unshadow */
1976 else
1977 *table &= ~_REGION_ENTRY_INVALID;
1978 } else {
1979 gmap_unshadow_sgt(sg, raddr);
1980 }
1981 spin_unlock(&sg->guest_table_lock);
1982 return rc;
1983out_free:
1984 spin_unlock(&sg->guest_table_lock);
1985 __free_pages(page, CRST_ALLOC_ORDER);
1986 return rc;
1987}
1988EXPORT_SYMBOL_GPL(gmap_shadow_sgt);
1989
1990/**
1991 * gmap_shadow_pgt_lookup - find a shadow page table
1992 * @sg: pointer to the shadow guest address space structure
1993 * @saddr: the address in the shadow aguest address space
1994 * @pgt: parent gmap address of the page table to get shadowed
1995 * @dat_protection: if the pgtable is marked as protected by dat
1996 * @fake: pgt references contiguous guest memory block, not a pgtable
1997 *
1998 * Returns 0 if the shadow page table was found and -EAGAIN if the page
1999 * table was not found.
2000 *
2001 * Called with sg->mm->mmap_lock in read.
2002 */
2003int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
2004 unsigned long *pgt, int *dat_protection,
2005 int *fake)
2006{
2007 unsigned long *table;
2008 struct page *page;
2009 int rc;
2010
2011 BUG_ON(!gmap_is_shadow(sg));
2012 spin_lock(&sg->guest_table_lock);
2013 table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
2014 if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
2015 /* Shadow page tables are full pages (pte+pgste) */
2016 page = pfn_to_page(*table >> PAGE_SHIFT);
2017 *pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
2018 *dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
2019 *fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
2020 rc = 0;
2021 } else {
2022 rc = -EAGAIN;
2023 }
2024 spin_unlock(&sg->guest_table_lock);
2025 return rc;
2026
2027}
2028EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup);
2029
2030/**
2031 * gmap_shadow_pgt - instantiate a shadow page table
2032 * @sg: pointer to the shadow guest address space structure
2033 * @saddr: faulting address in the shadow gmap
2034 * @pgt: parent gmap address of the page table to get shadowed
2035 * @fake: pgt references contiguous guest memory block, not a pgtable
2036 *
2037 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
2038 * shadow table structure is incomplete, -ENOMEM if out of memory,
2039 * -EFAULT if an address in the parent gmap could not be resolved and
2040 *
2041 * Called with gmap->mm->mmap_lock in read
2042 */
2043int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
2044 int fake)
2045{
2046 unsigned long raddr, origin;
2047 unsigned long *table;
2048 struct page *page;
2049 phys_addr_t s_pgt;
2050 int rc;
2051
2052 BUG_ON(!gmap_is_shadow(sg) || (pgt & _SEGMENT_ENTRY_LARGE));
2053 /* Allocate a shadow page table */
2054 page = page_table_alloc_pgste(sg->mm);
2055 if (!page)
2056 return -ENOMEM;
2057 page->index = pgt & _SEGMENT_ENTRY_ORIGIN;
2058 if (fake)
2059 page->index |= GMAP_SHADOW_FAKE_TABLE;
2060 s_pgt = page_to_phys(page);
2061 /* Install shadow page table */
2062 spin_lock(&sg->guest_table_lock);
2063 table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
2064 if (!table) {
2065 rc = -EAGAIN; /* Race with unshadow */
2066 goto out_free;
2067 }
2068 if (!(*table & _SEGMENT_ENTRY_INVALID)) {
2069 rc = 0; /* Already established */
2070 goto out_free;
2071 } else if (*table & _SEGMENT_ENTRY_ORIGIN) {
2072 rc = -EAGAIN; /* Race with shadow */
2073 goto out_free;
2074 }
2075 /* mark as invalid as long as the parent table is not protected */
2076 *table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
2077 (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID;
2078 list_add(&page->lru, &sg->pt_list);
2079 if (fake) {
2080 /* nothing to protect for fake tables */
2081 *table &= ~_SEGMENT_ENTRY_INVALID;
2082 spin_unlock(&sg->guest_table_lock);
2083 return 0;
2084 }
2085 spin_unlock(&sg->guest_table_lock);
2086 /* Make pgt read-only in parent gmap page table (not the pgste) */
2087 raddr = (saddr & _SEGMENT_MASK) | _SHADOW_RMAP_SEGMENT;
2088 origin = pgt & _SEGMENT_ENTRY_ORIGIN & PAGE_MASK;
2089 rc = gmap_protect_rmap(sg, raddr, origin, PAGE_SIZE);
2090 spin_lock(&sg->guest_table_lock);
2091 if (!rc) {
2092 table = gmap_table_walk(sg, saddr, 1);
2093 if (!table || (*table & _SEGMENT_ENTRY_ORIGIN) != s_pgt)
2094 rc = -EAGAIN; /* Race with unshadow */
2095 else
2096 *table &= ~_SEGMENT_ENTRY_INVALID;
2097 } else {
2098 gmap_unshadow_pgt(sg, raddr);
2099 }
2100 spin_unlock(&sg->guest_table_lock);
2101 return rc;
2102out_free:
2103 spin_unlock(&sg->guest_table_lock);
2104 page_table_free_pgste(page);
2105 return rc;
2106
2107}
2108EXPORT_SYMBOL_GPL(gmap_shadow_pgt);
2109
2110/**
2111 * gmap_shadow_page - create a shadow page mapping
2112 * @sg: pointer to the shadow guest address space structure
2113 * @saddr: faulting address in the shadow gmap
2114 * @pte: pte in parent gmap address space to get shadowed
2115 *
2116 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
2117 * shadow table structure is incomplete, -ENOMEM if out of memory and
2118 * -EFAULT if an address in the parent gmap could not be resolved.
2119 *
2120 * Called with sg->mm->mmap_lock in read.
2121 */
2122int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
2123{
2124 struct gmap *parent;
2125 struct gmap_rmap *rmap;
2126 unsigned long vmaddr, paddr;
2127 spinlock_t *ptl;
2128 pte_t *sptep, *tptep;
2129 int prot;
2130 int rc;
2131
2132 BUG_ON(!gmap_is_shadow(sg));
2133 parent = sg->parent;
2134 prot = (pte_val(pte) & _PAGE_PROTECT) ? PROT_READ : PROT_WRITE;
2135
2136 rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT);
2137 if (!rmap)
2138 return -ENOMEM;
2139 rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE;
2140
2141 while (1) {
2142 paddr = pte_val(pte) & PAGE_MASK;
2143 vmaddr = __gmap_translate(parent, paddr);
2144 if (IS_ERR_VALUE(vmaddr)) {
2145 rc = vmaddr;
2146 break;
2147 }
2148 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
2149 if (rc)
2150 break;
2151 rc = -EAGAIN;
2152 sptep = gmap_pte_op_walk(parent, paddr, &ptl);
2153 if (sptep) {
2154 spin_lock(&sg->guest_table_lock);
2155 /* Get page table pointer */
2156 tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
2157 if (!tptep) {
2158 spin_unlock(&sg->guest_table_lock);
2159 gmap_pte_op_end(ptl);
2160 radix_tree_preload_end();
2161 break;
2162 }
2163 rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte);
2164 if (rc > 0) {
2165 /* Success and a new mapping */
2166 gmap_insert_rmap(sg, vmaddr, rmap);
2167 rmap = NULL;
2168 rc = 0;
2169 }
2170 gmap_pte_op_end(ptl);
2171 spin_unlock(&sg->guest_table_lock);
2172 }
2173 radix_tree_preload_end();
2174 if (!rc)
2175 break;
2176 rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot);
2177 if (rc)
2178 break;
2179 }
2180 kfree(rmap);
2181 return rc;
2182}
2183EXPORT_SYMBOL_GPL(gmap_shadow_page);
2184
2185/*
2186 * gmap_shadow_notify - handle notifications for shadow gmap
2187 *
2188 * Called with sg->parent->shadow_lock.
2189 */
2190static void gmap_shadow_notify(struct gmap *sg, unsigned long vmaddr,
2191 unsigned long gaddr)
2192{
2193 struct gmap_rmap *rmap, *rnext, *head;
2194 unsigned long start, end, bits, raddr;
2195
2196 BUG_ON(!gmap_is_shadow(sg));
2197
2198 spin_lock(&sg->guest_table_lock);
2199 if (sg->removed) {
2200 spin_unlock(&sg->guest_table_lock);
2201 return;
2202 }
2203 /* Check for top level table */
2204 start = sg->orig_asce & _ASCE_ORIGIN;
2205 end = start + ((sg->orig_asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE;
2206 if (!(sg->orig_asce & _ASCE_REAL_SPACE) && gaddr >= start &&
2207 gaddr < end) {
2208 /* The complete shadow table has to go */
2209 gmap_unshadow(sg);
2210 spin_unlock(&sg->guest_table_lock);
2211 list_del(&sg->list);
2212 gmap_put(sg);
2213 return;
2214 }
2215 /* Remove the page table tree from on specific entry */
2216 head = radix_tree_delete(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
2217 gmap_for_each_rmap_safe(rmap, rnext, head) {
2218 bits = rmap->raddr & _SHADOW_RMAP_MASK;
2219 raddr = rmap->raddr ^ bits;
2220 switch (bits) {
2221 case _SHADOW_RMAP_REGION1:
2222 gmap_unshadow_r2t(sg, raddr);
2223 break;
2224 case _SHADOW_RMAP_REGION2:
2225 gmap_unshadow_r3t(sg, raddr);
2226 break;
2227 case _SHADOW_RMAP_REGION3:
2228 gmap_unshadow_sgt(sg, raddr);
2229 break;
2230 case _SHADOW_RMAP_SEGMENT:
2231 gmap_unshadow_pgt(sg, raddr);
2232 break;
2233 case _SHADOW_RMAP_PGTABLE:
2234 gmap_unshadow_page(sg, raddr);
2235 break;
2236 }
2237 kfree(rmap);
2238 }
2239 spin_unlock(&sg->guest_table_lock);
2240}
2241
2242/**
2243 * ptep_notify - call all invalidation callbacks for a specific pte.
2244 * @mm: pointer to the process mm_struct
2245 * @vmaddr: virtual address in the process address space
2246 * @pte: pointer to the page table entry
2247 * @bits: bits from the pgste that caused the notify call
2248 *
2249 * This function is assumed to be called with the page table lock held
2250 * for the pte to notify.
2251 */
2252void ptep_notify(struct mm_struct *mm, unsigned long vmaddr,
2253 pte_t *pte, unsigned long bits)
2254{
2255 unsigned long offset, gaddr = 0;
2256 unsigned long *table;
2257 struct gmap *gmap, *sg, *next;
2258
2259 offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
2260 offset = offset * (PAGE_SIZE / sizeof(pte_t));
2261 rcu_read_lock();
2262 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2263 spin_lock(&gmap->guest_table_lock);
2264 table = radix_tree_lookup(&gmap->host_to_guest,
2265 vmaddr >> PMD_SHIFT);
2266 if (table)
2267 gaddr = __gmap_segment_gaddr(table) + offset;
2268 spin_unlock(&gmap->guest_table_lock);
2269 if (!table)
2270 continue;
2271
2272 if (!list_empty(&gmap->children) && (bits & PGSTE_VSIE_BIT)) {
2273 spin_lock(&gmap->shadow_lock);
2274 list_for_each_entry_safe(sg, next,
2275 &gmap->children, list)
2276 gmap_shadow_notify(sg, vmaddr, gaddr);
2277 spin_unlock(&gmap->shadow_lock);
2278 }
2279 if (bits & PGSTE_IN_BIT)
2280 gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1);
2281 }
2282 rcu_read_unlock();
2283}
2284EXPORT_SYMBOL_GPL(ptep_notify);
2285
2286static void pmdp_notify_gmap(struct gmap *gmap, pmd_t *pmdp,
2287 unsigned long gaddr)
2288{
2289 set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN)));
2290 gmap_call_notifier(gmap, gaddr, gaddr + HPAGE_SIZE - 1);
2291}
2292
2293/**
2294 * gmap_pmdp_xchg - exchange a gmap pmd with another
2295 * @gmap: pointer to the guest address space structure
2296 * @pmdp: pointer to the pmd entry
2297 * @new: replacement entry
2298 * @gaddr: the affected guest address
2299 *
2300 * This function is assumed to be called with the guest_table_lock
2301 * held.
2302 */
2303static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *pmdp, pmd_t new,
2304 unsigned long gaddr)
2305{
2306 gaddr &= HPAGE_MASK;
2307 pmdp_notify_gmap(gmap, pmdp, gaddr);
2308 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_GMAP_IN));
2309 if (MACHINE_HAS_TLB_GUEST)
2310 __pmdp_idte(gaddr, (pmd_t *)pmdp, IDTE_GUEST_ASCE, gmap->asce,
2311 IDTE_GLOBAL);
2312 else if (MACHINE_HAS_IDTE)
2313 __pmdp_idte(gaddr, (pmd_t *)pmdp, 0, 0, IDTE_GLOBAL);
2314 else
2315 __pmdp_csp(pmdp);
2316 set_pmd(pmdp, new);
2317}
2318
2319static void gmap_pmdp_clear(struct mm_struct *mm, unsigned long vmaddr,
2320 int purge)
2321{
2322 pmd_t *pmdp;
2323 struct gmap *gmap;
2324 unsigned long gaddr;
2325
2326 rcu_read_lock();
2327 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2328 spin_lock(&gmap->guest_table_lock);
2329 pmdp = (pmd_t *)radix_tree_delete(&gmap->host_to_guest,
2330 vmaddr >> PMD_SHIFT);
2331 if (pmdp) {
2332 gaddr = __gmap_segment_gaddr((unsigned long *)pmdp);
2333 pmdp_notify_gmap(gmap, pmdp, gaddr);
2334 WARN_ON(pmd_val(*pmdp) & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2335 _SEGMENT_ENTRY_GMAP_UC));
2336 if (purge)
2337 __pmdp_csp(pmdp);
2338 set_pmd(pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
2339 }
2340 spin_unlock(&gmap->guest_table_lock);
2341 }
2342 rcu_read_unlock();
2343}
2344
2345/**
2346 * gmap_pmdp_invalidate - invalidate all affected guest pmd entries without
2347 * flushing
2348 * @mm: pointer to the process mm_struct
2349 * @vmaddr: virtual address in the process address space
2350 */
2351void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr)
2352{
2353 gmap_pmdp_clear(mm, vmaddr, 0);
2354}
2355EXPORT_SYMBOL_GPL(gmap_pmdp_invalidate);
2356
2357/**
2358 * gmap_pmdp_csp - csp all affected guest pmd entries
2359 * @mm: pointer to the process mm_struct
2360 * @vmaddr: virtual address in the process address space
2361 */
2362void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr)
2363{
2364 gmap_pmdp_clear(mm, vmaddr, 1);
2365}
2366EXPORT_SYMBOL_GPL(gmap_pmdp_csp);
2367
2368/**
2369 * gmap_pmdp_idte_local - invalidate and clear a guest pmd entry
2370 * @mm: pointer to the process mm_struct
2371 * @vmaddr: virtual address in the process address space
2372 */
2373void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr)
2374{
2375 unsigned long *entry, gaddr;
2376 struct gmap *gmap;
2377 pmd_t *pmdp;
2378
2379 rcu_read_lock();
2380 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2381 spin_lock(&gmap->guest_table_lock);
2382 entry = radix_tree_delete(&gmap->host_to_guest,
2383 vmaddr >> PMD_SHIFT);
2384 if (entry) {
2385 pmdp = (pmd_t *)entry;
2386 gaddr = __gmap_segment_gaddr(entry);
2387 pmdp_notify_gmap(gmap, pmdp, gaddr);
2388 WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2389 _SEGMENT_ENTRY_GMAP_UC));
2390 if (MACHINE_HAS_TLB_GUEST)
2391 __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
2392 gmap->asce, IDTE_LOCAL);
2393 else if (MACHINE_HAS_IDTE)
2394 __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_LOCAL);
2395 *entry = _SEGMENT_ENTRY_EMPTY;
2396 }
2397 spin_unlock(&gmap->guest_table_lock);
2398 }
2399 rcu_read_unlock();
2400}
2401EXPORT_SYMBOL_GPL(gmap_pmdp_idte_local);
2402
2403/**
2404 * gmap_pmdp_idte_global - invalidate and clear a guest pmd entry
2405 * @mm: pointer to the process mm_struct
2406 * @vmaddr: virtual address in the process address space
2407 */
2408void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr)
2409{
2410 unsigned long *entry, gaddr;
2411 struct gmap *gmap;
2412 pmd_t *pmdp;
2413
2414 rcu_read_lock();
2415 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2416 spin_lock(&gmap->guest_table_lock);
2417 entry = radix_tree_delete(&gmap->host_to_guest,
2418 vmaddr >> PMD_SHIFT);
2419 if (entry) {
2420 pmdp = (pmd_t *)entry;
2421 gaddr = __gmap_segment_gaddr(entry);
2422 pmdp_notify_gmap(gmap, pmdp, gaddr);
2423 WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2424 _SEGMENT_ENTRY_GMAP_UC));
2425 if (MACHINE_HAS_TLB_GUEST)
2426 __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
2427 gmap->asce, IDTE_GLOBAL);
2428 else if (MACHINE_HAS_IDTE)
2429 __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_GLOBAL);
2430 else
2431 __pmdp_csp(pmdp);
2432 *entry = _SEGMENT_ENTRY_EMPTY;
2433 }
2434 spin_unlock(&gmap->guest_table_lock);
2435 }
2436 rcu_read_unlock();
2437}
2438EXPORT_SYMBOL_GPL(gmap_pmdp_idte_global);
2439
2440/**
2441 * gmap_test_and_clear_dirty_pmd - test and reset segment dirty status
2442 * @gmap: pointer to guest address space
2443 * @pmdp: pointer to the pmd to be tested
2444 * @gaddr: virtual address in the guest address space
2445 *
2446 * This function is assumed to be called with the guest_table_lock
2447 * held.
2448 */
2449static bool gmap_test_and_clear_dirty_pmd(struct gmap *gmap, pmd_t *pmdp,
2450 unsigned long gaddr)
2451{
2452 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
2453 return false;
2454
2455 /* Already protected memory, which did not change is clean */
2456 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT &&
2457 !(pmd_val(*pmdp) & _SEGMENT_ENTRY_GMAP_UC))
2458 return false;
2459
2460 /* Clear UC indication and reset protection */
2461 set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_UC)));
2462 gmap_protect_pmd(gmap, gaddr, pmdp, PROT_READ, 0);
2463 return true;
2464}
2465
2466/**
2467 * gmap_sync_dirty_log_pmd - set bitmap based on dirty status of segment
2468 * @gmap: pointer to guest address space
2469 * @bitmap: dirty bitmap for this pmd
2470 * @gaddr: virtual address in the guest address space
2471 * @vmaddr: virtual address in the host address space
2472 *
2473 * This function is assumed to be called with the guest_table_lock
2474 * held.
2475 */
2476void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long bitmap[4],
2477 unsigned long gaddr, unsigned long vmaddr)
2478{
2479 int i;
2480 pmd_t *pmdp;
2481 pte_t *ptep;
2482 spinlock_t *ptl;
2483
2484 pmdp = gmap_pmd_op_walk(gmap, gaddr);
2485 if (!pmdp)
2486 return;
2487
2488 if (pmd_large(*pmdp)) {
2489 if (gmap_test_and_clear_dirty_pmd(gmap, pmdp, gaddr))
2490 bitmap_fill(bitmap, _PAGE_ENTRIES);
2491 } else {
2492 for (i = 0; i < _PAGE_ENTRIES; i++, vmaddr += PAGE_SIZE) {
2493 ptep = pte_alloc_map_lock(gmap->mm, pmdp, vmaddr, &ptl);
2494 if (!ptep)
2495 continue;
2496 if (ptep_test_and_clear_uc(gmap->mm, vmaddr, ptep))
2497 set_bit(i, bitmap);
2498 spin_unlock(ptl);
2499 }
2500 }
2501 gmap_pmd_op_end(gmap, pmdp);
2502}
2503EXPORT_SYMBOL_GPL(gmap_sync_dirty_log_pmd);
2504
2505#ifdef CONFIG_TRANSPARENT_HUGEPAGE
2506static int thp_split_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
2507 unsigned long end, struct mm_walk *walk)
2508{
2509 struct vm_area_struct *vma = walk->vma;
2510
2511 split_huge_pmd(vma, pmd, addr);
2512 return 0;
2513}
2514
2515static const struct mm_walk_ops thp_split_walk_ops = {
2516 .pmd_entry = thp_split_walk_pmd_entry,
2517};
2518
2519static inline void thp_split_mm(struct mm_struct *mm)
2520{
2521 struct vm_area_struct *vma;
2522 VMA_ITERATOR(vmi, mm, 0);
2523
2524 for_each_vma(vmi, vma) {
2525 vma->vm_flags &= ~VM_HUGEPAGE;
2526 vma->vm_flags |= VM_NOHUGEPAGE;
2527 walk_page_vma(vma, &thp_split_walk_ops, NULL);
2528 }
2529 mm->def_flags |= VM_NOHUGEPAGE;
2530}
2531#else
2532static inline void thp_split_mm(struct mm_struct *mm)
2533{
2534}
2535#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2536
2537/*
2538 * Remove all empty zero pages from the mapping for lazy refaulting
2539 * - This must be called after mm->context.has_pgste is set, to avoid
2540 * future creation of zero pages
2541 * - This must be called after THP was enabled
2542 */
2543static int __zap_zero_pages(pmd_t *pmd, unsigned long start,
2544 unsigned long end, struct mm_walk *walk)
2545{
2546 unsigned long addr;
2547
2548 for (addr = start; addr != end; addr += PAGE_SIZE) {
2549 pte_t *ptep;
2550 spinlock_t *ptl;
2551
2552 ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
2553 if (is_zero_pfn(pte_pfn(*ptep)))
2554 ptep_xchg_direct(walk->mm, addr, ptep, __pte(_PAGE_INVALID));
2555 pte_unmap_unlock(ptep, ptl);
2556 }
2557 return 0;
2558}
2559
2560static const struct mm_walk_ops zap_zero_walk_ops = {
2561 .pmd_entry = __zap_zero_pages,
2562};
2563
2564/*
2565 * switch on pgstes for its userspace process (for kvm)
2566 */
2567int s390_enable_sie(void)
2568{
2569 struct mm_struct *mm = current->mm;
2570
2571 /* Do we have pgstes? if yes, we are done */
2572 if (mm_has_pgste(mm))
2573 return 0;
2574 /* Fail if the page tables are 2K */
2575 if (!mm_alloc_pgste(mm))
2576 return -EINVAL;
2577 mmap_write_lock(mm);
2578 mm->context.has_pgste = 1;
2579 /* split thp mappings and disable thp for future mappings */
2580 thp_split_mm(mm);
2581 walk_page_range(mm, 0, TASK_SIZE, &zap_zero_walk_ops, NULL);
2582 mmap_write_unlock(mm);
2583 return 0;
2584}
2585EXPORT_SYMBOL_GPL(s390_enable_sie);
2586
2587int gmap_mark_unmergeable(void)
2588{
2589 struct mm_struct *mm = current->mm;
2590 struct vm_area_struct *vma;
2591 int ret;
2592 VMA_ITERATOR(vmi, mm, 0);
2593
2594 for_each_vma(vmi, vma) {
2595 ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
2596 MADV_UNMERGEABLE, &vma->vm_flags);
2597 if (ret)
2598 return ret;
2599 }
2600 mm->def_flags &= ~VM_MERGEABLE;
2601 return 0;
2602}
2603EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
2604
2605/*
2606 * Enable storage key handling from now on and initialize the storage
2607 * keys with the default key.
2608 */
2609static int __s390_enable_skey_pte(pte_t *pte, unsigned long addr,
2610 unsigned long next, struct mm_walk *walk)
2611{
2612 /* Clear storage key */
2613 ptep_zap_key(walk->mm, addr, pte);
2614 return 0;
2615}
2616
2617/*
2618 * Give a chance to schedule after setting a key to 256 pages.
2619 * We only hold the mm lock, which is a rwsem and the kvm srcu.
2620 * Both can sleep.
2621 */
2622static int __s390_enable_skey_pmd(pmd_t *pmd, unsigned long addr,
2623 unsigned long next, struct mm_walk *walk)
2624{
2625 cond_resched();
2626 return 0;
2627}
2628
2629static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
2630 unsigned long hmask, unsigned long next,
2631 struct mm_walk *walk)
2632{
2633 pmd_t *pmd = (pmd_t *)pte;
2634 unsigned long start, end;
2635 struct page *page = pmd_page(*pmd);
2636
2637 /*
2638 * The write check makes sure we do not set a key on shared
2639 * memory. This is needed as the walker does not differentiate
2640 * between actual guest memory and the process executable or
2641 * shared libraries.
2642 */
2643 if (pmd_val(*pmd) & _SEGMENT_ENTRY_INVALID ||
2644 !(pmd_val(*pmd) & _SEGMENT_ENTRY_WRITE))
2645 return 0;
2646
2647 start = pmd_val(*pmd) & HPAGE_MASK;
2648 end = start + HPAGE_SIZE - 1;
2649 __storage_key_init_range(start, end);
2650 set_bit(PG_arch_1, &page->flags);
2651 cond_resched();
2652 return 0;
2653}
2654
2655static const struct mm_walk_ops enable_skey_walk_ops = {
2656 .hugetlb_entry = __s390_enable_skey_hugetlb,
2657 .pte_entry = __s390_enable_skey_pte,
2658 .pmd_entry = __s390_enable_skey_pmd,
2659};
2660
2661int s390_enable_skey(void)
2662{
2663 struct mm_struct *mm = current->mm;
2664 int rc = 0;
2665
2666 mmap_write_lock(mm);
2667 if (mm_uses_skeys(mm))
2668 goto out_up;
2669
2670 mm->context.uses_skeys = 1;
2671 rc = gmap_mark_unmergeable();
2672 if (rc) {
2673 mm->context.uses_skeys = 0;
2674 goto out_up;
2675 }
2676 walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
2677
2678out_up:
2679 mmap_write_unlock(mm);
2680 return rc;
2681}
2682EXPORT_SYMBOL_GPL(s390_enable_skey);
2683
2684/*
2685 * Reset CMMA state, make all pages stable again.
2686 */
2687static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
2688 unsigned long next, struct mm_walk *walk)
2689{
2690 ptep_zap_unused(walk->mm, addr, pte, 1);
2691 return 0;
2692}
2693
2694static const struct mm_walk_ops reset_cmma_walk_ops = {
2695 .pte_entry = __s390_reset_cmma,
2696};
2697
2698void s390_reset_cmma(struct mm_struct *mm)
2699{
2700 mmap_write_lock(mm);
2701 walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
2702 mmap_write_unlock(mm);
2703}
2704EXPORT_SYMBOL_GPL(s390_reset_cmma);
2705
2706#define GATHER_GET_PAGES 32
2707
2708struct reset_walk_state {
2709 unsigned long next;
2710 unsigned long count;
2711 unsigned long pfns[GATHER_GET_PAGES];
2712};
2713
2714static int s390_gather_pages(pte_t *ptep, unsigned long addr,
2715 unsigned long next, struct mm_walk *walk)
2716{
2717 struct reset_walk_state *p = walk->private;
2718 pte_t pte = READ_ONCE(*ptep);
2719
2720 if (pte_present(pte)) {
2721 /* we have a reference from the mapping, take an extra one */
2722 get_page(phys_to_page(pte_val(pte)));
2723 p->pfns[p->count] = phys_to_pfn(pte_val(pte));
2724 p->next = next;
2725 p->count++;
2726 }
2727 return p->count >= GATHER_GET_PAGES;
2728}
2729
2730static const struct mm_walk_ops gather_pages_ops = {
2731 .pte_entry = s390_gather_pages,
2732};
2733
2734/*
2735 * Call the Destroy secure page UVC on each page in the given array of PFNs.
2736 * Each page needs to have an extra reference, which will be released here.
2737 */
2738void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns)
2739{
2740 unsigned long i;
2741
2742 for (i = 0; i < count; i++) {
2743 /* we always have an extra reference */
2744 uv_destroy_owned_page(pfn_to_phys(pfns[i]));
2745 /* get rid of the extra reference */
2746 put_page(pfn_to_page(pfns[i]));
2747 cond_resched();
2748 }
2749}
2750EXPORT_SYMBOL_GPL(s390_uv_destroy_pfns);
2751
2752/**
2753 * __s390_uv_destroy_range - Call the destroy secure page UVC on each page
2754 * in the given range of the given address space.
2755 * @mm: the mm to operate on
2756 * @start: the start of the range
2757 * @end: the end of the range
2758 * @interruptible: if not 0, stop when a fatal signal is received
2759 *
2760 * Walk the given range of the given address space and call the destroy
2761 * secure page UVC on each page. Optionally exit early if a fatal signal is
2762 * pending.
2763 *
2764 * Return: 0 on success, -EINTR if the function stopped before completing
2765 */
2766int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start,
2767 unsigned long end, bool interruptible)
2768{
2769 struct reset_walk_state state = { .next = start };
2770 int r = 1;
2771
2772 while (r > 0) {
2773 state.count = 0;
2774 mmap_read_lock(mm);
2775 r = walk_page_range(mm, state.next, end, &gather_pages_ops, &state);
2776 mmap_read_unlock(mm);
2777 cond_resched();
2778 s390_uv_destroy_pfns(state.count, state.pfns);
2779 if (interruptible && fatal_signal_pending(current))
2780 return -EINTR;
2781 }
2782 return 0;
2783}
2784EXPORT_SYMBOL_GPL(__s390_uv_destroy_range);
2785
2786/**
2787 * s390_unlist_old_asce - Remove the topmost level of page tables from the
2788 * list of page tables of the gmap.
2789 * @gmap: the gmap whose table is to be removed
2790 *
2791 * On s390x, KVM keeps a list of all pages containing the page tables of the
2792 * gmap (the CRST list). This list is used at tear down time to free all
2793 * pages that are now not needed anymore.
2794 *
2795 * This function removes the topmost page of the tree (the one pointed to by
2796 * the ASCE) from the CRST list.
2797 *
2798 * This means that it will not be freed when the VM is torn down, and needs
2799 * to be handled separately by the caller, unless a leak is actually
2800 * intended. Notice that this function will only remove the page from the
2801 * list, the page will still be used as a top level page table (and ASCE).
2802 */
2803void s390_unlist_old_asce(struct gmap *gmap)
2804{
2805 struct page *old;
2806
2807 old = virt_to_page(gmap->table);
2808 spin_lock(&gmap->guest_table_lock);
2809 list_del(&old->lru);
2810 /*
2811 * Sometimes the topmost page might need to be "removed" multiple
2812 * times, for example if the VM is rebooted into secure mode several
2813 * times concurrently, or if s390_replace_asce fails after calling
2814 * s390_remove_old_asce and is attempted again later. In that case
2815 * the old asce has been removed from the list, and therefore it
2816 * will not be freed when the VM terminates, but the ASCE is still
2817 * in use and still pointed to.
2818 * A subsequent call to replace_asce will follow the pointer and try
2819 * to remove the same page from the list again.
2820 * Therefore it's necessary that the page of the ASCE has valid
2821 * pointers, so list_del can work (and do nothing) without
2822 * dereferencing stale or invalid pointers.
2823 */
2824 INIT_LIST_HEAD(&old->lru);
2825 spin_unlock(&gmap->guest_table_lock);
2826}
2827EXPORT_SYMBOL_GPL(s390_unlist_old_asce);
2828
2829/**
2830 * s390_replace_asce - Try to replace the current ASCE of a gmap with a copy
2831 * @gmap: the gmap whose ASCE needs to be replaced
2832 *
2833 * If the allocation of the new top level page table fails, the ASCE is not
2834 * replaced.
2835 * In any case, the old ASCE is always removed from the gmap CRST list.
2836 * Therefore the caller has to make sure to save a pointer to it
2837 * beforehand, unless a leak is actually intended.
2838 */
2839int s390_replace_asce(struct gmap *gmap)
2840{
2841 unsigned long asce;
2842 struct page *page;
2843 void *table;
2844
2845 s390_unlist_old_asce(gmap);
2846
2847 page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
2848 if (!page)
2849 return -ENOMEM;
2850 table = page_to_virt(page);
2851 memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));
2852
2853 /*
2854 * The caller has to deal with the old ASCE, but here we make sure
2855 * the new one is properly added to the CRST list, so that
2856 * it will be freed when the VM is torn down.
2857 */
2858 spin_lock(&gmap->guest_table_lock);
2859 list_add(&page->lru, &gmap->crst_list);
2860 spin_unlock(&gmap->guest_table_lock);
2861
2862 /* Set new table origin while preserving existing ASCE control bits */
2863 asce = (gmap->asce & ~_ASCE_ORIGIN) | __pa(table);
2864 WRITE_ONCE(gmap->asce, asce);
2865 WRITE_ONCE(gmap->mm->context.gmap_asce, asce);
2866 WRITE_ONCE(gmap->table, table);
2867
2868 return 0;
2869}
2870EXPORT_SYMBOL_GPL(s390_replace_asce);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * KVM guest address space mapping code
4 *
5 * Copyright IBM Corp. 2007, 2020
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 * David Hildenbrand <david@redhat.com>
8 * Janosch Frank <frankja@linux.vnet.ibm.com>
9 */
10
11#include <linux/kernel.h>
12#include <linux/pagewalk.h>
13#include <linux/swap.h>
14#include <linux/smp.h>
15#include <linux/spinlock.h>
16#include <linux/slab.h>
17#include <linux/swapops.h>
18#include <linux/ksm.h>
19#include <linux/mman.h>
20#include <linux/pgtable.h>
21#include <asm/page-states.h>
22#include <asm/pgalloc.h>
23#include <asm/gmap.h>
24#include <asm/page.h>
25#include <asm/tlb.h>
26
27#define GMAP_SHADOW_FAKE_TABLE 1ULL
28
29static struct page *gmap_alloc_crst(void)
30{
31 struct page *page;
32
33 page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
34 if (!page)
35 return NULL;
36 __arch_set_page_dat(page_to_virt(page), 1UL << CRST_ALLOC_ORDER);
37 return page;
38}
39
40/**
41 * gmap_alloc - allocate and initialize a guest address space
42 * @limit: maximum address of the gmap address space
43 *
44 * Returns a guest address space structure.
45 */
46static struct gmap *gmap_alloc(unsigned long limit)
47{
48 struct gmap *gmap;
49 struct page *page;
50 unsigned long *table;
51 unsigned long etype, atype;
52
53 if (limit < _REGION3_SIZE) {
54 limit = _REGION3_SIZE - 1;
55 atype = _ASCE_TYPE_SEGMENT;
56 etype = _SEGMENT_ENTRY_EMPTY;
57 } else if (limit < _REGION2_SIZE) {
58 limit = _REGION2_SIZE - 1;
59 atype = _ASCE_TYPE_REGION3;
60 etype = _REGION3_ENTRY_EMPTY;
61 } else if (limit < _REGION1_SIZE) {
62 limit = _REGION1_SIZE - 1;
63 atype = _ASCE_TYPE_REGION2;
64 etype = _REGION2_ENTRY_EMPTY;
65 } else {
66 limit = -1UL;
67 atype = _ASCE_TYPE_REGION1;
68 etype = _REGION1_ENTRY_EMPTY;
69 }
70 gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL_ACCOUNT);
71 if (!gmap)
72 goto out;
73 INIT_LIST_HEAD(&gmap->crst_list);
74 INIT_LIST_HEAD(&gmap->children);
75 INIT_LIST_HEAD(&gmap->pt_list);
76 INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL_ACCOUNT);
77 INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC | __GFP_ACCOUNT);
78 INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC | __GFP_ACCOUNT);
79 spin_lock_init(&gmap->guest_table_lock);
80 spin_lock_init(&gmap->shadow_lock);
81 refcount_set(&gmap->ref_count, 1);
82 page = gmap_alloc_crst();
83 if (!page)
84 goto out_free;
85 page->index = 0;
86 list_add(&page->lru, &gmap->crst_list);
87 table = page_to_virt(page);
88 crst_table_init(table, etype);
89 gmap->table = table;
90 gmap->asce = atype | _ASCE_TABLE_LENGTH |
91 _ASCE_USER_BITS | __pa(table);
92 gmap->asce_end = limit;
93 return gmap;
94
95out_free:
96 kfree(gmap);
97out:
98 return NULL;
99}
100
101/**
102 * gmap_create - create a guest address space
103 * @mm: pointer to the parent mm_struct
104 * @limit: maximum size of the gmap address space
105 *
106 * Returns a guest address space structure.
107 */
108struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit)
109{
110 struct gmap *gmap;
111 unsigned long gmap_asce;
112
113 gmap = gmap_alloc(limit);
114 if (!gmap)
115 return NULL;
116 gmap->mm = mm;
117 spin_lock(&mm->context.lock);
118 list_add_rcu(&gmap->list, &mm->context.gmap_list);
119 if (list_is_singular(&mm->context.gmap_list))
120 gmap_asce = gmap->asce;
121 else
122 gmap_asce = -1UL;
123 WRITE_ONCE(mm->context.gmap_asce, gmap_asce);
124 spin_unlock(&mm->context.lock);
125 return gmap;
126}
127EXPORT_SYMBOL_GPL(gmap_create);
128
129static void gmap_flush_tlb(struct gmap *gmap)
130{
131 if (MACHINE_HAS_IDTE)
132 __tlb_flush_idte(gmap->asce);
133 else
134 __tlb_flush_global();
135}
136
137static void gmap_radix_tree_free(struct radix_tree_root *root)
138{
139 struct radix_tree_iter iter;
140 unsigned long indices[16];
141 unsigned long index;
142 void __rcu **slot;
143 int i, nr;
144
145 /* A radix tree is freed by deleting all of its entries */
146 index = 0;
147 do {
148 nr = 0;
149 radix_tree_for_each_slot(slot, root, &iter, index) {
150 indices[nr] = iter.index;
151 if (++nr == 16)
152 break;
153 }
154 for (i = 0; i < nr; i++) {
155 index = indices[i];
156 radix_tree_delete(root, index);
157 }
158 } while (nr > 0);
159}
160
161static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
162{
163 struct gmap_rmap *rmap, *rnext, *head;
164 struct radix_tree_iter iter;
165 unsigned long indices[16];
166 unsigned long index;
167 void __rcu **slot;
168 int i, nr;
169
170 /* A radix tree is freed by deleting all of its entries */
171 index = 0;
172 do {
173 nr = 0;
174 radix_tree_for_each_slot(slot, root, &iter, index) {
175 indices[nr] = iter.index;
176 if (++nr == 16)
177 break;
178 }
179 for (i = 0; i < nr; i++) {
180 index = indices[i];
181 head = radix_tree_delete(root, index);
182 gmap_for_each_rmap_safe(rmap, rnext, head)
183 kfree(rmap);
184 }
185 } while (nr > 0);
186}
187
188/**
189 * gmap_free - free a guest address space
190 * @gmap: pointer to the guest address space structure
191 *
192 * No locks required. There are no references to this gmap anymore.
193 */
194static void gmap_free(struct gmap *gmap)
195{
196 struct page *page, *next;
197
198 /* Flush tlb of all gmaps (if not already done for shadows) */
199 if (!(gmap_is_shadow(gmap) && gmap->removed))
200 gmap_flush_tlb(gmap);
201 /* Free all segment & region tables. */
202 list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
203 __free_pages(page, CRST_ALLOC_ORDER);
204 gmap_radix_tree_free(&gmap->guest_to_host);
205 gmap_radix_tree_free(&gmap->host_to_guest);
206
207 /* Free additional data for a shadow gmap */
208 if (gmap_is_shadow(gmap)) {
209 struct ptdesc *ptdesc, *n;
210
211 /* Free all page tables. */
212 list_for_each_entry_safe(ptdesc, n, &gmap->pt_list, pt_list)
213 page_table_free_pgste(ptdesc);
214 gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
215 /* Release reference to the parent */
216 gmap_put(gmap->parent);
217 }
218
219 kfree(gmap);
220}
221
222/**
223 * gmap_get - increase reference counter for guest address space
224 * @gmap: pointer to the guest address space structure
225 *
226 * Returns the gmap pointer
227 */
228struct gmap *gmap_get(struct gmap *gmap)
229{
230 refcount_inc(&gmap->ref_count);
231 return gmap;
232}
233EXPORT_SYMBOL_GPL(gmap_get);
234
235/**
236 * gmap_put - decrease reference counter for guest address space
237 * @gmap: pointer to the guest address space structure
238 *
239 * If the reference counter reaches zero the guest address space is freed.
240 */
241void gmap_put(struct gmap *gmap)
242{
243 if (refcount_dec_and_test(&gmap->ref_count))
244 gmap_free(gmap);
245}
246EXPORT_SYMBOL_GPL(gmap_put);
247
248/**
249 * gmap_remove - remove a guest address space but do not free it yet
250 * @gmap: pointer to the guest address space structure
251 */
252void gmap_remove(struct gmap *gmap)
253{
254 struct gmap *sg, *next;
255 unsigned long gmap_asce;
256
257 /* Remove all shadow gmaps linked to this gmap */
258 if (!list_empty(&gmap->children)) {
259 spin_lock(&gmap->shadow_lock);
260 list_for_each_entry_safe(sg, next, &gmap->children, list) {
261 list_del(&sg->list);
262 gmap_put(sg);
263 }
264 spin_unlock(&gmap->shadow_lock);
265 }
266 /* Remove gmap from the pre-mm list */
267 spin_lock(&gmap->mm->context.lock);
268 list_del_rcu(&gmap->list);
269 if (list_empty(&gmap->mm->context.gmap_list))
270 gmap_asce = 0;
271 else if (list_is_singular(&gmap->mm->context.gmap_list))
272 gmap_asce = list_first_entry(&gmap->mm->context.gmap_list,
273 struct gmap, list)->asce;
274 else
275 gmap_asce = -1UL;
276 WRITE_ONCE(gmap->mm->context.gmap_asce, gmap_asce);
277 spin_unlock(&gmap->mm->context.lock);
278 synchronize_rcu();
279 /* Put reference */
280 gmap_put(gmap);
281}
282EXPORT_SYMBOL_GPL(gmap_remove);
283
284/**
285 * gmap_enable - switch primary space to the guest address space
286 * @gmap: pointer to the guest address space structure
287 */
288void gmap_enable(struct gmap *gmap)
289{
290 S390_lowcore.gmap = (unsigned long) gmap;
291}
292EXPORT_SYMBOL_GPL(gmap_enable);
293
294/**
295 * gmap_disable - switch back to the standard primary address space
296 * @gmap: pointer to the guest address space structure
297 */
298void gmap_disable(struct gmap *gmap)
299{
300 S390_lowcore.gmap = 0UL;
301}
302EXPORT_SYMBOL_GPL(gmap_disable);
303
304/**
305 * gmap_get_enabled - get a pointer to the currently enabled gmap
306 *
307 * Returns a pointer to the currently enabled gmap. 0 if none is enabled.
308 */
309struct gmap *gmap_get_enabled(void)
310{
311 return (struct gmap *) S390_lowcore.gmap;
312}
313EXPORT_SYMBOL_GPL(gmap_get_enabled);
314
315/*
316 * gmap_alloc_table is assumed to be called with mmap_lock held
317 */
318static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
319 unsigned long init, unsigned long gaddr)
320{
321 struct page *page;
322 unsigned long *new;
323
324 /* since we dont free the gmap table until gmap_free we can unlock */
325 page = gmap_alloc_crst();
326 if (!page)
327 return -ENOMEM;
328 new = page_to_virt(page);
329 crst_table_init(new, init);
330 spin_lock(&gmap->guest_table_lock);
331 if (*table & _REGION_ENTRY_INVALID) {
332 list_add(&page->lru, &gmap->crst_list);
333 *table = __pa(new) | _REGION_ENTRY_LENGTH |
334 (*table & _REGION_ENTRY_TYPE_MASK);
335 page->index = gaddr;
336 page = NULL;
337 }
338 spin_unlock(&gmap->guest_table_lock);
339 if (page)
340 __free_pages(page, CRST_ALLOC_ORDER);
341 return 0;
342}
343
344/**
345 * __gmap_segment_gaddr - find virtual address from segment pointer
346 * @entry: pointer to a segment table entry in the guest address space
347 *
348 * Returns the virtual address in the guest address space for the segment
349 */
350static unsigned long __gmap_segment_gaddr(unsigned long *entry)
351{
352 struct page *page;
353 unsigned long offset;
354
355 offset = (unsigned long) entry / sizeof(unsigned long);
356 offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
357 page = pmd_pgtable_page((pmd_t *) entry);
358 return page->index + offset;
359}
360
361/**
362 * __gmap_unlink_by_vmaddr - unlink a single segment via a host address
363 * @gmap: pointer to the guest address space structure
364 * @vmaddr: address in the host process address space
365 *
366 * Returns 1 if a TLB flush is required
367 */
368static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr)
369{
370 unsigned long *entry;
371 int flush = 0;
372
373 BUG_ON(gmap_is_shadow(gmap));
374 spin_lock(&gmap->guest_table_lock);
375 entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
376 if (entry) {
377 flush = (*entry != _SEGMENT_ENTRY_EMPTY);
378 *entry = _SEGMENT_ENTRY_EMPTY;
379 }
380 spin_unlock(&gmap->guest_table_lock);
381 return flush;
382}
383
384/**
385 * __gmap_unmap_by_gaddr - unmap a single segment via a guest address
386 * @gmap: pointer to the guest address space structure
387 * @gaddr: address in the guest address space
388 *
389 * Returns 1 if a TLB flush is required
390 */
391static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr)
392{
393 unsigned long vmaddr;
394
395 vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host,
396 gaddr >> PMD_SHIFT);
397 return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0;
398}
399
400/**
401 * gmap_unmap_segment - unmap segment from the guest address space
402 * @gmap: pointer to the guest address space structure
403 * @to: address in the guest address space
404 * @len: length of the memory area to unmap
405 *
406 * Returns 0 if the unmap succeeded, -EINVAL if not.
407 */
408int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
409{
410 unsigned long off;
411 int flush;
412
413 BUG_ON(gmap_is_shadow(gmap));
414 if ((to | len) & (PMD_SIZE - 1))
415 return -EINVAL;
416 if (len == 0 || to + len < to)
417 return -EINVAL;
418
419 flush = 0;
420 mmap_write_lock(gmap->mm);
421 for (off = 0; off < len; off += PMD_SIZE)
422 flush |= __gmap_unmap_by_gaddr(gmap, to + off);
423 mmap_write_unlock(gmap->mm);
424 if (flush)
425 gmap_flush_tlb(gmap);
426 return 0;
427}
428EXPORT_SYMBOL_GPL(gmap_unmap_segment);
429
430/**
431 * gmap_map_segment - map a segment to the guest address space
432 * @gmap: pointer to the guest address space structure
433 * @from: source address in the parent address space
434 * @to: target address in the guest address space
435 * @len: length of the memory area to map
436 *
437 * Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not.
438 */
439int gmap_map_segment(struct gmap *gmap, unsigned long from,
440 unsigned long to, unsigned long len)
441{
442 unsigned long off;
443 int flush;
444
445 BUG_ON(gmap_is_shadow(gmap));
446 if ((from | to | len) & (PMD_SIZE - 1))
447 return -EINVAL;
448 if (len == 0 || from + len < from || to + len < to ||
449 from + len - 1 > TASK_SIZE_MAX || to + len - 1 > gmap->asce_end)
450 return -EINVAL;
451
452 flush = 0;
453 mmap_write_lock(gmap->mm);
454 for (off = 0; off < len; off += PMD_SIZE) {
455 /* Remove old translation */
456 flush |= __gmap_unmap_by_gaddr(gmap, to + off);
457 /* Store new translation */
458 if (radix_tree_insert(&gmap->guest_to_host,
459 (to + off) >> PMD_SHIFT,
460 (void *) from + off))
461 break;
462 }
463 mmap_write_unlock(gmap->mm);
464 if (flush)
465 gmap_flush_tlb(gmap);
466 if (off >= len)
467 return 0;
468 gmap_unmap_segment(gmap, to, len);
469 return -ENOMEM;
470}
471EXPORT_SYMBOL_GPL(gmap_map_segment);
472
473/**
474 * __gmap_translate - translate a guest address to a user space address
475 * @gmap: pointer to guest mapping meta data structure
476 * @gaddr: guest address
477 *
478 * Returns user space address which corresponds to the guest address or
479 * -EFAULT if no such mapping exists.
480 * This function does not establish potentially missing page table entries.
481 * The mmap_lock of the mm that belongs to the address space must be held
482 * when this function gets called.
483 *
484 * Note: Can also be called for shadow gmaps.
485 */
486unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
487{
488 unsigned long vmaddr;
489
490 vmaddr = (unsigned long)
491 radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
492 /* Note: guest_to_host is empty for a shadow gmap */
493 return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
494}
495EXPORT_SYMBOL_GPL(__gmap_translate);
496
497/**
498 * gmap_translate - translate a guest address to a user space address
499 * @gmap: pointer to guest mapping meta data structure
500 * @gaddr: guest address
501 *
502 * Returns user space address which corresponds to the guest address or
503 * -EFAULT if no such mapping exists.
504 * This function does not establish potentially missing page table entries.
505 */
506unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr)
507{
508 unsigned long rc;
509
510 mmap_read_lock(gmap->mm);
511 rc = __gmap_translate(gmap, gaddr);
512 mmap_read_unlock(gmap->mm);
513 return rc;
514}
515EXPORT_SYMBOL_GPL(gmap_translate);
516
517/**
518 * gmap_unlink - disconnect a page table from the gmap shadow tables
519 * @mm: pointer to the parent mm_struct
520 * @table: pointer to the host page table
521 * @vmaddr: vm address associated with the host page table
522 */
523void gmap_unlink(struct mm_struct *mm, unsigned long *table,
524 unsigned long vmaddr)
525{
526 struct gmap *gmap;
527 int flush;
528
529 rcu_read_lock();
530 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
531 flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
532 if (flush)
533 gmap_flush_tlb(gmap);
534 }
535 rcu_read_unlock();
536}
537
538static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *old, pmd_t new,
539 unsigned long gaddr);
540
541/**
542 * __gmap_link - set up shadow page tables to connect a host to a guest address
543 * @gmap: pointer to guest mapping meta data structure
544 * @gaddr: guest address
545 * @vmaddr: vm address
546 *
547 * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
548 * if the vm address is already mapped to a different guest segment.
549 * The mmap_lock of the mm that belongs to the address space must be held
550 * when this function gets called.
551 */
552int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
553{
554 struct mm_struct *mm;
555 unsigned long *table;
556 spinlock_t *ptl;
557 pgd_t *pgd;
558 p4d_t *p4d;
559 pud_t *pud;
560 pmd_t *pmd;
561 u64 unprot;
562 int rc;
563
564 BUG_ON(gmap_is_shadow(gmap));
565 /* Create higher level tables in the gmap page table */
566 table = gmap->table;
567 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
568 table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
569 if ((*table & _REGION_ENTRY_INVALID) &&
570 gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
571 gaddr & _REGION1_MASK))
572 return -ENOMEM;
573 table = __va(*table & _REGION_ENTRY_ORIGIN);
574 }
575 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
576 table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
577 if ((*table & _REGION_ENTRY_INVALID) &&
578 gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
579 gaddr & _REGION2_MASK))
580 return -ENOMEM;
581 table = __va(*table & _REGION_ENTRY_ORIGIN);
582 }
583 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
584 table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
585 if ((*table & _REGION_ENTRY_INVALID) &&
586 gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
587 gaddr & _REGION3_MASK))
588 return -ENOMEM;
589 table = __va(*table & _REGION_ENTRY_ORIGIN);
590 }
591 table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
592 /* Walk the parent mm page table */
593 mm = gmap->mm;
594 pgd = pgd_offset(mm, vmaddr);
595 VM_BUG_ON(pgd_none(*pgd));
596 p4d = p4d_offset(pgd, vmaddr);
597 VM_BUG_ON(p4d_none(*p4d));
598 pud = pud_offset(p4d, vmaddr);
599 VM_BUG_ON(pud_none(*pud));
600 /* large puds cannot yet be handled */
601 if (pud_leaf(*pud))
602 return -EFAULT;
603 pmd = pmd_offset(pud, vmaddr);
604 VM_BUG_ON(pmd_none(*pmd));
605 /* Are we allowed to use huge pages? */
606 if (pmd_leaf(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m)
607 return -EFAULT;
608 /* Link gmap segment table entry location to page table. */
609 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
610 if (rc)
611 return rc;
612 ptl = pmd_lock(mm, pmd);
613 spin_lock(&gmap->guest_table_lock);
614 if (*table == _SEGMENT_ENTRY_EMPTY) {
615 rc = radix_tree_insert(&gmap->host_to_guest,
616 vmaddr >> PMD_SHIFT, table);
617 if (!rc) {
618 if (pmd_leaf(*pmd)) {
619 *table = (pmd_val(*pmd) &
620 _SEGMENT_ENTRY_HARDWARE_BITS_LARGE)
621 | _SEGMENT_ENTRY_GMAP_UC;
622 } else
623 *table = pmd_val(*pmd) &
624 _SEGMENT_ENTRY_HARDWARE_BITS;
625 }
626 } else if (*table & _SEGMENT_ENTRY_PROTECT &&
627 !(pmd_val(*pmd) & _SEGMENT_ENTRY_PROTECT)) {
628 unprot = (u64)*table;
629 unprot &= ~_SEGMENT_ENTRY_PROTECT;
630 unprot |= _SEGMENT_ENTRY_GMAP_UC;
631 gmap_pmdp_xchg(gmap, (pmd_t *)table, __pmd(unprot), gaddr);
632 }
633 spin_unlock(&gmap->guest_table_lock);
634 spin_unlock(ptl);
635 radix_tree_preload_end();
636 return rc;
637}
638
639/**
640 * gmap_fault - resolve a fault on a guest address
641 * @gmap: pointer to guest mapping meta data structure
642 * @gaddr: guest address
643 * @fault_flags: flags to pass down to handle_mm_fault()
644 *
645 * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
646 * if the vm address is already mapped to a different guest segment.
647 */
648int gmap_fault(struct gmap *gmap, unsigned long gaddr,
649 unsigned int fault_flags)
650{
651 unsigned long vmaddr;
652 int rc;
653 bool unlocked;
654
655 mmap_read_lock(gmap->mm);
656
657retry:
658 unlocked = false;
659 vmaddr = __gmap_translate(gmap, gaddr);
660 if (IS_ERR_VALUE(vmaddr)) {
661 rc = vmaddr;
662 goto out_up;
663 }
664 if (fixup_user_fault(gmap->mm, vmaddr, fault_flags,
665 &unlocked)) {
666 rc = -EFAULT;
667 goto out_up;
668 }
669 /*
670 * In the case that fixup_user_fault unlocked the mmap_lock during
671 * faultin redo __gmap_translate to not race with a map/unmap_segment.
672 */
673 if (unlocked)
674 goto retry;
675
676 rc = __gmap_link(gmap, gaddr, vmaddr);
677out_up:
678 mmap_read_unlock(gmap->mm);
679 return rc;
680}
681EXPORT_SYMBOL_GPL(gmap_fault);
682
683/*
684 * this function is assumed to be called with mmap_lock held
685 */
686void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
687{
688 struct vm_area_struct *vma;
689 unsigned long vmaddr;
690 spinlock_t *ptl;
691 pte_t *ptep;
692
693 /* Find the vm address for the guest address */
694 vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
695 gaddr >> PMD_SHIFT);
696 if (vmaddr) {
697 vmaddr |= gaddr & ~PMD_MASK;
698
699 vma = vma_lookup(gmap->mm, vmaddr);
700 if (!vma || is_vm_hugetlb_page(vma))
701 return;
702
703 /* Get pointer to the page table entry */
704 ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
705 if (likely(ptep)) {
706 ptep_zap_unused(gmap->mm, vmaddr, ptep, 0);
707 pte_unmap_unlock(ptep, ptl);
708 }
709 }
710}
711EXPORT_SYMBOL_GPL(__gmap_zap);
712
713void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
714{
715 unsigned long gaddr, vmaddr, size;
716 struct vm_area_struct *vma;
717
718 mmap_read_lock(gmap->mm);
719 for (gaddr = from; gaddr < to;
720 gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
721 /* Find the vm address for the guest address */
722 vmaddr = (unsigned long)
723 radix_tree_lookup(&gmap->guest_to_host,
724 gaddr >> PMD_SHIFT);
725 if (!vmaddr)
726 continue;
727 vmaddr |= gaddr & ~PMD_MASK;
728 /* Find vma in the parent mm */
729 vma = find_vma(gmap->mm, vmaddr);
730 if (!vma)
731 continue;
732 /*
733 * We do not discard pages that are backed by
734 * hugetlbfs, so we don't have to refault them.
735 */
736 if (is_vm_hugetlb_page(vma))
737 continue;
738 size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
739 zap_page_range_single(vma, vmaddr, size, NULL);
740 }
741 mmap_read_unlock(gmap->mm);
742}
743EXPORT_SYMBOL_GPL(gmap_discard);
744
745static LIST_HEAD(gmap_notifier_list);
746static DEFINE_SPINLOCK(gmap_notifier_lock);
747
748/**
749 * gmap_register_pte_notifier - register a pte invalidation callback
750 * @nb: pointer to the gmap notifier block
751 */
752void gmap_register_pte_notifier(struct gmap_notifier *nb)
753{
754 spin_lock(&gmap_notifier_lock);
755 list_add_rcu(&nb->list, &gmap_notifier_list);
756 spin_unlock(&gmap_notifier_lock);
757}
758EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
759
760/**
761 * gmap_unregister_pte_notifier - remove a pte invalidation callback
762 * @nb: pointer to the gmap notifier block
763 */
764void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
765{
766 spin_lock(&gmap_notifier_lock);
767 list_del_rcu(&nb->list);
768 spin_unlock(&gmap_notifier_lock);
769 synchronize_rcu();
770}
771EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
772
773/**
774 * gmap_call_notifier - call all registered invalidation callbacks
775 * @gmap: pointer to guest mapping meta data structure
776 * @start: start virtual address in the guest address space
777 * @end: end virtual address in the guest address space
778 */
779static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
780 unsigned long end)
781{
782 struct gmap_notifier *nb;
783
784 list_for_each_entry(nb, &gmap_notifier_list, list)
785 nb->notifier_call(gmap, start, end);
786}
787
788/**
789 * gmap_table_walk - walk the gmap page tables
790 * @gmap: pointer to guest mapping meta data structure
791 * @gaddr: virtual address in the guest address space
792 * @level: page table level to stop at
793 *
794 * Returns a table entry pointer for the given guest address and @level
795 * @level=0 : returns a pointer to a page table table entry (or NULL)
796 * @level=1 : returns a pointer to a segment table entry (or NULL)
797 * @level=2 : returns a pointer to a region-3 table entry (or NULL)
798 * @level=3 : returns a pointer to a region-2 table entry (or NULL)
799 * @level=4 : returns a pointer to a region-1 table entry (or NULL)
800 *
801 * Returns NULL if the gmap page tables could not be walked to the
802 * requested level.
803 *
804 * Note: Can also be called for shadow gmaps.
805 */
806static inline unsigned long *gmap_table_walk(struct gmap *gmap,
807 unsigned long gaddr, int level)
808{
809 const int asce_type = gmap->asce & _ASCE_TYPE_MASK;
810 unsigned long *table = gmap->table;
811
812 if (gmap_is_shadow(gmap) && gmap->removed)
813 return NULL;
814
815 if (WARN_ON_ONCE(level > (asce_type >> 2) + 1))
816 return NULL;
817
818 if (asce_type != _ASCE_TYPE_REGION1 &&
819 gaddr & (-1UL << (31 + (asce_type >> 2) * 11)))
820 return NULL;
821
822 switch (asce_type) {
823 case _ASCE_TYPE_REGION1:
824 table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
825 if (level == 4)
826 break;
827 if (*table & _REGION_ENTRY_INVALID)
828 return NULL;
829 table = __va(*table & _REGION_ENTRY_ORIGIN);
830 fallthrough;
831 case _ASCE_TYPE_REGION2:
832 table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
833 if (level == 3)
834 break;
835 if (*table & _REGION_ENTRY_INVALID)
836 return NULL;
837 table = __va(*table & _REGION_ENTRY_ORIGIN);
838 fallthrough;
839 case _ASCE_TYPE_REGION3:
840 table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
841 if (level == 2)
842 break;
843 if (*table & _REGION_ENTRY_INVALID)
844 return NULL;
845 table = __va(*table & _REGION_ENTRY_ORIGIN);
846 fallthrough;
847 case _ASCE_TYPE_SEGMENT:
848 table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
849 if (level == 1)
850 break;
851 if (*table & _REGION_ENTRY_INVALID)
852 return NULL;
853 table = __va(*table & _SEGMENT_ENTRY_ORIGIN);
854 table += (gaddr & _PAGE_INDEX) >> _PAGE_SHIFT;
855 }
856 return table;
857}
858
859/**
860 * gmap_pte_op_walk - walk the gmap page table, get the page table lock
861 * and return the pte pointer
862 * @gmap: pointer to guest mapping meta data structure
863 * @gaddr: virtual address in the guest address space
864 * @ptl: pointer to the spinlock pointer
865 *
866 * Returns a pointer to the locked pte for a guest address, or NULL
867 */
868static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
869 spinlock_t **ptl)
870{
871 unsigned long *table;
872
873 BUG_ON(gmap_is_shadow(gmap));
874 /* Walk the gmap page table, lock and get pte pointer */
875 table = gmap_table_walk(gmap, gaddr, 1); /* get segment pointer */
876 if (!table || *table & _SEGMENT_ENTRY_INVALID)
877 return NULL;
878 return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl);
879}
880
881/**
882 * gmap_pte_op_fixup - force a page in and connect the gmap page table
883 * @gmap: pointer to guest mapping meta data structure
884 * @gaddr: virtual address in the guest address space
885 * @vmaddr: address in the host process address space
886 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
887 *
888 * Returns 0 if the caller can retry __gmap_translate (might fail again),
889 * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing
890 * up or connecting the gmap page table.
891 */
892static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
893 unsigned long vmaddr, int prot)
894{
895 struct mm_struct *mm = gmap->mm;
896 unsigned int fault_flags;
897 bool unlocked = false;
898
899 BUG_ON(gmap_is_shadow(gmap));
900 fault_flags = (prot == PROT_WRITE) ? FAULT_FLAG_WRITE : 0;
901 if (fixup_user_fault(mm, vmaddr, fault_flags, &unlocked))
902 return -EFAULT;
903 if (unlocked)
904 /* lost mmap_lock, caller has to retry __gmap_translate */
905 return 0;
906 /* Connect the page tables */
907 return __gmap_link(gmap, gaddr, vmaddr);
908}
909
910/**
911 * gmap_pte_op_end - release the page table lock
912 * @ptep: pointer to the locked pte
913 * @ptl: pointer to the page table spinlock
914 */
915static void gmap_pte_op_end(pte_t *ptep, spinlock_t *ptl)
916{
917 pte_unmap_unlock(ptep, ptl);
918}
919
920/**
921 * gmap_pmd_op_walk - walk the gmap tables, get the guest table lock
922 * and return the pmd pointer
923 * @gmap: pointer to guest mapping meta data structure
924 * @gaddr: virtual address in the guest address space
925 *
926 * Returns a pointer to the pmd for a guest address, or NULL
927 */
928static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr)
929{
930 pmd_t *pmdp;
931
932 BUG_ON(gmap_is_shadow(gmap));
933 pmdp = (pmd_t *) gmap_table_walk(gmap, gaddr, 1);
934 if (!pmdp)
935 return NULL;
936
937 /* without huge pages, there is no need to take the table lock */
938 if (!gmap->mm->context.allow_gmap_hpage_1m)
939 return pmd_none(*pmdp) ? NULL : pmdp;
940
941 spin_lock(&gmap->guest_table_lock);
942 if (pmd_none(*pmdp)) {
943 spin_unlock(&gmap->guest_table_lock);
944 return NULL;
945 }
946
947 /* 4k page table entries are locked via the pte (pte_alloc_map_lock). */
948 if (!pmd_leaf(*pmdp))
949 spin_unlock(&gmap->guest_table_lock);
950 return pmdp;
951}
952
953/**
954 * gmap_pmd_op_end - release the guest_table_lock if needed
955 * @gmap: pointer to the guest mapping meta data structure
956 * @pmdp: pointer to the pmd
957 */
958static inline void gmap_pmd_op_end(struct gmap *gmap, pmd_t *pmdp)
959{
960 if (pmd_leaf(*pmdp))
961 spin_unlock(&gmap->guest_table_lock);
962}
963
964/*
965 * gmap_protect_pmd - remove access rights to memory and set pmd notification bits
966 * @pmdp: pointer to the pmd to be protected
967 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
968 * @bits: notification bits to set
969 *
970 * Returns:
971 * 0 if successfully protected
972 * -EAGAIN if a fixup is needed
973 * -EINVAL if unsupported notifier bits have been specified
974 *
975 * Expected to be called with sg->mm->mmap_lock in read and
976 * guest_table_lock held.
977 */
978static int gmap_protect_pmd(struct gmap *gmap, unsigned long gaddr,
979 pmd_t *pmdp, int prot, unsigned long bits)
980{
981 int pmd_i = pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID;
982 int pmd_p = pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT;
983 pmd_t new = *pmdp;
984
985 /* Fixup needed */
986 if ((pmd_i && (prot != PROT_NONE)) || (pmd_p && (prot == PROT_WRITE)))
987 return -EAGAIN;
988
989 if (prot == PROT_NONE && !pmd_i) {
990 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
991 gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
992 }
993
994 if (prot == PROT_READ && !pmd_p) {
995 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
996 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_PROTECT));
997 gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
998 }
999
1000 if (bits & GMAP_NOTIFY_MPROT)
1001 set_pmd(pmdp, set_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN)));
1002
1003 /* Shadow GMAP protection needs split PMDs */
1004 if (bits & GMAP_NOTIFY_SHADOW)
1005 return -EINVAL;
1006
1007 return 0;
1008}
1009
1010/*
1011 * gmap_protect_pte - remove access rights to memory and set pgste bits
1012 * @gmap: pointer to guest mapping meta data structure
1013 * @gaddr: virtual address in the guest address space
1014 * @pmdp: pointer to the pmd associated with the pte
1015 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1016 * @bits: notification bits to set
1017 *
1018 * Returns 0 if successfully protected, -ENOMEM if out of memory and
1019 * -EAGAIN if a fixup is needed.
1020 *
1021 * Expected to be called with sg->mm->mmap_lock in read
1022 */
1023static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
1024 pmd_t *pmdp, int prot, unsigned long bits)
1025{
1026 int rc;
1027 pte_t *ptep;
1028 spinlock_t *ptl;
1029 unsigned long pbits = 0;
1030
1031 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
1032 return -EAGAIN;
1033
1034 ptep = pte_alloc_map_lock(gmap->mm, pmdp, gaddr, &ptl);
1035 if (!ptep)
1036 return -ENOMEM;
1037
1038 pbits |= (bits & GMAP_NOTIFY_MPROT) ? PGSTE_IN_BIT : 0;
1039 pbits |= (bits & GMAP_NOTIFY_SHADOW) ? PGSTE_VSIE_BIT : 0;
1040 /* Protect and unlock. */
1041 rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits);
1042 gmap_pte_op_end(ptep, ptl);
1043 return rc;
1044}
1045
1046/*
1047 * gmap_protect_range - remove access rights to memory and set pgste bits
1048 * @gmap: pointer to guest mapping meta data structure
1049 * @gaddr: virtual address in the guest address space
1050 * @len: size of area
1051 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1052 * @bits: pgste notification bits to set
1053 *
1054 * Returns 0 if successfully protected, -ENOMEM if out of memory and
1055 * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
1056 *
1057 * Called with sg->mm->mmap_lock in read.
1058 */
1059static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
1060 unsigned long len, int prot, unsigned long bits)
1061{
1062 unsigned long vmaddr, dist;
1063 pmd_t *pmdp;
1064 int rc;
1065
1066 BUG_ON(gmap_is_shadow(gmap));
1067 while (len) {
1068 rc = -EAGAIN;
1069 pmdp = gmap_pmd_op_walk(gmap, gaddr);
1070 if (pmdp) {
1071 if (!pmd_leaf(*pmdp)) {
1072 rc = gmap_protect_pte(gmap, gaddr, pmdp, prot,
1073 bits);
1074 if (!rc) {
1075 len -= PAGE_SIZE;
1076 gaddr += PAGE_SIZE;
1077 }
1078 } else {
1079 rc = gmap_protect_pmd(gmap, gaddr, pmdp, prot,
1080 bits);
1081 if (!rc) {
1082 dist = HPAGE_SIZE - (gaddr & ~HPAGE_MASK);
1083 len = len < dist ? 0 : len - dist;
1084 gaddr = (gaddr & HPAGE_MASK) + HPAGE_SIZE;
1085 }
1086 }
1087 gmap_pmd_op_end(gmap, pmdp);
1088 }
1089 if (rc) {
1090 if (rc == -EINVAL)
1091 return rc;
1092
1093 /* -EAGAIN, fixup of userspace mm and gmap */
1094 vmaddr = __gmap_translate(gmap, gaddr);
1095 if (IS_ERR_VALUE(vmaddr))
1096 return vmaddr;
1097 rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot);
1098 if (rc)
1099 return rc;
1100 }
1101 }
1102 return 0;
1103}
1104
1105/**
1106 * gmap_mprotect_notify - change access rights for a range of ptes and
1107 * call the notifier if any pte changes again
1108 * @gmap: pointer to guest mapping meta data structure
1109 * @gaddr: virtual address in the guest address space
1110 * @len: size of area
1111 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1112 *
1113 * Returns 0 if for each page in the given range a gmap mapping exists,
1114 * the new access rights could be set and the notifier could be armed.
1115 * If the gmap mapping is missing for one or more pages -EFAULT is
1116 * returned. If no memory could be allocated -ENOMEM is returned.
1117 * This function establishes missing page table entries.
1118 */
1119int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
1120 unsigned long len, int prot)
1121{
1122 int rc;
1123
1124 if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
1125 return -EINVAL;
1126 if (!MACHINE_HAS_ESOP && prot == PROT_READ)
1127 return -EINVAL;
1128 mmap_read_lock(gmap->mm);
1129 rc = gmap_protect_range(gmap, gaddr, len, prot, GMAP_NOTIFY_MPROT);
1130 mmap_read_unlock(gmap->mm);
1131 return rc;
1132}
1133EXPORT_SYMBOL_GPL(gmap_mprotect_notify);
1134
1135/**
1136 * gmap_read_table - get an unsigned long value from a guest page table using
1137 * absolute addressing, without marking the page referenced.
1138 * @gmap: pointer to guest mapping meta data structure
1139 * @gaddr: virtual address in the guest address space
1140 * @val: pointer to the unsigned long value to return
1141 *
1142 * Returns 0 if the value was read, -ENOMEM if out of memory and -EFAULT
1143 * if reading using the virtual address failed. -EINVAL if called on a gmap
1144 * shadow.
1145 *
1146 * Called with gmap->mm->mmap_lock in read.
1147 */
1148int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
1149{
1150 unsigned long address, vmaddr;
1151 spinlock_t *ptl;
1152 pte_t *ptep, pte;
1153 int rc;
1154
1155 if (gmap_is_shadow(gmap))
1156 return -EINVAL;
1157
1158 while (1) {
1159 rc = -EAGAIN;
1160 ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
1161 if (ptep) {
1162 pte = *ptep;
1163 if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) {
1164 address = pte_val(pte) & PAGE_MASK;
1165 address += gaddr & ~PAGE_MASK;
1166 *val = *(unsigned long *)__va(address);
1167 set_pte(ptep, set_pte_bit(*ptep, __pgprot(_PAGE_YOUNG)));
1168 /* Do *NOT* clear the _PAGE_INVALID bit! */
1169 rc = 0;
1170 }
1171 gmap_pte_op_end(ptep, ptl);
1172 }
1173 if (!rc)
1174 break;
1175 vmaddr = __gmap_translate(gmap, gaddr);
1176 if (IS_ERR_VALUE(vmaddr)) {
1177 rc = vmaddr;
1178 break;
1179 }
1180 rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, PROT_READ);
1181 if (rc)
1182 break;
1183 }
1184 return rc;
1185}
1186EXPORT_SYMBOL_GPL(gmap_read_table);
1187
1188/**
1189 * gmap_insert_rmap - add a rmap to the host_to_rmap radix tree
1190 * @sg: pointer to the shadow guest address space structure
1191 * @vmaddr: vm address associated with the rmap
1192 * @rmap: pointer to the rmap structure
1193 *
1194 * Called with the sg->guest_table_lock
1195 */
1196static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
1197 struct gmap_rmap *rmap)
1198{
1199 struct gmap_rmap *temp;
1200 void __rcu **slot;
1201
1202 BUG_ON(!gmap_is_shadow(sg));
1203 slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
1204 if (slot) {
1205 rmap->next = radix_tree_deref_slot_protected(slot,
1206 &sg->guest_table_lock);
1207 for (temp = rmap->next; temp; temp = temp->next) {
1208 if (temp->raddr == rmap->raddr) {
1209 kfree(rmap);
1210 return;
1211 }
1212 }
1213 radix_tree_replace_slot(&sg->host_to_rmap, slot, rmap);
1214 } else {
1215 rmap->next = NULL;
1216 radix_tree_insert(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT,
1217 rmap);
1218 }
1219}
1220
1221/**
1222 * gmap_protect_rmap - restrict access rights to memory (RO) and create an rmap
1223 * @sg: pointer to the shadow guest address space structure
1224 * @raddr: rmap address in the shadow gmap
1225 * @paddr: address in the parent guest address space
1226 * @len: length of the memory area to protect
1227 *
1228 * Returns 0 if successfully protected and the rmap was created, -ENOMEM
1229 * if out of memory and -EFAULT if paddr is invalid.
1230 */
1231static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
1232 unsigned long paddr, unsigned long len)
1233{
1234 struct gmap *parent;
1235 struct gmap_rmap *rmap;
1236 unsigned long vmaddr;
1237 spinlock_t *ptl;
1238 pte_t *ptep;
1239 int rc;
1240
1241 BUG_ON(!gmap_is_shadow(sg));
1242 parent = sg->parent;
1243 while (len) {
1244 vmaddr = __gmap_translate(parent, paddr);
1245 if (IS_ERR_VALUE(vmaddr))
1246 return vmaddr;
1247 rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT);
1248 if (!rmap)
1249 return -ENOMEM;
1250 rmap->raddr = raddr;
1251 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
1252 if (rc) {
1253 kfree(rmap);
1254 return rc;
1255 }
1256 rc = -EAGAIN;
1257 ptep = gmap_pte_op_walk(parent, paddr, &ptl);
1258 if (ptep) {
1259 spin_lock(&sg->guest_table_lock);
1260 rc = ptep_force_prot(parent->mm, paddr, ptep, PROT_READ,
1261 PGSTE_VSIE_BIT);
1262 if (!rc)
1263 gmap_insert_rmap(sg, vmaddr, rmap);
1264 spin_unlock(&sg->guest_table_lock);
1265 gmap_pte_op_end(ptep, ptl);
1266 }
1267 radix_tree_preload_end();
1268 if (rc) {
1269 kfree(rmap);
1270 rc = gmap_pte_op_fixup(parent, paddr, vmaddr, PROT_READ);
1271 if (rc)
1272 return rc;
1273 continue;
1274 }
1275 paddr += PAGE_SIZE;
1276 len -= PAGE_SIZE;
1277 }
1278 return 0;
1279}
1280
1281#define _SHADOW_RMAP_MASK 0x7
1282#define _SHADOW_RMAP_REGION1 0x5
1283#define _SHADOW_RMAP_REGION2 0x4
1284#define _SHADOW_RMAP_REGION3 0x3
1285#define _SHADOW_RMAP_SEGMENT 0x2
1286#define _SHADOW_RMAP_PGTABLE 0x1
1287
1288/**
1289 * gmap_idte_one - invalidate a single region or segment table entry
1290 * @asce: region or segment table *origin* + table-type bits
1291 * @vaddr: virtual address to identify the table entry to flush
1292 *
1293 * The invalid bit of a single region or segment table entry is set
1294 * and the associated TLB entries depending on the entry are flushed.
1295 * The table-type of the @asce identifies the portion of the @vaddr
1296 * that is used as the invalidation index.
1297 */
1298static inline void gmap_idte_one(unsigned long asce, unsigned long vaddr)
1299{
1300 asm volatile(
1301 " idte %0,0,%1"
1302 : : "a" (asce), "a" (vaddr) : "cc", "memory");
1303}
1304
1305/**
1306 * gmap_unshadow_page - remove a page from a shadow page table
1307 * @sg: pointer to the shadow guest address space structure
1308 * @raddr: rmap address in the shadow guest address space
1309 *
1310 * Called with the sg->guest_table_lock
1311 */
1312static void gmap_unshadow_page(struct gmap *sg, unsigned long raddr)
1313{
1314 unsigned long *table;
1315
1316 BUG_ON(!gmap_is_shadow(sg));
1317 table = gmap_table_walk(sg, raddr, 0); /* get page table pointer */
1318 if (!table || *table & _PAGE_INVALID)
1319 return;
1320 gmap_call_notifier(sg, raddr, raddr + _PAGE_SIZE - 1);
1321 ptep_unshadow_pte(sg->mm, raddr, (pte_t *) table);
1322}
1323
1324/**
1325 * __gmap_unshadow_pgt - remove all entries from a shadow page table
1326 * @sg: pointer to the shadow guest address space structure
1327 * @raddr: rmap address in the shadow guest address space
1328 * @pgt: pointer to the start of a shadow page table
1329 *
1330 * Called with the sg->guest_table_lock
1331 */
1332static void __gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr,
1333 unsigned long *pgt)
1334{
1335 int i;
1336
1337 BUG_ON(!gmap_is_shadow(sg));
1338 for (i = 0; i < _PAGE_ENTRIES; i++, raddr += _PAGE_SIZE)
1339 pgt[i] = _PAGE_INVALID;
1340}
1341
1342/**
1343 * gmap_unshadow_pgt - remove a shadow page table from a segment entry
1344 * @sg: pointer to the shadow guest address space structure
1345 * @raddr: address in the shadow guest address space
1346 *
1347 * Called with the sg->guest_table_lock
1348 */
1349static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
1350{
1351 unsigned long *ste;
1352 phys_addr_t sto, pgt;
1353 struct ptdesc *ptdesc;
1354
1355 BUG_ON(!gmap_is_shadow(sg));
1356 ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */
1357 if (!ste || !(*ste & _SEGMENT_ENTRY_ORIGIN))
1358 return;
1359 gmap_call_notifier(sg, raddr, raddr + _SEGMENT_SIZE - 1);
1360 sto = __pa(ste - ((raddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT));
1361 gmap_idte_one(sto | _ASCE_TYPE_SEGMENT, raddr);
1362 pgt = *ste & _SEGMENT_ENTRY_ORIGIN;
1363 *ste = _SEGMENT_ENTRY_EMPTY;
1364 __gmap_unshadow_pgt(sg, raddr, __va(pgt));
1365 /* Free page table */
1366 ptdesc = page_ptdesc(phys_to_page(pgt));
1367 list_del(&ptdesc->pt_list);
1368 page_table_free_pgste(ptdesc);
1369}
1370
1371/**
1372 * __gmap_unshadow_sgt - remove all entries from a shadow segment table
1373 * @sg: pointer to the shadow guest address space structure
1374 * @raddr: rmap address in the shadow guest address space
1375 * @sgt: pointer to the start of a shadow segment table
1376 *
1377 * Called with the sg->guest_table_lock
1378 */
1379static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
1380 unsigned long *sgt)
1381{
1382 struct ptdesc *ptdesc;
1383 phys_addr_t pgt;
1384 int i;
1385
1386 BUG_ON(!gmap_is_shadow(sg));
1387 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _SEGMENT_SIZE) {
1388 if (!(sgt[i] & _SEGMENT_ENTRY_ORIGIN))
1389 continue;
1390 pgt = sgt[i] & _REGION_ENTRY_ORIGIN;
1391 sgt[i] = _SEGMENT_ENTRY_EMPTY;
1392 __gmap_unshadow_pgt(sg, raddr, __va(pgt));
1393 /* Free page table */
1394 ptdesc = page_ptdesc(phys_to_page(pgt));
1395 list_del(&ptdesc->pt_list);
1396 page_table_free_pgste(ptdesc);
1397 }
1398}
1399
1400/**
1401 * gmap_unshadow_sgt - remove a shadow segment table from a region-3 entry
1402 * @sg: pointer to the shadow guest address space structure
1403 * @raddr: rmap address in the shadow guest address space
1404 *
1405 * Called with the shadow->guest_table_lock
1406 */
1407static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
1408{
1409 unsigned long r3o, *r3e;
1410 phys_addr_t sgt;
1411 struct page *page;
1412
1413 BUG_ON(!gmap_is_shadow(sg));
1414 r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
1415 if (!r3e || !(*r3e & _REGION_ENTRY_ORIGIN))
1416 return;
1417 gmap_call_notifier(sg, raddr, raddr + _REGION3_SIZE - 1);
1418 r3o = (unsigned long) (r3e - ((raddr & _REGION3_INDEX) >> _REGION3_SHIFT));
1419 gmap_idte_one(__pa(r3o) | _ASCE_TYPE_REGION3, raddr);
1420 sgt = *r3e & _REGION_ENTRY_ORIGIN;
1421 *r3e = _REGION3_ENTRY_EMPTY;
1422 __gmap_unshadow_sgt(sg, raddr, __va(sgt));
1423 /* Free segment table */
1424 page = phys_to_page(sgt);
1425 list_del(&page->lru);
1426 __free_pages(page, CRST_ALLOC_ORDER);
1427}
1428
1429/**
1430 * __gmap_unshadow_r3t - remove all entries from a shadow region-3 table
1431 * @sg: pointer to the shadow guest address space structure
1432 * @raddr: address in the shadow guest address space
1433 * @r3t: pointer to the start of a shadow region-3 table
1434 *
1435 * Called with the sg->guest_table_lock
1436 */
1437static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
1438 unsigned long *r3t)
1439{
1440 struct page *page;
1441 phys_addr_t sgt;
1442 int i;
1443
1444 BUG_ON(!gmap_is_shadow(sg));
1445 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION3_SIZE) {
1446 if (!(r3t[i] & _REGION_ENTRY_ORIGIN))
1447 continue;
1448 sgt = r3t[i] & _REGION_ENTRY_ORIGIN;
1449 r3t[i] = _REGION3_ENTRY_EMPTY;
1450 __gmap_unshadow_sgt(sg, raddr, __va(sgt));
1451 /* Free segment table */
1452 page = phys_to_page(sgt);
1453 list_del(&page->lru);
1454 __free_pages(page, CRST_ALLOC_ORDER);
1455 }
1456}
1457
1458/**
1459 * gmap_unshadow_r3t - remove a shadow region-3 table from a region-2 entry
1460 * @sg: pointer to the shadow guest address space structure
1461 * @raddr: rmap address in the shadow guest address space
1462 *
1463 * Called with the sg->guest_table_lock
1464 */
1465static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
1466{
1467 unsigned long r2o, *r2e;
1468 phys_addr_t r3t;
1469 struct page *page;
1470
1471 BUG_ON(!gmap_is_shadow(sg));
1472 r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
1473 if (!r2e || !(*r2e & _REGION_ENTRY_ORIGIN))
1474 return;
1475 gmap_call_notifier(sg, raddr, raddr + _REGION2_SIZE - 1);
1476 r2o = (unsigned long) (r2e - ((raddr & _REGION2_INDEX) >> _REGION2_SHIFT));
1477 gmap_idte_one(__pa(r2o) | _ASCE_TYPE_REGION2, raddr);
1478 r3t = *r2e & _REGION_ENTRY_ORIGIN;
1479 *r2e = _REGION2_ENTRY_EMPTY;
1480 __gmap_unshadow_r3t(sg, raddr, __va(r3t));
1481 /* Free region 3 table */
1482 page = phys_to_page(r3t);
1483 list_del(&page->lru);
1484 __free_pages(page, CRST_ALLOC_ORDER);
1485}
1486
1487/**
1488 * __gmap_unshadow_r2t - remove all entries from a shadow region-2 table
1489 * @sg: pointer to the shadow guest address space structure
1490 * @raddr: rmap address in the shadow guest address space
1491 * @r2t: pointer to the start of a shadow region-2 table
1492 *
1493 * Called with the sg->guest_table_lock
1494 */
1495static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
1496 unsigned long *r2t)
1497{
1498 phys_addr_t r3t;
1499 struct page *page;
1500 int i;
1501
1502 BUG_ON(!gmap_is_shadow(sg));
1503 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION2_SIZE) {
1504 if (!(r2t[i] & _REGION_ENTRY_ORIGIN))
1505 continue;
1506 r3t = r2t[i] & _REGION_ENTRY_ORIGIN;
1507 r2t[i] = _REGION2_ENTRY_EMPTY;
1508 __gmap_unshadow_r3t(sg, raddr, __va(r3t));
1509 /* Free region 3 table */
1510 page = phys_to_page(r3t);
1511 list_del(&page->lru);
1512 __free_pages(page, CRST_ALLOC_ORDER);
1513 }
1514}
1515
1516/**
1517 * gmap_unshadow_r2t - remove a shadow region-2 table from a region-1 entry
1518 * @sg: pointer to the shadow guest address space structure
1519 * @raddr: rmap address in the shadow guest address space
1520 *
1521 * Called with the sg->guest_table_lock
1522 */
1523static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
1524{
1525 unsigned long r1o, *r1e;
1526 struct page *page;
1527 phys_addr_t r2t;
1528
1529 BUG_ON(!gmap_is_shadow(sg));
1530 r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */
1531 if (!r1e || !(*r1e & _REGION_ENTRY_ORIGIN))
1532 return;
1533 gmap_call_notifier(sg, raddr, raddr + _REGION1_SIZE - 1);
1534 r1o = (unsigned long) (r1e - ((raddr & _REGION1_INDEX) >> _REGION1_SHIFT));
1535 gmap_idte_one(__pa(r1o) | _ASCE_TYPE_REGION1, raddr);
1536 r2t = *r1e & _REGION_ENTRY_ORIGIN;
1537 *r1e = _REGION1_ENTRY_EMPTY;
1538 __gmap_unshadow_r2t(sg, raddr, __va(r2t));
1539 /* Free region 2 table */
1540 page = phys_to_page(r2t);
1541 list_del(&page->lru);
1542 __free_pages(page, CRST_ALLOC_ORDER);
1543}
1544
1545/**
1546 * __gmap_unshadow_r1t - remove all entries from a shadow region-1 table
1547 * @sg: pointer to the shadow guest address space structure
1548 * @raddr: rmap address in the shadow guest address space
1549 * @r1t: pointer to the start of a shadow region-1 table
1550 *
1551 * Called with the shadow->guest_table_lock
1552 */
1553static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
1554 unsigned long *r1t)
1555{
1556 unsigned long asce;
1557 struct page *page;
1558 phys_addr_t r2t;
1559 int i;
1560
1561 BUG_ON(!gmap_is_shadow(sg));
1562 asce = __pa(r1t) | _ASCE_TYPE_REGION1;
1563 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION1_SIZE) {
1564 if (!(r1t[i] & _REGION_ENTRY_ORIGIN))
1565 continue;
1566 r2t = r1t[i] & _REGION_ENTRY_ORIGIN;
1567 __gmap_unshadow_r2t(sg, raddr, __va(r2t));
1568 /* Clear entry and flush translation r1t -> r2t */
1569 gmap_idte_one(asce, raddr);
1570 r1t[i] = _REGION1_ENTRY_EMPTY;
1571 /* Free region 2 table */
1572 page = phys_to_page(r2t);
1573 list_del(&page->lru);
1574 __free_pages(page, CRST_ALLOC_ORDER);
1575 }
1576}
1577
1578/**
1579 * gmap_unshadow - remove a shadow page table completely
1580 * @sg: pointer to the shadow guest address space structure
1581 *
1582 * Called with sg->guest_table_lock
1583 */
1584static void gmap_unshadow(struct gmap *sg)
1585{
1586 unsigned long *table;
1587
1588 BUG_ON(!gmap_is_shadow(sg));
1589 if (sg->removed)
1590 return;
1591 sg->removed = 1;
1592 gmap_call_notifier(sg, 0, -1UL);
1593 gmap_flush_tlb(sg);
1594 table = __va(sg->asce & _ASCE_ORIGIN);
1595 switch (sg->asce & _ASCE_TYPE_MASK) {
1596 case _ASCE_TYPE_REGION1:
1597 __gmap_unshadow_r1t(sg, 0, table);
1598 break;
1599 case _ASCE_TYPE_REGION2:
1600 __gmap_unshadow_r2t(sg, 0, table);
1601 break;
1602 case _ASCE_TYPE_REGION3:
1603 __gmap_unshadow_r3t(sg, 0, table);
1604 break;
1605 case _ASCE_TYPE_SEGMENT:
1606 __gmap_unshadow_sgt(sg, 0, table);
1607 break;
1608 }
1609}
1610
1611/**
1612 * gmap_find_shadow - find a specific asce in the list of shadow tables
1613 * @parent: pointer to the parent gmap
1614 * @asce: ASCE for which the shadow table is created
1615 * @edat_level: edat level to be used for the shadow translation
1616 *
1617 * Returns the pointer to a gmap if a shadow table with the given asce is
1618 * already available, ERR_PTR(-EAGAIN) if another one is just being created,
1619 * otherwise NULL
1620 */
1621static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce,
1622 int edat_level)
1623{
1624 struct gmap *sg;
1625
1626 list_for_each_entry(sg, &parent->children, list) {
1627 if (sg->orig_asce != asce || sg->edat_level != edat_level ||
1628 sg->removed)
1629 continue;
1630 if (!sg->initialized)
1631 return ERR_PTR(-EAGAIN);
1632 refcount_inc(&sg->ref_count);
1633 return sg;
1634 }
1635 return NULL;
1636}
1637
1638/**
1639 * gmap_shadow_valid - check if a shadow guest address space matches the
1640 * given properties and is still valid
1641 * @sg: pointer to the shadow guest address space structure
1642 * @asce: ASCE for which the shadow table is requested
1643 * @edat_level: edat level to be used for the shadow translation
1644 *
1645 * Returns 1 if the gmap shadow is still valid and matches the given
1646 * properties, the caller can continue using it. Returns 0 otherwise, the
1647 * caller has to request a new shadow gmap in this case.
1648 *
1649 */
1650int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)
1651{
1652 if (sg->removed)
1653 return 0;
1654 return sg->orig_asce == asce && sg->edat_level == edat_level;
1655}
1656EXPORT_SYMBOL_GPL(gmap_shadow_valid);
1657
1658/**
1659 * gmap_shadow - create/find a shadow guest address space
1660 * @parent: pointer to the parent gmap
1661 * @asce: ASCE for which the shadow table is created
1662 * @edat_level: edat level to be used for the shadow translation
1663 *
1664 * The pages of the top level page table referred by the asce parameter
1665 * will be set to read-only and marked in the PGSTEs of the kvm process.
1666 * The shadow table will be removed automatically on any change to the
1667 * PTE mapping for the source table.
1668 *
1669 * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory,
1670 * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the
1671 * parent gmap table could not be protected.
1672 */
1673struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
1674 int edat_level)
1675{
1676 struct gmap *sg, *new;
1677 unsigned long limit;
1678 int rc;
1679
1680 BUG_ON(parent->mm->context.allow_gmap_hpage_1m);
1681 BUG_ON(gmap_is_shadow(parent));
1682 spin_lock(&parent->shadow_lock);
1683 sg = gmap_find_shadow(parent, asce, edat_level);
1684 spin_unlock(&parent->shadow_lock);
1685 if (sg)
1686 return sg;
1687 /* Create a new shadow gmap */
1688 limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
1689 if (asce & _ASCE_REAL_SPACE)
1690 limit = -1UL;
1691 new = gmap_alloc(limit);
1692 if (!new)
1693 return ERR_PTR(-ENOMEM);
1694 new->mm = parent->mm;
1695 new->parent = gmap_get(parent);
1696 new->private = parent->private;
1697 new->orig_asce = asce;
1698 new->edat_level = edat_level;
1699 new->initialized = false;
1700 spin_lock(&parent->shadow_lock);
1701 /* Recheck if another CPU created the same shadow */
1702 sg = gmap_find_shadow(parent, asce, edat_level);
1703 if (sg) {
1704 spin_unlock(&parent->shadow_lock);
1705 gmap_free(new);
1706 return sg;
1707 }
1708 if (asce & _ASCE_REAL_SPACE) {
1709 /* only allow one real-space gmap shadow */
1710 list_for_each_entry(sg, &parent->children, list) {
1711 if (sg->orig_asce & _ASCE_REAL_SPACE) {
1712 spin_lock(&sg->guest_table_lock);
1713 gmap_unshadow(sg);
1714 spin_unlock(&sg->guest_table_lock);
1715 list_del(&sg->list);
1716 gmap_put(sg);
1717 break;
1718 }
1719 }
1720 }
1721 refcount_set(&new->ref_count, 2);
1722 list_add(&new->list, &parent->children);
1723 if (asce & _ASCE_REAL_SPACE) {
1724 /* nothing to protect, return right away */
1725 new->initialized = true;
1726 spin_unlock(&parent->shadow_lock);
1727 return new;
1728 }
1729 spin_unlock(&parent->shadow_lock);
1730 /* protect after insertion, so it will get properly invalidated */
1731 mmap_read_lock(parent->mm);
1732 rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
1733 ((asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE,
1734 PROT_READ, GMAP_NOTIFY_SHADOW);
1735 mmap_read_unlock(parent->mm);
1736 spin_lock(&parent->shadow_lock);
1737 new->initialized = true;
1738 if (rc) {
1739 list_del(&new->list);
1740 gmap_free(new);
1741 new = ERR_PTR(rc);
1742 }
1743 spin_unlock(&parent->shadow_lock);
1744 return new;
1745}
1746EXPORT_SYMBOL_GPL(gmap_shadow);
1747
1748/**
1749 * gmap_shadow_r2t - create an empty shadow region 2 table
1750 * @sg: pointer to the shadow guest address space structure
1751 * @saddr: faulting address in the shadow gmap
1752 * @r2t: parent gmap address of the region 2 table to get shadowed
1753 * @fake: r2t references contiguous guest memory block, not a r2t
1754 *
1755 * The r2t parameter specifies the address of the source table. The
1756 * four pages of the source table are made read-only in the parent gmap
1757 * address space. A write to the source table area @r2t will automatically
1758 * remove the shadow r2 table and all of its descendants.
1759 *
1760 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
1761 * shadow table structure is incomplete, -ENOMEM if out of memory and
1762 * -EFAULT if an address in the parent gmap could not be resolved.
1763 *
1764 * Called with sg->mm->mmap_lock in read.
1765 */
1766int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
1767 int fake)
1768{
1769 unsigned long raddr, origin, offset, len;
1770 unsigned long *table;
1771 phys_addr_t s_r2t;
1772 struct page *page;
1773 int rc;
1774
1775 BUG_ON(!gmap_is_shadow(sg));
1776 /* Allocate a shadow region second table */
1777 page = gmap_alloc_crst();
1778 if (!page)
1779 return -ENOMEM;
1780 page->index = r2t & _REGION_ENTRY_ORIGIN;
1781 if (fake)
1782 page->index |= GMAP_SHADOW_FAKE_TABLE;
1783 s_r2t = page_to_phys(page);
1784 /* Install shadow region second table */
1785 spin_lock(&sg->guest_table_lock);
1786 table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
1787 if (!table) {
1788 rc = -EAGAIN; /* Race with unshadow */
1789 goto out_free;
1790 }
1791 if (!(*table & _REGION_ENTRY_INVALID)) {
1792 rc = 0; /* Already established */
1793 goto out_free;
1794 } else if (*table & _REGION_ENTRY_ORIGIN) {
1795 rc = -EAGAIN; /* Race with shadow */
1796 goto out_free;
1797 }
1798 crst_table_init(__va(s_r2t), _REGION2_ENTRY_EMPTY);
1799 /* mark as invalid as long as the parent table is not protected */
1800 *table = s_r2t | _REGION_ENTRY_LENGTH |
1801 _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
1802 if (sg->edat_level >= 1)
1803 *table |= (r2t & _REGION_ENTRY_PROTECT);
1804 list_add(&page->lru, &sg->crst_list);
1805 if (fake) {
1806 /* nothing to protect for fake tables */
1807 *table &= ~_REGION_ENTRY_INVALID;
1808 spin_unlock(&sg->guest_table_lock);
1809 return 0;
1810 }
1811 spin_unlock(&sg->guest_table_lock);
1812 /* Make r2t read-only in parent gmap page table */
1813 raddr = (saddr & _REGION1_MASK) | _SHADOW_RMAP_REGION1;
1814 origin = r2t & _REGION_ENTRY_ORIGIN;
1815 offset = ((r2t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1816 len = ((r2t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1817 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1818 spin_lock(&sg->guest_table_lock);
1819 if (!rc) {
1820 table = gmap_table_walk(sg, saddr, 4);
1821 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r2t)
1822 rc = -EAGAIN; /* Race with unshadow */
1823 else
1824 *table &= ~_REGION_ENTRY_INVALID;
1825 } else {
1826 gmap_unshadow_r2t(sg, raddr);
1827 }
1828 spin_unlock(&sg->guest_table_lock);
1829 return rc;
1830out_free:
1831 spin_unlock(&sg->guest_table_lock);
1832 __free_pages(page, CRST_ALLOC_ORDER);
1833 return rc;
1834}
1835EXPORT_SYMBOL_GPL(gmap_shadow_r2t);
1836
1837/**
1838 * gmap_shadow_r3t - create a shadow region 3 table
1839 * @sg: pointer to the shadow guest address space structure
1840 * @saddr: faulting address in the shadow gmap
1841 * @r3t: parent gmap address of the region 3 table to get shadowed
1842 * @fake: r3t references contiguous guest memory block, not a r3t
1843 *
1844 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
1845 * shadow table structure is incomplete, -ENOMEM if out of memory and
1846 * -EFAULT if an address in the parent gmap could not be resolved.
1847 *
1848 * Called with sg->mm->mmap_lock in read.
1849 */
1850int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
1851 int fake)
1852{
1853 unsigned long raddr, origin, offset, len;
1854 unsigned long *table;
1855 phys_addr_t s_r3t;
1856 struct page *page;
1857 int rc;
1858
1859 BUG_ON(!gmap_is_shadow(sg));
1860 /* Allocate a shadow region second table */
1861 page = gmap_alloc_crst();
1862 if (!page)
1863 return -ENOMEM;
1864 page->index = r3t & _REGION_ENTRY_ORIGIN;
1865 if (fake)
1866 page->index |= GMAP_SHADOW_FAKE_TABLE;
1867 s_r3t = page_to_phys(page);
1868 /* Install shadow region second table */
1869 spin_lock(&sg->guest_table_lock);
1870 table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
1871 if (!table) {
1872 rc = -EAGAIN; /* Race with unshadow */
1873 goto out_free;
1874 }
1875 if (!(*table & _REGION_ENTRY_INVALID)) {
1876 rc = 0; /* Already established */
1877 goto out_free;
1878 } else if (*table & _REGION_ENTRY_ORIGIN) {
1879 rc = -EAGAIN; /* Race with shadow */
1880 goto out_free;
1881 }
1882 crst_table_init(__va(s_r3t), _REGION3_ENTRY_EMPTY);
1883 /* mark as invalid as long as the parent table is not protected */
1884 *table = s_r3t | _REGION_ENTRY_LENGTH |
1885 _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
1886 if (sg->edat_level >= 1)
1887 *table |= (r3t & _REGION_ENTRY_PROTECT);
1888 list_add(&page->lru, &sg->crst_list);
1889 if (fake) {
1890 /* nothing to protect for fake tables */
1891 *table &= ~_REGION_ENTRY_INVALID;
1892 spin_unlock(&sg->guest_table_lock);
1893 return 0;
1894 }
1895 spin_unlock(&sg->guest_table_lock);
1896 /* Make r3t read-only in parent gmap page table */
1897 raddr = (saddr & _REGION2_MASK) | _SHADOW_RMAP_REGION2;
1898 origin = r3t & _REGION_ENTRY_ORIGIN;
1899 offset = ((r3t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1900 len = ((r3t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1901 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1902 spin_lock(&sg->guest_table_lock);
1903 if (!rc) {
1904 table = gmap_table_walk(sg, saddr, 3);
1905 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r3t)
1906 rc = -EAGAIN; /* Race with unshadow */
1907 else
1908 *table &= ~_REGION_ENTRY_INVALID;
1909 } else {
1910 gmap_unshadow_r3t(sg, raddr);
1911 }
1912 spin_unlock(&sg->guest_table_lock);
1913 return rc;
1914out_free:
1915 spin_unlock(&sg->guest_table_lock);
1916 __free_pages(page, CRST_ALLOC_ORDER);
1917 return rc;
1918}
1919EXPORT_SYMBOL_GPL(gmap_shadow_r3t);
1920
1921/**
1922 * gmap_shadow_sgt - create a shadow segment table
1923 * @sg: pointer to the shadow guest address space structure
1924 * @saddr: faulting address in the shadow gmap
1925 * @sgt: parent gmap address of the segment table to get shadowed
1926 * @fake: sgt references contiguous guest memory block, not a sgt
1927 *
1928 * Returns: 0 if successfully shadowed or already shadowed, -EAGAIN if the
1929 * shadow table structure is incomplete, -ENOMEM if out of memory and
1930 * -EFAULT if an address in the parent gmap could not be resolved.
1931 *
1932 * Called with sg->mm->mmap_lock in read.
1933 */
1934int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
1935 int fake)
1936{
1937 unsigned long raddr, origin, offset, len;
1938 unsigned long *table;
1939 phys_addr_t s_sgt;
1940 struct page *page;
1941 int rc;
1942
1943 BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE));
1944 /* Allocate a shadow segment table */
1945 page = gmap_alloc_crst();
1946 if (!page)
1947 return -ENOMEM;
1948 page->index = sgt & _REGION_ENTRY_ORIGIN;
1949 if (fake)
1950 page->index |= GMAP_SHADOW_FAKE_TABLE;
1951 s_sgt = page_to_phys(page);
1952 /* Install shadow region second table */
1953 spin_lock(&sg->guest_table_lock);
1954 table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
1955 if (!table) {
1956 rc = -EAGAIN; /* Race with unshadow */
1957 goto out_free;
1958 }
1959 if (!(*table & _REGION_ENTRY_INVALID)) {
1960 rc = 0; /* Already established */
1961 goto out_free;
1962 } else if (*table & _REGION_ENTRY_ORIGIN) {
1963 rc = -EAGAIN; /* Race with shadow */
1964 goto out_free;
1965 }
1966 crst_table_init(__va(s_sgt), _SEGMENT_ENTRY_EMPTY);
1967 /* mark as invalid as long as the parent table is not protected */
1968 *table = s_sgt | _REGION_ENTRY_LENGTH |
1969 _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
1970 if (sg->edat_level >= 1)
1971 *table |= sgt & _REGION_ENTRY_PROTECT;
1972 list_add(&page->lru, &sg->crst_list);
1973 if (fake) {
1974 /* nothing to protect for fake tables */
1975 *table &= ~_REGION_ENTRY_INVALID;
1976 spin_unlock(&sg->guest_table_lock);
1977 return 0;
1978 }
1979 spin_unlock(&sg->guest_table_lock);
1980 /* Make sgt read-only in parent gmap page table */
1981 raddr = (saddr & _REGION3_MASK) | _SHADOW_RMAP_REGION3;
1982 origin = sgt & _REGION_ENTRY_ORIGIN;
1983 offset = ((sgt & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1984 len = ((sgt & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1985 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1986 spin_lock(&sg->guest_table_lock);
1987 if (!rc) {
1988 table = gmap_table_walk(sg, saddr, 2);
1989 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_sgt)
1990 rc = -EAGAIN; /* Race with unshadow */
1991 else
1992 *table &= ~_REGION_ENTRY_INVALID;
1993 } else {
1994 gmap_unshadow_sgt(sg, raddr);
1995 }
1996 spin_unlock(&sg->guest_table_lock);
1997 return rc;
1998out_free:
1999 spin_unlock(&sg->guest_table_lock);
2000 __free_pages(page, CRST_ALLOC_ORDER);
2001 return rc;
2002}
2003EXPORT_SYMBOL_GPL(gmap_shadow_sgt);
2004
2005/**
2006 * gmap_shadow_pgt_lookup - find a shadow page table
2007 * @sg: pointer to the shadow guest address space structure
2008 * @saddr: the address in the shadow aguest address space
2009 * @pgt: parent gmap address of the page table to get shadowed
2010 * @dat_protection: if the pgtable is marked as protected by dat
2011 * @fake: pgt references contiguous guest memory block, not a pgtable
2012 *
2013 * Returns 0 if the shadow page table was found and -EAGAIN if the page
2014 * table was not found.
2015 *
2016 * Called with sg->mm->mmap_lock in read.
2017 */
2018int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
2019 unsigned long *pgt, int *dat_protection,
2020 int *fake)
2021{
2022 unsigned long *table;
2023 struct page *page;
2024 int rc;
2025
2026 BUG_ON(!gmap_is_shadow(sg));
2027 spin_lock(&sg->guest_table_lock);
2028 table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
2029 if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
2030 /* Shadow page tables are full pages (pte+pgste) */
2031 page = pfn_to_page(*table >> PAGE_SHIFT);
2032 *pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
2033 *dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
2034 *fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
2035 rc = 0;
2036 } else {
2037 rc = -EAGAIN;
2038 }
2039 spin_unlock(&sg->guest_table_lock);
2040 return rc;
2041
2042}
2043EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup);
2044
2045/**
2046 * gmap_shadow_pgt - instantiate a shadow page table
2047 * @sg: pointer to the shadow guest address space structure
2048 * @saddr: faulting address in the shadow gmap
2049 * @pgt: parent gmap address of the page table to get shadowed
2050 * @fake: pgt references contiguous guest memory block, not a pgtable
2051 *
2052 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
2053 * shadow table structure is incomplete, -ENOMEM if out of memory,
2054 * -EFAULT if an address in the parent gmap could not be resolved and
2055 *
2056 * Called with gmap->mm->mmap_lock in read
2057 */
2058int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
2059 int fake)
2060{
2061 unsigned long raddr, origin;
2062 unsigned long *table;
2063 struct ptdesc *ptdesc;
2064 phys_addr_t s_pgt;
2065 int rc;
2066
2067 BUG_ON(!gmap_is_shadow(sg) || (pgt & _SEGMENT_ENTRY_LARGE));
2068 /* Allocate a shadow page table */
2069 ptdesc = page_table_alloc_pgste(sg->mm);
2070 if (!ptdesc)
2071 return -ENOMEM;
2072 ptdesc->pt_index = pgt & _SEGMENT_ENTRY_ORIGIN;
2073 if (fake)
2074 ptdesc->pt_index |= GMAP_SHADOW_FAKE_TABLE;
2075 s_pgt = page_to_phys(ptdesc_page(ptdesc));
2076 /* Install shadow page table */
2077 spin_lock(&sg->guest_table_lock);
2078 table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
2079 if (!table) {
2080 rc = -EAGAIN; /* Race with unshadow */
2081 goto out_free;
2082 }
2083 if (!(*table & _SEGMENT_ENTRY_INVALID)) {
2084 rc = 0; /* Already established */
2085 goto out_free;
2086 } else if (*table & _SEGMENT_ENTRY_ORIGIN) {
2087 rc = -EAGAIN; /* Race with shadow */
2088 goto out_free;
2089 }
2090 /* mark as invalid as long as the parent table is not protected */
2091 *table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
2092 (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID;
2093 list_add(&ptdesc->pt_list, &sg->pt_list);
2094 if (fake) {
2095 /* nothing to protect for fake tables */
2096 *table &= ~_SEGMENT_ENTRY_INVALID;
2097 spin_unlock(&sg->guest_table_lock);
2098 return 0;
2099 }
2100 spin_unlock(&sg->guest_table_lock);
2101 /* Make pgt read-only in parent gmap page table (not the pgste) */
2102 raddr = (saddr & _SEGMENT_MASK) | _SHADOW_RMAP_SEGMENT;
2103 origin = pgt & _SEGMENT_ENTRY_ORIGIN & PAGE_MASK;
2104 rc = gmap_protect_rmap(sg, raddr, origin, PAGE_SIZE);
2105 spin_lock(&sg->guest_table_lock);
2106 if (!rc) {
2107 table = gmap_table_walk(sg, saddr, 1);
2108 if (!table || (*table & _SEGMENT_ENTRY_ORIGIN) != s_pgt)
2109 rc = -EAGAIN; /* Race with unshadow */
2110 else
2111 *table &= ~_SEGMENT_ENTRY_INVALID;
2112 } else {
2113 gmap_unshadow_pgt(sg, raddr);
2114 }
2115 spin_unlock(&sg->guest_table_lock);
2116 return rc;
2117out_free:
2118 spin_unlock(&sg->guest_table_lock);
2119 page_table_free_pgste(ptdesc);
2120 return rc;
2121
2122}
2123EXPORT_SYMBOL_GPL(gmap_shadow_pgt);
2124
2125/**
2126 * gmap_shadow_page - create a shadow page mapping
2127 * @sg: pointer to the shadow guest address space structure
2128 * @saddr: faulting address in the shadow gmap
2129 * @pte: pte in parent gmap address space to get shadowed
2130 *
2131 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
2132 * shadow table structure is incomplete, -ENOMEM if out of memory and
2133 * -EFAULT if an address in the parent gmap could not be resolved.
2134 *
2135 * Called with sg->mm->mmap_lock in read.
2136 */
2137int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
2138{
2139 struct gmap *parent;
2140 struct gmap_rmap *rmap;
2141 unsigned long vmaddr, paddr;
2142 spinlock_t *ptl;
2143 pte_t *sptep, *tptep;
2144 int prot;
2145 int rc;
2146
2147 BUG_ON(!gmap_is_shadow(sg));
2148 parent = sg->parent;
2149 prot = (pte_val(pte) & _PAGE_PROTECT) ? PROT_READ : PROT_WRITE;
2150
2151 rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT);
2152 if (!rmap)
2153 return -ENOMEM;
2154 rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE;
2155
2156 while (1) {
2157 paddr = pte_val(pte) & PAGE_MASK;
2158 vmaddr = __gmap_translate(parent, paddr);
2159 if (IS_ERR_VALUE(vmaddr)) {
2160 rc = vmaddr;
2161 break;
2162 }
2163 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
2164 if (rc)
2165 break;
2166 rc = -EAGAIN;
2167 sptep = gmap_pte_op_walk(parent, paddr, &ptl);
2168 if (sptep) {
2169 spin_lock(&sg->guest_table_lock);
2170 /* Get page table pointer */
2171 tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
2172 if (!tptep) {
2173 spin_unlock(&sg->guest_table_lock);
2174 gmap_pte_op_end(sptep, ptl);
2175 radix_tree_preload_end();
2176 break;
2177 }
2178 rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte);
2179 if (rc > 0) {
2180 /* Success and a new mapping */
2181 gmap_insert_rmap(sg, vmaddr, rmap);
2182 rmap = NULL;
2183 rc = 0;
2184 }
2185 gmap_pte_op_end(sptep, ptl);
2186 spin_unlock(&sg->guest_table_lock);
2187 }
2188 radix_tree_preload_end();
2189 if (!rc)
2190 break;
2191 rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot);
2192 if (rc)
2193 break;
2194 }
2195 kfree(rmap);
2196 return rc;
2197}
2198EXPORT_SYMBOL_GPL(gmap_shadow_page);
2199
2200/*
2201 * gmap_shadow_notify - handle notifications for shadow gmap
2202 *
2203 * Called with sg->parent->shadow_lock.
2204 */
2205static void gmap_shadow_notify(struct gmap *sg, unsigned long vmaddr,
2206 unsigned long gaddr)
2207{
2208 struct gmap_rmap *rmap, *rnext, *head;
2209 unsigned long start, end, bits, raddr;
2210
2211 BUG_ON(!gmap_is_shadow(sg));
2212
2213 spin_lock(&sg->guest_table_lock);
2214 if (sg->removed) {
2215 spin_unlock(&sg->guest_table_lock);
2216 return;
2217 }
2218 /* Check for top level table */
2219 start = sg->orig_asce & _ASCE_ORIGIN;
2220 end = start + ((sg->orig_asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE;
2221 if (!(sg->orig_asce & _ASCE_REAL_SPACE) && gaddr >= start &&
2222 gaddr < end) {
2223 /* The complete shadow table has to go */
2224 gmap_unshadow(sg);
2225 spin_unlock(&sg->guest_table_lock);
2226 list_del(&sg->list);
2227 gmap_put(sg);
2228 return;
2229 }
2230 /* Remove the page table tree from on specific entry */
2231 head = radix_tree_delete(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
2232 gmap_for_each_rmap_safe(rmap, rnext, head) {
2233 bits = rmap->raddr & _SHADOW_RMAP_MASK;
2234 raddr = rmap->raddr ^ bits;
2235 switch (bits) {
2236 case _SHADOW_RMAP_REGION1:
2237 gmap_unshadow_r2t(sg, raddr);
2238 break;
2239 case _SHADOW_RMAP_REGION2:
2240 gmap_unshadow_r3t(sg, raddr);
2241 break;
2242 case _SHADOW_RMAP_REGION3:
2243 gmap_unshadow_sgt(sg, raddr);
2244 break;
2245 case _SHADOW_RMAP_SEGMENT:
2246 gmap_unshadow_pgt(sg, raddr);
2247 break;
2248 case _SHADOW_RMAP_PGTABLE:
2249 gmap_unshadow_page(sg, raddr);
2250 break;
2251 }
2252 kfree(rmap);
2253 }
2254 spin_unlock(&sg->guest_table_lock);
2255}
2256
2257/**
2258 * ptep_notify - call all invalidation callbacks for a specific pte.
2259 * @mm: pointer to the process mm_struct
2260 * @vmaddr: virtual address in the process address space
2261 * @pte: pointer to the page table entry
2262 * @bits: bits from the pgste that caused the notify call
2263 *
2264 * This function is assumed to be called with the page table lock held
2265 * for the pte to notify.
2266 */
2267void ptep_notify(struct mm_struct *mm, unsigned long vmaddr,
2268 pte_t *pte, unsigned long bits)
2269{
2270 unsigned long offset, gaddr = 0;
2271 unsigned long *table;
2272 struct gmap *gmap, *sg, *next;
2273
2274 offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
2275 offset = offset * (PAGE_SIZE / sizeof(pte_t));
2276 rcu_read_lock();
2277 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2278 spin_lock(&gmap->guest_table_lock);
2279 table = radix_tree_lookup(&gmap->host_to_guest,
2280 vmaddr >> PMD_SHIFT);
2281 if (table)
2282 gaddr = __gmap_segment_gaddr(table) + offset;
2283 spin_unlock(&gmap->guest_table_lock);
2284 if (!table)
2285 continue;
2286
2287 if (!list_empty(&gmap->children) && (bits & PGSTE_VSIE_BIT)) {
2288 spin_lock(&gmap->shadow_lock);
2289 list_for_each_entry_safe(sg, next,
2290 &gmap->children, list)
2291 gmap_shadow_notify(sg, vmaddr, gaddr);
2292 spin_unlock(&gmap->shadow_lock);
2293 }
2294 if (bits & PGSTE_IN_BIT)
2295 gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1);
2296 }
2297 rcu_read_unlock();
2298}
2299EXPORT_SYMBOL_GPL(ptep_notify);
2300
2301static void pmdp_notify_gmap(struct gmap *gmap, pmd_t *pmdp,
2302 unsigned long gaddr)
2303{
2304 set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN)));
2305 gmap_call_notifier(gmap, gaddr, gaddr + HPAGE_SIZE - 1);
2306}
2307
2308/**
2309 * gmap_pmdp_xchg - exchange a gmap pmd with another
2310 * @gmap: pointer to the guest address space structure
2311 * @pmdp: pointer to the pmd entry
2312 * @new: replacement entry
2313 * @gaddr: the affected guest address
2314 *
2315 * This function is assumed to be called with the guest_table_lock
2316 * held.
2317 */
2318static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *pmdp, pmd_t new,
2319 unsigned long gaddr)
2320{
2321 gaddr &= HPAGE_MASK;
2322 pmdp_notify_gmap(gmap, pmdp, gaddr);
2323 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_GMAP_IN));
2324 if (MACHINE_HAS_TLB_GUEST)
2325 __pmdp_idte(gaddr, (pmd_t *)pmdp, IDTE_GUEST_ASCE, gmap->asce,
2326 IDTE_GLOBAL);
2327 else if (MACHINE_HAS_IDTE)
2328 __pmdp_idte(gaddr, (pmd_t *)pmdp, 0, 0, IDTE_GLOBAL);
2329 else
2330 __pmdp_csp(pmdp);
2331 set_pmd(pmdp, new);
2332}
2333
2334static void gmap_pmdp_clear(struct mm_struct *mm, unsigned long vmaddr,
2335 int purge)
2336{
2337 pmd_t *pmdp;
2338 struct gmap *gmap;
2339 unsigned long gaddr;
2340
2341 rcu_read_lock();
2342 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2343 spin_lock(&gmap->guest_table_lock);
2344 pmdp = (pmd_t *)radix_tree_delete(&gmap->host_to_guest,
2345 vmaddr >> PMD_SHIFT);
2346 if (pmdp) {
2347 gaddr = __gmap_segment_gaddr((unsigned long *)pmdp);
2348 pmdp_notify_gmap(gmap, pmdp, gaddr);
2349 WARN_ON(pmd_val(*pmdp) & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2350 _SEGMENT_ENTRY_GMAP_UC));
2351 if (purge)
2352 __pmdp_csp(pmdp);
2353 set_pmd(pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
2354 }
2355 spin_unlock(&gmap->guest_table_lock);
2356 }
2357 rcu_read_unlock();
2358}
2359
2360/**
2361 * gmap_pmdp_invalidate - invalidate all affected guest pmd entries without
2362 * flushing
2363 * @mm: pointer to the process mm_struct
2364 * @vmaddr: virtual address in the process address space
2365 */
2366void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr)
2367{
2368 gmap_pmdp_clear(mm, vmaddr, 0);
2369}
2370EXPORT_SYMBOL_GPL(gmap_pmdp_invalidate);
2371
2372/**
2373 * gmap_pmdp_csp - csp all affected guest pmd entries
2374 * @mm: pointer to the process mm_struct
2375 * @vmaddr: virtual address in the process address space
2376 */
2377void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr)
2378{
2379 gmap_pmdp_clear(mm, vmaddr, 1);
2380}
2381EXPORT_SYMBOL_GPL(gmap_pmdp_csp);
2382
2383/**
2384 * gmap_pmdp_idte_local - invalidate and clear a guest pmd entry
2385 * @mm: pointer to the process mm_struct
2386 * @vmaddr: virtual address in the process address space
2387 */
2388void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr)
2389{
2390 unsigned long *entry, gaddr;
2391 struct gmap *gmap;
2392 pmd_t *pmdp;
2393
2394 rcu_read_lock();
2395 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2396 spin_lock(&gmap->guest_table_lock);
2397 entry = radix_tree_delete(&gmap->host_to_guest,
2398 vmaddr >> PMD_SHIFT);
2399 if (entry) {
2400 pmdp = (pmd_t *)entry;
2401 gaddr = __gmap_segment_gaddr(entry);
2402 pmdp_notify_gmap(gmap, pmdp, gaddr);
2403 WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2404 _SEGMENT_ENTRY_GMAP_UC));
2405 if (MACHINE_HAS_TLB_GUEST)
2406 __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
2407 gmap->asce, IDTE_LOCAL);
2408 else if (MACHINE_HAS_IDTE)
2409 __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_LOCAL);
2410 *entry = _SEGMENT_ENTRY_EMPTY;
2411 }
2412 spin_unlock(&gmap->guest_table_lock);
2413 }
2414 rcu_read_unlock();
2415}
2416EXPORT_SYMBOL_GPL(gmap_pmdp_idte_local);
2417
2418/**
2419 * gmap_pmdp_idte_global - invalidate and clear a guest pmd entry
2420 * @mm: pointer to the process mm_struct
2421 * @vmaddr: virtual address in the process address space
2422 */
2423void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr)
2424{
2425 unsigned long *entry, gaddr;
2426 struct gmap *gmap;
2427 pmd_t *pmdp;
2428
2429 rcu_read_lock();
2430 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2431 spin_lock(&gmap->guest_table_lock);
2432 entry = radix_tree_delete(&gmap->host_to_guest,
2433 vmaddr >> PMD_SHIFT);
2434 if (entry) {
2435 pmdp = (pmd_t *)entry;
2436 gaddr = __gmap_segment_gaddr(entry);
2437 pmdp_notify_gmap(gmap, pmdp, gaddr);
2438 WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2439 _SEGMENT_ENTRY_GMAP_UC));
2440 if (MACHINE_HAS_TLB_GUEST)
2441 __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
2442 gmap->asce, IDTE_GLOBAL);
2443 else if (MACHINE_HAS_IDTE)
2444 __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_GLOBAL);
2445 else
2446 __pmdp_csp(pmdp);
2447 *entry = _SEGMENT_ENTRY_EMPTY;
2448 }
2449 spin_unlock(&gmap->guest_table_lock);
2450 }
2451 rcu_read_unlock();
2452}
2453EXPORT_SYMBOL_GPL(gmap_pmdp_idte_global);
2454
2455/**
2456 * gmap_test_and_clear_dirty_pmd - test and reset segment dirty status
2457 * @gmap: pointer to guest address space
2458 * @pmdp: pointer to the pmd to be tested
2459 * @gaddr: virtual address in the guest address space
2460 *
2461 * This function is assumed to be called with the guest_table_lock
2462 * held.
2463 */
2464static bool gmap_test_and_clear_dirty_pmd(struct gmap *gmap, pmd_t *pmdp,
2465 unsigned long gaddr)
2466{
2467 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
2468 return false;
2469
2470 /* Already protected memory, which did not change is clean */
2471 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT &&
2472 !(pmd_val(*pmdp) & _SEGMENT_ENTRY_GMAP_UC))
2473 return false;
2474
2475 /* Clear UC indication and reset protection */
2476 set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_UC)));
2477 gmap_protect_pmd(gmap, gaddr, pmdp, PROT_READ, 0);
2478 return true;
2479}
2480
2481/**
2482 * gmap_sync_dirty_log_pmd - set bitmap based on dirty status of segment
2483 * @gmap: pointer to guest address space
2484 * @bitmap: dirty bitmap for this pmd
2485 * @gaddr: virtual address in the guest address space
2486 * @vmaddr: virtual address in the host address space
2487 *
2488 * This function is assumed to be called with the guest_table_lock
2489 * held.
2490 */
2491void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long bitmap[4],
2492 unsigned long gaddr, unsigned long vmaddr)
2493{
2494 int i;
2495 pmd_t *pmdp;
2496 pte_t *ptep;
2497 spinlock_t *ptl;
2498
2499 pmdp = gmap_pmd_op_walk(gmap, gaddr);
2500 if (!pmdp)
2501 return;
2502
2503 if (pmd_leaf(*pmdp)) {
2504 if (gmap_test_and_clear_dirty_pmd(gmap, pmdp, gaddr))
2505 bitmap_fill(bitmap, _PAGE_ENTRIES);
2506 } else {
2507 for (i = 0; i < _PAGE_ENTRIES; i++, vmaddr += PAGE_SIZE) {
2508 ptep = pte_alloc_map_lock(gmap->mm, pmdp, vmaddr, &ptl);
2509 if (!ptep)
2510 continue;
2511 if (ptep_test_and_clear_uc(gmap->mm, vmaddr, ptep))
2512 set_bit(i, bitmap);
2513 pte_unmap_unlock(ptep, ptl);
2514 }
2515 }
2516 gmap_pmd_op_end(gmap, pmdp);
2517}
2518EXPORT_SYMBOL_GPL(gmap_sync_dirty_log_pmd);
2519
2520#ifdef CONFIG_TRANSPARENT_HUGEPAGE
2521static int thp_split_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
2522 unsigned long end, struct mm_walk *walk)
2523{
2524 struct vm_area_struct *vma = walk->vma;
2525
2526 split_huge_pmd(vma, pmd, addr);
2527 return 0;
2528}
2529
2530static const struct mm_walk_ops thp_split_walk_ops = {
2531 .pmd_entry = thp_split_walk_pmd_entry,
2532 .walk_lock = PGWALK_WRLOCK_VERIFY,
2533};
2534
2535static inline void thp_split_mm(struct mm_struct *mm)
2536{
2537 struct vm_area_struct *vma;
2538 VMA_ITERATOR(vmi, mm, 0);
2539
2540 for_each_vma(vmi, vma) {
2541 vm_flags_mod(vma, VM_NOHUGEPAGE, VM_HUGEPAGE);
2542 walk_page_vma(vma, &thp_split_walk_ops, NULL);
2543 }
2544 mm->def_flags |= VM_NOHUGEPAGE;
2545}
2546#else
2547static inline void thp_split_mm(struct mm_struct *mm)
2548{
2549}
2550#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2551
2552/*
2553 * switch on pgstes for its userspace process (for kvm)
2554 */
2555int s390_enable_sie(void)
2556{
2557 struct mm_struct *mm = current->mm;
2558
2559 /* Do we have pgstes? if yes, we are done */
2560 if (mm_has_pgste(mm))
2561 return 0;
2562 /* Fail if the page tables are 2K */
2563 if (!mm_alloc_pgste(mm))
2564 return -EINVAL;
2565 mmap_write_lock(mm);
2566 mm->context.has_pgste = 1;
2567 /* split thp mappings and disable thp for future mappings */
2568 thp_split_mm(mm);
2569 mmap_write_unlock(mm);
2570 return 0;
2571}
2572EXPORT_SYMBOL_GPL(s390_enable_sie);
2573
2574static int find_zeropage_pte_entry(pte_t *pte, unsigned long addr,
2575 unsigned long end, struct mm_walk *walk)
2576{
2577 unsigned long *found_addr = walk->private;
2578
2579 /* Return 1 of the page is a zeropage. */
2580 if (is_zero_pfn(pte_pfn(*pte))) {
2581 /*
2582 * Shared zeropage in e.g., a FS DAX mapping? We cannot do the
2583 * right thing and likely don't care: FAULT_FLAG_UNSHARE
2584 * currently only works in COW mappings, which is also where
2585 * mm_forbids_zeropage() is checked.
2586 */
2587 if (!is_cow_mapping(walk->vma->vm_flags))
2588 return -EFAULT;
2589
2590 *found_addr = addr;
2591 return 1;
2592 }
2593 return 0;
2594}
2595
2596static const struct mm_walk_ops find_zeropage_ops = {
2597 .pte_entry = find_zeropage_pte_entry,
2598 .walk_lock = PGWALK_WRLOCK,
2599};
2600
2601/*
2602 * Unshare all shared zeropages, replacing them by anonymous pages. Note that
2603 * we cannot simply zap all shared zeropages, because this could later
2604 * trigger unexpected userfaultfd missing events.
2605 *
2606 * This must be called after mm->context.allow_cow_sharing was
2607 * set to 0, to avoid future mappings of shared zeropages.
2608 *
2609 * mm contracts with s390, that even if mm were to remove a page table,
2610 * and racing with walk_page_range_vma() calling pte_offset_map_lock()
2611 * would fail, it will never insert a page table containing empty zero
2612 * pages once mm_forbids_zeropage(mm) i.e.
2613 * mm->context.allow_cow_sharing is set to 0.
2614 */
2615static int __s390_unshare_zeropages(struct mm_struct *mm)
2616{
2617 struct vm_area_struct *vma;
2618 VMA_ITERATOR(vmi, mm, 0);
2619 unsigned long addr;
2620 vm_fault_t fault;
2621 int rc;
2622
2623 for_each_vma(vmi, vma) {
2624 /*
2625 * We could only look at COW mappings, but it's more future
2626 * proof to catch unexpected zeropages in other mappings and
2627 * fail.
2628 */
2629 if ((vma->vm_flags & VM_PFNMAP) || is_vm_hugetlb_page(vma))
2630 continue;
2631 addr = vma->vm_start;
2632
2633retry:
2634 rc = walk_page_range_vma(vma, addr, vma->vm_end,
2635 &find_zeropage_ops, &addr);
2636 if (rc < 0)
2637 return rc;
2638 else if (!rc)
2639 continue;
2640
2641 /* addr was updated by find_zeropage_pte_entry() */
2642 fault = handle_mm_fault(vma, addr,
2643 FAULT_FLAG_UNSHARE | FAULT_FLAG_REMOTE,
2644 NULL);
2645 if (fault & VM_FAULT_OOM)
2646 return -ENOMEM;
2647 /*
2648 * See break_ksm(): even after handle_mm_fault() returned 0, we
2649 * must start the lookup from the current address, because
2650 * handle_mm_fault() may back out if there's any difficulty.
2651 *
2652 * VM_FAULT_SIGBUS and VM_FAULT_SIGSEGV are unexpected but
2653 * maybe they could trigger in the future on concurrent
2654 * truncation. In that case, the shared zeropage would be gone
2655 * and we can simply retry and make progress.
2656 */
2657 cond_resched();
2658 goto retry;
2659 }
2660
2661 return 0;
2662}
2663
2664static int __s390_disable_cow_sharing(struct mm_struct *mm)
2665{
2666 int rc;
2667
2668 if (!mm->context.allow_cow_sharing)
2669 return 0;
2670
2671 mm->context.allow_cow_sharing = 0;
2672
2673 /* Replace all shared zeropages by anonymous pages. */
2674 rc = __s390_unshare_zeropages(mm);
2675 /*
2676 * Make sure to disable KSM (if enabled for the whole process or
2677 * individual VMAs). Note that nothing currently hinders user space
2678 * from re-enabling it.
2679 */
2680 if (!rc)
2681 rc = ksm_disable(mm);
2682 if (rc)
2683 mm->context.allow_cow_sharing = 1;
2684 return rc;
2685}
2686
2687/*
2688 * Disable most COW-sharing of memory pages for the whole process:
2689 * (1) Disable KSM and unmerge/unshare any KSM pages.
2690 * (2) Disallow shared zeropages and unshare any zerpages that are mapped.
2691 *
2692 * Not that we currently don't bother with COW-shared pages that are shared
2693 * with parent/child processes due to fork().
2694 */
2695int s390_disable_cow_sharing(void)
2696{
2697 int rc;
2698
2699 mmap_write_lock(current->mm);
2700 rc = __s390_disable_cow_sharing(current->mm);
2701 mmap_write_unlock(current->mm);
2702 return rc;
2703}
2704EXPORT_SYMBOL_GPL(s390_disable_cow_sharing);
2705
2706/*
2707 * Enable storage key handling from now on and initialize the storage
2708 * keys with the default key.
2709 */
2710static int __s390_enable_skey_pte(pte_t *pte, unsigned long addr,
2711 unsigned long next, struct mm_walk *walk)
2712{
2713 /* Clear storage key */
2714 ptep_zap_key(walk->mm, addr, pte);
2715 return 0;
2716}
2717
2718/*
2719 * Give a chance to schedule after setting a key to 256 pages.
2720 * We only hold the mm lock, which is a rwsem and the kvm srcu.
2721 * Both can sleep.
2722 */
2723static int __s390_enable_skey_pmd(pmd_t *pmd, unsigned long addr,
2724 unsigned long next, struct mm_walk *walk)
2725{
2726 cond_resched();
2727 return 0;
2728}
2729
2730static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
2731 unsigned long hmask, unsigned long next,
2732 struct mm_walk *walk)
2733{
2734 pmd_t *pmd = (pmd_t *)pte;
2735 unsigned long start, end;
2736 struct page *page = pmd_page(*pmd);
2737
2738 /*
2739 * The write check makes sure we do not set a key on shared
2740 * memory. This is needed as the walker does not differentiate
2741 * between actual guest memory and the process executable or
2742 * shared libraries.
2743 */
2744 if (pmd_val(*pmd) & _SEGMENT_ENTRY_INVALID ||
2745 !(pmd_val(*pmd) & _SEGMENT_ENTRY_WRITE))
2746 return 0;
2747
2748 start = pmd_val(*pmd) & HPAGE_MASK;
2749 end = start + HPAGE_SIZE;
2750 __storage_key_init_range(start, end);
2751 set_bit(PG_arch_1, &page->flags);
2752 cond_resched();
2753 return 0;
2754}
2755
2756static const struct mm_walk_ops enable_skey_walk_ops = {
2757 .hugetlb_entry = __s390_enable_skey_hugetlb,
2758 .pte_entry = __s390_enable_skey_pte,
2759 .pmd_entry = __s390_enable_skey_pmd,
2760 .walk_lock = PGWALK_WRLOCK,
2761};
2762
2763int s390_enable_skey(void)
2764{
2765 struct mm_struct *mm = current->mm;
2766 int rc = 0;
2767
2768 mmap_write_lock(mm);
2769 if (mm_uses_skeys(mm))
2770 goto out_up;
2771
2772 mm->context.uses_skeys = 1;
2773 rc = __s390_disable_cow_sharing(mm);
2774 if (rc) {
2775 mm->context.uses_skeys = 0;
2776 goto out_up;
2777 }
2778 walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
2779
2780out_up:
2781 mmap_write_unlock(mm);
2782 return rc;
2783}
2784EXPORT_SYMBOL_GPL(s390_enable_skey);
2785
2786/*
2787 * Reset CMMA state, make all pages stable again.
2788 */
2789static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
2790 unsigned long next, struct mm_walk *walk)
2791{
2792 ptep_zap_unused(walk->mm, addr, pte, 1);
2793 return 0;
2794}
2795
2796static const struct mm_walk_ops reset_cmma_walk_ops = {
2797 .pte_entry = __s390_reset_cmma,
2798 .walk_lock = PGWALK_WRLOCK,
2799};
2800
2801void s390_reset_cmma(struct mm_struct *mm)
2802{
2803 mmap_write_lock(mm);
2804 walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
2805 mmap_write_unlock(mm);
2806}
2807EXPORT_SYMBOL_GPL(s390_reset_cmma);
2808
2809#define GATHER_GET_PAGES 32
2810
2811struct reset_walk_state {
2812 unsigned long next;
2813 unsigned long count;
2814 unsigned long pfns[GATHER_GET_PAGES];
2815};
2816
2817static int s390_gather_pages(pte_t *ptep, unsigned long addr,
2818 unsigned long next, struct mm_walk *walk)
2819{
2820 struct reset_walk_state *p = walk->private;
2821 pte_t pte = READ_ONCE(*ptep);
2822
2823 if (pte_present(pte)) {
2824 /* we have a reference from the mapping, take an extra one */
2825 get_page(phys_to_page(pte_val(pte)));
2826 p->pfns[p->count] = phys_to_pfn(pte_val(pte));
2827 p->next = next;
2828 p->count++;
2829 }
2830 return p->count >= GATHER_GET_PAGES;
2831}
2832
2833static const struct mm_walk_ops gather_pages_ops = {
2834 .pte_entry = s390_gather_pages,
2835 .walk_lock = PGWALK_RDLOCK,
2836};
2837
2838/*
2839 * Call the Destroy secure page UVC on each page in the given array of PFNs.
2840 * Each page needs to have an extra reference, which will be released here.
2841 */
2842void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns)
2843{
2844 unsigned long i;
2845
2846 for (i = 0; i < count; i++) {
2847 /* we always have an extra reference */
2848 uv_destroy_owned_page(pfn_to_phys(pfns[i]));
2849 /* get rid of the extra reference */
2850 put_page(pfn_to_page(pfns[i]));
2851 cond_resched();
2852 }
2853}
2854EXPORT_SYMBOL_GPL(s390_uv_destroy_pfns);
2855
2856/**
2857 * __s390_uv_destroy_range - Call the destroy secure page UVC on each page
2858 * in the given range of the given address space.
2859 * @mm: the mm to operate on
2860 * @start: the start of the range
2861 * @end: the end of the range
2862 * @interruptible: if not 0, stop when a fatal signal is received
2863 *
2864 * Walk the given range of the given address space and call the destroy
2865 * secure page UVC on each page. Optionally exit early if a fatal signal is
2866 * pending.
2867 *
2868 * Return: 0 on success, -EINTR if the function stopped before completing
2869 */
2870int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start,
2871 unsigned long end, bool interruptible)
2872{
2873 struct reset_walk_state state = { .next = start };
2874 int r = 1;
2875
2876 while (r > 0) {
2877 state.count = 0;
2878 mmap_read_lock(mm);
2879 r = walk_page_range(mm, state.next, end, &gather_pages_ops, &state);
2880 mmap_read_unlock(mm);
2881 cond_resched();
2882 s390_uv_destroy_pfns(state.count, state.pfns);
2883 if (interruptible && fatal_signal_pending(current))
2884 return -EINTR;
2885 }
2886 return 0;
2887}
2888EXPORT_SYMBOL_GPL(__s390_uv_destroy_range);
2889
2890/**
2891 * s390_unlist_old_asce - Remove the topmost level of page tables from the
2892 * list of page tables of the gmap.
2893 * @gmap: the gmap whose table is to be removed
2894 *
2895 * On s390x, KVM keeps a list of all pages containing the page tables of the
2896 * gmap (the CRST list). This list is used at tear down time to free all
2897 * pages that are now not needed anymore.
2898 *
2899 * This function removes the topmost page of the tree (the one pointed to by
2900 * the ASCE) from the CRST list.
2901 *
2902 * This means that it will not be freed when the VM is torn down, and needs
2903 * to be handled separately by the caller, unless a leak is actually
2904 * intended. Notice that this function will only remove the page from the
2905 * list, the page will still be used as a top level page table (and ASCE).
2906 */
2907void s390_unlist_old_asce(struct gmap *gmap)
2908{
2909 struct page *old;
2910
2911 old = virt_to_page(gmap->table);
2912 spin_lock(&gmap->guest_table_lock);
2913 list_del(&old->lru);
2914 /*
2915 * Sometimes the topmost page might need to be "removed" multiple
2916 * times, for example if the VM is rebooted into secure mode several
2917 * times concurrently, or if s390_replace_asce fails after calling
2918 * s390_remove_old_asce and is attempted again later. In that case
2919 * the old asce has been removed from the list, and therefore it
2920 * will not be freed when the VM terminates, but the ASCE is still
2921 * in use and still pointed to.
2922 * A subsequent call to replace_asce will follow the pointer and try
2923 * to remove the same page from the list again.
2924 * Therefore it's necessary that the page of the ASCE has valid
2925 * pointers, so list_del can work (and do nothing) without
2926 * dereferencing stale or invalid pointers.
2927 */
2928 INIT_LIST_HEAD(&old->lru);
2929 spin_unlock(&gmap->guest_table_lock);
2930}
2931EXPORT_SYMBOL_GPL(s390_unlist_old_asce);
2932
2933/**
2934 * s390_replace_asce - Try to replace the current ASCE of a gmap with a copy
2935 * @gmap: the gmap whose ASCE needs to be replaced
2936 *
2937 * If the ASCE is a SEGMENT type then this function will return -EINVAL,
2938 * otherwise the pointers in the host_to_guest radix tree will keep pointing
2939 * to the wrong pages, causing use-after-free and memory corruption.
2940 * If the allocation of the new top level page table fails, the ASCE is not
2941 * replaced.
2942 * In any case, the old ASCE is always removed from the gmap CRST list.
2943 * Therefore the caller has to make sure to save a pointer to it
2944 * beforehand, unless a leak is actually intended.
2945 */
2946int s390_replace_asce(struct gmap *gmap)
2947{
2948 unsigned long asce;
2949 struct page *page;
2950 void *table;
2951
2952 s390_unlist_old_asce(gmap);
2953
2954 /* Replacing segment type ASCEs would cause serious issues */
2955 if ((gmap->asce & _ASCE_TYPE_MASK) == _ASCE_TYPE_SEGMENT)
2956 return -EINVAL;
2957
2958 page = gmap_alloc_crst();
2959 if (!page)
2960 return -ENOMEM;
2961 page->index = 0;
2962 table = page_to_virt(page);
2963 memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));
2964
2965 /*
2966 * The caller has to deal with the old ASCE, but here we make sure
2967 * the new one is properly added to the CRST list, so that
2968 * it will be freed when the VM is torn down.
2969 */
2970 spin_lock(&gmap->guest_table_lock);
2971 list_add(&page->lru, &gmap->crst_list);
2972 spin_unlock(&gmap->guest_table_lock);
2973
2974 /* Set new table origin while preserving existing ASCE control bits */
2975 asce = (gmap->asce & ~_ASCE_ORIGIN) | __pa(table);
2976 WRITE_ONCE(gmap->asce, asce);
2977 WRITE_ONCE(gmap->mm->context.gmap_asce, asce);
2978 WRITE_ONCE(gmap->table, table);
2979
2980 return 0;
2981}
2982EXPORT_SYMBOL_GPL(s390_replace_asce);