diff options
Diffstat (limited to 'arch/s390/mm/gmap.c')
-rw-r--r-- | arch/s390/mm/gmap.c | 215 |
1 files changed, 66 insertions, 149 deletions
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 3b57837f3e..12d22a7fa3 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -206,9 +206,11 @@ static void gmap_free(struct gmap *gmap) /* Free additional data for a shadow gmap */ if (gmap_is_shadow(gmap)) { + struct ptdesc *ptdesc, *n; + /* Free all page tables. */ - list_for_each_entry_safe(page, next, &gmap->pt_list, lru) - page_table_free_pgste(page); + list_for_each_entry_safe(ptdesc, n, &gmap->pt_list, pt_list) + page_table_free_pgste(ptdesc); gmap_rmap_radix_tree_free(&gmap->host_to_rmap); /* Release reference to the parent */ gmap_put(gmap->parent); @@ -601,7 +603,7 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr) pmd = pmd_offset(pud, vmaddr); VM_BUG_ON(pmd_none(*pmd)); /* Are we allowed to use huge pages? */ - if (pmd_large(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m) + if (pmd_leaf(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m) return -EFAULT; /* Link gmap segment table entry location to page table. */ rc = radix_tree_preload(GFP_KERNEL_ACCOUNT); @@ -613,7 +615,7 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr) rc = radix_tree_insert(&gmap->host_to_guest, vmaddr >> PMD_SHIFT, table); if (!rc) { - if (pmd_large(*pmd)) { + if (pmd_leaf(*pmd)) { *table = (pmd_val(*pmd) & _SEGMENT_ENTRY_HARDWARE_BITS_LARGE) | _SEGMENT_ENTRY_GMAP_UC; @@ -943,7 +945,7 @@ static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr) } /* 4k page table entries are locked via the pte (pte_alloc_map_lock). */ - if (!pmd_large(*pmdp)) + if (!pmd_leaf(*pmdp)) spin_unlock(&gmap->guest_table_lock); return pmdp; } @@ -955,7 +957,7 @@ static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr) */ static inline void gmap_pmd_op_end(struct gmap *gmap, pmd_t *pmdp) { - if (pmd_large(*pmdp)) + if (pmd_leaf(*pmdp)) spin_unlock(&gmap->guest_table_lock); } @@ -1066,7 +1068,7 @@ static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr, rc = -EAGAIN; pmdp = gmap_pmd_op_walk(gmap, gaddr); if (pmdp) { - if (!pmd_large(*pmdp)) { + if (!pmd_leaf(*pmdp)) { rc = gmap_protect_pte(gmap, gaddr, pmdp, prot, bits); if (!rc) { @@ -1348,7 +1350,7 @@ static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr) { unsigned long *ste; phys_addr_t sto, pgt; - struct page *page; + struct ptdesc *ptdesc; BUG_ON(!gmap_is_shadow(sg)); ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */ @@ -1361,9 +1363,9 @@ static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr) *ste = _SEGMENT_ENTRY_EMPTY; __gmap_unshadow_pgt(sg, raddr, __va(pgt)); /* Free page table */ - page = phys_to_page(pgt); - list_del(&page->lru); - page_table_free_pgste(page); + ptdesc = page_ptdesc(phys_to_page(pgt)); + list_del(&ptdesc->pt_list); + page_table_free_pgste(ptdesc); } /** @@ -1377,7 +1379,7 @@ static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr) static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr, unsigned long *sgt) { - struct page *page; + struct ptdesc *ptdesc; phys_addr_t pgt; int i; @@ -1389,9 +1391,9 @@ static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr, sgt[i] = _SEGMENT_ENTRY_EMPTY; __gmap_unshadow_pgt(sg, raddr, __va(pgt)); /* Free page table */ - page = phys_to_page(pgt); - list_del(&page->lru); - page_table_free_pgste(page); + ptdesc = page_ptdesc(phys_to_page(pgt)); + list_del(&ptdesc->pt_list); + page_table_free_pgste(ptdesc); } } @@ -2058,19 +2060,19 @@ int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt, { unsigned long raddr, origin; unsigned long *table; - struct page *page; + struct ptdesc *ptdesc; phys_addr_t s_pgt; int rc; BUG_ON(!gmap_is_shadow(sg) || (pgt & _SEGMENT_ENTRY_LARGE)); /* Allocate a shadow page table */ - page = page_table_alloc_pgste(sg->mm); - if (!page) + ptdesc = page_table_alloc_pgste(sg->mm); + if (!ptdesc) return -ENOMEM; - page->index = pgt & _SEGMENT_ENTRY_ORIGIN; + ptdesc->pt_index = pgt & _SEGMENT_ENTRY_ORIGIN; if (fake) - page->index |= GMAP_SHADOW_FAKE_TABLE; - s_pgt = page_to_phys(page); + ptdesc->pt_index |= GMAP_SHADOW_FAKE_TABLE; + s_pgt = page_to_phys(ptdesc_page(ptdesc)); /* Install shadow page table */ spin_lock(&sg->guest_table_lock); table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */ @@ -2088,7 +2090,7 @@ int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt, /* mark as invalid as long as the parent table is not protected */ *table = (unsigned long) s_pgt | _SEGMENT_ENTRY | (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID; - list_add(&page->lru, &sg->pt_list); + list_add(&ptdesc->pt_list, &sg->pt_list); if (fake) { /* nothing to protect for fake tables */ *table &= ~_SEGMENT_ENTRY_INVALID; @@ -2114,7 +2116,7 @@ int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt, return rc; out_free: spin_unlock(&sg->guest_table_lock); - page_table_free_pgste(page); + page_table_free_pgste(ptdesc); return rc; } @@ -2498,7 +2500,7 @@ void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long bitmap[4], if (!pmdp) return; - if (pmd_large(*pmdp)) { + if (pmd_leaf(*pmdp)) { if (gmap_test_and_clear_dirty_pmd(gmap, pmdp, gaddr)) bitmap_fill(bitmap, _PAGE_ENTRIES); } else { @@ -2548,6 +2550,41 @@ static inline void thp_split_mm(struct mm_struct *mm) #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ /* + * Remove all empty zero pages from the mapping for lazy refaulting + * - This must be called after mm->context.has_pgste is set, to avoid + * future creation of zero pages + * - This must be called after THP was disabled. + * + * mm contracts with s390, that even if mm were to remove a page table, + * racing with the loop below and so causing pte_offset_map_lock() to fail, + * it will never insert a page table containing empty zero pages once + * mm_forbids_zeropage(mm) i.e. mm->context.has_pgste is set. + */ +static int __zap_zero_pages(pmd_t *pmd, unsigned long start, + unsigned long end, struct mm_walk *walk) +{ + unsigned long addr; + + for (addr = start; addr != end; addr += PAGE_SIZE) { + pte_t *ptep; + spinlock_t *ptl; + + ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + if (!ptep) + break; + if (is_zero_pfn(pte_pfn(*ptep))) + ptep_xchg_direct(walk->mm, addr, ptep, __pte(_PAGE_INVALID)); + pte_unmap_unlock(ptep, ptl); + } + return 0; +} + +static const struct mm_walk_ops zap_zero_walk_ops = { + .pmd_entry = __zap_zero_pages, + .walk_lock = PGWALK_WRLOCK, +}; + +/* * switch on pgstes for its userspace process (for kvm) */ int s390_enable_sie(void) @@ -2564,142 +2601,22 @@ int s390_enable_sie(void) mm->context.has_pgste = 1; /* split thp mappings and disable thp for future mappings */ thp_split_mm(mm); + walk_page_range(mm, 0, TASK_SIZE, &zap_zero_walk_ops, NULL); mmap_write_unlock(mm); return 0; } EXPORT_SYMBOL_GPL(s390_enable_sie); -static int find_zeropage_pte_entry(pte_t *pte, unsigned long addr, - unsigned long end, struct mm_walk *walk) -{ - unsigned long *found_addr = walk->private; - - /* Return 1 of the page is a zeropage. */ - if (is_zero_pfn(pte_pfn(*pte))) { - /* - * Shared zeropage in e.g., a FS DAX mapping? We cannot do the - * right thing and likely don't care: FAULT_FLAG_UNSHARE - * currently only works in COW mappings, which is also where - * mm_forbids_zeropage() is checked. - */ - if (!is_cow_mapping(walk->vma->vm_flags)) - return -EFAULT; - - *found_addr = addr; - return 1; - } - return 0; -} - -static const struct mm_walk_ops find_zeropage_ops = { - .pte_entry = find_zeropage_pte_entry, - .walk_lock = PGWALK_WRLOCK, -}; - -/* - * Unshare all shared zeropages, replacing them by anonymous pages. Note that - * we cannot simply zap all shared zeropages, because this could later - * trigger unexpected userfaultfd missing events. - * - * This must be called after mm->context.allow_cow_sharing was - * set to 0, to avoid future mappings of shared zeropages. - * - * mm contracts with s390, that even if mm were to remove a page table, - * and racing with walk_page_range_vma() calling pte_offset_map_lock() - * would fail, it will never insert a page table containing empty zero - * pages once mm_forbids_zeropage(mm) i.e. - * mm->context.allow_cow_sharing is set to 0. - */ -static int __s390_unshare_zeropages(struct mm_struct *mm) -{ - struct vm_area_struct *vma; - VMA_ITERATOR(vmi, mm, 0); - unsigned long addr; - vm_fault_t fault; - int rc; - - for_each_vma(vmi, vma) { - /* - * We could only look at COW mappings, but it's more future - * proof to catch unexpected zeropages in other mappings and - * fail. - */ - if ((vma->vm_flags & VM_PFNMAP) || is_vm_hugetlb_page(vma)) - continue; - addr = vma->vm_start; - -retry: - rc = walk_page_range_vma(vma, addr, vma->vm_end, - &find_zeropage_ops, &addr); - if (rc < 0) - return rc; - else if (!rc) - continue; - - /* addr was updated by find_zeropage_pte_entry() */ - fault = handle_mm_fault(vma, addr, - FAULT_FLAG_UNSHARE | FAULT_FLAG_REMOTE, - NULL); - if (fault & VM_FAULT_OOM) - return -ENOMEM; - /* - * See break_ksm(): even after handle_mm_fault() returned 0, we - * must start the lookup from the current address, because - * handle_mm_fault() may back out if there's any difficulty. - * - * VM_FAULT_SIGBUS and VM_FAULT_SIGSEGV are unexpected but - * maybe they could trigger in the future on concurrent - * truncation. In that case, the shared zeropage would be gone - * and we can simply retry and make progress. - */ - cond_resched(); - goto retry; - } - - return 0; -} - -static int __s390_disable_cow_sharing(struct mm_struct *mm) +int gmap_mark_unmergeable(void) { - int rc; - - if (!mm->context.allow_cow_sharing) - return 0; - - mm->context.allow_cow_sharing = 0; - - /* Replace all shared zeropages by anonymous pages. */ - rc = __s390_unshare_zeropages(mm); /* * Make sure to disable KSM (if enabled for the whole process or * individual VMAs). Note that nothing currently hinders user space * from re-enabling it. */ - if (!rc) - rc = ksm_disable(mm); - if (rc) - mm->context.allow_cow_sharing = 1; - return rc; -} - -/* - * Disable most COW-sharing of memory pages for the whole process: - * (1) Disable KSM and unmerge/unshare any KSM pages. - * (2) Disallow shared zeropages and unshare any zerpages that are mapped. - * - * Not that we currently don't bother with COW-shared pages that are shared - * with parent/child processes due to fork(). - */ -int s390_disable_cow_sharing(void) -{ - int rc; - - mmap_write_lock(current->mm); - rc = __s390_disable_cow_sharing(current->mm); - mmap_write_unlock(current->mm); - return rc; + return ksm_disable(current->mm); } -EXPORT_SYMBOL_GPL(s390_disable_cow_sharing); +EXPORT_SYMBOL_GPL(gmap_mark_unmergeable); /* * Enable storage key handling from now on and initialize the storage @@ -2768,7 +2685,7 @@ int s390_enable_skey(void) goto out_up; mm->context.uses_skeys = 1; - rc = __s390_disable_cow_sharing(mm); + rc = gmap_mark_unmergeable(); if (rc) { mm->context.uses_skeys = 0; goto out_up; |