~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/s390/mm/gmap.c

Version: ~ [ linux-5.8 ] ~ [ linux-5.7.14 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.57 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.138 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.193 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.232 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.232 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  *  KVM guest address space mapping code
  4  *
  5  *    Copyright IBM Corp. 2007, 2016, 2018
  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  * @mm: pointer to the parent mm_struct
 31  * @limit: maximum address of the gmap address space
 32  *
 33  * Returns a guest address space structure.
 34  */
 35 static struct gmap *gmap_alloc(unsigned long limit)
 36 {
 37         struct gmap *gmap;
 38         struct page *page;
 39         unsigned long *table;
 40         unsigned long etype, atype;
 41 
 42         if (limit < _REGION3_SIZE) {
 43                 limit = _REGION3_SIZE - 1;
 44                 atype = _ASCE_TYPE_SEGMENT;
 45                 etype = _SEGMENT_ENTRY_EMPTY;
 46         } else if (limit < _REGION2_SIZE) {
 47                 limit = _REGION2_SIZE - 1;
 48                 atype = _ASCE_TYPE_REGION3;
 49                 etype = _REGION3_ENTRY_EMPTY;
 50         } else if (limit < _REGION1_SIZE) {
 51                 limit = _REGION1_SIZE - 1;
 52                 atype = _ASCE_TYPE_REGION2;
 53                 etype = _REGION2_ENTRY_EMPTY;
 54         } else {
 55                 limit = -1UL;
 56                 atype = _ASCE_TYPE_REGION1;
 57                 etype = _REGION1_ENTRY_EMPTY;
 58         }
 59         gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL);
 60         if (!gmap)
 61                 goto out;
 62         INIT_LIST_HEAD(&gmap->crst_list);
 63         INIT_LIST_HEAD(&gmap->children);
 64         INIT_LIST_HEAD(&gmap->pt_list);
 65         INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL);
 66         INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC);
 67         INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC);
 68         spin_lock_init(&gmap->guest_table_lock);
 69         spin_lock_init(&gmap->shadow_lock);
 70         refcount_set(&gmap->ref_count, 1);
 71         page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
 72         if (!page)
 73                 goto out_free;
 74         page->index = 0;
 75         list_add(&page->lru, &gmap->crst_list);
 76         table = (unsigned long *) page_to_phys(page);
 77         crst_table_init(table, etype);
 78         gmap->table = table;
 79         gmap->asce = atype | _ASCE_TABLE_LENGTH |
 80                 _ASCE_USER_BITS | __pa(table);
 81         gmap->asce_end = limit;
 82         return gmap;
 83 
 84 out_free:
 85         kfree(gmap);
 86 out:
 87         return NULL;
 88 }
 89 
 90 /**
 91  * gmap_create - create a guest address space
 92  * @mm: pointer to the parent mm_struct
 93  * @limit: maximum size of the gmap address space
 94  *
 95  * Returns a guest address space structure.
 96  */
 97 struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit)
 98 {
 99         struct gmap *gmap;
100         unsigned long gmap_asce;
101 
102         gmap = gmap_alloc(limit);
103         if (!gmap)
104                 return NULL;
105         gmap->mm = mm;
106         spin_lock(&mm->context.lock);
107         list_add_rcu(&gmap->list, &mm->context.gmap_list);
108         if (list_is_singular(&mm->context.gmap_list))
109                 gmap_asce = gmap->asce;
110         else
111                 gmap_asce = -1UL;
112         WRITE_ONCE(mm->context.gmap_asce, gmap_asce);
113         spin_unlock(&mm->context.lock);
114         return gmap;
115 }
116 EXPORT_SYMBOL_GPL(gmap_create);
117 
118 static void gmap_flush_tlb(struct gmap *gmap)
119 {
120         if (MACHINE_HAS_IDTE)
121                 __tlb_flush_idte(gmap->asce);
122         else
123                 __tlb_flush_global();
124 }
125 
126 static void gmap_radix_tree_free(struct radix_tree_root *root)
127 {
128         struct radix_tree_iter iter;
129         unsigned long indices[16];
130         unsigned long index;
131         void __rcu **slot;
132         int i, nr;
133 
134         /* A radix tree is freed by deleting all of its entries */
135         index = 0;
136         do {
137                 nr = 0;
138                 radix_tree_for_each_slot(slot, root, &iter, index) {
139                         indices[nr] = iter.index;
140                         if (++nr == 16)
141                                 break;
142                 }
143                 for (i = 0; i < nr; i++) {
144                         index = indices[i];
145                         radix_tree_delete(root, index);
146                 }
147         } while (nr > 0);
148 }
149 
150 static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
151 {
152         struct gmap_rmap *rmap, *rnext, *head;
153         struct radix_tree_iter iter;
154         unsigned long indices[16];
155         unsigned long index;
156         void __rcu **slot;
157         int i, nr;
158 
159         /* A radix tree is freed by deleting all of its entries */
160         index = 0;
161         do {
162                 nr = 0;
163                 radix_tree_for_each_slot(slot, root, &iter, index) {
164                         indices[nr] = iter.index;
165                         if (++nr == 16)
166                                 break;
167                 }
168                 for (i = 0; i < nr; i++) {
169                         index = indices[i];
170                         head = radix_tree_delete(root, index);
171                         gmap_for_each_rmap_safe(rmap, rnext, head)
172                                 kfree(rmap);
173                 }
174         } while (nr > 0);
175 }
176 
177 /**
178  * gmap_free - free a guest address space
179  * @gmap: pointer to the guest address space structure
180  *
181  * No locks required. There are no references to this gmap anymore.
182  */
183 static void gmap_free(struct gmap *gmap)
184 {
185         struct page *page, *next;
186 
187         /* Flush tlb of all gmaps (if not already done for shadows) */
188         if (!(gmap_is_shadow(gmap) && gmap->removed))
189                 gmap_flush_tlb(gmap);
190         /* Free all segment & region tables. */
191         list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
192                 __free_pages(page, CRST_ALLOC_ORDER);
193         gmap_radix_tree_free(&gmap->guest_to_host);
194         gmap_radix_tree_free(&gmap->host_to_guest);
195 
196         /* Free additional data for a shadow gmap */
197         if (gmap_is_shadow(gmap)) {
198                 /* Free all page tables. */
199                 list_for_each_entry_safe(page, next, &gmap->pt_list, lru)
200                         page_table_free_pgste(page);
201                 gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
202                 /* Release reference to the parent */
203                 gmap_put(gmap->parent);
204         }
205 
206         kfree(gmap);
207 }
208 
209 /**
210  * gmap_get - increase reference counter for guest address space
211  * @gmap: pointer to the guest address space structure
212  *
213  * Returns the gmap pointer
214  */
215 struct gmap *gmap_get(struct gmap *gmap)
216 {
217         refcount_inc(&gmap->ref_count);
218         return gmap;
219 }
220 EXPORT_SYMBOL_GPL(gmap_get);
221 
222 /**
223  * gmap_put - decrease reference counter for guest address space
224  * @gmap: pointer to the guest address space structure
225  *
226  * If the reference counter reaches zero the guest address space is freed.
227  */
228 void gmap_put(struct gmap *gmap)
229 {
230         if (refcount_dec_and_test(&gmap->ref_count))
231                 gmap_free(gmap);
232 }
233 EXPORT_SYMBOL_GPL(gmap_put);
234 
235 /**
236  * gmap_remove - remove a guest address space but do not free it yet
237  * @gmap: pointer to the guest address space structure
238  */
239 void gmap_remove(struct gmap *gmap)
240 {
241         struct gmap *sg, *next;
242         unsigned long gmap_asce;
243 
244         /* Remove all shadow gmaps linked to this gmap */
245         if (!list_empty(&gmap->children)) {
246                 spin_lock(&gmap->shadow_lock);
247                 list_for_each_entry_safe(sg, next, &gmap->children, list) {
248                         list_del(&sg->list);
249                         gmap_put(sg);
250                 }
251                 spin_unlock(&gmap->shadow_lock);
252         }
253         /* Remove gmap from the pre-mm list */
254         spin_lock(&gmap->mm->context.lock);
255         list_del_rcu(&gmap->list);
256         if (list_empty(&gmap->mm->context.gmap_list))
257                 gmap_asce = 0;
258         else if (list_is_singular(&gmap->mm->context.gmap_list))
259                 gmap_asce = list_first_entry(&gmap->mm->context.gmap_list,
260                                              struct gmap, list)->asce;
261         else
262                 gmap_asce = -1UL;
263         WRITE_ONCE(gmap->mm->context.gmap_asce, gmap_asce);
264         spin_unlock(&gmap->mm->context.lock);
265         synchronize_rcu();
266         /* Put reference */
267         gmap_put(gmap);
268 }
269 EXPORT_SYMBOL_GPL(gmap_remove);
270 
271 /**
272  * gmap_enable - switch primary space to the guest address space
273  * @gmap: pointer to the guest address space structure
274  */
275 void gmap_enable(struct gmap *gmap)
276 {
277         S390_lowcore.gmap = (unsigned long) gmap;
278 }
279 EXPORT_SYMBOL_GPL(gmap_enable);
280 
281 /**
282  * gmap_disable - switch back to the standard primary address space
283  * @gmap: pointer to the guest address space structure
284  */
285 void gmap_disable(struct gmap *gmap)
286 {
287         S390_lowcore.gmap = 0UL;
288 }
289 EXPORT_SYMBOL_GPL(gmap_disable);
290 
291 /**
292  * gmap_get_enabled - get a pointer to the currently enabled gmap
293  *
294  * Returns a pointer to the currently enabled gmap. 0 if none is enabled.
295  */
296 struct gmap *gmap_get_enabled(void)
297 {
298         return (struct gmap *) S390_lowcore.gmap;
299 }
300 EXPORT_SYMBOL_GPL(gmap_get_enabled);
301 
302 /*
303  * gmap_alloc_table is assumed to be called with mmap_lock held
304  */
305 static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
306                             unsigned long init, unsigned long gaddr)
307 {
308         struct page *page;
309         unsigned long *new;
310 
311         /* since we dont free the gmap table until gmap_free we can unlock */
312         page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
313         if (!page)
314                 return -ENOMEM;
315         new = (unsigned long *) page_to_phys(page);
316         crst_table_init(new, init);
317         spin_lock(&gmap->guest_table_lock);
318         if (*table & _REGION_ENTRY_INVALID) {
319                 list_add(&page->lru, &gmap->crst_list);
320                 *table = (unsigned long) new | _REGION_ENTRY_LENGTH |
321                         (*table & _REGION_ENTRY_TYPE_MASK);
322                 page->index = gaddr;
323                 page = NULL;
324         }
325         spin_unlock(&gmap->guest_table_lock);
326         if (page)
327                 __free_pages(page, CRST_ALLOC_ORDER);
328         return 0;
329 }
330 
331 /**
332  * __gmap_segment_gaddr - find virtual address from segment pointer
333  * @entry: pointer to a segment table entry in the guest address space
334  *
335  * Returns the virtual address in the guest address space for the segment
336  */
337 static unsigned long __gmap_segment_gaddr(unsigned long *entry)
338 {
339         struct page *page;
340         unsigned long offset, mask;
341 
342         offset = (unsigned long) entry / sizeof(unsigned long);
343         offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
344         mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
345         page = virt_to_page((void *)((unsigned long) entry & mask));
346         return page->index + offset;
347 }
348 
349 /**
350  * __gmap_unlink_by_vmaddr - unlink a single segment via a host address
351  * @gmap: pointer to the guest address space structure
352  * @vmaddr: address in the host process address space
353  *
354  * Returns 1 if a TLB flush is required
355  */
356 static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr)
357 {
358         unsigned long *entry;
359         int flush = 0;
360 
361         BUG_ON(gmap_is_shadow(gmap));
362         spin_lock(&gmap->guest_table_lock);
363         entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
364         if (entry) {
365                 flush = (*entry != _SEGMENT_ENTRY_EMPTY);
366                 *entry = _SEGMENT_ENTRY_EMPTY;
367         }
368         spin_unlock(&gmap->guest_table_lock);
369         return flush;
370 }
371 
372 /**
373  * __gmap_unmap_by_gaddr - unmap a single segment via a guest address
374  * @gmap: pointer to the guest address space structure
375  * @gaddr: address in the guest address space
376  *
377  * Returns 1 if a TLB flush is required
378  */
379 static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr)
380 {
381         unsigned long vmaddr;
382 
383         vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host,
384                                                    gaddr >> PMD_SHIFT);
385         return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0;
386 }
387 
388 /**
389  * gmap_unmap_segment - unmap segment from the guest address space
390  * @gmap: pointer to the guest address space structure
391  * @to: address in the guest address space
392  * @len: length of the memory area to unmap
393  *
394  * Returns 0 if the unmap succeeded, -EINVAL if not.
395  */
396 int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
397 {
398         unsigned long off;
399         int flush;
400 
401         BUG_ON(gmap_is_shadow(gmap));
402         if ((to | len) & (PMD_SIZE - 1))
403                 return -EINVAL;
404         if (len == 0 || to + len < to)
405                 return -EINVAL;
406 
407         flush = 0;
408         mmap_write_lock(gmap->mm);
409         for (off = 0; off < len; off += PMD_SIZE)
410                 flush |= __gmap_unmap_by_gaddr(gmap, to + off);
411         mmap_write_unlock(gmap->mm);
412         if (flush)
413                 gmap_flush_tlb(gmap);
414         return 0;
415 }
416 EXPORT_SYMBOL_GPL(gmap_unmap_segment);
417 
418 /**
419  * gmap_map_segment - map a segment to the guest address space
420  * @gmap: pointer to the guest address space structure
421  * @from: source address in the parent address space
422  * @to: target address in the guest address space
423  * @len: length of the memory area to map
424  *
425  * Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not.
426  */
427 int gmap_map_segment(struct gmap *gmap, unsigned long from,
428                      unsigned long to, unsigned long len)
429 {
430         unsigned long off;
431         int flush;
432 
433         BUG_ON(gmap_is_shadow(gmap));
434         if ((from | to | len) & (PMD_SIZE - 1))
435                 return -EINVAL;
436         if (len == 0 || from + len < from || to + len < to ||
437             from + len - 1 > TASK_SIZE_MAX || to + len - 1 > gmap->asce_end)
438                 return -EINVAL;
439 
440         flush = 0;
441         mmap_write_lock(gmap->mm);
442         for (off = 0; off < len; off += PMD_SIZE) {
443                 /* Remove old translation */
444                 flush |= __gmap_unmap_by_gaddr(gmap, to + off);
445                 /* Store new translation */
446                 if (radix_tree_insert(&gmap->guest_to_host,
447                                       (to + off) >> PMD_SHIFT,
448                                       (void *) from + off))
449                         break;
450         }
451         mmap_write_unlock(gmap->mm);
452         if (flush)
453                 gmap_flush_tlb(gmap);
454         if (off >= len)
455                 return 0;
456         gmap_unmap_segment(gmap, to, len);
457         return -ENOMEM;
458 }
459 EXPORT_SYMBOL_GPL(gmap_map_segment);
460 
461 /**
462  * __gmap_translate - translate a guest address to a user space address
463  * @gmap: pointer to guest mapping meta data structure
464  * @gaddr: guest address
465  *
466  * Returns user space address which corresponds to the guest address or
467  * -EFAULT if no such mapping exists.
468  * This function does not establish potentially missing page table entries.
469  * The mmap_lock of the mm that belongs to the address space must be held
470  * when this function gets called.
471  *
472  * Note: Can also be called for shadow gmaps.
473  */
474 unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
475 {
476         unsigned long vmaddr;
477 
478         vmaddr = (unsigned long)
479                 radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
480         /* Note: guest_to_host is empty for a shadow gmap */
481         return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
482 }
483 EXPORT_SYMBOL_GPL(__gmap_translate);
484 
485 /**
486  * gmap_translate - translate a guest address to a user space address
487  * @gmap: pointer to guest mapping meta data structure
488  * @gaddr: guest address
489  *
490  * Returns user space address which corresponds to the guest address or
491  * -EFAULT if no such mapping exists.
492  * This function does not establish potentially missing page table entries.
493  */
494 unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr)
495 {
496         unsigned long rc;
497 
498         mmap_read_lock(gmap->mm);
499         rc = __gmap_translate(gmap, gaddr);
500         mmap_read_unlock(gmap->mm);
501         return rc;
502 }
503 EXPORT_SYMBOL_GPL(gmap_translate);
504 
505 /**
506  * gmap_unlink - disconnect a page table from the gmap shadow tables
507  * @gmap: pointer to guest mapping meta data structure
508  * @table: pointer to the host page table
509  * @vmaddr: vm address associated with the host page table
510  */
511 void gmap_unlink(struct mm_struct *mm, unsigned long *table,
512                  unsigned long vmaddr)
513 {
514         struct gmap *gmap;
515         int flush;
516 
517         rcu_read_lock();
518         list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
519                 flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
520                 if (flush)
521                         gmap_flush_tlb(gmap);
522         }
523         rcu_read_unlock();
524 }
525 
526 static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *old, pmd_t new,
527                            unsigned long gaddr);
528 
529 /**
530  * gmap_link - set up shadow page tables to connect a host to a guest address
531  * @gmap: pointer to guest mapping meta data structure
532  * @gaddr: guest address
533  * @vmaddr: vm address
534  *
535  * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
536  * if the vm address is already mapped to a different guest segment.
537  * The mmap_lock of the mm that belongs to the address space must be held
538  * when this function gets called.
539  */
540 int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
541 {
542         struct mm_struct *mm;
543         unsigned long *table;
544         spinlock_t *ptl;
545         pgd_t *pgd;
546         p4d_t *p4d;
547         pud_t *pud;
548         pmd_t *pmd;
549         u64 unprot;
550         int rc;
551 
552         BUG_ON(gmap_is_shadow(gmap));
553         /* Create higher level tables in the gmap page table */
554         table = gmap->table;
555         if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
556                 table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
557                 if ((*table & _REGION_ENTRY_INVALID) &&
558                     gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
559                                      gaddr & _REGION1_MASK))
560                         return -ENOMEM;
561                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
562         }
563         if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
564                 table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
565                 if ((*table & _REGION_ENTRY_INVALID) &&
566                     gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
567                                      gaddr & _REGION2_MASK))
568                         return -ENOMEM;
569                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
570         }
571         if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
572                 table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
573                 if ((*table & _REGION_ENTRY_INVALID) &&
574                     gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
575                                      gaddr & _REGION3_MASK))
576                         return -ENOMEM;
577                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
578         }
579         table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
580         /* Walk the parent mm page table */
581         mm = gmap->mm;
582         pgd = pgd_offset(mm, vmaddr);
583         VM_BUG_ON(pgd_none(*pgd));
584         p4d = p4d_offset(pgd, vmaddr);
585         VM_BUG_ON(p4d_none(*p4d));
586         pud = pud_offset(p4d, vmaddr);
587         VM_BUG_ON(pud_none(*pud));
588         /* large puds cannot yet be handled */
589         if (pud_large(*pud))
590                 return -EFAULT;
591         pmd = pmd_offset(pud, vmaddr);
592         VM_BUG_ON(pmd_none(*pmd));
593         /* Are we allowed to use huge pages? */
594         if (pmd_large(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m)
595                 return -EFAULT;
596         /* Link gmap segment table entry location to page table. */
597         rc = radix_tree_preload(GFP_KERNEL);
598         if (rc)
599                 return rc;
600         ptl = pmd_lock(mm, pmd);
601         spin_lock(&gmap->guest_table_lock);
602         if (*table == _SEGMENT_ENTRY_EMPTY) {
603                 rc = radix_tree_insert(&gmap->host_to_guest,
604                                        vmaddr >> PMD_SHIFT, table);
605                 if (!rc) {
606                         if (pmd_large(*pmd)) {
607                                 *table = (pmd_val(*pmd) &
608                                           _SEGMENT_ENTRY_HARDWARE_BITS_LARGE)
609                                         | _SEGMENT_ENTRY_GMAP_UC;
610                         } else
611                                 *table = pmd_val(*pmd) &
612                                         _SEGMENT_ENTRY_HARDWARE_BITS;
613                 }
614         } else if (*table & _SEGMENT_ENTRY_PROTECT &&
615                    !(pmd_val(*pmd) & _SEGMENT_ENTRY_PROTECT)) {
616                 unprot = (u64)*table;
617                 unprot &= ~_SEGMENT_ENTRY_PROTECT;
618                 unprot |= _SEGMENT_ENTRY_GMAP_UC;
619                 gmap_pmdp_xchg(gmap, (pmd_t *)table, __pmd(unprot), gaddr);
620         }
621         spin_unlock(&gmap->guest_table_lock);
622         spin_unlock(ptl);
623         radix_tree_preload_end();
624         return rc;
625 }
626 
627 /**
628  * gmap_fault - resolve a fault on a guest address
629  * @gmap: pointer to guest mapping meta data structure
630  * @gaddr: guest address
631  * @fault_flags: flags to pass down to handle_mm_fault()
632  *
633  * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
634  * if the vm address is already mapped to a different guest segment.
635  */
636 int gmap_fault(struct gmap *gmap, unsigned long gaddr,
637                unsigned int fault_flags)
638 {
639         unsigned long vmaddr;
640         int rc;
641         bool unlocked;
642 
643         mmap_read_lock(gmap->mm);
644 
645 retry:
646         unlocked = false;
647         vmaddr = __gmap_translate(gmap, gaddr);
648         if (IS_ERR_VALUE(vmaddr)) {
649                 rc = vmaddr;
650                 goto out_up;
651         }
652         if (fixup_user_fault(current, gmap->mm, vmaddr, fault_flags,
653                              &unlocked)) {
654                 rc = -EFAULT;
655                 goto out_up;
656         }
657         /*
658          * In the case that fixup_user_fault unlocked the mmap_lock during
659          * faultin redo __gmap_translate to not race with a map/unmap_segment.
660          */
661         if (unlocked)
662                 goto retry;
663 
664         rc = __gmap_link(gmap, gaddr, vmaddr);
665 out_up:
666         mmap_read_unlock(gmap->mm);
667         return rc;
668 }
669 EXPORT_SYMBOL_GPL(gmap_fault);
670 
671 /*
672  * this function is assumed to be called with mmap_lock held
673  */
674 void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
675 {
676         unsigned long vmaddr;
677         spinlock_t *ptl;
678         pte_t *ptep;
679 
680         /* Find the vm address for the guest address */
681         vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
682                                                    gaddr >> PMD_SHIFT);
683         if (vmaddr) {
684                 vmaddr |= gaddr & ~PMD_MASK;
685                 /* Get pointer to the page table entry */
686                 ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
687                 if (likely(ptep))
688                         ptep_zap_unused(gmap->mm, vmaddr, ptep, 0);
689                 pte_unmap_unlock(ptep, ptl);
690         }
691 }
692 EXPORT_SYMBOL_GPL(__gmap_zap);
693 
694 void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
695 {
696         unsigned long gaddr, vmaddr, size;
697         struct vm_area_struct *vma;
698 
699         mmap_read_lock(gmap->mm);
700         for (gaddr = from; gaddr < to;
701              gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
702                 /* Find the vm address for the guest address */
703                 vmaddr = (unsigned long)
704                         radix_tree_lookup(&gmap->guest_to_host,
705                                           gaddr >> PMD_SHIFT);
706                 if (!vmaddr)
707                         continue;
708                 vmaddr |= gaddr & ~PMD_MASK;
709                 /* Find vma in the parent mm */
710                 vma = find_vma(gmap->mm, vmaddr);
711                 if (!vma)
712                         continue;
713                 /*
714                  * We do not discard pages that are backed by
715                  * hugetlbfs, so we don't have to refault them.
716                  */
717                 if (is_vm_hugetlb_page(vma))
718                         continue;
719                 size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
720                 zap_page_range(vma, vmaddr, size);
721         }
722         mmap_read_unlock(gmap->mm);
723 }
724 EXPORT_SYMBOL_GPL(gmap_discard);
725 
726 static LIST_HEAD(gmap_notifier_list);
727 static DEFINE_SPINLOCK(gmap_notifier_lock);
728 
729 /**
730  * gmap_register_pte_notifier - register a pte invalidation callback
731  * @nb: pointer to the gmap notifier block
732  */
733 void gmap_register_pte_notifier(struct gmap_notifier *nb)
734 {
735         spin_lock(&gmap_notifier_lock);
736         list_add_rcu(&nb->list, &gmap_notifier_list);
737         spin_unlock(&gmap_notifier_lock);
738 }
739 EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
740 
741 /**
742  * gmap_unregister_pte_notifier - remove a pte invalidation callback
743  * @nb: pointer to the gmap notifier block
744  */
745 void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
746 {
747         spin_lock(&gmap_notifier_lock);
748         list_del_rcu(&nb->list);
749         spin_unlock(&gmap_notifier_lock);
750         synchronize_rcu();
751 }
752 EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
753 
754 /**
755  * gmap_call_notifier - call all registered invalidation callbacks
756  * @gmap: pointer to guest mapping meta data structure
757  * @start: start virtual address in the guest address space
758  * @end: end virtual address in the guest address space
759  */
760 static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
761                                unsigned long end)
762 {
763         struct gmap_notifier *nb;
764 
765         list_for_each_entry(nb, &gmap_notifier_list, list)
766                 nb->notifier_call(gmap, start, end);
767 }
768 
769 /**
770  * gmap_table_walk - walk the gmap page tables
771  * @gmap: pointer to guest mapping meta data structure
772  * @gaddr: virtual address in the guest address space
773  * @level: page table level to stop at
774  *
775  * Returns a table entry pointer for the given guest address and @level
776  * @level=0 : returns a pointer to a page table table entry (or NULL)
777  * @level=1 : returns a pointer to a segment table entry (or NULL)
778  * @level=2 : returns a pointer to a region-3 table entry (or NULL)
779  * @level=3 : returns a pointer to a region-2 table entry (or NULL)
780  * @level=4 : returns a pointer to a region-1 table entry (or NULL)
781  *
782  * Returns NULL if the gmap page tables could not be walked to the
783  * requested level.
784  *
785  * Note: Can also be called for shadow gmaps.
786  */
787 static inline unsigned long *gmap_table_walk(struct gmap *gmap,
788                                              unsigned long gaddr, int level)
789 {
790         const int asce_type = gmap->asce & _ASCE_TYPE_MASK;
791         unsigned long *table = gmap->table;
792 
793         if (gmap_is_shadow(gmap) && gmap->removed)
794                 return NULL;
795 
796         if (WARN_ON_ONCE(level > (asce_type >> 2) + 1))
797                 return NULL;
798 
799         if (asce_type != _ASCE_TYPE_REGION1 &&
800             gaddr & (-1UL << (31 + (asce_type >> 2) * 11)))
801                 return NULL;
802 
803         switch (asce_type) {
804         case _ASCE_TYPE_REGION1:
805                 table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
806                 if (level == 4)
807                         break;
808                 if (*table & _REGION_ENTRY_INVALID)
809                         return NULL;
810                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
811                 fallthrough;
812         case _ASCE_TYPE_REGION2:
813                 table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
814                 if (level == 3)
815                         break;
816                 if (*table & _REGION_ENTRY_INVALID)
817                         return NULL;
818                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
819                 fallthrough;
820         case _ASCE_TYPE_REGION3:
821                 table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
822                 if (level == 2)
823                         break;
824                 if (*table & _REGION_ENTRY_INVALID)
825                         return NULL;
826                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
827                 fallthrough;
828         case _ASCE_TYPE_SEGMENT:
829                 table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
830                 if (level == 1)
831                         break;
832                 if (*table & _REGION_ENTRY_INVALID)
833                         return NULL;
834                 table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
835                 table += (gaddr & _PAGE_INDEX) >> _PAGE_SHIFT;
836         }
837         return table;
838 }
839 
840 /**
841  * gmap_pte_op_walk - walk the gmap page table, get the page table lock
842  *                    and return the pte pointer
843  * @gmap: pointer to guest mapping meta data structure
844  * @gaddr: virtual address in the guest address space
845  * @ptl: pointer to the spinlock pointer
846  *
847  * Returns a pointer to the locked pte for a guest address, or NULL
848  */
849 static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
850                                spinlock_t **ptl)
851 {
852         unsigned long *table;
853 
854         BUG_ON(gmap_is_shadow(gmap));
855         /* Walk the gmap page table, lock and get pte pointer */
856         table = gmap_table_walk(gmap, gaddr, 1); /* get segment pointer */
857         if (!table || *table & _SEGMENT_ENTRY_INVALID)
858                 return NULL;
859         return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl);
860 }
861 
862 /**
863  * gmap_pte_op_fixup - force a page in and connect the gmap page table
864  * @gmap: pointer to guest mapping meta data structure
865  * @gaddr: virtual address in the guest address space
866  * @vmaddr: address in the host process address space
867  * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
868  *
869  * Returns 0 if the caller can retry __gmap_translate (might fail again),
870  * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing
871  * up or connecting the gmap page table.
872  */
873 static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
874                              unsigned long vmaddr, int prot)
875 {
876         struct mm_struct *mm = gmap->mm;
877         unsigned int fault_flags;
878         bool unlocked = false;
879 
880         BUG_ON(gmap_is_shadow(gmap));
881         fault_flags = (prot == PROT_WRITE) ? FAULT_FLAG_WRITE : 0;
882         if (fixup_user_fault(current, mm, vmaddr, fault_flags, &unlocked))
883                 return -EFAULT;
884         if (unlocked)
885                 /* lost mmap_lock, caller has to retry __gmap_translate */
886                 return 0;
887         /* Connect the page tables */
888         return __gmap_link(gmap, gaddr, vmaddr);
889 }
890 
891 /**
892  * gmap_pte_op_end - release the page table lock
893  * @ptl: pointer to the spinlock pointer
894  */
895 static void gmap_pte_op_end(spinlock_t *ptl)
896 {
897         if (ptl)
898                 spin_unlock(ptl);
899 }
900 
901 /**
902  * gmap_pmd_op_walk - walk the gmap tables, get the guest table lock
903  *                    and return the pmd pointer
904  * @gmap: pointer to guest mapping meta data structure
905  * @gaddr: virtual address in the guest address space
906  *
907  * Returns a pointer to the pmd for a guest address, or NULL
908  */
909 static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr)
910 {
911         pmd_t *pmdp;
912 
913         BUG_ON(gmap_is_shadow(gmap));
914         pmdp = (pmd_t *) gmap_table_walk(gmap, gaddr, 1);
915         if (!pmdp)
916                 return NULL;
917 
918         /* without huge pages, there is no need to take the table lock */
919         if (!gmap->mm->context.allow_gmap_hpage_1m)
920                 return pmd_none(*pmdp) ? NULL : pmdp;
921 
922         spin_lock(&gmap->guest_table_lock);
923         if (pmd_none(*pmdp)) {
924                 spin_unlock(&gmap->guest_table_lock);
925                 return NULL;
926         }
927 
928         /* 4k page table entries are locked via the pte (pte_alloc_map_lock). */
929         if (!pmd_large(*pmdp))
930                 spin_unlock(&gmap->guest_table_lock);
931         return pmdp;
932 }
933 
934 /**
935  * gmap_pmd_op_end - release the guest_table_lock if needed
936  * @gmap: pointer to the guest mapping meta data structure
937  * @pmdp: pointer to the pmd
938  */
939 static inline void gmap_pmd_op_end(struct gmap *gmap, pmd_t *pmdp)
940 {
941         if (pmd_large(*pmdp))
942                 spin_unlock(&gmap->guest_table_lock);
943 }
944 
945 /*
946  * gmap_protect_pmd - remove access rights to memory and set pmd notification bits
947  * @pmdp: pointer to the pmd to be protected
948  * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
949  * @bits: notification bits to set
950  *
951  * Returns:
952  * 0 if successfully protected
953  * -EAGAIN if a fixup is needed
954  * -EINVAL if unsupported notifier bits have been specified
955  *
956  * Expected to be called with sg->mm->mmap_lock in read and
957  * guest_table_lock held.
958  */
959 static int gmap_protect_pmd(struct gmap *gmap, unsigned long gaddr,
960                             pmd_t *pmdp, int prot, unsigned long bits)
961 {
962         int pmd_i = pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID;
963         int pmd_p = pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT;
964         pmd_t new = *pmdp;
965 
966         /* Fixup needed */
967         if ((pmd_i && (prot != PROT_NONE)) || (pmd_p && (prot == PROT_WRITE)))
968                 return -EAGAIN;
969 
970         if (prot == PROT_NONE && !pmd_i) {
971                 pmd_val(new) |= _SEGMENT_ENTRY_INVALID;
972                 gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
973         }
974 
975         if (prot == PROT_READ && !pmd_p) {
976                 pmd_val(new) &= ~_SEGMENT_ENTRY_INVALID;
977                 pmd_val(new) |= _SEGMENT_ENTRY_PROTECT;
978                 gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
979         }
980 
981         if (bits & GMAP_NOTIFY_MPROT)
982                 pmd_val(*pmdp) |= _SEGMENT_ENTRY_GMAP_IN;
983 
984         /* Shadow GMAP protection needs split PMDs */
985         if (bits & GMAP_NOTIFY_SHADOW)
986                 return -EINVAL;
987 
988         return 0;
989 }
990 
991 /*
992  * gmap_protect_pte - remove access rights to memory and set pgste bits
993  * @gmap: pointer to guest mapping meta data structure
994  * @gaddr: virtual address in the guest address space
995  * @pmdp: pointer to the pmd associated with the pte
996  * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
997  * @bits: notification bits to set
998  *
999  * Returns 0 if successfully protected, -ENOMEM if out of memory and
1000  * -EAGAIN if a fixup is needed.
1001  *
1002  * Expected to be called with sg->mm->mmap_lock in read
1003  */
1004 static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
1005                             pmd_t *pmdp, int prot, unsigned long bits)
1006 {
1007         int rc;
1008         pte_t *ptep;
1009         spinlock_t *ptl = NULL;
1010         unsigned long pbits = 0;
1011 
1012         if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
1013                 return -EAGAIN;
1014 
1015         ptep = pte_alloc_map_lock(gmap->mm, pmdp, gaddr, &ptl);
1016         if (!ptep)
1017                 return -ENOMEM;
1018 
1019         pbits |= (bits & GMAP_NOTIFY_MPROT) ? PGSTE_IN_BIT : 0;
1020         pbits |= (bits & GMAP_NOTIFY_SHADOW) ? PGSTE_VSIE_BIT : 0;
1021         /* Protect and unlock. */
1022         rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits);
1023         gmap_pte_op_end(ptl);
1024         return rc;
1025 }
1026 
1027 /*
1028  * gmap_protect_range - remove access rights to memory and set pgste bits
1029  * @gmap: pointer to guest mapping meta data structure
1030  * @gaddr: virtual address in the guest address space
1031  * @len: size of area
1032  * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1033  * @bits: pgste notification bits to set
1034  *
1035  * Returns 0 if successfully protected, -ENOMEM if out of memory and
1036  * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
1037  *
1038  * Called with sg->mm->mmap_lock in read.
1039  */
1040 static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
1041                               unsigned long len, int prot, unsigned long bits)
1042 {
1043         unsigned long vmaddr, dist;
1044         pmd_t *pmdp;
1045         int rc;
1046 
1047         BUG_ON(gmap_is_shadow(gmap));
1048         while (len) {
1049                 rc = -EAGAIN;
1050                 pmdp = gmap_pmd_op_walk(gmap, gaddr);
1051                 if (pmdp) {
1052                         if (!pmd_large(*pmdp)) {
1053                                 rc = gmap_protect_pte(gmap, gaddr, pmdp, prot,
1054                                                       bits);
1055                                 if (!rc) {
1056                                         len -= PAGE_SIZE;
1057                                         gaddr += PAGE_SIZE;
1058                                 }
1059                         } else {
1060                                 rc = gmap_protect_pmd(gmap, gaddr, pmdp, prot,
1061                                                       bits);
1062                                 if (!rc) {
1063                                         dist = HPAGE_SIZE - (gaddr & ~HPAGE_MASK);
1064                                         len = len < dist ? 0 : len - dist;
1065                                         gaddr = (gaddr & HPAGE_MASK) + HPAGE_SIZE;
1066                                 }
1067                         }
1068                         gmap_pmd_op_end(gmap, pmdp);
1069                 }
1070                 if (rc) {
1071                         if (rc == -EINVAL)
1072                                 return rc;
1073 
1074                         /* -EAGAIN, fixup of userspace mm and gmap */
1075                         vmaddr = __gmap_translate(gmap, gaddr);
1076                         if (IS_ERR_VALUE(vmaddr))
1077                                 return vmaddr;
1078                         rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot);
1079                         if (rc)
1080                                 return rc;
1081                 }
1082         }
1083         return 0;
1084 }
1085 
1086 /**
1087  * gmap_mprotect_notify - change access rights for a range of ptes and
1088  *                        call the notifier if any pte changes again
1089  * @gmap: pointer to guest mapping meta data structure
1090  * @gaddr: virtual address in the guest address space
1091  * @len: size of area
1092  * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1093  *
1094  * Returns 0 if for each page in the given range a gmap mapping exists,
1095  * the new access rights could be set and the notifier could be armed.
1096  * If the gmap mapping is missing for one or more pages -EFAULT is
1097  * returned. If no memory could be allocated -ENOMEM is returned.
1098  * This function establishes missing page table entries.
1099  */
1100 int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
1101                          unsigned long len, int prot)
1102 {
1103         int rc;
1104 
1105         if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
1106                 return -EINVAL;
1107         if (!MACHINE_HAS_ESOP && prot == PROT_READ)
1108                 return -EINVAL;
1109         mmap_read_lock(gmap->mm);
1110         rc = gmap_protect_range(gmap, gaddr, len, prot, GMAP_NOTIFY_MPROT);
1111         mmap_read_unlock(gmap->mm);
1112         return rc;
1113 }
1114 EXPORT_SYMBOL_GPL(gmap_mprotect_notify);
1115 
1116 /**
1117  * gmap_read_table - get an unsigned long value from a guest page table using
1118  *                   absolute addressing, without marking the page referenced.
1119  * @gmap: pointer to guest mapping meta data structure
1120  * @gaddr: virtual address in the guest address space
1121  * @val: pointer to the unsigned long value to return
1122  *
1123  * Returns 0 if the value was read, -ENOMEM if out of memory and -EFAULT
1124  * if reading using the virtual address failed. -EINVAL if called on a gmap
1125  * shadow.
1126  *
1127  * Called with gmap->mm->mmap_lock in read.
1128  */
1129 int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
1130 {
1131         unsigned long address, vmaddr;
1132         spinlock_t *ptl;
1133         pte_t *ptep, pte;
1134         int rc;
1135 
1136         if (gmap_is_shadow(gmap))
1137                 return -EINVAL;
1138 
1139         while (1) {
1140                 rc = -EAGAIN;
1141                 ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
1142                 if (ptep) {
1143                         pte = *ptep;
1144                         if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) {
1145                                 address = pte_val(pte) & PAGE_MASK;
1146                                 address += gaddr & ~PAGE_MASK;
1147                                 *val = *(unsigned long *) address;
1148                                 pte_val(*ptep) |= _PAGE_YOUNG;
1149                                 /* Do *NOT* clear the _PAGE_INVALID bit! */
1150                                 rc = 0;
1151                         }
1152                         gmap_pte_op_end(ptl);
1153                 }
1154                 if (!rc)
1155                         break;
1156                 vmaddr = __gmap_translate(gmap, gaddr);
1157                 if (IS_ERR_VALUE(vmaddr)) {
1158                         rc = vmaddr;
1159                         break;
1160                 }
1161                 rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, PROT_READ);
1162                 if (rc)
1163                         break;
1164         }
1165         return rc;
1166 }
1167 EXPORT_SYMBOL_GPL(gmap_read_table);
1168 
1169 /**
1170  * gmap_insert_rmap - add a rmap to the host_to_rmap radix tree
1171  * @sg: pointer to the shadow guest address space structure
1172  * @vmaddr: vm address associated with the rmap
1173  * @rmap: pointer to the rmap structure
1174  *
1175  * Called with the sg->guest_table_lock
1176  */
1177 static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
1178                                     struct gmap_rmap *rmap)
1179 {
1180         void __rcu **slot;
1181 
1182         BUG_ON(!gmap_is_shadow(sg));
1183         slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
1184         if (slot) {
1185                 rmap->next = radix_tree_deref_slot_protected(slot,
1186                                                         &sg->guest_table_lock);
1187                 radix_tree_replace_slot(&sg->host_to_rmap, slot, rmap);
1188         } else {
1189                 rmap->next = NULL;
1190                 radix_tree_insert(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT,
1191                                   rmap);
1192         }
1193 }
1194 
1195 /**
1196  * gmap_protect_rmap - restrict access rights to memory (RO) and create an rmap
1197  * @sg: pointer to the shadow guest address space structure
1198  * @raddr: rmap address in the shadow gmap
1199  * @paddr: address in the parent guest address space
1200  * @len: length of the memory area to protect
1201  *
1202  * Returns 0 if successfully protected and the rmap was created, -ENOMEM
1203  * if out of memory and -EFAULT if paddr is invalid.
1204  */
1205 static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
1206                              unsigned long paddr, unsigned long len)
1207 {
1208         struct gmap *parent;
1209         struct gmap_rmap *rmap;
1210         unsigned long vmaddr;
1211         spinlock_t *ptl;
1212         pte_t *ptep;
1213         int rc;
1214 
1215         BUG_ON(!gmap_is_shadow(sg));
1216         parent = sg->parent;
1217         while (len) {
1218                 vmaddr = __gmap_translate(parent, paddr);
1219                 if (IS_ERR_VALUE(vmaddr))
1220                         return vmaddr;
1221                 rmap = kzalloc(sizeof(*rmap), GFP_KERNEL);
1222                 if (!rmap)
1223                         return -ENOMEM;
1224                 rmap->raddr = raddr;
1225                 rc = radix_tree_preload(GFP_KERNEL);
1226                 if (rc) {
1227                         kfree(rmap);
1228                         return rc;
1229                 }
1230                 rc = -EAGAIN;
1231                 ptep = gmap_pte_op_walk(parent, paddr, &ptl);
1232                 if (ptep) {
1233                         spin_lock(&sg->guest_table_lock);
1234                         rc = ptep_force_prot(parent->mm, paddr, ptep, PROT_READ,
1235                                              PGSTE_VSIE_BIT);
1236                         if (!rc)
1237                                 gmap_insert_rmap(sg, vmaddr, rmap);
1238                         spin_unlock(&sg->guest_table_lock);
1239                         gmap_pte_op_end(ptl);
1240                 }
1241                 radix_tree_preload_end();
1242                 if (rc) {
1243                         kfree(rmap);
1244                         rc = gmap_pte_op_fixup(parent, paddr, vmaddr, PROT_READ);
1245                         if (rc)
1246                                 return rc;
1247                         continue;
1248                 }
1249                 paddr += PAGE_SIZE;
1250                 len -= PAGE_SIZE;
1251         }
1252         return 0;
1253 }
1254 
1255 #define _SHADOW_RMAP_MASK       0x7
1256 #define _SHADOW_RMAP_REGION1    0x5
1257 #define _SHADOW_RMAP_REGION2    0x4
1258 #define _SHADOW_RMAP_REGION3    0x3
1259 #define _SHADOW_RMAP_SEGMENT    0x2
1260 #define _SHADOW_RMAP_PGTABLE    0x1
1261 
1262 /**
1263  * gmap_idte_one - invalidate a single region or segment table entry
1264  * @asce: region or segment table *origin* + table-type bits
1265  * @vaddr: virtual address to identify the table entry to flush
1266  *
1267  * The invalid bit of a single region or segment table entry is set
1268  * and the associated TLB entries depending on the entry are flushed.
1269  * The table-type of the @asce identifies the portion of the @vaddr
1270  * that is used as the invalidation index.
1271  */
1272 static inline void gmap_idte_one(unsigned long asce, unsigned long vaddr)
1273 {
1274         asm volatile(
1275                 "       .insn   rrf,0xb98e0000,%0,%1,0,0"
1276                 : : "a" (asce), "a" (vaddr) : "cc", "memory");
1277 }
1278 
1279 /**
1280  * gmap_unshadow_page - remove a page from a shadow page table
1281  * @sg: pointer to the shadow guest address space structure
1282  * @raddr: rmap address in the shadow guest address space
1283  *
1284  * Called with the sg->guest_table_lock
1285  */
1286 static void gmap_unshadow_page(struct gmap *sg, unsigned long raddr)
1287 {
1288         unsigned long *table;
1289 
1290         BUG_ON(!gmap_is_shadow(sg));
1291         table = gmap_table_walk(sg, raddr, 0); /* get page table pointer */
1292         if (!table || *table & _PAGE_INVALID)
1293                 return;
1294         gmap_call_notifier(sg, raddr, raddr + _PAGE_SIZE - 1);
1295         ptep_unshadow_pte(sg->mm, raddr, (pte_t *) table);
1296 }
1297 
1298 /**
1299  * __gmap_unshadow_pgt - remove all entries from a shadow page table
1300  * @sg: pointer to the shadow guest address space structure
1301  * @raddr: rmap address in the shadow guest address space
1302  * @pgt: pointer to the start of a shadow page table
1303  *
1304  * Called with the sg->guest_table_lock
1305  */
1306 static void __gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr,
1307                                 unsigned long *pgt)
1308 {
1309         int i;
1310 
1311         BUG_ON(!gmap_is_shadow(sg));
1312         for (i = 0; i < _PAGE_ENTRIES; i++, raddr += _PAGE_SIZE)
1313                 pgt[i] = _PAGE_INVALID;
1314 }
1315 
1316 /**
1317  * gmap_unshadow_pgt - remove a shadow page table from a segment entry
1318  * @sg: pointer to the shadow guest address space structure
1319  * @raddr: address in the shadow guest address space
1320  *
1321  * Called with the sg->guest_table_lock
1322  */
1323 static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
1324 {
1325         unsigned long sto, *ste, *pgt;
1326         struct page *page;
1327 
1328         BUG_ON(!gmap_is_shadow(sg));
1329         ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */
1330         if (!ste || !(*ste & _SEGMENT_ENTRY_ORIGIN))
1331                 return;
1332         gmap_call_notifier(sg, raddr, raddr + _SEGMENT_SIZE - 1);
1333         sto = (unsigned long) (ste - ((raddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT));
1334         gmap_idte_one(sto | _ASCE_TYPE_SEGMENT, raddr);
1335         pgt = (unsigned long *)(*ste & _SEGMENT_ENTRY_ORIGIN);
1336         *ste = _SEGMENT_ENTRY_EMPTY;
1337         __gmap_unshadow_pgt(sg, raddr, pgt);
1338         /* Free page table */
1339         page = pfn_to_page(__pa(pgt) >> PAGE_SHIFT);
1340         list_del(&page->lru);
1341         page_table_free_pgste(page);
1342 }
1343 
1344 /**
1345  * __gmap_unshadow_sgt - remove all entries from a shadow segment table
1346  * @sg: pointer to the shadow guest address space structure
1347  * @raddr: rmap address in the shadow guest address space
1348  * @sgt: pointer to the start of a shadow segment table
1349  *
1350  * Called with the sg->guest_table_lock
1351  */
1352 static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
1353                                 unsigned long *sgt)
1354 {
1355         unsigned long *pgt;
1356         struct page *page;
1357         int i;
1358 
1359         BUG_ON(!gmap_is_shadow(sg));
1360         for (i = 0; i < _CRST_ENTRIES; i++, raddr += _SEGMENT_SIZE) {
1361                 if (!(sgt[i] & _SEGMENT_ENTRY_ORIGIN))
1362                         continue;
1363                 pgt = (unsigned long *)(sgt[i] & _REGION_ENTRY_ORIGIN);
1364                 sgt[i] = _SEGMENT_ENTRY_EMPTY;
1365                 __gmap_unshadow_pgt(sg, raddr, pgt);
1366                 /* Free page table */
1367                 page = pfn_to_page(__pa(pgt) >> PAGE_SHIFT);
1368                 list_del(&page->lru);
1369                 page_table_free_pgste(page);
1370         }
1371 }
1372 
1373 /**
1374  * gmap_unshadow_sgt - remove a shadow segment table from a region-3 entry
1375  * @sg: pointer to the shadow guest address space structure
1376  * @raddr: rmap address in the shadow guest address space
1377  *
1378  * Called with the shadow->guest_table_lock
1379  */
1380 static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
1381 {
1382         unsigned long r3o, *r3e, *sgt;
1383         struct page *page;
1384 
1385         BUG_ON(!gmap_is_shadow(sg));
1386         r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
1387         if (!r3e || !(*r3e & _REGION_ENTRY_ORIGIN))
1388                 return;
1389         gmap_call_notifier(sg, raddr, raddr + _REGION3_SIZE - 1);
1390         r3o = (unsigned long) (r3e - ((raddr & _REGION3_INDEX) >> _REGION3_SHIFT));
1391         gmap_idte_one(r3o | _ASCE_TYPE_REGION3, raddr);
1392         sgt = (unsigned long *)(*r3e & _REGION_ENTRY_ORIGIN);
1393         *r3e = _REGION3_ENTRY_EMPTY;
1394         __gmap_unshadow_sgt(sg, raddr, sgt);
1395         /* Free segment table */
1396         page = pfn_to_page(__pa(sgt) >> PAGE_SHIFT);
1397         list_del(&page->lru);
1398         __free_pages(page, CRST_ALLOC_ORDER);
1399 }
1400 
1401 /**
1402  * __gmap_unshadow_r3t - remove all entries from a shadow region-3 table
1403  * @sg: pointer to the shadow guest address space structure
1404  * @raddr: address in the shadow guest address space
1405  * @r3t: pointer to the start of a shadow region-3 table
1406  *
1407  * Called with the sg->guest_table_lock
1408  */
1409 static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
1410                                 unsigned long *r3t)
1411 {
1412         unsigned long *sgt;
1413         struct page *page;
1414         int i;
1415 
1416         BUG_ON(!gmap_is_shadow(sg));
1417         for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION3_SIZE) {
1418                 if (!(r3t[i] & _REGION_ENTRY_ORIGIN))
1419                         continue;
1420                 sgt = (unsigned long *)(r3t[i] & _REGION_ENTRY_ORIGIN);
1421                 r3t[i] = _REGION3_ENTRY_EMPTY;
1422                 __gmap_unshadow_sgt(sg, raddr, sgt);
1423                 /* Free segment table */
1424                 page = pfn_to_page(__pa(sgt) >> PAGE_SHIFT);
1425                 list_del(&page->lru);
1426                 __free_pages(page, CRST_ALLOC_ORDER);
1427         }
1428 }
1429 
1430 /**
1431  * gmap_unshadow_r3t - remove a shadow region-3 table from a region-2 entry
1432  * @sg: pointer to the shadow guest address space structure
1433  * @raddr: rmap address in the shadow guest address space
1434  *
1435  * Called with the sg->guest_table_lock
1436  */
1437 static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
1438 {
1439         unsigned long r2o, *r2e, *r3t;
1440         struct page *page;
1441 
1442         BUG_ON(!gmap_is_shadow(sg));
1443         r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
1444         if (!r2e || !(*r2e & _REGION_ENTRY_ORIGIN))
1445                 return;
1446         gmap_call_notifier(sg, raddr, raddr + _REGION2_SIZE - 1);
1447         r2o = (unsigned long) (r2e - ((raddr & _REGION2_INDEX) >> _REGION2_SHIFT));
1448         gmap_idte_one(r2o | _ASCE_TYPE_REGION2, raddr);
1449         r3t = (unsigned long *)(*r2e & _REGION_ENTRY_ORIGIN);
1450         *r2e = _REGION2_ENTRY_EMPTY;
1451         __gmap_unshadow_r3t(sg, raddr, r3t);
1452         /* Free region 3 table */
1453         page = pfn_to_page(__pa(r3t) >> PAGE_SHIFT);
1454         list_del(&page->lru);
1455         __free_pages(page, CRST_ALLOC_ORDER);
1456 }
1457 
1458 /**
1459  * __gmap_unshadow_r2t - remove all entries from a shadow region-2 table
1460  * @sg: pointer to the shadow guest address space structure
1461  * @raddr: rmap address in the shadow guest address space
1462  * @r2t: pointer to the start of a shadow region-2 table
1463  *
1464  * Called with the sg->guest_table_lock
1465  */
1466 static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
1467                                 unsigned long *r2t)
1468 {
1469         unsigned long *r3t;
1470         struct page *page;
1471         int i;
1472 
1473         BUG_ON(!gmap_is_shadow(sg));
1474         for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION2_SIZE) {
1475                 if (!(r2t[i] & _REGION_ENTRY_ORIGIN))
1476                         continue;
1477                 r3t = (unsigned long *)(r2t[i] & _REGION_ENTRY_ORIGIN);
1478                 r2t[i] = _REGION2_ENTRY_EMPTY;
1479                 __gmap_unshadow_r3t(sg, raddr, r3t);
1480                 /* Free region 3 table */
1481                 page = pfn_to_page(__pa(r3t) >> PAGE_SHIFT);
1482                 list_del(&page->lru);
1483                 __free_pages(page, CRST_ALLOC_ORDER);
1484         }
1485 }
1486 
1487 /**
1488  * gmap_unshadow_r2t - remove a shadow region-2 table from a region-1 entry
1489  * @sg: pointer to the shadow guest address space structure
1490  * @raddr: rmap address in the shadow guest address space
1491  *
1492  * Called with the sg->guest_table_lock
1493  */
1494 static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
1495 {
1496         unsigned long r1o, *r1e, *r2t;
1497         struct page *page;
1498 
1499         BUG_ON(!gmap_is_shadow(sg));
1500         r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */
1501         if (!r1e || !(*r1e & _REGION_ENTRY_ORIGIN))
1502                 return;
1503         gmap_call_notifier(sg, raddr, raddr + _REGION1_SIZE - 1);
1504         r1o = (unsigned long) (r1e - ((raddr & _REGION1_INDEX) >> _REGION1_SHIFT));
1505         gmap_idte_one(r1o | _ASCE_TYPE_REGION1, raddr);
1506         r2t = (unsigned long *)(*r1e & _REGION_ENTRY_ORIGIN);
1507         *r1e = _REGION1_ENTRY_EMPTY;
1508         __gmap_unshadow_r2t(sg, raddr, r2t);
1509         /* Free region 2 table */
1510         page = pfn_to_page(__pa(r2t) >> PAGE_SHIFT);
1511         list_del(&page->lru);
1512         __free_pages(page, CRST_ALLOC_ORDER);
1513 }
1514 
1515 /**
1516  * __gmap_unshadow_r1t - remove all entries from a shadow region-1 table
1517  * @sg: pointer to the shadow guest address space structure
1518  * @raddr: rmap address in the shadow guest address space
1519  * @r1t: pointer to the start of a shadow region-1 table
1520  *
1521  * Called with the shadow->guest_table_lock
1522  */
1523 static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
1524                                 unsigned long *r1t)
1525 {
1526         unsigned long asce, *r2t;
1527         struct page *page;
1528         int i;
1529 
1530         BUG_ON(!gmap_is_shadow(sg));
1531         asce = (unsigned long) r1t | _ASCE_TYPE_REGION1;
1532         for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION1_SIZE) {
1533                 if (!(r1t[i] & _REGION_ENTRY_ORIGIN))
1534                         continue;
1535                 r2t = (unsigned long *)(r1t[i] & _REGION_ENTRY_ORIGIN);
1536                 __gmap_unshadow_r2t(sg, raddr, r2t);
1537                 /* Clear entry and flush translation r1t -> r2t */
1538                 gmap_idte_one(asce, raddr);
1539                 r1t[i] = _REGION1_ENTRY_EMPTY;
1540                 /* Free region 2 table */
1541                 page = pfn_to_page(__pa(r2t) >> PAGE_SHIFT);
1542                 list_del(&page->lru);
1543                 __free_pages(page, CRST_ALLOC_ORDER);
1544         }
1545 }
1546 
1547 /**
1548  * gmap_unshadow - remove a shadow page table completely
1549  * @sg: pointer to the shadow guest address space structure
1550  *
1551  * Called with sg->guest_table_lock
1552  */
1553 static void gmap_unshadow(struct gmap *sg)
1554 {
1555         unsigned long *table;
1556 
1557         BUG_ON(!gmap_is_shadow(sg));
1558         if (sg->removed)
1559                 return;
1560         sg->removed = 1;
1561         gmap_call_notifier(sg, 0, -1UL);
1562         gmap_flush_tlb(sg);
1563         table = (unsigned long *)(sg->asce & _ASCE_ORIGIN);
1564         switch (sg->asce & _ASCE_TYPE_MASK) {
1565         case _ASCE_TYPE_REGION1:
1566                 __gmap_unshadow_r1t(sg, 0, table);
1567                 break;
1568         case _ASCE_TYPE_REGION2:
1569                 __gmap_unshadow_r2t(sg, 0, table);
1570                 break;
1571         case _ASCE_TYPE_REGION3:
1572                 __gmap_unshadow_r3t(sg, 0, table);
1573                 break;
1574         case _ASCE_TYPE_SEGMENT:
1575                 __gmap_unshadow_sgt(sg, 0, table);
1576                 break;
1577         }
1578 }
1579 
1580 /**
1581  * gmap_find_shadow - find a specific asce in the list of shadow tables
1582  * @parent: pointer to the parent gmap
1583  * @asce: ASCE for which the shadow table is created
1584  * @edat_level: edat level to be used for the shadow translation
1585  *
1586  * Returns the pointer to a gmap if a shadow table with the given asce is
1587  * already available, ERR_PTR(-EAGAIN) if another one is just being created,
1588  * otherwise NULL
1589  */
1590 static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce,
1591                                      int edat_level)
1592 {
1593         struct gmap *sg;
1594 
1595         list_for_each_entry(sg, &parent->children, list) {
1596                 if (sg->orig_asce != asce || sg->edat_level != edat_level ||
1597                     sg->removed)
1598                         continue;
1599                 if (!sg->initialized)
1600                         return ERR_PTR(-EAGAIN);
1601                 refcount_inc(&sg->ref_count);
1602                 return sg;
1603         }
1604         return NULL;
1605 }
1606 
1607 /**
1608  * gmap_shadow_valid - check if a shadow guest address space matches the
1609  *                     given properties and is still valid
1610  * @sg: pointer to the shadow guest address space structure
1611  * @asce: ASCE for which the shadow table is requested
1612  * @edat_level: edat level to be used for the shadow translation
1613  *
1614  * Returns 1 if the gmap shadow is still valid and matches the given
1615  * properties, the caller can continue using it. Returns 0 otherwise, the
1616  * caller has to request a new shadow gmap in this case.
1617  *
1618  */
1619 int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)
1620 {
1621         if (sg->removed)
1622                 return 0;
1623         return sg->orig_asce == asce && sg->edat_level == edat_level;
1624 }
1625 EXPORT_SYMBOL_GPL(gmap_shadow_valid);
1626 
1627 /**
1628  * gmap_shadow - create/find a shadow guest address space
1629  * @parent: pointer to the parent gmap
1630  * @asce: ASCE for which the shadow table is created
1631  * @edat_level: edat level to be used for the shadow translation
1632  *
1633  * The pages of the top level page table referred by the asce parameter
1634  * will be set to read-only and marked in the PGSTEs of the kvm process.
1635  * The shadow table will be removed automatically on any change to the
1636  * PTE mapping for the source table.
1637  *
1638  * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory,
1639  * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the
1640  * parent gmap table could not be protected.
1641  */
1642 struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
1643                          int edat_level)
1644 {
1645         struct gmap *sg, *new;
1646         unsigned long limit;
1647         int rc;
1648 
1649         BUG_ON(parent->mm->context.allow_gmap_hpage_1m);
1650         BUG_ON(gmap_is_shadow(parent));
1651         spin_lock(&parent->shadow_lock);
1652         sg = gmap_find_shadow(parent, asce, edat_level);
1653         spin_unlock(&parent->shadow_lock);
1654         if (sg)
1655                 return sg;
1656         /* Create a new shadow gmap */
1657         limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
1658         if (asce & _ASCE_REAL_SPACE)
1659                 limit = -1UL;
1660         new = gmap_alloc(limit);
1661         if (!new)
1662                 return ERR_PTR(-ENOMEM);
1663         new->mm = parent->mm;
1664         new->parent = gmap_get(parent);
1665         new->orig_asce = asce;
1666         new->edat_level = edat_level;
1667         new->initialized = false;
1668         spin_lock(&parent->shadow_lock);
1669         /* Recheck if another CPU created the same shadow */
1670         sg = gmap_find_shadow(parent, asce, edat_level);
1671         if (sg) {
1672                 spin_unlock(&parent->shadow_lock);
1673                 gmap_free(new);
1674                 return sg;
1675         }
1676         if (asce & _ASCE_REAL_SPACE) {
1677                 /* only allow one real-space gmap shadow */
1678                 list_for_each_entry(sg, &parent->children, list) {
1679                         if (sg->orig_asce & _ASCE_REAL_SPACE) {
1680                                 spin_lock(&sg->guest_table_lock);
1681                                 gmap_unshadow(sg);
1682                                 spin_unlock(&sg->guest_table_lock);
1683                                 list_del(&sg->list);
1684                                 gmap_put(sg);
1685                                 break;
1686                         }
1687                 }
1688         }
1689         refcount_set(&new->ref_count, 2);
1690         list_add(&new->list, &parent->children);
1691         if (asce & _ASCE_REAL_SPACE) {
1692                 /* nothing to protect, return right away */
1693                 new->initialized = true;
1694                 spin_unlock(&parent->shadow_lock);
1695                 return new;
1696         }
1697         spin_unlock(&parent->shadow_lock);
1698         /* protect after insertion, so it will get properly invalidated */
1699         mmap_read_lock(parent->mm);
1700         rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
1701                                 ((asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE,
1702                                 PROT_READ, GMAP_NOTIFY_SHADOW);
1703         mmap_read_unlock(parent->mm);
1704         spin_lock(&parent->shadow_lock);
1705         new->initialized = true;
1706         if (rc) {
1707                 list_del(&new->list);
1708                 gmap_free(new);
1709                 new = ERR_PTR(rc);
1710         }
1711         spin_unlock(&parent->shadow_lock);
1712         return new;
1713 }
1714 EXPORT_SYMBOL_GPL(gmap_shadow);
1715 
1716 /**
1717  * gmap_shadow_r2t - create an empty shadow region 2 table
1718  * @sg: pointer to the shadow guest address space structure
1719  * @saddr: faulting address in the shadow gmap
1720  * @r2t: parent gmap address of the region 2 table to get shadowed
1721  * @fake: r2t references contiguous guest memory block, not a r2t
1722  *
1723  * The r2t parameter specifies the address of the source table. The
1724  * four pages of the source table are made read-only in the parent gmap
1725  * address space. A write to the source table area @r2t will automatically
1726  * remove the shadow r2 table and all of its decendents.
1727  *
1728  * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
1729  * shadow table structure is incomplete, -ENOMEM if out of memory and
1730  * -EFAULT if an address in the parent gmap could not be resolved.
1731  *
1732  * Called with sg->mm->mmap_lock in read.
1733  */
1734 int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
1735                     int fake)
1736 {
1737         unsigned long raddr, origin, offset, len;
1738         unsigned long *s_r2t, *table;
1739         struct page *page;
1740         int rc;
1741 
1742         BUG_ON(!gmap_is_shadow(sg));
1743         /* Allocate a shadow region second table */
1744         page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
1745         if (!page)
1746                 return -ENOMEM;
1747         page->index = r2t & _REGION_ENTRY_ORIGIN;
1748         if (fake)
1749                 page->index |= GMAP_SHADOW_FAKE_TABLE;
1750         s_r2t = (unsigned long *) page_to_phys(page);
1751         /* Install shadow region second table */
1752         spin_lock(&sg->guest_table_lock);
1753         table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
1754         if (!table) {
1755                 rc = -EAGAIN;           /* Race with unshadow */
1756                 goto out_free;
1757         }
1758         if (!(*table & _REGION_ENTRY_INVALID)) {
1759                 rc = 0;                 /* Already established */
1760                 goto out_free;
1761         } else if (*table & _REGION_ENTRY_ORIGIN) {
1762                 rc = -EAGAIN;           /* Race with shadow */
1763                 goto out_free;
1764         }
1765         crst_table_init(s_r2t, _REGION2_ENTRY_EMPTY);
1766         /* mark as invalid as long as the parent table is not protected */
1767         *table = (unsigned long) s_r2t | _REGION_ENTRY_LENGTH |
1768                  _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
1769         if (sg->edat_level >= 1)
1770                 *table |= (r2t & _REGION_ENTRY_PROTECT);
1771         list_add(&page->lru, &sg->crst_list);
1772         if (fake) {
1773                 /* nothing to protect for fake tables */
1774                 *table &= ~_REGION_ENTRY_INVALID;
1775                 spin_unlock(&sg->guest_table_lock);
1776                 return 0;
1777         }
1778         spin_unlock(&sg->guest_table_lock);
1779         /* Make r2t read-only in parent gmap page table */
1780         raddr = (saddr & _REGION1_MASK) | _SHADOW_RMAP_REGION1;
1781         origin = r2t & _REGION_ENTRY_ORIGIN;
1782         offset = ((r2t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1783         len = ((r2t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1784         rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1785         spin_lock(&sg->guest_table_lock);
1786         if (!rc) {
1787                 table = gmap_table_walk(sg, saddr, 4);
1788                 if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
1789                               (unsigned long) s_r2t)
1790                         rc = -EAGAIN;           /* Race with unshadow */
1791                 else
1792                         *table &= ~_REGION_ENTRY_INVALID;
1793         } else {
1794                 gmap_unshadow_r2t(sg, raddr);
1795         }
1796         spin_unlock(&sg->guest_table_lock);
1797         return rc;
1798 out_free:
1799         spin_unlock(&sg->guest_table_lock);
1800         __free_pages(page, CRST_ALLOC_ORDER);
1801         return rc;
1802 }
1803 EXPORT_SYMBOL_GPL(gmap_shadow_r2t);
1804 
1805 /**
1806  * gmap_shadow_r3t - create a shadow region 3 table
1807  * @sg: pointer to the shadow guest address space structure
1808  * @saddr: faulting address in the shadow gmap
1809  * @r3t: parent gmap address of the region 3 table to get shadowed
1810  * @fake: r3t references contiguous guest memory block, not a r3t
1811  *
1812  * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
1813  * shadow table structure is incomplete, -ENOMEM if out of memory and
1814  * -EFAULT if an address in the parent gmap could not be resolved.
1815  *
1816  * Called with sg->mm->mmap_lock in read.
1817  */
1818 int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
1819                     int fake)
1820 {
1821         unsigned long raddr, origin, offset, len;
1822         unsigned long *s_r3t, *table;
1823         struct page *page;
1824         int rc;
1825 
1826         BUG_ON(!gmap_is_shadow(sg));
1827         /* Allocate a shadow region second table */
1828         page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
1829         if (!page)
1830                 return -ENOMEM;
1831         page->index = r3t & _REGION_ENTRY_ORIGIN;
1832         if (fake)
1833                 page->index |= GMAP_SHADOW_FAKE_TABLE;
1834         s_r3t = (unsigned long *) page_to_phys(page);
1835         /* Install shadow region second table */
1836         spin_lock(&sg->guest_table_lock);
1837         table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
1838         if (!table) {
1839                 rc = -EAGAIN;           /* Race with unshadow */
1840                 goto out_free;
1841         }
1842         if (!(*table & _REGION_ENTRY_INVALID)) {
1843                 rc = 0;                 /* Already established */
1844                 goto out_free;
1845         } else if (*table & _REGION_ENTRY_ORIGIN) {
1846                 rc = -EAGAIN;           /* Race with shadow */
1847                 goto out_free;
1848         }
1849         crst_table_init(s_r3t, _REGION3_ENTRY_EMPTY);
1850         /* mark as invalid as long as the parent table is not protected */
1851         *table = (unsigned long) s_r3t | _REGION_ENTRY_LENGTH |
1852                  _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
1853         if (sg->edat_level >= 1)
1854                 *table |= (r3t & _REGION_ENTRY_PROTECT);
1855         list_add(&page->lru, &sg->crst_list);
1856         if (fake) {
1857                 /* nothing to protect for fake tables */
1858                 *table &= ~_REGION_ENTRY_INVALID;
1859                 spin_unlock(&sg->guest_table_lock);
1860                 return 0;
1861         }
1862         spin_unlock(&sg->guest_table_lock);
1863         /* Make r3t read-only in parent gmap page table */
1864         raddr = (saddr & _REGION2_MASK) | _SHADOW_RMAP_REGION2;
1865         origin = r3t & _REGION_ENTRY_ORIGIN;
1866         offset = ((r3t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1867         len = ((r3t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1868         rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1869         spin_lock(&sg->guest_table_lock);
1870         if (!rc) {
1871                 table = gmap_table_walk(sg, saddr, 3);
1872                 if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
1873                               (unsigned long) s_r3t)
1874                         rc = -EAGAIN;           /* Race with unshadow */
1875                 else
1876                         *table &= ~_REGION_ENTRY_INVALID;
1877         } else {
1878                 gmap_unshadow_r3t(sg, raddr);
1879         }
1880         spin_unlock(&sg->guest_table_lock);
1881         return rc;
1882 out_free:
1883         spin_unlock(&sg->guest_table_lock);
1884         __free_pages(page, CRST_ALLOC_ORDER);
1885         return rc;
1886 }
1887 EXPORT_SYMBOL_GPL(gmap_shadow_r3t);
1888 
1889 /**
1890  * gmap_shadow_sgt - create a shadow segment table
1891  * @sg: pointer to the shadow guest address space structure
1892  * @saddr: faulting address in the shadow gmap
1893  * @sgt: parent gmap address of the segment table to get shadowed
1894  * @fake: sgt references contiguous guest memory block, not a sgt
1895  *
1896  * Returns: 0 if successfully shadowed or already shadowed, -EAGAIN if the
1897  * shadow table structure is incomplete, -ENOMEM if out of memory and
1898  * -EFAULT if an address in the parent gmap could not be resolved.
1899  *
1900  * Called with sg->mm->mmap_lock in read.
1901  */
1902 int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
1903                     int fake)
1904 {
1905         unsigned long raddr, origin, offset, len;
1906         unsigned long *s_sgt, *table;
1907         struct page *page;
1908         int rc;
1909 
1910         BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE));
1911         /* Allocate a shadow segment table */
1912         page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
1913         if (!page)
1914                 return -ENOMEM;
1915         page->index = sgt & _REGION_ENTRY_ORIGIN;
1916         if (fake)
1917                 page->index |= GMAP_SHADOW_FAKE_TABLE;
1918         s_sgt = (unsigned long *) page_to_phys(page);
1919         /* Install shadow region second table */
1920         spin_lock(&sg->guest_table_lock);
1921         table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
1922         if (!table) {
1923                 rc = -EAGAIN;           /* Race with unshadow */
1924                 goto out_free;
1925         }
1926         if (!(*table & _REGION_ENTRY_INVALID)) {
1927                 rc = 0;                 /* Already established */
1928                 goto out_free;
1929         } else if (*table & _REGION_ENTRY_ORIGIN) {
1930                 rc = -EAGAIN;           /* Race with shadow */
1931                 goto out_free;
1932         }
1933         crst_table_init(s_sgt, _SEGMENT_ENTRY_EMPTY);
1934         /* mark as invalid as long as the parent table is not protected */
1935         *table = (unsigned long) s_sgt | _REGION_ENTRY_LENGTH |
1936                  _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
1937         if (sg->edat_level >= 1)
1938                 *table |= sgt & _REGION_ENTRY_PROTECT;
1939         list_add(&page->lru, &sg->crst_list);
1940         if (fake) {
1941                 /* nothing to protect for fake tables */
1942                 *table &= ~_REGION_ENTRY_INVALID;
1943                 spin_unlock(&sg->guest_table_lock);
1944                 return 0;
1945         }
1946         spin_unlock(&sg->guest_table_lock);
1947         /* Make sgt read-only in parent gmap page table */
1948         raddr = (saddr & _REGION3_MASK) | _SHADOW_RMAP_REGION3;
1949         origin = sgt & _REGION_ENTRY_ORIGIN;
1950         offset = ((sgt & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1951         len = ((sgt & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1952         rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1953         spin_lock(&sg->guest_table_lock);
1954         if (!rc) {
1955                 table = gmap_table_walk(sg, saddr, 2);
1956                 if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
1957                               (unsigned long) s_sgt)
1958                         rc = -EAGAIN;           /* Race with unshadow */
1959                 else
1960                         *table &= ~_REGION_ENTRY_INVALID;
1961         } else {
1962                 gmap_unshadow_sgt(sg, raddr);
1963         }
1964         spin_unlock(&sg->guest_table_lock);
1965         return rc;
1966 out_free:
1967         spin_unlock(&sg->guest_table_lock);
1968         __free_pages(page, CRST_ALLOC_ORDER);
1969         return rc;
1970 }
1971 EXPORT_SYMBOL_GPL(gmap_shadow_sgt);
1972 
1973 /**
1974  * gmap_shadow_lookup_pgtable - find a shadow page table
1975  * @sg: pointer to the shadow guest address space structure
1976  * @saddr: the address in the shadow aguest address space
1977  * @pgt: parent gmap address of the page table to get shadowed
1978  * @dat_protection: if the pgtable is marked as protected by dat
1979  * @fake: pgt references contiguous guest memory block, not a pgtable
1980  *
1981  * Returns 0 if the shadow page table was found and -EAGAIN if the page
1982  * table was not found.
1983  *
1984  * Called with sg->mm->mmap_lock in read.
1985  */
1986 int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
1987                            unsigned long *pgt, int *dat_protection,
1988                            int *fake)
1989 {
1990         unsigned long *table;
1991         struct page *page;
1992         int rc;
1993 
1994         BUG_ON(!gmap_is_shadow(sg));
1995         spin_lock(&sg->guest_table_lock);
1996         table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
1997         if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
1998                 /* Shadow page tables are full pages (pte+pgste) */
1999                 page = pfn_to_page(*table >> PAGE_SHIFT);
2000                 *pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
2001                 *dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
2002                 *fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
2003                 rc = 0;
2004         } else  {
2005                 rc = -EAGAIN;
2006         }
2007         spin_unlock(&sg->guest_table_lock);
2008         return rc;
2009 
2010 }
2011 EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup);
2012 
2013 /**
2014  * gmap_shadow_pgt - instantiate a shadow page table
2015  * @sg: pointer to the shadow guest address space structure
2016  * @saddr: faulting address in the shadow gmap
2017  * @pgt: parent gmap address of the page table to get shadowed
2018  * @fake: pgt references contiguous guest memory block, not a pgtable
2019  *
2020  * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
2021  * shadow table structure is incomplete, -ENOMEM if out of memory,
2022  * -EFAULT if an address in the parent gmap could not be resolved and
2023  *
2024  * Called with gmap->mm->mmap_lock in read
2025  */
2026 int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
2027                     int fake)
2028 {
2029         unsigned long raddr, origin;
2030         unsigned long *s_pgt, *table;
2031         struct page *page;
2032         int rc;
2033 
2034         BUG_ON(!gmap_is_shadow(sg) || (pgt & _SEGMENT_ENTRY_LARGE));
2035         /* Allocate a shadow page table */
2036         page = page_table_alloc_pgste(sg->mm);
2037         if (!page)
2038                 return -ENOMEM;
2039         page->index = pgt & _SEGMENT_ENTRY_ORIGIN;
2040         if (fake)
2041                 page->index |= GMAP_SHADOW_FAKE_TABLE;
2042         s_pgt = (unsigned long *) page_to_phys(page);
2043         /* Install shadow page table */
2044         spin_lock(&sg->guest_table_lock);
2045         table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
2046         if (!table) {
2047                 rc = -EAGAIN;           /* Race with unshadow */
2048                 goto out_free;
2049         }
2050         if (!(*table & _SEGMENT_ENTRY_INVALID)) {
2051                 rc = 0;                 /* Already established */
2052                 goto out_free;
2053         } else if (*table & _SEGMENT_ENTRY_ORIGIN) {
2054                 rc = -EAGAIN;           /* Race with shadow */
2055                 goto out_free;
2056         }
2057         /* mark as invalid as long as the parent table is not protected */
2058         *table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
2059                  (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID;
2060         list_add(&page->lru, &sg->pt_list);
2061         if (fake) {
2062                 /* nothing to protect for fake tables */
2063                 *table &= ~_SEGMENT_ENTRY_INVALID;
2064                 spin_unlock(&sg->guest_table_lock);
2065                 return 0;
2066         }
2067         spin_unlock(&sg->guest_table_lock);
2068         /* Make pgt read-only in parent gmap page table (not the pgste) */
2069         raddr = (saddr & _SEGMENT_MASK) | _SHADOW_RMAP_SEGMENT;
2070         origin = pgt & _SEGMENT_ENTRY_ORIGIN & PAGE_MASK;
2071         rc = gmap_protect_rmap(sg, raddr, origin, PAGE_SIZE);
2072         spin_lock(&sg->guest_table_lock);
2073         if (!rc) {
2074                 table = gmap_table_walk(sg, saddr, 1);
2075                 if (!table || (*table & _SEGMENT_ENTRY_ORIGIN) !=
2076                               (unsigned long) s_pgt)
2077                         rc = -EAGAIN;           /* Race with unshadow */
2078                 else
2079                         *table &= ~_SEGMENT_ENTRY_INVALID;
2080         } else {
2081                 gmap_unshadow_pgt(sg, raddr);
2082         }
2083         spin_unlock(&sg->guest_table_lock);
2084         return rc;
2085 out_free:
2086         spin_unlock(&sg->guest_table_lock);
2087         page_table_free_pgste(page);
2088         return rc;
2089 
2090 }
2091 EXPORT_SYMBOL_GPL(gmap_shadow_pgt);
2092 
2093 /**
2094  * gmap_shadow_page - create a shadow page mapping
2095  * @sg: pointer to the shadow guest address space structure
2096  * @saddr: faulting address in the shadow gmap
2097  * @pte: pte in parent gmap address space to get shadowed
2098  *
2099  * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
2100  * shadow table structure is incomplete, -ENOMEM if out of memory and
2101  * -EFAULT if an address in the parent gmap could not be resolved.
2102  *
2103  * Called with sg->mm->mmap_lock in read.
2104  */
2105 int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
2106 {
2107         struct gmap *parent;
2108         struct gmap_rmap *rmap;
2109         unsigned long vmaddr, paddr;
2110         spinlock_t *ptl;
2111         pte_t *sptep, *tptep;
2112         int prot;
2113         int rc;
2114 
2115         BUG_ON(!gmap_is_shadow(sg));
2116         parent = sg->parent;
2117         prot = (pte_val(pte) & _PAGE_PROTECT) ? PROT_READ : PROT_WRITE;
2118 
2119         rmap = kzalloc(sizeof(*rmap), GFP_KERNEL);
2120         if (!rmap)
2121                 return -ENOMEM;
2122         rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE;
2123 
2124         while (1) {
2125                 paddr = pte_val(pte) & PAGE_MASK;
2126                 vmaddr = __gmap_translate(parent, paddr);
2127                 if (IS_ERR_VALUE(vmaddr)) {
2128                         rc = vmaddr;
2129                         break;
2130                 }
2131                 rc = radix_tree_preload(GFP_KERNEL);
2132                 if (rc)
2133                         break;
2134                 rc = -EAGAIN;
2135                 sptep = gmap_pte_op_walk(parent, paddr, &ptl);
2136                 if (sptep) {
2137                         spin_lock(&sg->guest_table_lock);
2138                         /* Get page table pointer */
2139                         tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
2140                         if (!tptep) {
2141                                 spin_unlock(&sg->guest_table_lock);
2142                                 gmap_pte_op_end(ptl);
2143                                 radix_tree_preload_end();
2144                                 break;
2145                         }
2146                         rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte);
2147                         if (rc > 0) {
2148                                 /* Success and a new mapping */
2149                                 gmap_insert_rmap(sg, vmaddr, rmap);
2150                                 rmap = NULL;
2151                                 rc = 0;
2152                         }
2153                         gmap_pte_op_end(ptl);
2154                         spin_unlock(&sg->guest_table_lock);
2155                 }
2156                 radix_tree_preload_end();
2157                 if (!rc)
2158                         break;
2159                 rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot);
2160                 if (rc)
2161                         break;
2162         }
2163         kfree(rmap);
2164         return rc;
2165 }
2166 EXPORT_SYMBOL_GPL(gmap_shadow_page);
2167 
2168 /**
2169  * gmap_shadow_notify - handle notifications for shadow gmap
2170  *
2171  * Called with sg->parent->shadow_lock.
2172  */
2173 static void gmap_shadow_notify(struct gmap *sg, unsigned long vmaddr,
2174                                unsigned long gaddr)
2175 {
2176         struct gmap_rmap *rmap, *rnext, *head;
2177         unsigned long start, end, bits, raddr;
2178 
2179         BUG_ON(!gmap_is_shadow(sg));
2180 
2181         spin_lock(&sg->guest_table_lock);
2182         if (sg->removed) {
2183                 spin_unlock(&sg->guest_table_lock);
2184                 return;
2185         }
2186         /* Check for top level table */
2187         start = sg->orig_asce & _ASCE_ORIGIN;
2188         end = start + ((sg->orig_asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE;
2189         if (!(sg->orig_asce & _ASCE_REAL_SPACE) && gaddr >= start &&
2190             gaddr < end) {
2191                 /* The complete shadow table has to go */
2192                 gmap_unshadow(sg);
2193                 spin_unlock(&sg->guest_table_lock);
2194                 list_del(&sg->list);
2195                 gmap_put(sg);
2196                 return;
2197         }
2198         /* Remove the page table tree from on specific entry */
2199         head = radix_tree_delete(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
2200         gmap_for_each_rmap_safe(rmap, rnext, head) {
2201                 bits = rmap->raddr & _SHADOW_RMAP_MASK;
2202                 raddr = rmap->raddr ^ bits;
2203                 switch (bits) {
2204                 case _SHADOW_RMAP_REGION1:
2205                         gmap_unshadow_r2t(sg, raddr);
2206                         break;
2207                 case _SHADOW_RMAP_REGION2:
2208                         gmap_unshadow_r3t(sg, raddr);
2209                         break;
2210                 case _SHADOW_RMAP_REGION3:
2211                         gmap_unshadow_sgt(sg, raddr);
2212                         break;
2213                 case _SHADOW_RMAP_SEGMENT:
2214                         gmap_unshadow_pgt(sg, raddr);
2215                         break;
2216                 case _SHADOW_RMAP_PGTABLE:
2217                         gmap_unshadow_page(sg, raddr);
2218                         break;
2219                 }
2220                 kfree(rmap);
2221         }
2222         spin_unlock(&sg->guest_table_lock);
2223 }
2224 
2225 /**
2226  * ptep_notify - call all invalidation callbacks for a specific pte.
2227  * @mm: pointer to the process mm_struct
2228  * @addr: virtual address in the process address space
2229  * @pte: pointer to the page table entry
2230  * @bits: bits from the pgste that caused the notify call
2231  *
2232  * This function is assumed to be called with the page table lock held
2233  * for the pte to notify.
2234  */
2235 void ptep_notify(struct mm_struct *mm, unsigned long vmaddr,
2236                  pte_t *pte, unsigned long bits)
2237 {
2238         unsigned long offset, gaddr = 0;
2239         unsigned long *table;
2240         struct gmap *gmap, *sg, *next;
2241 
2242         offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
2243         offset = offset * (PAGE_SIZE / sizeof(pte_t));
2244         rcu_read_lock();
2245         list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2246                 spin_lock(&gmap->guest_table_lock);
2247                 table = radix_tree_lookup(&gmap->host_to_guest,
2248                                           vmaddr >> PMD_SHIFT);
2249                 if (table)
2250                         gaddr = __gmap_segment_gaddr(table) + offset;
2251                 spin_unlock(&gmap->guest_table_lock);
2252                 if (!table)
2253                         continue;
2254 
2255                 if (!list_empty(&gmap->children) && (bits & PGSTE_VSIE_BIT)) {
2256                         spin_lock(&gmap->shadow_lock);
2257                         list_for_each_entry_safe(sg, next,
2258                                                  &gmap->children, list)
2259                                 gmap_shadow_notify(sg, vmaddr, gaddr);
2260                         spin_unlock(&gmap->shadow_lock);
2261                 }
2262                 if (bits & PGSTE_IN_BIT)
2263                         gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1);
2264         }
2265         rcu_read_unlock();
2266 }
2267 EXPORT_SYMBOL_GPL(ptep_notify);
2268 
2269 static void pmdp_notify_gmap(struct gmap *gmap, pmd_t *pmdp,
2270                              unsigned long gaddr)
2271 {
2272         pmd_val(*pmdp) &= ~_SEGMENT_ENTRY_GMAP_IN;
2273         gmap_call_notifier(gmap, gaddr, gaddr + HPAGE_SIZE - 1);
2274 }
2275 
2276 /**
2277  * gmap_pmdp_xchg - exchange a gmap pmd with another
2278  * @gmap: pointer to the guest address space structure
2279  * @pmdp: pointer to the pmd entry
2280  * @new: replacement entry
2281  * @gaddr: the affected guest address
2282  *
2283  * This function is assumed to be called with the guest_table_lock
2284  * held.
2285  */
2286 static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *pmdp, pmd_t new,
2287                            unsigned long gaddr)
2288 {
2289         gaddr &= HPAGE_MASK;
2290         pmdp_notify_gmap(gmap, pmdp, gaddr);
2291         pmd_val(new) &= ~_SEGMENT_ENTRY_GMAP_IN;
2292         if (MACHINE_HAS_TLB_GUEST)
2293                 __pmdp_idte(gaddr, (pmd_t *)pmdp, IDTE_GUEST_ASCE, gmap->asce,
2294                             IDTE_GLOBAL);
2295         else if (MACHINE_HAS_IDTE)
2296                 __pmdp_idte(gaddr, (pmd_t *)pmdp, 0, 0, IDTE_GLOBAL);
2297         else
2298                 __pmdp_csp(pmdp);
2299         *pmdp = new;
2300 }
2301 
2302 static void gmap_pmdp_clear(struct mm_struct *mm, unsigned long vmaddr,
2303                             int purge)
2304 {
2305         pmd_t *pmdp;
2306         struct gmap *gmap;
2307         unsigned long gaddr;
2308 
2309         rcu_read_lock();
2310         list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2311                 spin_lock(&gmap->guest_table_lock);
2312                 pmdp = (pmd_t *)radix_tree_delete(&gmap->host_to_guest,
2313                                                   vmaddr >> PMD_SHIFT);
2314                 if (pmdp) {
2315                         gaddr = __gmap_segment_gaddr((unsigned long *)pmdp);
2316                         pmdp_notify_gmap(gmap, pmdp, gaddr);
2317                         WARN_ON(pmd_val(*pmdp) & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2318                                                    _SEGMENT_ENTRY_GMAP_UC));
2319                         if (purge)
2320                                 __pmdp_csp(pmdp);
2321                         pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY;
2322                 }
2323                 spin_unlock(&gmap->guest_table_lock);
2324         }
2325         rcu_read_unlock();
2326 }
2327 
2328 /**
2329  * gmap_pmdp_invalidate - invalidate all affected guest pmd entries without
2330  *                        flushing
2331  * @mm: pointer to the process mm_struct
2332  * @vmaddr: virtual address in the process address space
2333  */
2334 void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr)
2335 {
2336         gmap_pmdp_clear(mm, vmaddr, 0);
2337 }
2338 EXPORT_SYMBOL_GPL(gmap_pmdp_invalidate);
2339 
2340 /**
2341  * gmap_pmdp_csp - csp all affected guest pmd entries
2342  * @mm: pointer to the process mm_struct
2343  * @vmaddr: virtual address in the process address space
2344  */
2345 void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr)
2346 {
2347         gmap_pmdp_clear(mm, vmaddr, 1);
2348 }
2349 EXPORT_SYMBOL_GPL(gmap_pmdp_csp);
2350 
2351 /**
2352  * gmap_pmdp_idte_local - invalidate and clear a guest pmd entry
2353  * @mm: pointer to the process mm_struct
2354  * @vmaddr: virtual address in the process address space
2355  */
2356 void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr)
2357 {
2358         unsigned long *entry, gaddr;
2359         struct gmap *gmap;
2360         pmd_t *pmdp;
2361 
2362         rcu_read_lock();
2363         list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2364                 spin_lock(&gmap->guest_table_lock);
2365                 entry = radix_tree_delete(&gmap->host_to_guest,
2366                                           vmaddr >> PMD_SHIFT);
2367                 if (entry) {
2368                         pmdp = (pmd_t *)entry;
2369                         gaddr = __gmap_segment_gaddr(entry);
2370                         pmdp_notify_gmap(gmap, pmdp, gaddr);
2371                         WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2372                                            _SEGMENT_ENTRY_GMAP_UC));
2373                         if (MACHINE_HAS_TLB_GUEST)
2374                                 __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
2375                                             gmap->asce, IDTE_LOCAL);
2376                         else if (MACHINE_HAS_IDTE)
2377                                 __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_LOCAL);
2378                         *entry = _SEGMENT_ENTRY_EMPTY;
2379                 }
2380                 spin_unlock(&gmap->guest_table_lock);
2381         }
2382         rcu_read_unlock();
2383 }
2384 EXPORT_SYMBOL_GPL(gmap_pmdp_idte_local);
2385 
2386 /**
2387  * gmap_pmdp_idte_global - invalidate and clear a guest pmd entry
2388  * @mm: pointer to the process mm_struct
2389  * @vmaddr: virtual address in the process address space
2390  */
2391 void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr)
2392 {
2393         unsigned long *entry, gaddr;
2394         struct gmap *gmap;
2395         pmd_t *pmdp;
2396 
2397         rcu_read_lock();
2398         list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2399                 spin_lock(&gmap->guest_table_lock);
2400                 entry = radix_tree_delete(&gmap->host_to_guest,
2401                                           vmaddr >> PMD_SHIFT);
2402                 if (entry) {
2403                         pmdp = (pmd_t *)entry;
2404                         gaddr = __gmap_segment_gaddr(entry);
2405                         pmdp_notify_gmap(gmap, pmdp, gaddr);
2406                         WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2407                                            _SEGMENT_ENTRY_GMAP_UC));
2408                         if (MACHINE_HAS_TLB_GUEST)
2409                                 __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
2410                                             gmap->asce, IDTE_GLOBAL);
2411                         else if (MACHINE_HAS_IDTE)
2412                                 __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_GLOBAL);
2413                         else
2414                                 __pmdp_csp(pmdp);
2415                         *entry = _SEGMENT_ENTRY_EMPTY;
2416                 }
2417                 spin_unlock(&gmap->guest_table_lock);
2418         }
2419         rcu_read_unlock();
2420 }
2421 EXPORT_SYMBOL_GPL(gmap_pmdp_idte_global);
2422 
2423 /**
2424  * gmap_test_and_clear_dirty_pmd - test and reset segment dirty status
2425  * @gmap: pointer to guest address space
2426  * @pmdp: pointer to the pmd to be tested
2427  * @gaddr: virtual address in the guest address space
2428  *
2429  * This function is assumed to be called with the guest_table_lock
2430  * held.
2431  */
2432 static bool gmap_test_and_clear_dirty_pmd(struct gmap *gmap, pmd_t *pmdp,
2433                                           unsigned long gaddr)
2434 {
2435         if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
2436                 return false;
2437 
2438         /* Already protected memory, which did not change is clean */
2439         if (pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT &&
2440             !(pmd_val(*pmdp) & _SEGMENT_ENTRY_GMAP_UC))
2441                 return false;
2442 
2443         /* Clear UC indication and reset protection */
2444         pmd_val(*pmdp) &= ~_SEGMENT_ENTRY_GMAP_UC;
2445         gmap_protect_pmd(gmap, gaddr, pmdp, PROT_READ, 0);
2446         return true;
2447 }
2448 
2449 /**
2450  * gmap_sync_dirty_log_pmd - set bitmap based on dirty status of segment
2451  * @gmap: pointer to guest address space
2452  * @bitmap: dirty bitmap for this pmd
2453  * @gaddr: virtual address in the guest address space
2454  * @vmaddr: virtual address in the host address space
2455  *
2456  * This function is assumed to be called with the guest_table_lock
2457  * held.
2458  */
2459 void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long bitmap[4],
2460                              unsigned long gaddr, unsigned long vmaddr)
2461 {
2462         int i;
2463         pmd_t *pmdp;
2464         pte_t *ptep;
2465         spinlock_t *ptl;
2466 
2467         pmdp = gmap_pmd_op_walk(gmap, gaddr);
2468         if (!pmdp)
2469                 return;
2470 
2471         if (pmd_large(*pmdp)) {
2472                 if (gmap_test_and_clear_dirty_pmd(gmap, pmdp, gaddr))
2473                         bitmap_fill(bitmap, _PAGE_ENTRIES);
2474         } else {
2475                 for (i = 0; i < _PAGE_ENTRIES; i++, vmaddr += PAGE_SIZE) {
2476                         ptep = pte_alloc_map_lock(gmap->mm, pmdp, vmaddr, &ptl);
2477                         if (!ptep)
2478                                 continue;
2479                         if (ptep_test_and_clear_uc(gmap->mm, vmaddr, ptep))
2480                                 set_bit(i, bitmap);
2481                         spin_unlock(ptl);
2482                 }
2483         }
2484         gmap_pmd_op_end(gmap, pmdp);
2485 }
2486 EXPORT_SYMBOL_GPL(gmap_sync_dirty_log_pmd);
2487 
2488 static inline void thp_split_mm(struct mm_struct *mm)
2489 {
2490 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2491         struct vm_area_struct *vma;
2492         unsigned long addr;
2493 
2494         for (vma = mm->mmap; vma != NULL; vma = vma->vm_next) {
2495                 for (addr = vma->vm_start;
2496                      addr < vma->vm_end;
2497                      addr += PAGE_SIZE)
2498                         follow_page(vma, addr, FOLL_SPLIT);
2499                 vma->vm_flags &= ~VM_HUGEPAGE;
2500                 vma->vm_flags |= VM_NOHUGEPAGE;
2501         }
2502         mm->def_flags |= VM_NOHUGEPAGE;
2503 #endif
2504 }
2505 
2506 /*
2507  * Remove all empty zero pages from the mapping for lazy refaulting
2508  * - This must be called after mm->context.has_pgste is set, to avoid
2509  *   future creation of zero pages
2510  * - This must be called after THP was enabled
2511  */
2512 static int __zap_zero_pages(pmd_t *pmd, unsigned long start,
2513                            unsigned long end, struct mm_walk *walk)
2514 {
2515         unsigned long addr;
2516 
2517         for (addr = start; addr != end; addr += PAGE_SIZE) {
2518                 pte_t *ptep;
2519                 spinlock_t *ptl;
2520 
2521                 ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
2522                 if (is_zero_pfn(pte_pfn(*ptep)))
2523                         ptep_xchg_direct(walk->mm, addr, ptep, __pte(_PAGE_INVALID));
2524                 pte_unmap_unlock(ptep, ptl);
2525         }
2526         return 0;
2527 }
2528 
2529 static const struct mm_walk_ops zap_zero_walk_ops = {
2530         .pmd_entry      = __zap_zero_pages,
2531 };
2532 
2533 /*
2534  * switch on pgstes for its userspace process (for kvm)
2535  */
2536 int s390_enable_sie(void)
2537 {
2538         struct mm_struct *mm = current->mm;
2539 
2540         /* Do we have pgstes? if yes, we are done */
2541         if (mm_has_pgste(mm))
2542                 return 0;
2543         /* Fail if the page tables are 2K */
2544         if (!mm_alloc_pgste(mm))
2545                 return -EINVAL;
2546         mmap_write_lock(mm);
2547         mm->context.has_pgste = 1;
2548         /* split thp mappings and disable thp for future mappings */
2549         thp_split_mm(mm);
2550         walk_page_range(mm, 0, TASK_SIZE, &zap_zero_walk_ops, NULL);
2551         mmap_write_unlock(mm);
2552         return 0;
2553 }
2554 EXPORT_SYMBOL_GPL(s390_enable_sie);
2555 
2556 int gmap_mark_unmergeable(void)
2557 {
2558         struct mm_struct *mm = current->mm;
2559         struct vm_area_struct *vma;
2560         int ret;
2561 
2562         for (vma = mm->mmap; vma; vma = vma->vm_next) {
2563                 ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
2564                                   MADV_UNMERGEABLE, &vma->vm_flags);
2565                 if (ret)
2566                         return ret;
2567         }
2568         mm->def_flags &= ~VM_MERGEABLE;
2569         return 0;
2570 }
2571 EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
2572 
2573 /*
2574  * Enable storage key handling from now on and initialize the storage
2575  * keys with the default key.
2576  */
2577 static int __s390_enable_skey_pte(pte_t *pte, unsigned long addr,
2578                                   unsigned long next, struct mm_walk *walk)
2579 {
2580         /* Clear storage key */
2581         ptep_zap_key(walk->mm, addr, pte);
2582         return 0;
2583 }
2584 
2585 static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
2586                                       unsigned long hmask, unsigned long next,
2587                                       struct mm_walk *walk)
2588 {
2589         pmd_t *pmd = (pmd_t *)pte;
2590         unsigned long start, end;
2591         struct page *page = pmd_page(*pmd);
2592 
2593         /*
2594          * The write check makes sure we do not set a key on shared
2595          * memory. This is needed as the walker does not differentiate
2596          * between actual guest memory and the process executable or
2597          * shared libraries.
2598          */
2599         if (pmd_val(*pmd) & _SEGMENT_ENTRY_INVALID ||
2600             !(pmd_val(*pmd) & _SEGMENT_ENTRY_WRITE))
2601                 return 0;
2602 
2603         start = pmd_val(*pmd) & HPAGE_MASK;
2604         end = start + HPAGE_SIZE - 1;
2605         __storage_key_init_range(start, end);
2606         set_bit(PG_arch_1, &page->flags);
2607         return 0;
2608 }
2609 
2610 static const struct mm_walk_ops enable_skey_walk_ops = {
2611         .hugetlb_entry          = __s390_enable_skey_hugetlb,
2612         .pte_entry              = __s390_enable_skey_pte,
2613 };
2614 
2615 int s390_enable_skey(void)
2616 {
2617         struct mm_struct *mm = current->mm;
2618         int rc = 0;
2619 
2620         mmap_write_lock(mm);
2621         if (mm_uses_skeys(mm))
2622                 goto out_up;
2623 
2624         mm->context.uses_skeys = 1;
2625         rc = gmap_mark_unmergeable();
2626         if (rc) {
2627                 mm->context.uses_skeys = 0;
2628                 goto out_up;
2629         }
2630         walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
2631 
2632 out_up:
2633         mmap_write_unlock(mm);
2634         return rc;
2635 }
2636 EXPORT_SYMBOL_GPL(s390_enable_skey);
2637 
2638 /*
2639  * Reset CMMA state, make all pages stable again.
2640  */
2641 static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
2642                              unsigned long next, struct mm_walk *walk)
2643 {
2644         ptep_zap_unused(walk->mm, addr, pte, 1);
2645         return 0;
2646 }
2647 
2648 static const struct mm_walk_ops reset_cmma_walk_ops = {
2649         .pte_entry              = __s390_reset_cmma,
2650 };
2651 
2652 void s390_reset_cmma(struct mm_struct *mm)
2653 {
2654         mmap_write_lock(mm);
2655         walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
2656         mmap_write_unlock(mm);
2657 }
2658 EXPORT_SYMBOL_GPL(s390_reset_cmma);
2659 
2660 /*
2661  * make inaccessible pages accessible again
2662  */
2663 static int __s390_reset_acc(pte_t *ptep, unsigned long addr,
2664                             unsigned long next, struct mm_walk *walk)
2665 {
2666         pte_t pte = READ_ONCE(*ptep);
2667 
2668         if (pte_present(pte))
2669                 WARN_ON_ONCE(uv_convert_from_secure(pte_val(pte) & PAGE_MASK));
2670         return 0;
2671 }
2672 
2673 static const struct mm_walk_ops reset_acc_walk_ops = {
2674         .pte_entry              = __s390_reset_acc,
2675 };
2676 
2677 #include <linux/sched/mm.h>
2678 void s390_reset_acc(struct mm_struct *mm)
2679 {
2680         /*
2681          * we might be called during
2682          * reset:                             we walk the pages and clear
2683          * close of all kvm file descriptors: we walk the pages and clear
2684          * exit of process on fd closure:     vma already gone, do nothing
2685          */
2686         if (!mmget_not_zero(mm))
2687                 return;
2688         mmap_read_lock(mm);
2689         walk_page_range(mm, 0, TASK_SIZE, &reset_acc_walk_ops, NULL);
2690         mmap_read_unlock(mm);
2691         mmput(mm);
2692 }
2693 EXPORT_SYMBOL_GPL(s390_reset_acc);
2694 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp