1 // SPDX-License-Identifier: GPL-2.0
3 * KVM guest address space mapping code
5 * Copyright IBM Corp. 2007, 2020
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 * David Hildenbrand <david@redhat.com>
8 * Janosch Frank <frankja@linux.vnet.ibm.com>
11 #include <linux/kernel.h>
12 #include <linux/pagewalk.h>
13 #include <linux/swap.h>
14 #include <linux/smp.h>
15 #include <linux/spinlock.h>
16 #include <linux/slab.h>
17 #include <linux/swapops.h>
18 #include <linux/ksm.h>
19 #include <linux/mman.h>
20 #include <linux/pgtable.h>
21 #include <asm/page-states.h>
22 #include <asm/pgalloc.h>
27 #define GMAP_SHADOW_FAKE_TABLE 1ULL
29 static struct page *gmap_alloc_crst(void)
33 page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
36 __arch_set_page_dat(page_to_virt(page), 1UL << CRST_ALLOC_ORDER);
41 * gmap_alloc - allocate and initialize a guest address space
42 * @limit: maximum address of the gmap address space
44 * Returns a guest address space structure.
46 static struct gmap *gmap_alloc(unsigned long limit)
51 unsigned long etype, atype;
53 if (limit < _REGION3_SIZE) {
54 limit = _REGION3_SIZE - 1;
55 atype = _ASCE_TYPE_SEGMENT;
56 etype = _SEGMENT_ENTRY_EMPTY;
57 } else if (limit < _REGION2_SIZE) {
58 limit = _REGION2_SIZE - 1;
59 atype = _ASCE_TYPE_REGION3;
60 etype = _REGION3_ENTRY_EMPTY;
61 } else if (limit < _REGION1_SIZE) {
62 limit = _REGION1_SIZE - 1;
63 atype = _ASCE_TYPE_REGION2;
64 etype = _REGION2_ENTRY_EMPTY;
67 atype = _ASCE_TYPE_REGION1;
68 etype = _REGION1_ENTRY_EMPTY;
70 gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL_ACCOUNT);
73 INIT_LIST_HEAD(&gmap->crst_list);
74 INIT_LIST_HEAD(&gmap->children);
75 INIT_LIST_HEAD(&gmap->pt_list);
76 INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL_ACCOUNT);
77 INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC | __GFP_ACCOUNT);
78 INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC | __GFP_ACCOUNT);
79 spin_lock_init(&gmap->guest_table_lock);
80 spin_lock_init(&gmap->shadow_lock);
81 refcount_set(&gmap->ref_count, 1);
82 page = gmap_alloc_crst();
86 list_add(&page->lru, &gmap->crst_list);
87 table = page_to_virt(page);
88 crst_table_init(table, etype);
90 gmap->asce = atype | _ASCE_TABLE_LENGTH |
91 _ASCE_USER_BITS | __pa(table);
92 gmap->asce_end = limit;
102 * gmap_create - create a guest address space
103 * @mm: pointer to the parent mm_struct
104 * @limit: maximum size of the gmap address space
106 * Returns a guest address space structure.
108 struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit)
111 unsigned long gmap_asce;
113 gmap = gmap_alloc(limit);
117 spin_lock(&mm->context.lock);
118 list_add_rcu(&gmap->list, &mm->context.gmap_list);
119 if (list_is_singular(&mm->context.gmap_list))
120 gmap_asce = gmap->asce;
123 WRITE_ONCE(mm->context.gmap_asce, gmap_asce);
124 spin_unlock(&mm->context.lock);
127 EXPORT_SYMBOL_GPL(gmap_create);
129 static void gmap_flush_tlb(struct gmap *gmap)
131 if (MACHINE_HAS_IDTE)
132 __tlb_flush_idte(gmap->asce);
134 __tlb_flush_global();
137 static void gmap_radix_tree_free(struct radix_tree_root *root)
139 struct radix_tree_iter iter;
140 unsigned long indices[16];
145 /* A radix tree is freed by deleting all of its entries */
149 radix_tree_for_each_slot(slot, root, &iter, index) {
150 indices[nr] = iter.index;
154 for (i = 0; i < nr; i++) {
156 radix_tree_delete(root, index);
161 static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
163 struct gmap_rmap *rmap, *rnext, *head;
164 struct radix_tree_iter iter;
165 unsigned long indices[16];
170 /* A radix tree is freed by deleting all of its entries */
174 radix_tree_for_each_slot(slot, root, &iter, index) {
175 indices[nr] = iter.index;
179 for (i = 0; i < nr; i++) {
181 head = radix_tree_delete(root, index);
182 gmap_for_each_rmap_safe(rmap, rnext, head)
189 * gmap_free - free a guest address space
190 * @gmap: pointer to the guest address space structure
192 * No locks required. There are no references to this gmap anymore.
194 static void gmap_free(struct gmap *gmap)
196 struct page *page, *next;
198 /* Flush tlb of all gmaps (if not already done for shadows) */
199 if (!(gmap_is_shadow(gmap) && gmap->removed))
200 gmap_flush_tlb(gmap);
201 /* Free all segment & region tables. */
202 list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
203 __free_pages(page, CRST_ALLOC_ORDER);
204 gmap_radix_tree_free(&gmap->guest_to_host);
205 gmap_radix_tree_free(&gmap->host_to_guest);
207 /* Free additional data for a shadow gmap */
208 if (gmap_is_shadow(gmap)) {
209 /* Free all page tables. */
210 list_for_each_entry_safe(page, next, &gmap->pt_list, lru)
211 page_table_free_pgste(page);
212 gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
213 /* Release reference to the parent */
214 gmap_put(gmap->parent);
221 * gmap_get - increase reference counter for guest address space
222 * @gmap: pointer to the guest address space structure
224 * Returns the gmap pointer
226 struct gmap *gmap_get(struct gmap *gmap)
228 refcount_inc(&gmap->ref_count);
231 EXPORT_SYMBOL_GPL(gmap_get);
234 * gmap_put - decrease reference counter for guest address space
235 * @gmap: pointer to the guest address space structure
237 * If the reference counter reaches zero the guest address space is freed.
239 void gmap_put(struct gmap *gmap)
241 if (refcount_dec_and_test(&gmap->ref_count))
244 EXPORT_SYMBOL_GPL(gmap_put);
247 * gmap_remove - remove a guest address space but do not free it yet
248 * @gmap: pointer to the guest address space structure
250 void gmap_remove(struct gmap *gmap)
252 struct gmap *sg, *next;
253 unsigned long gmap_asce;
255 /* Remove all shadow gmaps linked to this gmap */
256 if (!list_empty(&gmap->children)) {
257 spin_lock(&gmap->shadow_lock);
258 list_for_each_entry_safe(sg, next, &gmap->children, list) {
262 spin_unlock(&gmap->shadow_lock);
264 /* Remove gmap from the pre-mm list */
265 spin_lock(&gmap->mm->context.lock);
266 list_del_rcu(&gmap->list);
267 if (list_empty(&gmap->mm->context.gmap_list))
269 else if (list_is_singular(&gmap->mm->context.gmap_list))
270 gmap_asce = list_first_entry(&gmap->mm->context.gmap_list,
271 struct gmap, list)->asce;
274 WRITE_ONCE(gmap->mm->context.gmap_asce, gmap_asce);
275 spin_unlock(&gmap->mm->context.lock);
280 EXPORT_SYMBOL_GPL(gmap_remove);
283 * gmap_enable - switch primary space to the guest address space
284 * @gmap: pointer to the guest address space structure
286 void gmap_enable(struct gmap *gmap)
288 S390_lowcore.gmap = (unsigned long) gmap;
290 EXPORT_SYMBOL_GPL(gmap_enable);
293 * gmap_disable - switch back to the standard primary address space
294 * @gmap: pointer to the guest address space structure
296 void gmap_disable(struct gmap *gmap)
298 S390_lowcore.gmap = 0UL;
300 EXPORT_SYMBOL_GPL(gmap_disable);
303 * gmap_get_enabled - get a pointer to the currently enabled gmap
305 * Returns a pointer to the currently enabled gmap. 0 if none is enabled.
307 struct gmap *gmap_get_enabled(void)
309 return (struct gmap *) S390_lowcore.gmap;
311 EXPORT_SYMBOL_GPL(gmap_get_enabled);
314 * gmap_alloc_table is assumed to be called with mmap_lock held
316 static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
317 unsigned long init, unsigned long gaddr)
322 /* since we dont free the gmap table until gmap_free we can unlock */
323 page = gmap_alloc_crst();
326 new = page_to_virt(page);
327 crst_table_init(new, init);
328 spin_lock(&gmap->guest_table_lock);
329 if (*table & _REGION_ENTRY_INVALID) {
330 list_add(&page->lru, &gmap->crst_list);
331 *table = __pa(new) | _REGION_ENTRY_LENGTH |
332 (*table & _REGION_ENTRY_TYPE_MASK);
336 spin_unlock(&gmap->guest_table_lock);
338 __free_pages(page, CRST_ALLOC_ORDER);
343 * __gmap_segment_gaddr - find virtual address from segment pointer
344 * @entry: pointer to a segment table entry in the guest address space
346 * Returns the virtual address in the guest address space for the segment
348 static unsigned long __gmap_segment_gaddr(unsigned long *entry)
351 unsigned long offset;
353 offset = (unsigned long) entry / sizeof(unsigned long);
354 offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
355 page = pmd_pgtable_page((pmd_t *) entry);
356 return page->index + offset;
360 * __gmap_unlink_by_vmaddr - unlink a single segment via a host address
361 * @gmap: pointer to the guest address space structure
362 * @vmaddr: address in the host process address space
364 * Returns 1 if a TLB flush is required
366 static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr)
368 unsigned long *entry;
371 BUG_ON(gmap_is_shadow(gmap));
372 spin_lock(&gmap->guest_table_lock);
373 entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
375 flush = (*entry != _SEGMENT_ENTRY_EMPTY);
376 *entry = _SEGMENT_ENTRY_EMPTY;
378 spin_unlock(&gmap->guest_table_lock);
383 * __gmap_unmap_by_gaddr - unmap a single segment via a guest address
384 * @gmap: pointer to the guest address space structure
385 * @gaddr: address in the guest address space
387 * Returns 1 if a TLB flush is required
389 static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr)
391 unsigned long vmaddr;
393 vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host,
395 return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0;
399 * gmap_unmap_segment - unmap segment from the guest address space
400 * @gmap: pointer to the guest address space structure
401 * @to: address in the guest address space
402 * @len: length of the memory area to unmap
404 * Returns 0 if the unmap succeeded, -EINVAL if not.
406 int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
411 BUG_ON(gmap_is_shadow(gmap));
412 if ((to | len) & (PMD_SIZE - 1))
414 if (len == 0 || to + len < to)
418 mmap_write_lock(gmap->mm);
419 for (off = 0; off < len; off += PMD_SIZE)
420 flush |= __gmap_unmap_by_gaddr(gmap, to + off);
421 mmap_write_unlock(gmap->mm);
423 gmap_flush_tlb(gmap);
426 EXPORT_SYMBOL_GPL(gmap_unmap_segment);
429 * gmap_map_segment - map a segment to the guest address space
430 * @gmap: pointer to the guest address space structure
431 * @from: source address in the parent address space
432 * @to: target address in the guest address space
433 * @len: length of the memory area to map
435 * Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not.
437 int gmap_map_segment(struct gmap *gmap, unsigned long from,
438 unsigned long to, unsigned long len)
443 BUG_ON(gmap_is_shadow(gmap));
444 if ((from | to | len) & (PMD_SIZE - 1))
446 if (len == 0 || from + len < from || to + len < to ||
447 from + len - 1 > TASK_SIZE_MAX || to + len - 1 > gmap->asce_end)
451 mmap_write_lock(gmap->mm);
452 for (off = 0; off < len; off += PMD_SIZE) {
453 /* Remove old translation */
454 flush |= __gmap_unmap_by_gaddr(gmap, to + off);
455 /* Store new translation */
456 if (radix_tree_insert(&gmap->guest_to_host,
457 (to + off) >> PMD_SHIFT,
458 (void *) from + off))
461 mmap_write_unlock(gmap->mm);
463 gmap_flush_tlb(gmap);
466 gmap_unmap_segment(gmap, to, len);
469 EXPORT_SYMBOL_GPL(gmap_map_segment);
472 * __gmap_translate - translate a guest address to a user space address
473 * @gmap: pointer to guest mapping meta data structure
474 * @gaddr: guest address
476 * Returns user space address which corresponds to the guest address or
477 * -EFAULT if no such mapping exists.
478 * This function does not establish potentially missing page table entries.
479 * The mmap_lock of the mm that belongs to the address space must be held
480 * when this function gets called.
482 * Note: Can also be called for shadow gmaps.
484 unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
486 unsigned long vmaddr;
488 vmaddr = (unsigned long)
489 radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
490 /* Note: guest_to_host is empty for a shadow gmap */
491 return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
493 EXPORT_SYMBOL_GPL(__gmap_translate);
496 * gmap_translate - translate a guest address to a user space address
497 * @gmap: pointer to guest mapping meta data structure
498 * @gaddr: guest address
500 * Returns user space address which corresponds to the guest address or
501 * -EFAULT if no such mapping exists.
502 * This function does not establish potentially missing page table entries.
504 unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr)
508 mmap_read_lock(gmap->mm);
509 rc = __gmap_translate(gmap, gaddr);
510 mmap_read_unlock(gmap->mm);
513 EXPORT_SYMBOL_GPL(gmap_translate);
516 * gmap_unlink - disconnect a page table from the gmap shadow tables
517 * @mm: pointer to the parent mm_struct
518 * @table: pointer to the host page table
519 * @vmaddr: vm address associated with the host page table
521 void gmap_unlink(struct mm_struct *mm, unsigned long *table,
522 unsigned long vmaddr)
528 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
529 flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
531 gmap_flush_tlb(gmap);
536 static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *old, pmd_t new,
537 unsigned long gaddr);
540 * __gmap_link - set up shadow page tables to connect a host to a guest address
541 * @gmap: pointer to guest mapping meta data structure
542 * @gaddr: guest address
543 * @vmaddr: vm address
545 * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
546 * if the vm address is already mapped to a different guest segment.
547 * The mmap_lock of the mm that belongs to the address space must be held
548 * when this function gets called.
550 int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
552 struct mm_struct *mm;
553 unsigned long *table;
562 BUG_ON(gmap_is_shadow(gmap));
563 /* Create higher level tables in the gmap page table */
565 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
566 table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
567 if ((*table & _REGION_ENTRY_INVALID) &&
568 gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
569 gaddr & _REGION1_MASK))
571 table = __va(*table & _REGION_ENTRY_ORIGIN);
573 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
574 table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
575 if ((*table & _REGION_ENTRY_INVALID) &&
576 gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
577 gaddr & _REGION2_MASK))
579 table = __va(*table & _REGION_ENTRY_ORIGIN);
581 if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
582 table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
583 if ((*table & _REGION_ENTRY_INVALID) &&
584 gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
585 gaddr & _REGION3_MASK))
587 table = __va(*table & _REGION_ENTRY_ORIGIN);
589 table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
590 /* Walk the parent mm page table */
592 pgd = pgd_offset(mm, vmaddr);
593 VM_BUG_ON(pgd_none(*pgd));
594 p4d = p4d_offset(pgd, vmaddr);
595 VM_BUG_ON(p4d_none(*p4d));
596 pud = pud_offset(p4d, vmaddr);
597 VM_BUG_ON(pud_none(*pud));
598 /* large puds cannot yet be handled */
601 pmd = pmd_offset(pud, vmaddr);
602 VM_BUG_ON(pmd_none(*pmd));
603 /* Are we allowed to use huge pages? */
604 if (pmd_large(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m)
606 /* Link gmap segment table entry location to page table. */
607 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
610 ptl = pmd_lock(mm, pmd);
611 spin_lock(&gmap->guest_table_lock);
612 if (*table == _SEGMENT_ENTRY_EMPTY) {
613 rc = radix_tree_insert(&gmap->host_to_guest,
614 vmaddr >> PMD_SHIFT, table);
616 if (pmd_large(*pmd)) {
617 *table = (pmd_val(*pmd) &
618 _SEGMENT_ENTRY_HARDWARE_BITS_LARGE)
619 | _SEGMENT_ENTRY_GMAP_UC;
621 *table = pmd_val(*pmd) &
622 _SEGMENT_ENTRY_HARDWARE_BITS;
624 } else if (*table & _SEGMENT_ENTRY_PROTECT &&
625 !(pmd_val(*pmd) & _SEGMENT_ENTRY_PROTECT)) {
626 unprot = (u64)*table;
627 unprot &= ~_SEGMENT_ENTRY_PROTECT;
628 unprot |= _SEGMENT_ENTRY_GMAP_UC;
629 gmap_pmdp_xchg(gmap, (pmd_t *)table, __pmd(unprot), gaddr);
631 spin_unlock(&gmap->guest_table_lock);
633 radix_tree_preload_end();
638 * gmap_fault - resolve a fault on a guest address
639 * @gmap: pointer to guest mapping meta data structure
640 * @gaddr: guest address
641 * @fault_flags: flags to pass down to handle_mm_fault()
643 * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
644 * if the vm address is already mapped to a different guest segment.
646 int gmap_fault(struct gmap *gmap, unsigned long gaddr,
647 unsigned int fault_flags)
649 unsigned long vmaddr;
653 mmap_read_lock(gmap->mm);
657 vmaddr = __gmap_translate(gmap, gaddr);
658 if (IS_ERR_VALUE(vmaddr)) {
662 if (fixup_user_fault(gmap->mm, vmaddr, fault_flags,
668 * In the case that fixup_user_fault unlocked the mmap_lock during
669 * faultin redo __gmap_translate to not race with a map/unmap_segment.
674 rc = __gmap_link(gmap, gaddr, vmaddr);
676 mmap_read_unlock(gmap->mm);
679 EXPORT_SYMBOL_GPL(gmap_fault);
682 * this function is assumed to be called with mmap_lock held
684 void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
686 struct vm_area_struct *vma;
687 unsigned long vmaddr;
691 /* Find the vm address for the guest address */
692 vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
695 vmaddr |= gaddr & ~PMD_MASK;
697 vma = vma_lookup(gmap->mm, vmaddr);
698 if (!vma || is_vm_hugetlb_page(vma))
701 /* Get pointer to the page table entry */
702 ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
704 ptep_zap_unused(gmap->mm, vmaddr, ptep, 0);
705 pte_unmap_unlock(ptep, ptl);
709 EXPORT_SYMBOL_GPL(__gmap_zap);
711 void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
713 unsigned long gaddr, vmaddr, size;
714 struct vm_area_struct *vma;
716 mmap_read_lock(gmap->mm);
717 for (gaddr = from; gaddr < to;
718 gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
719 /* Find the vm address for the guest address */
720 vmaddr = (unsigned long)
721 radix_tree_lookup(&gmap->guest_to_host,
725 vmaddr |= gaddr & ~PMD_MASK;
726 /* Find vma in the parent mm */
727 vma = find_vma(gmap->mm, vmaddr);
731 * We do not discard pages that are backed by
732 * hugetlbfs, so we don't have to refault them.
734 if (is_vm_hugetlb_page(vma))
736 size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
737 zap_page_range_single(vma, vmaddr, size, NULL);
739 mmap_read_unlock(gmap->mm);
741 EXPORT_SYMBOL_GPL(gmap_discard);
743 static LIST_HEAD(gmap_notifier_list);
744 static DEFINE_SPINLOCK(gmap_notifier_lock);
747 * gmap_register_pte_notifier - register a pte invalidation callback
748 * @nb: pointer to the gmap notifier block
750 void gmap_register_pte_notifier(struct gmap_notifier *nb)
752 spin_lock(&gmap_notifier_lock);
753 list_add_rcu(&nb->list, &gmap_notifier_list);
754 spin_unlock(&gmap_notifier_lock);
756 EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
759 * gmap_unregister_pte_notifier - remove a pte invalidation callback
760 * @nb: pointer to the gmap notifier block
762 void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
764 spin_lock(&gmap_notifier_lock);
765 list_del_rcu(&nb->list);
766 spin_unlock(&gmap_notifier_lock);
769 EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
772 * gmap_call_notifier - call all registered invalidation callbacks
773 * @gmap: pointer to guest mapping meta data structure
774 * @start: start virtual address in the guest address space
775 * @end: end virtual address in the guest address space
777 static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
780 struct gmap_notifier *nb;
782 list_for_each_entry(nb, &gmap_notifier_list, list)
783 nb->notifier_call(gmap, start, end);
787 * gmap_table_walk - walk the gmap page tables
788 * @gmap: pointer to guest mapping meta data structure
789 * @gaddr: virtual address in the guest address space
790 * @level: page table level to stop at
792 * Returns a table entry pointer for the given guest address and @level
793 * @level=0 : returns a pointer to a page table table entry (or NULL)
794 * @level=1 : returns a pointer to a segment table entry (or NULL)
795 * @level=2 : returns a pointer to a region-3 table entry (or NULL)
796 * @level=3 : returns a pointer to a region-2 table entry (or NULL)
797 * @level=4 : returns a pointer to a region-1 table entry (or NULL)
799 * Returns NULL if the gmap page tables could not be walked to the
802 * Note: Can also be called for shadow gmaps.
804 static inline unsigned long *gmap_table_walk(struct gmap *gmap,
805 unsigned long gaddr, int level)
807 const int asce_type = gmap->asce & _ASCE_TYPE_MASK;
808 unsigned long *table = gmap->table;
810 if (gmap_is_shadow(gmap) && gmap->removed)
813 if (WARN_ON_ONCE(level > (asce_type >> 2) + 1))
816 if (asce_type != _ASCE_TYPE_REGION1 &&
817 gaddr & (-1UL << (31 + (asce_type >> 2) * 11)))
821 case _ASCE_TYPE_REGION1:
822 table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
825 if (*table & _REGION_ENTRY_INVALID)
827 table = __va(*table & _REGION_ENTRY_ORIGIN);
829 case _ASCE_TYPE_REGION2:
830 table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
833 if (*table & _REGION_ENTRY_INVALID)
835 table = __va(*table & _REGION_ENTRY_ORIGIN);
837 case _ASCE_TYPE_REGION3:
838 table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
841 if (*table & _REGION_ENTRY_INVALID)
843 table = __va(*table & _REGION_ENTRY_ORIGIN);
845 case _ASCE_TYPE_SEGMENT:
846 table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
849 if (*table & _REGION_ENTRY_INVALID)
851 table = __va(*table & _SEGMENT_ENTRY_ORIGIN);
852 table += (gaddr & _PAGE_INDEX) >> _PAGE_SHIFT;
858 * gmap_pte_op_walk - walk the gmap page table, get the page table lock
859 * and return the pte pointer
860 * @gmap: pointer to guest mapping meta data structure
861 * @gaddr: virtual address in the guest address space
862 * @ptl: pointer to the spinlock pointer
864 * Returns a pointer to the locked pte for a guest address, or NULL
866 static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
869 unsigned long *table;
871 BUG_ON(gmap_is_shadow(gmap));
872 /* Walk the gmap page table, lock and get pte pointer */
873 table = gmap_table_walk(gmap, gaddr, 1); /* get segment pointer */
874 if (!table || *table & _SEGMENT_ENTRY_INVALID)
876 return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl);
880 * gmap_pte_op_fixup - force a page in and connect the gmap page table
881 * @gmap: pointer to guest mapping meta data structure
882 * @gaddr: virtual address in the guest address space
883 * @vmaddr: address in the host process address space
884 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
886 * Returns 0 if the caller can retry __gmap_translate (might fail again),
887 * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing
888 * up or connecting the gmap page table.
890 static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
891 unsigned long vmaddr, int prot)
893 struct mm_struct *mm = gmap->mm;
894 unsigned int fault_flags;
895 bool unlocked = false;
897 BUG_ON(gmap_is_shadow(gmap));
898 fault_flags = (prot == PROT_WRITE) ? FAULT_FLAG_WRITE : 0;
899 if (fixup_user_fault(mm, vmaddr, fault_flags, &unlocked))
902 /* lost mmap_lock, caller has to retry __gmap_translate */
904 /* Connect the page tables */
905 return __gmap_link(gmap, gaddr, vmaddr);
909 * gmap_pte_op_end - release the page table lock
910 * @ptep: pointer to the locked pte
911 * @ptl: pointer to the page table spinlock
913 static void gmap_pte_op_end(pte_t *ptep, spinlock_t *ptl)
915 pte_unmap_unlock(ptep, ptl);
919 * gmap_pmd_op_walk - walk the gmap tables, get the guest table lock
920 * and return the pmd pointer
921 * @gmap: pointer to guest mapping meta data structure
922 * @gaddr: virtual address in the guest address space
924 * Returns a pointer to the pmd for a guest address, or NULL
926 static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr)
930 BUG_ON(gmap_is_shadow(gmap));
931 pmdp = (pmd_t *) gmap_table_walk(gmap, gaddr, 1);
935 /* without huge pages, there is no need to take the table lock */
936 if (!gmap->mm->context.allow_gmap_hpage_1m)
937 return pmd_none(*pmdp) ? NULL : pmdp;
939 spin_lock(&gmap->guest_table_lock);
940 if (pmd_none(*pmdp)) {
941 spin_unlock(&gmap->guest_table_lock);
945 /* 4k page table entries are locked via the pte (pte_alloc_map_lock). */
946 if (!pmd_large(*pmdp))
947 spin_unlock(&gmap->guest_table_lock);
952 * gmap_pmd_op_end - release the guest_table_lock if needed
953 * @gmap: pointer to the guest mapping meta data structure
954 * @pmdp: pointer to the pmd
956 static inline void gmap_pmd_op_end(struct gmap *gmap, pmd_t *pmdp)
958 if (pmd_large(*pmdp))
959 spin_unlock(&gmap->guest_table_lock);
963 * gmap_protect_pmd - remove access rights to memory and set pmd notification bits
964 * @pmdp: pointer to the pmd to be protected
965 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
966 * @bits: notification bits to set
969 * 0 if successfully protected
970 * -EAGAIN if a fixup is needed
971 * -EINVAL if unsupported notifier bits have been specified
973 * Expected to be called with sg->mm->mmap_lock in read and
974 * guest_table_lock held.
976 static int gmap_protect_pmd(struct gmap *gmap, unsigned long gaddr,
977 pmd_t *pmdp, int prot, unsigned long bits)
979 int pmd_i = pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID;
980 int pmd_p = pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT;
984 if ((pmd_i && (prot != PROT_NONE)) || (pmd_p && (prot == PROT_WRITE)))
987 if (prot == PROT_NONE && !pmd_i) {
988 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
989 gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
992 if (prot == PROT_READ && !pmd_p) {
993 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
994 new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_PROTECT));
995 gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
998 if (bits & GMAP_NOTIFY_MPROT)
999 set_pmd(pmdp, set_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN)));
1001 /* Shadow GMAP protection needs split PMDs */
1002 if (bits & GMAP_NOTIFY_SHADOW)
1009 * gmap_protect_pte - remove access rights to memory and set pgste bits
1010 * @gmap: pointer to guest mapping meta data structure
1011 * @gaddr: virtual address in the guest address space
1012 * @pmdp: pointer to the pmd associated with the pte
1013 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1014 * @bits: notification bits to set
1016 * Returns 0 if successfully protected, -ENOMEM if out of memory and
1017 * -EAGAIN if a fixup is needed.
1019 * Expected to be called with sg->mm->mmap_lock in read
1021 static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
1022 pmd_t *pmdp, int prot, unsigned long bits)
1027 unsigned long pbits = 0;
1029 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
1032 ptep = pte_alloc_map_lock(gmap->mm, pmdp, gaddr, &ptl);
1036 pbits |= (bits & GMAP_NOTIFY_MPROT) ? PGSTE_IN_BIT : 0;
1037 pbits |= (bits & GMAP_NOTIFY_SHADOW) ? PGSTE_VSIE_BIT : 0;
1038 /* Protect and unlock. */
1039 rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits);
1040 gmap_pte_op_end(ptep, ptl);
1045 * gmap_protect_range - remove access rights to memory and set pgste bits
1046 * @gmap: pointer to guest mapping meta data structure
1047 * @gaddr: virtual address in the guest address space
1048 * @len: size of area
1049 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1050 * @bits: pgste notification bits to set
1052 * Returns 0 if successfully protected, -ENOMEM if out of memory and
1053 * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
1055 * Called with sg->mm->mmap_lock in read.
1057 static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
1058 unsigned long len, int prot, unsigned long bits)
1060 unsigned long vmaddr, dist;
1064 BUG_ON(gmap_is_shadow(gmap));
1067 pmdp = gmap_pmd_op_walk(gmap, gaddr);
1069 if (!pmd_large(*pmdp)) {
1070 rc = gmap_protect_pte(gmap, gaddr, pmdp, prot,
1077 rc = gmap_protect_pmd(gmap, gaddr, pmdp, prot,
1080 dist = HPAGE_SIZE - (gaddr & ~HPAGE_MASK);
1081 len = len < dist ? 0 : len - dist;
1082 gaddr = (gaddr & HPAGE_MASK) + HPAGE_SIZE;
1085 gmap_pmd_op_end(gmap, pmdp);
1091 /* -EAGAIN, fixup of userspace mm and gmap */
1092 vmaddr = __gmap_translate(gmap, gaddr);
1093 if (IS_ERR_VALUE(vmaddr))
1095 rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot);
1104 * gmap_mprotect_notify - change access rights for a range of ptes and
1105 * call the notifier if any pte changes again
1106 * @gmap: pointer to guest mapping meta data structure
1107 * @gaddr: virtual address in the guest address space
1108 * @len: size of area
1109 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
1111 * Returns 0 if for each page in the given range a gmap mapping exists,
1112 * the new access rights could be set and the notifier could be armed.
1113 * If the gmap mapping is missing for one or more pages -EFAULT is
1114 * returned. If no memory could be allocated -ENOMEM is returned.
1115 * This function establishes missing page table entries.
1117 int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
1118 unsigned long len, int prot)
1122 if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
1124 if (!MACHINE_HAS_ESOP && prot == PROT_READ)
1126 mmap_read_lock(gmap->mm);
1127 rc = gmap_protect_range(gmap, gaddr, len, prot, GMAP_NOTIFY_MPROT);
1128 mmap_read_unlock(gmap->mm);
1131 EXPORT_SYMBOL_GPL(gmap_mprotect_notify);
1134 * gmap_read_table - get an unsigned long value from a guest page table using
1135 * absolute addressing, without marking the page referenced.
1136 * @gmap: pointer to guest mapping meta data structure
1137 * @gaddr: virtual address in the guest address space
1138 * @val: pointer to the unsigned long value to return
1140 * Returns 0 if the value was read, -ENOMEM if out of memory and -EFAULT
1141 * if reading using the virtual address failed. -EINVAL if called on a gmap
1144 * Called with gmap->mm->mmap_lock in read.
1146 int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
1148 unsigned long address, vmaddr;
1153 if (gmap_is_shadow(gmap))
1158 ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
1161 if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) {
1162 address = pte_val(pte) & PAGE_MASK;
1163 address += gaddr & ~PAGE_MASK;
1164 *val = *(unsigned long *)__va(address);
1165 set_pte(ptep, set_pte_bit(*ptep, __pgprot(_PAGE_YOUNG)));
1166 /* Do *NOT* clear the _PAGE_INVALID bit! */
1169 gmap_pte_op_end(ptep, ptl);
1173 vmaddr = __gmap_translate(gmap, gaddr);
1174 if (IS_ERR_VALUE(vmaddr)) {
1178 rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, PROT_READ);
1184 EXPORT_SYMBOL_GPL(gmap_read_table);
1187 * gmap_insert_rmap - add a rmap to the host_to_rmap radix tree
1188 * @sg: pointer to the shadow guest address space structure
1189 * @vmaddr: vm address associated with the rmap
1190 * @rmap: pointer to the rmap structure
1192 * Called with the sg->guest_table_lock
1194 static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
1195 struct gmap_rmap *rmap)
1197 struct gmap_rmap *temp;
1200 BUG_ON(!gmap_is_shadow(sg));
1201 slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
1203 rmap->next = radix_tree_deref_slot_protected(slot,
1204 &sg->guest_table_lock);
1205 for (temp = rmap->next; temp; temp = temp->next) {
1206 if (temp->raddr == rmap->raddr) {
1211 radix_tree_replace_slot(&sg->host_to_rmap, slot, rmap);
1214 radix_tree_insert(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT,
1220 * gmap_protect_rmap - restrict access rights to memory (RO) and create an rmap
1221 * @sg: pointer to the shadow guest address space structure
1222 * @raddr: rmap address in the shadow gmap
1223 * @paddr: address in the parent guest address space
1224 * @len: length of the memory area to protect
1226 * Returns 0 if successfully protected and the rmap was created, -ENOMEM
1227 * if out of memory and -EFAULT if paddr is invalid.
1229 static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
1230 unsigned long paddr, unsigned long len)
1232 struct gmap *parent;
1233 struct gmap_rmap *rmap;
1234 unsigned long vmaddr;
1239 BUG_ON(!gmap_is_shadow(sg));
1240 parent = sg->parent;
1242 vmaddr = __gmap_translate(parent, paddr);
1243 if (IS_ERR_VALUE(vmaddr))
1245 rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT);
1248 rmap->raddr = raddr;
1249 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
1255 ptep = gmap_pte_op_walk(parent, paddr, &ptl);
1257 spin_lock(&sg->guest_table_lock);
1258 rc = ptep_force_prot(parent->mm, paddr, ptep, PROT_READ,
1261 gmap_insert_rmap(sg, vmaddr, rmap);
1262 spin_unlock(&sg->guest_table_lock);
1263 gmap_pte_op_end(ptep, ptl);
1265 radix_tree_preload_end();
1268 rc = gmap_pte_op_fixup(parent, paddr, vmaddr, PROT_READ);
1279 #define _SHADOW_RMAP_MASK 0x7
1280 #define _SHADOW_RMAP_REGION1 0x5
1281 #define _SHADOW_RMAP_REGION2 0x4
1282 #define _SHADOW_RMAP_REGION3 0x3
1283 #define _SHADOW_RMAP_SEGMENT 0x2
1284 #define _SHADOW_RMAP_PGTABLE 0x1
1287 * gmap_idte_one - invalidate a single region or segment table entry
1288 * @asce: region or segment table *origin* + table-type bits
1289 * @vaddr: virtual address to identify the table entry to flush
1291 * The invalid bit of a single region or segment table entry is set
1292 * and the associated TLB entries depending on the entry are flushed.
1293 * The table-type of the @asce identifies the portion of the @vaddr
1294 * that is used as the invalidation index.
1296 static inline void gmap_idte_one(unsigned long asce, unsigned long vaddr)
1300 : : "a" (asce), "a" (vaddr) : "cc", "memory");
1304 * gmap_unshadow_page - remove a page from a shadow page table
1305 * @sg: pointer to the shadow guest address space structure
1306 * @raddr: rmap address in the shadow guest address space
1308 * Called with the sg->guest_table_lock
1310 static void gmap_unshadow_page(struct gmap *sg, unsigned long raddr)
1312 unsigned long *table;
1314 BUG_ON(!gmap_is_shadow(sg));
1315 table = gmap_table_walk(sg, raddr, 0); /* get page table pointer */
1316 if (!table || *table & _PAGE_INVALID)
1318 gmap_call_notifier(sg, raddr, raddr + _PAGE_SIZE - 1);
1319 ptep_unshadow_pte(sg->mm, raddr, (pte_t *) table);
1323 * __gmap_unshadow_pgt - remove all entries from a shadow page table
1324 * @sg: pointer to the shadow guest address space structure
1325 * @raddr: rmap address in the shadow guest address space
1326 * @pgt: pointer to the start of a shadow page table
1328 * Called with the sg->guest_table_lock
1330 static void __gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr,
1335 BUG_ON(!gmap_is_shadow(sg));
1336 for (i = 0; i < _PAGE_ENTRIES; i++, raddr += _PAGE_SIZE)
1337 pgt[i] = _PAGE_INVALID;
1341 * gmap_unshadow_pgt - remove a shadow page table from a segment entry
1342 * @sg: pointer to the shadow guest address space structure
1343 * @raddr: address in the shadow guest address space
1345 * Called with the sg->guest_table_lock
1347 static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
1350 phys_addr_t sto, pgt;
1353 BUG_ON(!gmap_is_shadow(sg));
1354 ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */
1355 if (!ste || !(*ste & _SEGMENT_ENTRY_ORIGIN))
1357 gmap_call_notifier(sg, raddr, raddr + _SEGMENT_SIZE - 1);
1358 sto = __pa(ste - ((raddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT));
1359 gmap_idte_one(sto | _ASCE_TYPE_SEGMENT, raddr);
1360 pgt = *ste & _SEGMENT_ENTRY_ORIGIN;
1361 *ste = _SEGMENT_ENTRY_EMPTY;
1362 __gmap_unshadow_pgt(sg, raddr, __va(pgt));
1363 /* Free page table */
1364 page = phys_to_page(pgt);
1365 list_del(&page->lru);
1366 page_table_free_pgste(page);
1370 * __gmap_unshadow_sgt - remove all entries from a shadow segment table
1371 * @sg: pointer to the shadow guest address space structure
1372 * @raddr: rmap address in the shadow guest address space
1373 * @sgt: pointer to the start of a shadow segment table
1375 * Called with the sg->guest_table_lock
1377 static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
1384 BUG_ON(!gmap_is_shadow(sg));
1385 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _SEGMENT_SIZE) {
1386 if (!(sgt[i] & _SEGMENT_ENTRY_ORIGIN))
1388 pgt = sgt[i] & _REGION_ENTRY_ORIGIN;
1389 sgt[i] = _SEGMENT_ENTRY_EMPTY;
1390 __gmap_unshadow_pgt(sg, raddr, __va(pgt));
1391 /* Free page table */
1392 page = phys_to_page(pgt);
1393 list_del(&page->lru);
1394 page_table_free_pgste(page);
1399 * gmap_unshadow_sgt - remove a shadow segment table from a region-3 entry
1400 * @sg: pointer to the shadow guest address space structure
1401 * @raddr: rmap address in the shadow guest address space
1403 * Called with the shadow->guest_table_lock
1405 static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
1407 unsigned long r3o, *r3e;
1411 BUG_ON(!gmap_is_shadow(sg));
1412 r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
1413 if (!r3e || !(*r3e & _REGION_ENTRY_ORIGIN))
1415 gmap_call_notifier(sg, raddr, raddr + _REGION3_SIZE - 1);
1416 r3o = (unsigned long) (r3e - ((raddr & _REGION3_INDEX) >> _REGION3_SHIFT));
1417 gmap_idte_one(__pa(r3o) | _ASCE_TYPE_REGION3, raddr);
1418 sgt = *r3e & _REGION_ENTRY_ORIGIN;
1419 *r3e = _REGION3_ENTRY_EMPTY;
1420 __gmap_unshadow_sgt(sg, raddr, __va(sgt));
1421 /* Free segment table */
1422 page = phys_to_page(sgt);
1423 list_del(&page->lru);
1424 __free_pages(page, CRST_ALLOC_ORDER);
1428 * __gmap_unshadow_r3t - remove all entries from a shadow region-3 table
1429 * @sg: pointer to the shadow guest address space structure
1430 * @raddr: address in the shadow guest address space
1431 * @r3t: pointer to the start of a shadow region-3 table
1433 * Called with the sg->guest_table_lock
1435 static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
1442 BUG_ON(!gmap_is_shadow(sg));
1443 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION3_SIZE) {
1444 if (!(r3t[i] & _REGION_ENTRY_ORIGIN))
1446 sgt = r3t[i] & _REGION_ENTRY_ORIGIN;
1447 r3t[i] = _REGION3_ENTRY_EMPTY;
1448 __gmap_unshadow_sgt(sg, raddr, __va(sgt));
1449 /* Free segment table */
1450 page = phys_to_page(sgt);
1451 list_del(&page->lru);
1452 __free_pages(page, CRST_ALLOC_ORDER);
1457 * gmap_unshadow_r3t - remove a shadow region-3 table from a region-2 entry
1458 * @sg: pointer to the shadow guest address space structure
1459 * @raddr: rmap address in the shadow guest address space
1461 * Called with the sg->guest_table_lock
1463 static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
1465 unsigned long r2o, *r2e;
1469 BUG_ON(!gmap_is_shadow(sg));
1470 r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
1471 if (!r2e || !(*r2e & _REGION_ENTRY_ORIGIN))
1473 gmap_call_notifier(sg, raddr, raddr + _REGION2_SIZE - 1);
1474 r2o = (unsigned long) (r2e - ((raddr & _REGION2_INDEX) >> _REGION2_SHIFT));
1475 gmap_idte_one(__pa(r2o) | _ASCE_TYPE_REGION2, raddr);
1476 r3t = *r2e & _REGION_ENTRY_ORIGIN;
1477 *r2e = _REGION2_ENTRY_EMPTY;
1478 __gmap_unshadow_r3t(sg, raddr, __va(r3t));
1479 /* Free region 3 table */
1480 page = phys_to_page(r3t);
1481 list_del(&page->lru);
1482 __free_pages(page, CRST_ALLOC_ORDER);
1486 * __gmap_unshadow_r2t - remove all entries from a shadow region-2 table
1487 * @sg: pointer to the shadow guest address space structure
1488 * @raddr: rmap address in the shadow guest address space
1489 * @r2t: pointer to the start of a shadow region-2 table
1491 * Called with the sg->guest_table_lock
1493 static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
1500 BUG_ON(!gmap_is_shadow(sg));
1501 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION2_SIZE) {
1502 if (!(r2t[i] & _REGION_ENTRY_ORIGIN))
1504 r3t = r2t[i] & _REGION_ENTRY_ORIGIN;
1505 r2t[i] = _REGION2_ENTRY_EMPTY;
1506 __gmap_unshadow_r3t(sg, raddr, __va(r3t));
1507 /* Free region 3 table */
1508 page = phys_to_page(r3t);
1509 list_del(&page->lru);
1510 __free_pages(page, CRST_ALLOC_ORDER);
1515 * gmap_unshadow_r2t - remove a shadow region-2 table from a region-1 entry
1516 * @sg: pointer to the shadow guest address space structure
1517 * @raddr: rmap address in the shadow guest address space
1519 * Called with the sg->guest_table_lock
1521 static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
1523 unsigned long r1o, *r1e;
1527 BUG_ON(!gmap_is_shadow(sg));
1528 r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */
1529 if (!r1e || !(*r1e & _REGION_ENTRY_ORIGIN))
1531 gmap_call_notifier(sg, raddr, raddr + _REGION1_SIZE - 1);
1532 r1o = (unsigned long) (r1e - ((raddr & _REGION1_INDEX) >> _REGION1_SHIFT));
1533 gmap_idte_one(__pa(r1o) | _ASCE_TYPE_REGION1, raddr);
1534 r2t = *r1e & _REGION_ENTRY_ORIGIN;
1535 *r1e = _REGION1_ENTRY_EMPTY;
1536 __gmap_unshadow_r2t(sg, raddr, __va(r2t));
1537 /* Free region 2 table */
1538 page = phys_to_page(r2t);
1539 list_del(&page->lru);
1540 __free_pages(page, CRST_ALLOC_ORDER);
1544 * __gmap_unshadow_r1t - remove all entries from a shadow region-1 table
1545 * @sg: pointer to the shadow guest address space structure
1546 * @raddr: rmap address in the shadow guest address space
1547 * @r1t: pointer to the start of a shadow region-1 table
1549 * Called with the shadow->guest_table_lock
1551 static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
1559 BUG_ON(!gmap_is_shadow(sg));
1560 asce = __pa(r1t) | _ASCE_TYPE_REGION1;
1561 for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION1_SIZE) {
1562 if (!(r1t[i] & _REGION_ENTRY_ORIGIN))
1564 r2t = r1t[i] & _REGION_ENTRY_ORIGIN;
1565 __gmap_unshadow_r2t(sg, raddr, __va(r2t));
1566 /* Clear entry and flush translation r1t -> r2t */
1567 gmap_idte_one(asce, raddr);
1568 r1t[i] = _REGION1_ENTRY_EMPTY;
1569 /* Free region 2 table */
1570 page = phys_to_page(r2t);
1571 list_del(&page->lru);
1572 __free_pages(page, CRST_ALLOC_ORDER);
1577 * gmap_unshadow - remove a shadow page table completely
1578 * @sg: pointer to the shadow guest address space structure
1580 * Called with sg->guest_table_lock
1582 static void gmap_unshadow(struct gmap *sg)
1584 unsigned long *table;
1586 BUG_ON(!gmap_is_shadow(sg));
1590 gmap_call_notifier(sg, 0, -1UL);
1592 table = __va(sg->asce & _ASCE_ORIGIN);
1593 switch (sg->asce & _ASCE_TYPE_MASK) {
1594 case _ASCE_TYPE_REGION1:
1595 __gmap_unshadow_r1t(sg, 0, table);
1597 case _ASCE_TYPE_REGION2:
1598 __gmap_unshadow_r2t(sg, 0, table);
1600 case _ASCE_TYPE_REGION3:
1601 __gmap_unshadow_r3t(sg, 0, table);
1603 case _ASCE_TYPE_SEGMENT:
1604 __gmap_unshadow_sgt(sg, 0, table);
1610 * gmap_find_shadow - find a specific asce in the list of shadow tables
1611 * @parent: pointer to the parent gmap
1612 * @asce: ASCE for which the shadow table is created
1613 * @edat_level: edat level to be used for the shadow translation
1615 * Returns the pointer to a gmap if a shadow table with the given asce is
1616 * already available, ERR_PTR(-EAGAIN) if another one is just being created,
1619 static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce,
1624 list_for_each_entry(sg, &parent->children, list) {
1625 if (sg->orig_asce != asce || sg->edat_level != edat_level ||
1628 if (!sg->initialized)
1629 return ERR_PTR(-EAGAIN);
1630 refcount_inc(&sg->ref_count);
1637 * gmap_shadow_valid - check if a shadow guest address space matches the
1638 * given properties and is still valid
1639 * @sg: pointer to the shadow guest address space structure
1640 * @asce: ASCE for which the shadow table is requested
1641 * @edat_level: edat level to be used for the shadow translation
1643 * Returns 1 if the gmap shadow is still valid and matches the given
1644 * properties, the caller can continue using it. Returns 0 otherwise, the
1645 * caller has to request a new shadow gmap in this case.
1648 int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)
1652 return sg->orig_asce == asce && sg->edat_level == edat_level;
1654 EXPORT_SYMBOL_GPL(gmap_shadow_valid);
1657 * gmap_shadow - create/find a shadow guest address space
1658 * @parent: pointer to the parent gmap
1659 * @asce: ASCE for which the shadow table is created
1660 * @edat_level: edat level to be used for the shadow translation
1662 * The pages of the top level page table referred by the asce parameter
1663 * will be set to read-only and marked in the PGSTEs of the kvm process.
1664 * The shadow table will be removed automatically on any change to the
1665 * PTE mapping for the source table.
1667 * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory,
1668 * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the
1669 * parent gmap table could not be protected.
1671 struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
1674 struct gmap *sg, *new;
1675 unsigned long limit;
1678 BUG_ON(parent->mm->context.allow_gmap_hpage_1m);
1679 BUG_ON(gmap_is_shadow(parent));
1680 spin_lock(&parent->shadow_lock);
1681 sg = gmap_find_shadow(parent, asce, edat_level);
1682 spin_unlock(&parent->shadow_lock);
1685 /* Create a new shadow gmap */
1686 limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
1687 if (asce & _ASCE_REAL_SPACE)
1689 new = gmap_alloc(limit);
1691 return ERR_PTR(-ENOMEM);
1692 new->mm = parent->mm;
1693 new->parent = gmap_get(parent);
1694 new->private = parent->private;
1695 new->orig_asce = asce;
1696 new->edat_level = edat_level;
1697 new->initialized = false;
1698 spin_lock(&parent->shadow_lock);
1699 /* Recheck if another CPU created the same shadow */
1700 sg = gmap_find_shadow(parent, asce, edat_level);
1702 spin_unlock(&parent->shadow_lock);
1706 if (asce & _ASCE_REAL_SPACE) {
1707 /* only allow one real-space gmap shadow */
1708 list_for_each_entry(sg, &parent->children, list) {
1709 if (sg->orig_asce & _ASCE_REAL_SPACE) {
1710 spin_lock(&sg->guest_table_lock);
1712 spin_unlock(&sg->guest_table_lock);
1713 list_del(&sg->list);
1719 refcount_set(&new->ref_count, 2);
1720 list_add(&new->list, &parent->children);
1721 if (asce & _ASCE_REAL_SPACE) {
1722 /* nothing to protect, return right away */
1723 new->initialized = true;
1724 spin_unlock(&parent->shadow_lock);
1727 spin_unlock(&parent->shadow_lock);
1728 /* protect after insertion, so it will get properly invalidated */
1729 mmap_read_lock(parent->mm);
1730 rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
1731 ((asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE,
1732 PROT_READ, GMAP_NOTIFY_SHADOW);
1733 mmap_read_unlock(parent->mm);
1734 spin_lock(&parent->shadow_lock);
1735 new->initialized = true;
1737 list_del(&new->list);
1741 spin_unlock(&parent->shadow_lock);
1744 EXPORT_SYMBOL_GPL(gmap_shadow);
1747 * gmap_shadow_r2t - create an empty shadow region 2 table
1748 * @sg: pointer to the shadow guest address space structure
1749 * @saddr: faulting address in the shadow gmap
1750 * @r2t: parent gmap address of the region 2 table to get shadowed
1751 * @fake: r2t references contiguous guest memory block, not a r2t
1753 * The r2t parameter specifies the address of the source table. The
1754 * four pages of the source table are made read-only in the parent gmap
1755 * address space. A write to the source table area @r2t will automatically
1756 * remove the shadow r2 table and all of its descendants.
1758 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
1759 * shadow table structure is incomplete, -ENOMEM if out of memory and
1760 * -EFAULT if an address in the parent gmap could not be resolved.
1762 * Called with sg->mm->mmap_lock in read.
1764 int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
1767 unsigned long raddr, origin, offset, len;
1768 unsigned long *table;
1773 BUG_ON(!gmap_is_shadow(sg));
1774 /* Allocate a shadow region second table */
1775 page = gmap_alloc_crst();
1778 page->index = r2t & _REGION_ENTRY_ORIGIN;
1780 page->index |= GMAP_SHADOW_FAKE_TABLE;
1781 s_r2t = page_to_phys(page);
1782 /* Install shadow region second table */
1783 spin_lock(&sg->guest_table_lock);
1784 table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
1786 rc = -EAGAIN; /* Race with unshadow */
1789 if (!(*table & _REGION_ENTRY_INVALID)) {
1790 rc = 0; /* Already established */
1792 } else if (*table & _REGION_ENTRY_ORIGIN) {
1793 rc = -EAGAIN; /* Race with shadow */
1796 crst_table_init(__va(s_r2t), _REGION2_ENTRY_EMPTY);
1797 /* mark as invalid as long as the parent table is not protected */
1798 *table = s_r2t | _REGION_ENTRY_LENGTH |
1799 _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
1800 if (sg->edat_level >= 1)
1801 *table |= (r2t & _REGION_ENTRY_PROTECT);
1802 list_add(&page->lru, &sg->crst_list);
1804 /* nothing to protect for fake tables */
1805 *table &= ~_REGION_ENTRY_INVALID;
1806 spin_unlock(&sg->guest_table_lock);
1809 spin_unlock(&sg->guest_table_lock);
1810 /* Make r2t read-only in parent gmap page table */
1811 raddr = (saddr & _REGION1_MASK) | _SHADOW_RMAP_REGION1;
1812 origin = r2t & _REGION_ENTRY_ORIGIN;
1813 offset = ((r2t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1814 len = ((r2t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1815 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1816 spin_lock(&sg->guest_table_lock);
1818 table = gmap_table_walk(sg, saddr, 4);
1819 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r2t)
1820 rc = -EAGAIN; /* Race with unshadow */
1822 *table &= ~_REGION_ENTRY_INVALID;
1824 gmap_unshadow_r2t(sg, raddr);
1826 spin_unlock(&sg->guest_table_lock);
1829 spin_unlock(&sg->guest_table_lock);
1830 __free_pages(page, CRST_ALLOC_ORDER);
1833 EXPORT_SYMBOL_GPL(gmap_shadow_r2t);
1836 * gmap_shadow_r3t - create a shadow region 3 table
1837 * @sg: pointer to the shadow guest address space structure
1838 * @saddr: faulting address in the shadow gmap
1839 * @r3t: parent gmap address of the region 3 table to get shadowed
1840 * @fake: r3t references contiguous guest memory block, not a r3t
1842 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
1843 * shadow table structure is incomplete, -ENOMEM if out of memory and
1844 * -EFAULT if an address in the parent gmap could not be resolved.
1846 * Called with sg->mm->mmap_lock in read.
1848 int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
1851 unsigned long raddr, origin, offset, len;
1852 unsigned long *table;
1857 BUG_ON(!gmap_is_shadow(sg));
1858 /* Allocate a shadow region second table */
1859 page = gmap_alloc_crst();
1862 page->index = r3t & _REGION_ENTRY_ORIGIN;
1864 page->index |= GMAP_SHADOW_FAKE_TABLE;
1865 s_r3t = page_to_phys(page);
1866 /* Install shadow region second table */
1867 spin_lock(&sg->guest_table_lock);
1868 table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
1870 rc = -EAGAIN; /* Race with unshadow */
1873 if (!(*table & _REGION_ENTRY_INVALID)) {
1874 rc = 0; /* Already established */
1876 } else if (*table & _REGION_ENTRY_ORIGIN) {
1877 rc = -EAGAIN; /* Race with shadow */
1880 crst_table_init(__va(s_r3t), _REGION3_ENTRY_EMPTY);
1881 /* mark as invalid as long as the parent table is not protected */
1882 *table = s_r3t | _REGION_ENTRY_LENGTH |
1883 _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
1884 if (sg->edat_level >= 1)
1885 *table |= (r3t & _REGION_ENTRY_PROTECT);
1886 list_add(&page->lru, &sg->crst_list);
1888 /* nothing to protect for fake tables */
1889 *table &= ~_REGION_ENTRY_INVALID;
1890 spin_unlock(&sg->guest_table_lock);
1893 spin_unlock(&sg->guest_table_lock);
1894 /* Make r3t read-only in parent gmap page table */
1895 raddr = (saddr & _REGION2_MASK) | _SHADOW_RMAP_REGION2;
1896 origin = r3t & _REGION_ENTRY_ORIGIN;
1897 offset = ((r3t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1898 len = ((r3t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1899 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1900 spin_lock(&sg->guest_table_lock);
1902 table = gmap_table_walk(sg, saddr, 3);
1903 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r3t)
1904 rc = -EAGAIN; /* Race with unshadow */
1906 *table &= ~_REGION_ENTRY_INVALID;
1908 gmap_unshadow_r3t(sg, raddr);
1910 spin_unlock(&sg->guest_table_lock);
1913 spin_unlock(&sg->guest_table_lock);
1914 __free_pages(page, CRST_ALLOC_ORDER);
1917 EXPORT_SYMBOL_GPL(gmap_shadow_r3t);
1920 * gmap_shadow_sgt - create a shadow segment table
1921 * @sg: pointer to the shadow guest address space structure
1922 * @saddr: faulting address in the shadow gmap
1923 * @sgt: parent gmap address of the segment table to get shadowed
1924 * @fake: sgt references contiguous guest memory block, not a sgt
1926 * Returns: 0 if successfully shadowed or already shadowed, -EAGAIN if the
1927 * shadow table structure is incomplete, -ENOMEM if out of memory and
1928 * -EFAULT if an address in the parent gmap could not be resolved.
1930 * Called with sg->mm->mmap_lock in read.
1932 int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
1935 unsigned long raddr, origin, offset, len;
1936 unsigned long *table;
1941 BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE));
1942 /* Allocate a shadow segment table */
1943 page = gmap_alloc_crst();
1946 page->index = sgt & _REGION_ENTRY_ORIGIN;
1948 page->index |= GMAP_SHADOW_FAKE_TABLE;
1949 s_sgt = page_to_phys(page);
1950 /* Install shadow region second table */
1951 spin_lock(&sg->guest_table_lock);
1952 table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
1954 rc = -EAGAIN; /* Race with unshadow */
1957 if (!(*table & _REGION_ENTRY_INVALID)) {
1958 rc = 0; /* Already established */
1960 } else if (*table & _REGION_ENTRY_ORIGIN) {
1961 rc = -EAGAIN; /* Race with shadow */
1964 crst_table_init(__va(s_sgt), _SEGMENT_ENTRY_EMPTY);
1965 /* mark as invalid as long as the parent table is not protected */
1966 *table = s_sgt | _REGION_ENTRY_LENGTH |
1967 _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
1968 if (sg->edat_level >= 1)
1969 *table |= sgt & _REGION_ENTRY_PROTECT;
1970 list_add(&page->lru, &sg->crst_list);
1972 /* nothing to protect for fake tables */
1973 *table &= ~_REGION_ENTRY_INVALID;
1974 spin_unlock(&sg->guest_table_lock);
1977 spin_unlock(&sg->guest_table_lock);
1978 /* Make sgt read-only in parent gmap page table */
1979 raddr = (saddr & _REGION3_MASK) | _SHADOW_RMAP_REGION3;
1980 origin = sgt & _REGION_ENTRY_ORIGIN;
1981 offset = ((sgt & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
1982 len = ((sgt & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
1983 rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
1984 spin_lock(&sg->guest_table_lock);
1986 table = gmap_table_walk(sg, saddr, 2);
1987 if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_sgt)
1988 rc = -EAGAIN; /* Race with unshadow */
1990 *table &= ~_REGION_ENTRY_INVALID;
1992 gmap_unshadow_sgt(sg, raddr);
1994 spin_unlock(&sg->guest_table_lock);
1997 spin_unlock(&sg->guest_table_lock);
1998 __free_pages(page, CRST_ALLOC_ORDER);
2001 EXPORT_SYMBOL_GPL(gmap_shadow_sgt);
2004 * gmap_shadow_pgt_lookup - find a shadow page table
2005 * @sg: pointer to the shadow guest address space structure
2006 * @saddr: the address in the shadow aguest address space
2007 * @pgt: parent gmap address of the page table to get shadowed
2008 * @dat_protection: if the pgtable is marked as protected by dat
2009 * @fake: pgt references contiguous guest memory block, not a pgtable
2011 * Returns 0 if the shadow page table was found and -EAGAIN if the page
2012 * table was not found.
2014 * Called with sg->mm->mmap_lock in read.
2016 int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
2017 unsigned long *pgt, int *dat_protection,
2020 unsigned long *table;
2024 BUG_ON(!gmap_is_shadow(sg));
2025 spin_lock(&sg->guest_table_lock);
2026 table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
2027 if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
2028 /* Shadow page tables are full pages (pte+pgste) */
2029 page = pfn_to_page(*table >> PAGE_SHIFT);
2030 *pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
2031 *dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
2032 *fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
2037 spin_unlock(&sg->guest_table_lock);
2041 EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup);
2044 * gmap_shadow_pgt - instantiate a shadow page table
2045 * @sg: pointer to the shadow guest address space structure
2046 * @saddr: faulting address in the shadow gmap
2047 * @pgt: parent gmap address of the page table to get shadowed
2048 * @fake: pgt references contiguous guest memory block, not a pgtable
2050 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
2051 * shadow table structure is incomplete, -ENOMEM if out of memory,
2052 * -EFAULT if an address in the parent gmap could not be resolved and
2054 * Called with gmap->mm->mmap_lock in read
2056 int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
2059 unsigned long raddr, origin;
2060 unsigned long *table;
2065 BUG_ON(!gmap_is_shadow(sg) || (pgt & _SEGMENT_ENTRY_LARGE));
2066 /* Allocate a shadow page table */
2067 page = page_table_alloc_pgste(sg->mm);
2070 page->index = pgt & _SEGMENT_ENTRY_ORIGIN;
2072 page->index |= GMAP_SHADOW_FAKE_TABLE;
2073 s_pgt = page_to_phys(page);
2074 /* Install shadow page table */
2075 spin_lock(&sg->guest_table_lock);
2076 table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
2078 rc = -EAGAIN; /* Race with unshadow */
2081 if (!(*table & _SEGMENT_ENTRY_INVALID)) {
2082 rc = 0; /* Already established */
2084 } else if (*table & _SEGMENT_ENTRY_ORIGIN) {
2085 rc = -EAGAIN; /* Race with shadow */
2088 /* mark as invalid as long as the parent table is not protected */
2089 *table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
2090 (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID;
2091 list_add(&page->lru, &sg->pt_list);
2093 /* nothing to protect for fake tables */
2094 *table &= ~_SEGMENT_ENTRY_INVALID;
2095 spin_unlock(&sg->guest_table_lock);
2098 spin_unlock(&sg->guest_table_lock);
2099 /* Make pgt read-only in parent gmap page table (not the pgste) */
2100 raddr = (saddr & _SEGMENT_MASK) | _SHADOW_RMAP_SEGMENT;
2101 origin = pgt & _SEGMENT_ENTRY_ORIGIN & PAGE_MASK;
2102 rc = gmap_protect_rmap(sg, raddr, origin, PAGE_SIZE);
2103 spin_lock(&sg->guest_table_lock);
2105 table = gmap_table_walk(sg, saddr, 1);
2106 if (!table || (*table & _SEGMENT_ENTRY_ORIGIN) != s_pgt)
2107 rc = -EAGAIN; /* Race with unshadow */
2109 *table &= ~_SEGMENT_ENTRY_INVALID;
2111 gmap_unshadow_pgt(sg, raddr);
2113 spin_unlock(&sg->guest_table_lock);
2116 spin_unlock(&sg->guest_table_lock);
2117 page_table_free_pgste(page);
2121 EXPORT_SYMBOL_GPL(gmap_shadow_pgt);
2124 * gmap_shadow_page - create a shadow page mapping
2125 * @sg: pointer to the shadow guest address space structure
2126 * @saddr: faulting address in the shadow gmap
2127 * @pte: pte in parent gmap address space to get shadowed
2129 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
2130 * shadow table structure is incomplete, -ENOMEM if out of memory and
2131 * -EFAULT if an address in the parent gmap could not be resolved.
2133 * Called with sg->mm->mmap_lock in read.
2135 int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
2137 struct gmap *parent;
2138 struct gmap_rmap *rmap;
2139 unsigned long vmaddr, paddr;
2141 pte_t *sptep, *tptep;
2145 BUG_ON(!gmap_is_shadow(sg));
2146 parent = sg->parent;
2147 prot = (pte_val(pte) & _PAGE_PROTECT) ? PROT_READ : PROT_WRITE;
2149 rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT);
2152 rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE;
2155 paddr = pte_val(pte) & PAGE_MASK;
2156 vmaddr = __gmap_translate(parent, paddr);
2157 if (IS_ERR_VALUE(vmaddr)) {
2161 rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
2165 sptep = gmap_pte_op_walk(parent, paddr, &ptl);
2167 spin_lock(&sg->guest_table_lock);
2168 /* Get page table pointer */
2169 tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
2171 spin_unlock(&sg->guest_table_lock);
2172 gmap_pte_op_end(sptep, ptl);
2173 radix_tree_preload_end();
2176 rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte);
2178 /* Success and a new mapping */
2179 gmap_insert_rmap(sg, vmaddr, rmap);
2183 gmap_pte_op_end(sptep, ptl);
2184 spin_unlock(&sg->guest_table_lock);
2186 radix_tree_preload_end();
2189 rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot);
2196 EXPORT_SYMBOL_GPL(gmap_shadow_page);
2199 * gmap_shadow_notify - handle notifications for shadow gmap
2201 * Called with sg->parent->shadow_lock.
2203 static void gmap_shadow_notify(struct gmap *sg, unsigned long vmaddr,
2204 unsigned long gaddr)
2206 struct gmap_rmap *rmap, *rnext, *head;
2207 unsigned long start, end, bits, raddr;
2209 BUG_ON(!gmap_is_shadow(sg));
2211 spin_lock(&sg->guest_table_lock);
2213 spin_unlock(&sg->guest_table_lock);
2216 /* Check for top level table */
2217 start = sg->orig_asce & _ASCE_ORIGIN;
2218 end = start + ((sg->orig_asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE;
2219 if (!(sg->orig_asce & _ASCE_REAL_SPACE) && gaddr >= start &&
2221 /* The complete shadow table has to go */
2223 spin_unlock(&sg->guest_table_lock);
2224 list_del(&sg->list);
2228 /* Remove the page table tree from on specific entry */
2229 head = radix_tree_delete(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
2230 gmap_for_each_rmap_safe(rmap, rnext, head) {
2231 bits = rmap->raddr & _SHADOW_RMAP_MASK;
2232 raddr = rmap->raddr ^ bits;
2234 case _SHADOW_RMAP_REGION1:
2235 gmap_unshadow_r2t(sg, raddr);
2237 case _SHADOW_RMAP_REGION2:
2238 gmap_unshadow_r3t(sg, raddr);
2240 case _SHADOW_RMAP_REGION3:
2241 gmap_unshadow_sgt(sg, raddr);
2243 case _SHADOW_RMAP_SEGMENT:
2244 gmap_unshadow_pgt(sg, raddr);
2246 case _SHADOW_RMAP_PGTABLE:
2247 gmap_unshadow_page(sg, raddr);
2252 spin_unlock(&sg->guest_table_lock);
2256 * ptep_notify - call all invalidation callbacks for a specific pte.
2257 * @mm: pointer to the process mm_struct
2258 * @vmaddr: virtual address in the process address space
2259 * @pte: pointer to the page table entry
2260 * @bits: bits from the pgste that caused the notify call
2262 * This function is assumed to be called with the page table lock held
2263 * for the pte to notify.
2265 void ptep_notify(struct mm_struct *mm, unsigned long vmaddr,
2266 pte_t *pte, unsigned long bits)
2268 unsigned long offset, gaddr = 0;
2269 unsigned long *table;
2270 struct gmap *gmap, *sg, *next;
2272 offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
2273 offset = offset * (PAGE_SIZE / sizeof(pte_t));
2275 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2276 spin_lock(&gmap->guest_table_lock);
2277 table = radix_tree_lookup(&gmap->host_to_guest,
2278 vmaddr >> PMD_SHIFT);
2280 gaddr = __gmap_segment_gaddr(table) + offset;
2281 spin_unlock(&gmap->guest_table_lock);
2285 if (!list_empty(&gmap->children) && (bits & PGSTE_VSIE_BIT)) {
2286 spin_lock(&gmap->shadow_lock);
2287 list_for_each_entry_safe(sg, next,
2288 &gmap->children, list)
2289 gmap_shadow_notify(sg, vmaddr, gaddr);
2290 spin_unlock(&gmap->shadow_lock);
2292 if (bits & PGSTE_IN_BIT)
2293 gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1);
2297 EXPORT_SYMBOL_GPL(ptep_notify);
2299 static void pmdp_notify_gmap(struct gmap *gmap, pmd_t *pmdp,
2300 unsigned long gaddr)
2302 set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN)));
2303 gmap_call_notifier(gmap, gaddr, gaddr + HPAGE_SIZE - 1);
2307 * gmap_pmdp_xchg - exchange a gmap pmd with another
2308 * @gmap: pointer to the guest address space structure
2309 * @pmdp: pointer to the pmd entry
2310 * @new: replacement entry
2311 * @gaddr: the affected guest address
2313 * This function is assumed to be called with the guest_table_lock
2316 static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *pmdp, pmd_t new,
2317 unsigned long gaddr)
2319 gaddr &= HPAGE_MASK;
2320 pmdp_notify_gmap(gmap, pmdp, gaddr);
2321 new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_GMAP_IN));
2322 if (MACHINE_HAS_TLB_GUEST)
2323 __pmdp_idte(gaddr, (pmd_t *)pmdp, IDTE_GUEST_ASCE, gmap->asce,
2325 else if (MACHINE_HAS_IDTE)
2326 __pmdp_idte(gaddr, (pmd_t *)pmdp, 0, 0, IDTE_GLOBAL);
2332 static void gmap_pmdp_clear(struct mm_struct *mm, unsigned long vmaddr,
2337 unsigned long gaddr;
2340 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2341 spin_lock(&gmap->guest_table_lock);
2342 pmdp = (pmd_t *)radix_tree_delete(&gmap->host_to_guest,
2343 vmaddr >> PMD_SHIFT);
2345 gaddr = __gmap_segment_gaddr((unsigned long *)pmdp);
2346 pmdp_notify_gmap(gmap, pmdp, gaddr);
2347 WARN_ON(pmd_val(*pmdp) & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2348 _SEGMENT_ENTRY_GMAP_UC));
2351 set_pmd(pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
2353 spin_unlock(&gmap->guest_table_lock);
2359 * gmap_pmdp_invalidate - invalidate all affected guest pmd entries without
2361 * @mm: pointer to the process mm_struct
2362 * @vmaddr: virtual address in the process address space
2364 void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr)
2366 gmap_pmdp_clear(mm, vmaddr, 0);
2368 EXPORT_SYMBOL_GPL(gmap_pmdp_invalidate);
2371 * gmap_pmdp_csp - csp all affected guest pmd entries
2372 * @mm: pointer to the process mm_struct
2373 * @vmaddr: virtual address in the process address space
2375 void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr)
2377 gmap_pmdp_clear(mm, vmaddr, 1);
2379 EXPORT_SYMBOL_GPL(gmap_pmdp_csp);
2382 * gmap_pmdp_idte_local - invalidate and clear a guest pmd entry
2383 * @mm: pointer to the process mm_struct
2384 * @vmaddr: virtual address in the process address space
2386 void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr)
2388 unsigned long *entry, gaddr;
2393 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2394 spin_lock(&gmap->guest_table_lock);
2395 entry = radix_tree_delete(&gmap->host_to_guest,
2396 vmaddr >> PMD_SHIFT);
2398 pmdp = (pmd_t *)entry;
2399 gaddr = __gmap_segment_gaddr(entry);
2400 pmdp_notify_gmap(gmap, pmdp, gaddr);
2401 WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2402 _SEGMENT_ENTRY_GMAP_UC));
2403 if (MACHINE_HAS_TLB_GUEST)
2404 __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
2405 gmap->asce, IDTE_LOCAL);
2406 else if (MACHINE_HAS_IDTE)
2407 __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_LOCAL);
2408 *entry = _SEGMENT_ENTRY_EMPTY;
2410 spin_unlock(&gmap->guest_table_lock);
2414 EXPORT_SYMBOL_GPL(gmap_pmdp_idte_local);
2417 * gmap_pmdp_idte_global - invalidate and clear a guest pmd entry
2418 * @mm: pointer to the process mm_struct
2419 * @vmaddr: virtual address in the process address space
2421 void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr)
2423 unsigned long *entry, gaddr;
2428 list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2429 spin_lock(&gmap->guest_table_lock);
2430 entry = radix_tree_delete(&gmap->host_to_guest,
2431 vmaddr >> PMD_SHIFT);
2433 pmdp = (pmd_t *)entry;
2434 gaddr = __gmap_segment_gaddr(entry);
2435 pmdp_notify_gmap(gmap, pmdp, gaddr);
2436 WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
2437 _SEGMENT_ENTRY_GMAP_UC));
2438 if (MACHINE_HAS_TLB_GUEST)
2439 __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
2440 gmap->asce, IDTE_GLOBAL);
2441 else if (MACHINE_HAS_IDTE)
2442 __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_GLOBAL);
2445 *entry = _SEGMENT_ENTRY_EMPTY;
2447 spin_unlock(&gmap->guest_table_lock);
2451 EXPORT_SYMBOL_GPL(gmap_pmdp_idte_global);
2454 * gmap_test_and_clear_dirty_pmd - test and reset segment dirty status
2455 * @gmap: pointer to guest address space
2456 * @pmdp: pointer to the pmd to be tested
2457 * @gaddr: virtual address in the guest address space
2459 * This function is assumed to be called with the guest_table_lock
2462 static bool gmap_test_and_clear_dirty_pmd(struct gmap *gmap, pmd_t *pmdp,
2463 unsigned long gaddr)
2465 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
2468 /* Already protected memory, which did not change is clean */
2469 if (pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT &&
2470 !(pmd_val(*pmdp) & _SEGMENT_ENTRY_GMAP_UC))
2473 /* Clear UC indication and reset protection */
2474 set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_UC)));
2475 gmap_protect_pmd(gmap, gaddr, pmdp, PROT_READ, 0);
2480 * gmap_sync_dirty_log_pmd - set bitmap based on dirty status of segment
2481 * @gmap: pointer to guest address space
2482 * @bitmap: dirty bitmap for this pmd
2483 * @gaddr: virtual address in the guest address space
2484 * @vmaddr: virtual address in the host address space
2486 * This function is assumed to be called with the guest_table_lock
2489 void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long bitmap[4],
2490 unsigned long gaddr, unsigned long vmaddr)
2497 pmdp = gmap_pmd_op_walk(gmap, gaddr);
2501 if (pmd_large(*pmdp)) {
2502 if (gmap_test_and_clear_dirty_pmd(gmap, pmdp, gaddr))
2503 bitmap_fill(bitmap, _PAGE_ENTRIES);
2505 for (i = 0; i < _PAGE_ENTRIES; i++, vmaddr += PAGE_SIZE) {
2506 ptep = pte_alloc_map_lock(gmap->mm, pmdp, vmaddr, &ptl);
2509 if (ptep_test_and_clear_uc(gmap->mm, vmaddr, ptep))
2511 pte_unmap_unlock(ptep, ptl);
2514 gmap_pmd_op_end(gmap, pmdp);
2516 EXPORT_SYMBOL_GPL(gmap_sync_dirty_log_pmd);
2518 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2519 static int thp_split_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
2520 unsigned long end, struct mm_walk *walk)
2522 struct vm_area_struct *vma = walk->vma;
2524 split_huge_pmd(vma, pmd, addr);
2528 static const struct mm_walk_ops thp_split_walk_ops = {
2529 .pmd_entry = thp_split_walk_pmd_entry,
2530 .walk_lock = PGWALK_WRLOCK_VERIFY,
2533 static inline void thp_split_mm(struct mm_struct *mm)
2535 struct vm_area_struct *vma;
2536 VMA_ITERATOR(vmi, mm, 0);
2538 for_each_vma(vmi, vma) {
2539 vm_flags_mod(vma, VM_NOHUGEPAGE, VM_HUGEPAGE);
2540 walk_page_vma(vma, &thp_split_walk_ops, NULL);
2542 mm->def_flags |= VM_NOHUGEPAGE;
2545 static inline void thp_split_mm(struct mm_struct *mm)
2548 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2551 * Remove all empty zero pages from the mapping for lazy refaulting
2552 * - This must be called after mm->context.has_pgste is set, to avoid
2553 * future creation of zero pages
2554 * - This must be called after THP was disabled.
2556 * mm contracts with s390, that even if mm were to remove a page table,
2557 * racing with the loop below and so causing pte_offset_map_lock() to fail,
2558 * it will never insert a page table containing empty zero pages once
2559 * mm_forbids_zeropage(mm) i.e. mm->context.has_pgste is set.
2561 static int __zap_zero_pages(pmd_t *pmd, unsigned long start,
2562 unsigned long end, struct mm_walk *walk)
2566 for (addr = start; addr != end; addr += PAGE_SIZE) {
2570 ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
2573 if (is_zero_pfn(pte_pfn(*ptep)))
2574 ptep_xchg_direct(walk->mm, addr, ptep, __pte(_PAGE_INVALID));
2575 pte_unmap_unlock(ptep, ptl);
2580 static const struct mm_walk_ops zap_zero_walk_ops = {
2581 .pmd_entry = __zap_zero_pages,
2582 .walk_lock = PGWALK_WRLOCK,
2586 * switch on pgstes for its userspace process (for kvm)
2588 int s390_enable_sie(void)
2590 struct mm_struct *mm = current->mm;
2592 /* Do we have pgstes? if yes, we are done */
2593 if (mm_has_pgste(mm))
2595 /* Fail if the page tables are 2K */
2596 if (!mm_alloc_pgste(mm))
2598 mmap_write_lock(mm);
2599 mm->context.has_pgste = 1;
2600 /* split thp mappings and disable thp for future mappings */
2602 walk_page_range(mm, 0, TASK_SIZE, &zap_zero_walk_ops, NULL);
2603 mmap_write_unlock(mm);
2606 EXPORT_SYMBOL_GPL(s390_enable_sie);
2608 int gmap_mark_unmergeable(void)
2611 * Make sure to disable KSM (if enabled for the whole process or
2612 * individual VMAs). Note that nothing currently hinders user space
2613 * from re-enabling it.
2615 return ksm_disable(current->mm);
2617 EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
2620 * Enable storage key handling from now on and initialize the storage
2621 * keys with the default key.
2623 static int __s390_enable_skey_pte(pte_t *pte, unsigned long addr,
2624 unsigned long next, struct mm_walk *walk)
2626 /* Clear storage key */
2627 ptep_zap_key(walk->mm, addr, pte);
2632 * Give a chance to schedule after setting a key to 256 pages.
2633 * We only hold the mm lock, which is a rwsem and the kvm srcu.
2636 static int __s390_enable_skey_pmd(pmd_t *pmd, unsigned long addr,
2637 unsigned long next, struct mm_walk *walk)
2643 static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
2644 unsigned long hmask, unsigned long next,
2645 struct mm_walk *walk)
2647 pmd_t *pmd = (pmd_t *)pte;
2648 unsigned long start, end;
2649 struct page *page = pmd_page(*pmd);
2652 * The write check makes sure we do not set a key on shared
2653 * memory. This is needed as the walker does not differentiate
2654 * between actual guest memory and the process executable or
2657 if (pmd_val(*pmd) & _SEGMENT_ENTRY_INVALID ||
2658 !(pmd_val(*pmd) & _SEGMENT_ENTRY_WRITE))
2661 start = pmd_val(*pmd) & HPAGE_MASK;
2662 end = start + HPAGE_SIZE - 1;
2663 __storage_key_init_range(start, end);
2664 set_bit(PG_arch_1, &page->flags);
2669 static const struct mm_walk_ops enable_skey_walk_ops = {
2670 .hugetlb_entry = __s390_enable_skey_hugetlb,
2671 .pte_entry = __s390_enable_skey_pte,
2672 .pmd_entry = __s390_enable_skey_pmd,
2673 .walk_lock = PGWALK_WRLOCK,
2676 int s390_enable_skey(void)
2678 struct mm_struct *mm = current->mm;
2681 mmap_write_lock(mm);
2682 if (mm_uses_skeys(mm))
2685 mm->context.uses_skeys = 1;
2686 rc = gmap_mark_unmergeable();
2688 mm->context.uses_skeys = 0;
2691 walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
2694 mmap_write_unlock(mm);
2697 EXPORT_SYMBOL_GPL(s390_enable_skey);
2700 * Reset CMMA state, make all pages stable again.
2702 static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
2703 unsigned long next, struct mm_walk *walk)
2705 ptep_zap_unused(walk->mm, addr, pte, 1);
2709 static const struct mm_walk_ops reset_cmma_walk_ops = {
2710 .pte_entry = __s390_reset_cmma,
2711 .walk_lock = PGWALK_WRLOCK,
2714 void s390_reset_cmma(struct mm_struct *mm)
2716 mmap_write_lock(mm);
2717 walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
2718 mmap_write_unlock(mm);
2720 EXPORT_SYMBOL_GPL(s390_reset_cmma);
2722 #define GATHER_GET_PAGES 32
2724 struct reset_walk_state {
2726 unsigned long count;
2727 unsigned long pfns[GATHER_GET_PAGES];
2730 static int s390_gather_pages(pte_t *ptep, unsigned long addr,
2731 unsigned long next, struct mm_walk *walk)
2733 struct reset_walk_state *p = walk->private;
2734 pte_t pte = READ_ONCE(*ptep);
2736 if (pte_present(pte)) {
2737 /* we have a reference from the mapping, take an extra one */
2738 get_page(phys_to_page(pte_val(pte)));
2739 p->pfns[p->count] = phys_to_pfn(pte_val(pte));
2743 return p->count >= GATHER_GET_PAGES;
2746 static const struct mm_walk_ops gather_pages_ops = {
2747 .pte_entry = s390_gather_pages,
2748 .walk_lock = PGWALK_RDLOCK,
2752 * Call the Destroy secure page UVC on each page in the given array of PFNs.
2753 * Each page needs to have an extra reference, which will be released here.
2755 void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns)
2759 for (i = 0; i < count; i++) {
2760 /* we always have an extra reference */
2761 uv_destroy_owned_page(pfn_to_phys(pfns[i]));
2762 /* get rid of the extra reference */
2763 put_page(pfn_to_page(pfns[i]));
2767 EXPORT_SYMBOL_GPL(s390_uv_destroy_pfns);
2770 * __s390_uv_destroy_range - Call the destroy secure page UVC on each page
2771 * in the given range of the given address space.
2772 * @mm: the mm to operate on
2773 * @start: the start of the range
2774 * @end: the end of the range
2775 * @interruptible: if not 0, stop when a fatal signal is received
2777 * Walk the given range of the given address space and call the destroy
2778 * secure page UVC on each page. Optionally exit early if a fatal signal is
2781 * Return: 0 on success, -EINTR if the function stopped before completing
2783 int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start,
2784 unsigned long end, bool interruptible)
2786 struct reset_walk_state state = { .next = start };
2792 r = walk_page_range(mm, state.next, end, &gather_pages_ops, &state);
2793 mmap_read_unlock(mm);
2795 s390_uv_destroy_pfns(state.count, state.pfns);
2796 if (interruptible && fatal_signal_pending(current))
2801 EXPORT_SYMBOL_GPL(__s390_uv_destroy_range);
2804 * s390_unlist_old_asce - Remove the topmost level of page tables from the
2805 * list of page tables of the gmap.
2806 * @gmap: the gmap whose table is to be removed
2808 * On s390x, KVM keeps a list of all pages containing the page tables of the
2809 * gmap (the CRST list). This list is used at tear down time to free all
2810 * pages that are now not needed anymore.
2812 * This function removes the topmost page of the tree (the one pointed to by
2813 * the ASCE) from the CRST list.
2815 * This means that it will not be freed when the VM is torn down, and needs
2816 * to be handled separately by the caller, unless a leak is actually
2817 * intended. Notice that this function will only remove the page from the
2818 * list, the page will still be used as a top level page table (and ASCE).
2820 void s390_unlist_old_asce(struct gmap *gmap)
2824 old = virt_to_page(gmap->table);
2825 spin_lock(&gmap->guest_table_lock);
2826 list_del(&old->lru);
2828 * Sometimes the topmost page might need to be "removed" multiple
2829 * times, for example if the VM is rebooted into secure mode several
2830 * times concurrently, or if s390_replace_asce fails after calling
2831 * s390_remove_old_asce and is attempted again later. In that case
2832 * the old asce has been removed from the list, and therefore it
2833 * will not be freed when the VM terminates, but the ASCE is still
2834 * in use and still pointed to.
2835 * A subsequent call to replace_asce will follow the pointer and try
2836 * to remove the same page from the list again.
2837 * Therefore it's necessary that the page of the ASCE has valid
2838 * pointers, so list_del can work (and do nothing) without
2839 * dereferencing stale or invalid pointers.
2841 INIT_LIST_HEAD(&old->lru);
2842 spin_unlock(&gmap->guest_table_lock);
2844 EXPORT_SYMBOL_GPL(s390_unlist_old_asce);
2847 * s390_replace_asce - Try to replace the current ASCE of a gmap with a copy
2848 * @gmap: the gmap whose ASCE needs to be replaced
2850 * If the ASCE is a SEGMENT type then this function will return -EINVAL,
2851 * otherwise the pointers in the host_to_guest radix tree will keep pointing
2852 * to the wrong pages, causing use-after-free and memory corruption.
2853 * If the allocation of the new top level page table fails, the ASCE is not
2855 * In any case, the old ASCE is always removed from the gmap CRST list.
2856 * Therefore the caller has to make sure to save a pointer to it
2857 * beforehand, unless a leak is actually intended.
2859 int s390_replace_asce(struct gmap *gmap)
2865 s390_unlist_old_asce(gmap);
2867 /* Replacing segment type ASCEs would cause serious issues */
2868 if ((gmap->asce & _ASCE_TYPE_MASK) == _ASCE_TYPE_SEGMENT)
2871 page = gmap_alloc_crst();
2875 table = page_to_virt(page);
2876 memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));
2879 * The caller has to deal with the old ASCE, but here we make sure
2880 * the new one is properly added to the CRST list, so that
2881 * it will be freed when the VM is torn down.
2883 spin_lock(&gmap->guest_table_lock);
2884 list_add(&page->lru, &gmap->crst_list);
2885 spin_unlock(&gmap->guest_table_lock);
2887 /* Set new table origin while preserving existing ASCE control bits */
2888 asce = (gmap->asce & ~_ASCE_ORIGIN) | __pa(table);
2889 WRITE_ONCE(gmap->asce, asce);
2890 WRITE_ONCE(gmap->mm->context.gmap_asce, asce);
2891 WRITE_ONCE(gmap->table, table);
2895 EXPORT_SYMBOL_GPL(s390_replace_asce);