diff options
Diffstat (limited to 'arch/s390/mm/gmap.c')
| -rw-r--r-- | arch/s390/mm/gmap.c | 2894 |
1 files changed, 2894 insertions, 0 deletions
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c new file mode 100644 index 0000000000..20786f6883 --- /dev/null +++ b/arch/s390/mm/gmap.c @@ -0,0 +1,2894 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KVM guest address space mapping code + * + * Copyright IBM Corp. 2007, 2020 + * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> + * David Hildenbrand <david@redhat.com> + * Janosch Frank <frankja@linux.vnet.ibm.com> + */ + +#include <linux/kernel.h> +#include <linux/pagewalk.h> +#include <linux/swap.h> +#include <linux/smp.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/swapops.h> +#include <linux/ksm.h> +#include <linux/mman.h> +#include <linux/pgtable.h> + +#include <asm/pgalloc.h> +#include <asm/gmap.h> +#include <asm/page.h> +#include <asm/tlb.h> + +#define GMAP_SHADOW_FAKE_TABLE 1ULL + +static struct page *gmap_alloc_crst(void) +{ + struct page *page; + + page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER); + if (!page) + return NULL; + arch_set_page_dat(page, CRST_ALLOC_ORDER); + return page; +} + +/** + * gmap_alloc - allocate and initialize a guest address space + * @limit: maximum address of the gmap address space + * + * Returns a guest address space structure. + */ +static struct gmap *gmap_alloc(unsigned long limit) +{ + struct gmap *gmap; + struct page *page; + unsigned long *table; + unsigned long etype, atype; + + if (limit < _REGION3_SIZE) { + limit = _REGION3_SIZE - 1; + atype = _ASCE_TYPE_SEGMENT; + etype = _SEGMENT_ENTRY_EMPTY; + } else if (limit < _REGION2_SIZE) { + limit = _REGION2_SIZE - 1; + atype = _ASCE_TYPE_REGION3; + etype = _REGION3_ENTRY_EMPTY; + } else if (limit < _REGION1_SIZE) { + limit = _REGION1_SIZE - 1; + atype = _ASCE_TYPE_REGION2; + etype = _REGION2_ENTRY_EMPTY; + } else { + limit = -1UL; + atype = _ASCE_TYPE_REGION1; + etype = _REGION1_ENTRY_EMPTY; + } + gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL_ACCOUNT); + if (!gmap) + goto out; + INIT_LIST_HEAD(&gmap->crst_list); + INIT_LIST_HEAD(&gmap->children); + INIT_LIST_HEAD(&gmap->pt_list); + INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL_ACCOUNT); + INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC | __GFP_ACCOUNT); + INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC | __GFP_ACCOUNT); + spin_lock_init(&gmap->guest_table_lock); + spin_lock_init(&gmap->shadow_lock); + refcount_set(&gmap->ref_count, 1); + page = gmap_alloc_crst(); + if (!page) + goto out_free; + page->index = 0; + list_add(&page->lru, &gmap->crst_list); + table = page_to_virt(page); + crst_table_init(table, etype); + gmap->table = table; + gmap->asce = atype | _ASCE_TABLE_LENGTH | + _ASCE_USER_BITS | __pa(table); + gmap->asce_end = limit; + return gmap; + +out_free: + kfree(gmap); +out: + return NULL; +} + +/** + * gmap_create - create a guest address space + * @mm: pointer to the parent mm_struct + * @limit: maximum size of the gmap address space + * + * Returns a guest address space structure. + */ +struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit) +{ + struct gmap *gmap; + unsigned long gmap_asce; + + gmap = gmap_alloc(limit); + if (!gmap) + return NULL; + gmap->mm = mm; + spin_lock(&mm->context.lock); + list_add_rcu(&gmap->list, &mm->context.gmap_list); + if (list_is_singular(&mm->context.gmap_list)) + gmap_asce = gmap->asce; + else + gmap_asce = -1UL; + WRITE_ONCE(mm->context.gmap_asce, gmap_asce); + spin_unlock(&mm->context.lock); + return gmap; +} +EXPORT_SYMBOL_GPL(gmap_create); + +static void gmap_flush_tlb(struct gmap *gmap) +{ + if (MACHINE_HAS_IDTE) + __tlb_flush_idte(gmap->asce); + else + __tlb_flush_global(); +} + +static void gmap_radix_tree_free(struct radix_tree_root *root) +{ + struct radix_tree_iter iter; + unsigned long indices[16]; + unsigned long index; + void __rcu **slot; + int i, nr; + + /* A radix tree is freed by deleting all of its entries */ + index = 0; + do { + nr = 0; + radix_tree_for_each_slot(slot, root, &iter, index) { + indices[nr] = iter.index; + if (++nr == 16) + break; + } + for (i = 0; i < nr; i++) { + index = indices[i]; + radix_tree_delete(root, index); + } + } while (nr > 0); +} + +static void gmap_rmap_radix_tree_free(struct radix_tree_root *root) +{ + struct gmap_rmap *rmap, *rnext, *head; + struct radix_tree_iter iter; + unsigned long indices[16]; + unsigned long index; + void __rcu **slot; + int i, nr; + + /* A radix tree is freed by deleting all of its entries */ + index = 0; + do { + nr = 0; + radix_tree_for_each_slot(slot, root, &iter, index) { + indices[nr] = iter.index; + if (++nr == 16) + break; + } + for (i = 0; i < nr; i++) { + index = indices[i]; + head = radix_tree_delete(root, index); + gmap_for_each_rmap_safe(rmap, rnext, head) + kfree(rmap); + } + } while (nr > 0); +} + +/** + * gmap_free - free a guest address space + * @gmap: pointer to the guest address space structure + * + * No locks required. There are no references to this gmap anymore. + */ +static void gmap_free(struct gmap *gmap) +{ + struct page *page, *next; + + /* Flush tlb of all gmaps (if not already done for shadows) */ + if (!(gmap_is_shadow(gmap) && gmap->removed)) + gmap_flush_tlb(gmap); + /* Free all segment & region tables. */ + list_for_each_entry_safe(page, next, &gmap->crst_list, lru) + __free_pages(page, CRST_ALLOC_ORDER); + gmap_radix_tree_free(&gmap->guest_to_host); + gmap_radix_tree_free(&gmap->host_to_guest); + + /* Free additional data for a shadow gmap */ + if (gmap_is_shadow(gmap)) { + /* Free all page tables. */ + list_for_each_entry_safe(page, next, &gmap->pt_list, lru) + page_table_free_pgste(page); + gmap_rmap_radix_tree_free(&gmap->host_to_rmap); + /* Release reference to the parent */ + gmap_put(gmap->parent); + } + + kfree(gmap); +} + +/** + * gmap_get - increase reference counter for guest address space + * @gmap: pointer to the guest address space structure + * + * Returns the gmap pointer + */ +struct gmap *gmap_get(struct gmap *gmap) +{ + refcount_inc(&gmap->ref_count); + return gmap; +} +EXPORT_SYMBOL_GPL(gmap_get); + +/** + * gmap_put - decrease reference counter for guest address space + * @gmap: pointer to the guest address space structure + * + * If the reference counter reaches zero the guest address space is freed. + */ +void gmap_put(struct gmap *gmap) +{ + if (refcount_dec_and_test(&gmap->ref_count)) + gmap_free(gmap); +} +EXPORT_SYMBOL_GPL(gmap_put); + +/** + * gmap_remove - remove a guest address space but do not free it yet + * @gmap: pointer to the guest address space structure + */ +void gmap_remove(struct gmap *gmap) +{ + struct gmap *sg, *next; + unsigned long gmap_asce; + + /* Remove all shadow gmaps linked to this gmap */ + if (!list_empty(&gmap->children)) { + spin_lock(&gmap->shadow_lock); + list_for_each_entry_safe(sg, next, &gmap->children, list) { + list_del(&sg->list); + gmap_put(sg); + } + spin_unlock(&gmap->shadow_lock); + } + /* Remove gmap from the pre-mm list */ + spin_lock(&gmap->mm->context.lock); + list_del_rcu(&gmap->list); + if (list_empty(&gmap->mm->context.gmap_list)) + gmap_asce = 0; + else if (list_is_singular(&gmap->mm->context.gmap_list)) + gmap_asce = list_first_entry(&gmap->mm->context.gmap_list, + struct gmap, list)->asce; + else + gmap_asce = -1UL; + WRITE_ONCE(gmap->mm->context.gmap_asce, gmap_asce); + spin_unlock(&gmap->mm->context.lock); + synchronize_rcu(); + /* Put reference */ + gmap_put(gmap); +} +EXPORT_SYMBOL_GPL(gmap_remove); + +/** + * gmap_enable - switch primary space to the guest address space + * @gmap: pointer to the guest address space structure + */ +void gmap_enable(struct gmap *gmap) +{ + S390_lowcore.gmap = (unsigned long) gmap; +} +EXPORT_SYMBOL_GPL(gmap_enable); + +/** + * gmap_disable - switch back to the standard primary address space + * @gmap: pointer to the guest address space structure + */ +void gmap_disable(struct gmap *gmap) +{ + S390_lowcore.gmap = 0UL; +} +EXPORT_SYMBOL_GPL(gmap_disable); + +/** + * gmap_get_enabled - get a pointer to the currently enabled gmap + * + * Returns a pointer to the currently enabled gmap. 0 if none is enabled. + */ +struct gmap *gmap_get_enabled(void) +{ + return (struct gmap *) S390_lowcore.gmap; +} +EXPORT_SYMBOL_GPL(gmap_get_enabled); + +/* + * gmap_alloc_table is assumed to be called with mmap_lock held + */ +static int gmap_alloc_table(struct gmap *gmap, unsigned long *table, + unsigned long init, unsigned long gaddr) +{ + struct page *page; + unsigned long *new; + + /* since we dont free the gmap table until gmap_free we can unlock */ + page = gmap_alloc_crst(); + if (!page) + return -ENOMEM; + new = page_to_virt(page); + crst_table_init(new, init); + spin_lock(&gmap->guest_table_lock); + if (*table & _REGION_ENTRY_INVALID) { + list_add(&page->lru, &gmap->crst_list); + *table = __pa(new) | _REGION_ENTRY_LENGTH | + (*table & _REGION_ENTRY_TYPE_MASK); + page->index = gaddr; + page = NULL; + } + spin_unlock(&gmap->guest_table_lock); + if (page) + __free_pages(page, CRST_ALLOC_ORDER); + return 0; +} + +/** + * __gmap_segment_gaddr - find virtual address from segment pointer + * @entry: pointer to a segment table entry in the guest address space + * + * Returns the virtual address in the guest address space for the segment + */ +static unsigned long __gmap_segment_gaddr(unsigned long *entry) +{ + struct page *page; + unsigned long offset; + + offset = (unsigned long) entry / sizeof(unsigned long); + offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE; + page = pmd_pgtable_page((pmd_t *) entry); + return page->index + offset; +} + +/** + * __gmap_unlink_by_vmaddr - unlink a single segment via a host address + * @gmap: pointer to the guest address space structure + * @vmaddr: address in the host process address space + * + * Returns 1 if a TLB flush is required + */ +static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr) +{ + unsigned long *entry; + int flush = 0; + + BUG_ON(gmap_is_shadow(gmap)); + spin_lock(&gmap->guest_table_lock); + entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT); + if (entry) { + flush = (*entry != _SEGMENT_ENTRY_EMPTY); + *entry = _SEGMENT_ENTRY_EMPTY; + } + spin_unlock(&gmap->guest_table_lock); + return flush; +} + +/** + * __gmap_unmap_by_gaddr - unmap a single segment via a guest address + * @gmap: pointer to the guest address space structure + * @gaddr: address in the guest address space + * + * Returns 1 if a TLB flush is required + */ +static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr) +{ + unsigned long vmaddr; + + vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host, + gaddr >> PMD_SHIFT); + return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0; +} + +/** + * gmap_unmap_segment - unmap segment from the guest address space + * @gmap: pointer to the guest address space structure + * @to: address in the guest address space + * @len: length of the memory area to unmap + * + * Returns 0 if the unmap succeeded, -EINVAL if not. + */ +int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len) +{ + unsigned long off; + int flush; + + BUG_ON(gmap_is_shadow(gmap)); + if ((to | len) & (PMD_SIZE - 1)) + return -EINVAL; + if (len == 0 || to + len < to) + return -EINVAL; + + flush = 0; + mmap_write_lock(gmap->mm); + for (off = 0; off < len; off += PMD_SIZE) + flush |= __gmap_unmap_by_gaddr(gmap, to + off); + mmap_write_unlock(gmap->mm); + if (flush) + gmap_flush_tlb(gmap); + return 0; +} +EXPORT_SYMBOL_GPL(gmap_unmap_segment); + +/** + * gmap_map_segment - map a segment to the guest address space + * @gmap: pointer to the guest address space structure + * @from: source address in the parent address space + * @to: target address in the guest address space + * @len: length of the memory area to map + * + * Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not. + */ +int gmap_map_segment(struct gmap *gmap, unsigned long from, + unsigned long to, unsigned long len) +{ + unsigned long off; + int flush; + + BUG_ON(gmap_is_shadow(gmap)); + if ((from | to | len) & (PMD_SIZE - 1)) + return -EINVAL; + if (len == 0 || from + len < from || to + len < to || + from + len - 1 > TASK_SIZE_MAX || to + len - 1 > gmap->asce_end) + return -EINVAL; + + flush = 0; + mmap_write_lock(gmap->mm); + for (off = 0; off < len; off += PMD_SIZE) { + /* Remove old translation */ + flush |= __gmap_unmap_by_gaddr(gmap, to + off); + /* Store new translation */ + if (radix_tree_insert(&gmap->guest_to_host, + (to + off) >> PMD_SHIFT, + (void *) from + off)) + break; + } + mmap_write_unlock(gmap->mm); + if (flush) + gmap_flush_tlb(gmap); + if (off >= len) + return 0; + gmap_unmap_segment(gmap, to, len); + return -ENOMEM; +} +EXPORT_SYMBOL_GPL(gmap_map_segment); + +/** + * __gmap_translate - translate a guest address to a user space address + * @gmap: pointer to guest mapping meta data structure + * @gaddr: guest address + * + * Returns user space address which corresponds to the guest address or + * -EFAULT if no such mapping exists. + * This function does not establish potentially missing page table entries. + * The mmap_lock of the mm that belongs to the address space must be held + * when this function gets called. + * + * Note: Can also be called for shadow gmaps. + */ +unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr) +{ + unsigned long vmaddr; + + vmaddr = (unsigned long) + radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT); + /* Note: guest_to_host is empty for a shadow gmap */ + return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT; +} +EXPORT_SYMBOL_GPL(__gmap_translate); + +/** + * gmap_translate - translate a guest address to a user space address + * @gmap: pointer to guest mapping meta data structure + * @gaddr: guest address + * + * Returns user space address which corresponds to the guest address or + * -EFAULT if no such mapping exists. + * This function does not establish potentially missing page table entries. + */ +unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr) +{ + unsigned long rc; + + mmap_read_lock(gmap->mm); + rc = __gmap_translate(gmap, gaddr); + mmap_read_unlock(gmap->mm); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_translate); + +/** + * gmap_unlink - disconnect a page table from the gmap shadow tables + * @mm: pointer to the parent mm_struct + * @table: pointer to the host page table + * @vmaddr: vm address associated with the host page table + */ +void gmap_unlink(struct mm_struct *mm, unsigned long *table, + unsigned long vmaddr) +{ + struct gmap *gmap; + int flush; + + rcu_read_lock(); + list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) { + flush = __gmap_unlink_by_vmaddr(gmap, vmaddr); + if (flush) + gmap_flush_tlb(gmap); + } + rcu_read_unlock(); +} + +static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *old, pmd_t new, + unsigned long gaddr); + +/** + * __gmap_link - set up shadow page tables to connect a host to a guest address + * @gmap: pointer to guest mapping meta data structure + * @gaddr: guest address + * @vmaddr: vm address + * + * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT + * if the vm address is already mapped to a different guest segment. + * The mmap_lock of the mm that belongs to the address space must be held + * when this function gets called. + */ +int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr) +{ + struct mm_struct *mm; + unsigned long *table; + spinlock_t *ptl; + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + u64 unprot; + int rc; + + BUG_ON(gmap_is_shadow(gmap)); + /* Create higher level tables in the gmap page table */ + table = gmap->table; + if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) { + table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT; + if ((*table & _REGION_ENTRY_INVALID) && + gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY, + gaddr & _REGION1_MASK)) + return -ENOMEM; + table = __va(*table & _REGION_ENTRY_ORIGIN); + } + if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) { + table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT; + if ((*table & _REGION_ENTRY_INVALID) && + gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY, + gaddr & _REGION2_MASK)) + return -ENOMEM; + table = __va(*table & _REGION_ENTRY_ORIGIN); + } + if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) { + table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT; + if ((*table & _REGION_ENTRY_INVALID) && + gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY, + gaddr & _REGION3_MASK)) + return -ENOMEM; + table = __va(*table & _REGION_ENTRY_ORIGIN); + } + table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT; + /* Walk the parent mm page table */ + mm = gmap->mm; + pgd = pgd_offset(mm, vmaddr); + VM_BUG_ON(pgd_none(*pgd)); + p4d = p4d_offset(pgd, vmaddr); + VM_BUG_ON(p4d_none(*p4d)); + pud = pud_offset(p4d, vmaddr); + VM_BUG_ON(pud_none(*pud)); + /* large puds cannot yet be handled */ + if (pud_large(*pud)) + return -EFAULT; + 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) + return -EFAULT; + /* Link gmap segment table entry location to page table. */ + rc = radix_tree_preload(GFP_KERNEL_ACCOUNT); + if (rc) + return rc; + ptl = pmd_lock(mm, pmd); + spin_lock(&gmap->guest_table_lock); + if (*table == _SEGMENT_ENTRY_EMPTY) { + rc = radix_tree_insert(&gmap->host_to_guest, + vmaddr >> PMD_SHIFT, table); + if (!rc) { + if (pmd_large(*pmd)) { + *table = (pmd_val(*pmd) & + _SEGMENT_ENTRY_HARDWARE_BITS_LARGE) + | _SEGMENT_ENTRY_GMAP_UC; + } else + *table = pmd_val(*pmd) & + _SEGMENT_ENTRY_HARDWARE_BITS; + } + } else if (*table & _SEGMENT_ENTRY_PROTECT && + !(pmd_val(*pmd) & _SEGMENT_ENTRY_PROTECT)) { + unprot = (u64)*table; + unprot &= ~_SEGMENT_ENTRY_PROTECT; + unprot |= _SEGMENT_ENTRY_GMAP_UC; + gmap_pmdp_xchg(gmap, (pmd_t *)table, __pmd(unprot), gaddr); + } + spin_unlock(&gmap->guest_table_lock); + spin_unlock(ptl); + radix_tree_preload_end(); + return rc; +} + +/** + * gmap_fault - resolve a fault on a guest address + * @gmap: pointer to guest mapping meta data structure + * @gaddr: guest address + * @fault_flags: flags to pass down to handle_mm_fault() + * + * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT + * if the vm address is already mapped to a different guest segment. + */ +int gmap_fault(struct gmap *gmap, unsigned long gaddr, + unsigned int fault_flags) +{ + unsigned long vmaddr; + int rc; + bool unlocked; + + mmap_read_lock(gmap->mm); + +retry: + unlocked = false; + vmaddr = __gmap_translate(gmap, gaddr); + if (IS_ERR_VALUE(vmaddr)) { + rc = vmaddr; + goto out_up; + } + if (fixup_user_fault(gmap->mm, vmaddr, fault_flags, + &unlocked)) { + rc = -EFAULT; + goto out_up; + } + /* + * In the case that fixup_user_fault unlocked the mmap_lock during + * faultin redo __gmap_translate to not race with a map/unmap_segment. + */ + if (unlocked) + goto retry; + + rc = __gmap_link(gmap, gaddr, vmaddr); +out_up: + mmap_read_unlock(gmap->mm); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_fault); + +/* + * this function is assumed to be called with mmap_lock held + */ +void __gmap_zap(struct gmap *gmap, unsigned long gaddr) +{ + struct vm_area_struct *vma; + unsigned long vmaddr; + spinlock_t *ptl; + pte_t *ptep; + + /* Find the vm address for the guest address */ + vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host, + gaddr >> PMD_SHIFT); + if (vmaddr) { + vmaddr |= gaddr & ~PMD_MASK; + + vma = vma_lookup(gmap->mm, vmaddr); + if (!vma || is_vm_hugetlb_page(vma)) + return; + + /* Get pointer to the page table entry */ + ptep = get_locked_pte(gmap->mm, vmaddr, &ptl); + if (likely(ptep)) { + ptep_zap_unused(gmap->mm, vmaddr, ptep, 0); + pte_unmap_unlock(ptep, ptl); + } + } +} +EXPORT_SYMBOL_GPL(__gmap_zap); + +void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to) +{ + unsigned long gaddr, vmaddr, size; + struct vm_area_struct *vma; + + mmap_read_lock(gmap->mm); + for (gaddr = from; gaddr < to; + gaddr = (gaddr + PMD_SIZE) & PMD_MASK) { + /* Find the vm address for the guest address */ + vmaddr = (unsigned long) + radix_tree_lookup(&gmap->guest_to_host, + gaddr >> PMD_SHIFT); + if (!vmaddr) + continue; + vmaddr |= gaddr & ~PMD_MASK; + /* Find vma in the parent mm */ + vma = find_vma(gmap->mm, vmaddr); + if (!vma) + continue; + /* + * We do not discard pages that are backed by + * hugetlbfs, so we don't have to refault them. + */ + if (is_vm_hugetlb_page(vma)) + continue; + size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK)); + zap_page_range_single(vma, vmaddr, size, NULL); + } + mmap_read_unlock(gmap->mm); +} +EXPORT_SYMBOL_GPL(gmap_discard); + +static LIST_HEAD(gmap_notifier_list); +static DEFINE_SPINLOCK(gmap_notifier_lock); + +/** + * gmap_register_pte_notifier - register a pte invalidation callback + * @nb: pointer to the gmap notifier block + */ +void gmap_register_pte_notifier(struct gmap_notifier *nb) +{ + spin_lock(&gmap_notifier_lock); + list_add_rcu(&nb->list, &gmap_notifier_list); + spin_unlock(&gmap_notifier_lock); +} +EXPORT_SYMBOL_GPL(gmap_register_pte_notifier); + +/** + * gmap_unregister_pte_notifier - remove a pte invalidation callback + * @nb: pointer to the gmap notifier block + */ +void gmap_unregister_pte_notifier(struct gmap_notifier *nb) +{ + spin_lock(&gmap_notifier_lock); + list_del_rcu(&nb->list); + spin_unlock(&gmap_notifier_lock); + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier); + +/** + * gmap_call_notifier - call all registered invalidation callbacks + * @gmap: pointer to guest mapping meta data structure + * @start: start virtual address in the guest address space + * @end: end virtual address in the guest address space + */ +static void gmap_call_notifier(struct gmap *gmap, unsigned long start, + unsigned long end) +{ + struct gmap_notifier *nb; + + list_for_each_entry(nb, &gmap_notifier_list, list) + nb->notifier_call(gmap, start, end); +} + +/** + * gmap_table_walk - walk the gmap page tables + * @gmap: pointer to guest mapping meta data structure + * @gaddr: virtual address in the guest address space + * @level: page table level to stop at + * + * Returns a table entry pointer for the given guest address and @level + * @level=0 : returns a pointer to a page table table entry (or NULL) + * @level=1 : returns a pointer to a segment table entry (or NULL) + * @level=2 : returns a pointer to a region-3 table entry (or NULL) + * @level=3 : returns a pointer to a region-2 table entry (or NULL) + * @level=4 : returns a pointer to a region-1 table entry (or NULL) + * + * Returns NULL if the gmap page tables could not be walked to the + * requested level. + * + * Note: Can also be called for shadow gmaps. + */ +static inline unsigned long *gmap_table_walk(struct gmap *gmap, + unsigned long gaddr, int level) +{ + const int asce_type = gmap->asce & _ASCE_TYPE_MASK; + unsigned long *table = gmap->table; + + if (gmap_is_shadow(gmap) && gmap->removed) + return NULL; + + if (WARN_ON_ONCE(level > (asce_type >> 2) + 1)) + return NULL; + + if (asce_type != _ASCE_TYPE_REGION1 && + gaddr & (-1UL << (31 + (asce_type >> 2) * 11))) + return NULL; + + switch (asce_type) { + case _ASCE_TYPE_REGION1: + table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT; + if (level == 4) + break; + if (*table & _REGION_ENTRY_INVALID) + return NULL; + table = __va(*table & _REGION_ENTRY_ORIGIN); + fallthrough; + case _ASCE_TYPE_REGION2: + table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT; + if (level == 3) + break; + if (*table & _REGION_ENTRY_INVALID) + return NULL; + table = __va(*table & _REGION_ENTRY_ORIGIN); + fallthrough; + case _ASCE_TYPE_REGION3: + table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT; + if (level == 2) + break; + if (*table & _REGION_ENTRY_INVALID) + return NULL; + table = __va(*table & _REGION_ENTRY_ORIGIN); + fallthrough; + case _ASCE_TYPE_SEGMENT: + table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT; + if (level == 1) + break; + if (*table & _REGION_ENTRY_INVALID) + return NULL; + table = __va(*table & _SEGMENT_ENTRY_ORIGIN); + table += (gaddr & _PAGE_INDEX) >> _PAGE_SHIFT; + } + return table; +} + +/** + * gmap_pte_op_walk - walk the gmap page table, get the page table lock + * and return the pte pointer + * @gmap: pointer to guest mapping meta data structure + * @gaddr: virtual address in the guest address space + * @ptl: pointer to the spinlock pointer + * + * Returns a pointer to the locked pte for a guest address, or NULL + */ +static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr, + spinlock_t **ptl) +{ + unsigned long *table; + + BUG_ON(gmap_is_shadow(gmap)); + /* Walk the gmap page table, lock and get pte pointer */ + table = gmap_table_walk(gmap, gaddr, 1); /* get segment pointer */ + if (!table || *table & _SEGMENT_ENTRY_INVALID) + return NULL; + return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl); +} + +/** + * gmap_pte_op_fixup - force a page in and connect the gmap page table + * @gmap: pointer to guest mapping meta data structure + * @gaddr: virtual address in the guest address space + * @vmaddr: address in the host process address space + * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE + * + * Returns 0 if the caller can retry __gmap_translate (might fail again), + * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing + * up or connecting the gmap page table. + */ +static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr, + unsigned long vmaddr, int prot) +{ + struct mm_struct *mm = gmap->mm; + unsigned int fault_flags; + bool unlocked = false; + + BUG_ON(gmap_is_shadow(gmap)); + fault_flags = (prot == PROT_WRITE) ? FAULT_FLAG_WRITE : 0; + if (fixup_user_fault(mm, vmaddr, fault_flags, &unlocked)) + return -EFAULT; + if (unlocked) + /* lost mmap_lock, caller has to retry __gmap_translate */ + return 0; + /* Connect the page tables */ + return __gmap_link(gmap, gaddr, vmaddr); +} + +/** + * gmap_pte_op_end - release the page table lock + * @ptep: pointer to the locked pte + * @ptl: pointer to the page table spinlock + */ +static void gmap_pte_op_end(pte_t *ptep, spinlock_t *ptl) +{ + pte_unmap_unlock(ptep, ptl); +} + +/** + * gmap_pmd_op_walk - walk the gmap tables, get the guest table lock + * and return the pmd pointer + * @gmap: pointer to guest mapping meta data structure + * @gaddr: virtual address in the guest address space + * + * Returns a pointer to the pmd for a guest address, or NULL + */ +static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr) +{ + pmd_t *pmdp; + + BUG_ON(gmap_is_shadow(gmap)); + pmdp = (pmd_t *) gmap_table_walk(gmap, gaddr, 1); + if (!pmdp) + return NULL; + + /* without huge pages, there is no need to take the table lock */ + if (!gmap->mm->context.allow_gmap_hpage_1m) + return pmd_none(*pmdp) ? NULL : pmdp; + + spin_lock(&gmap->guest_table_lock); + if (pmd_none(*pmdp)) { + spin_unlock(&gmap->guest_table_lock); + return NULL; + } + + /* 4k page table entries are locked via the pte (pte_alloc_map_lock). */ + if (!pmd_large(*pmdp)) + spin_unlock(&gmap->guest_table_lock); + return pmdp; +} + +/** + * gmap_pmd_op_end - release the guest_table_lock if needed + * @gmap: pointer to the guest mapping meta data structure + * @pmdp: pointer to the pmd + */ +static inline void gmap_pmd_op_end(struct gmap *gmap, pmd_t *pmdp) +{ + if (pmd_large(*pmdp)) + spin_unlock(&gmap->guest_table_lock); +} + +/* + * gmap_protect_pmd - remove access rights to memory and set pmd notification bits + * @pmdp: pointer to the pmd to be protected + * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE + * @bits: notification bits to set + * + * Returns: + * 0 if successfully protected + * -EAGAIN if a fixup is needed + * -EINVAL if unsupported notifier bits have been specified + * + * Expected to be called with sg->mm->mmap_lock in read and + * guest_table_lock held. + */ +static int gmap_protect_pmd(struct gmap *gmap, unsigned long gaddr, + pmd_t *pmdp, int prot, unsigned long bits) +{ + int pmd_i = pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID; + int pmd_p = pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT; + pmd_t new = *pmdp; + + /* Fixup needed */ + if ((pmd_i && (prot != PROT_NONE)) || (pmd_p && (prot == PROT_WRITE))) + return -EAGAIN; + + if (prot == PROT_NONE && !pmd_i) { + new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID)); + gmap_pmdp_xchg(gmap, pmdp, new, gaddr); + } + + if (prot == PROT_READ && !pmd_p) { + new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID)); + new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_PROTECT)); + gmap_pmdp_xchg(gmap, pmdp, new, gaddr); + } + + if (bits & GMAP_NOTIFY_MPROT) + set_pmd(pmdp, set_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN))); + + /* Shadow GMAP protection needs split PMDs */ + if (bits & GMAP_NOTIFY_SHADOW) + return -EINVAL; + + return 0; +} + +/* + * gmap_protect_pte - remove access rights to memory and set pgste bits + * @gmap: pointer to guest mapping meta data structure + * @gaddr: virtual address in the guest address space + * @pmdp: pointer to the pmd associated with the pte + * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE + * @bits: notification bits to set + * + * Returns 0 if successfully protected, -ENOMEM if out of memory and + * -EAGAIN if a fixup is needed. + * + * Expected to be called with sg->mm->mmap_lock in read + */ +static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr, + pmd_t *pmdp, int prot, unsigned long bits) +{ + int rc; + pte_t *ptep; + spinlock_t *ptl; + unsigned long pbits = 0; + + if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID) + return -EAGAIN; + + ptep = pte_alloc_map_lock(gmap->mm, pmdp, gaddr, &ptl); + if (!ptep) + return -ENOMEM; + + pbits |= (bits & GMAP_NOTIFY_MPROT) ? PGSTE_IN_BIT : 0; + pbits |= (bits & GMAP_NOTIFY_SHADOW) ? PGSTE_VSIE_BIT : 0; + /* Protect and unlock. */ + rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits); + gmap_pte_op_end(ptep, ptl); + return rc; +} + +/* + * gmap_protect_range - remove access rights to memory and set pgste bits + * @gmap: pointer to guest mapping meta data structure + * @gaddr: virtual address in the guest address space + * @len: size of area + * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE + * @bits: pgste notification bits to set + * + * Returns 0 if successfully protected, -ENOMEM if out of memory and + * -EFAULT if gaddr is invalid (or mapping for shadows is missing). + * + * Called with sg->mm->mmap_lock in read. + */ +static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr, + unsigned long len, int prot, unsigned long bits) +{ + unsigned long vmaddr, dist; + pmd_t *pmdp; + int rc; + + BUG_ON(gmap_is_shadow(gmap)); + while (len) { + rc = -EAGAIN; + pmdp = gmap_pmd_op_walk(gmap, gaddr); + if (pmdp) { + if (!pmd_large(*pmdp)) { + rc = gmap_protect_pte(gmap, gaddr, pmdp, prot, + bits); + if (!rc) { + len -= PAGE_SIZE; + gaddr += PAGE_SIZE; + } + } else { + rc = gmap_protect_pmd(gmap, gaddr, pmdp, prot, + bits); + if (!rc) { + dist = HPAGE_SIZE - (gaddr & ~HPAGE_MASK); + len = len < dist ? 0 : len - dist; + gaddr = (gaddr & HPAGE_MASK) + HPAGE_SIZE; + } + } + gmap_pmd_op_end(gmap, pmdp); + } + if (rc) { + if (rc == -EINVAL) + return rc; + + /* -EAGAIN, fixup of userspace mm and gmap */ + vmaddr = __gmap_translate(gmap, gaddr); + if (IS_ERR_VALUE(vmaddr)) + return vmaddr; + rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot); + if (rc) + return rc; + } + } + return 0; +} + +/** + * gmap_mprotect_notify - change access rights for a range of ptes and + * call the notifier if any pte changes again + * @gmap: pointer to guest mapping meta data structure + * @gaddr: virtual address in the guest address space + * @len: size of area + * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE + * + * Returns 0 if for each page in the given range a gmap mapping exists, + * the new access rights could be set and the notifier could be armed. + * If the gmap mapping is missing for one or more pages -EFAULT is + * returned. If no memory could be allocated -ENOMEM is returned. + * This function establishes missing page table entries. + */ +int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr, + unsigned long len, int prot) +{ + int rc; + + if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap)) + return -EINVAL; + if (!MACHINE_HAS_ESOP && prot == PROT_READ) + return -EINVAL; + mmap_read_lock(gmap->mm); + rc = gmap_protect_range(gmap, gaddr, len, prot, GMAP_NOTIFY_MPROT); + mmap_read_unlock(gmap->mm); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_mprotect_notify); + +/** + * gmap_read_table - get an unsigned long value from a guest page table using + * absolute addressing, without marking the page referenced. + * @gmap: pointer to guest mapping meta data structure + * @gaddr: virtual address in the guest address space + * @val: pointer to the unsigned long value to return + * + * Returns 0 if the value was read, -ENOMEM if out of memory and -EFAULT + * if reading using the virtual address failed. -EINVAL if called on a gmap + * shadow. + * + * Called with gmap->mm->mmap_lock in read. + */ +int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val) +{ + unsigned long address, vmaddr; + spinlock_t *ptl; + pte_t *ptep, pte; + int rc; + + if (gmap_is_shadow(gmap)) + return -EINVAL; + + while (1) { + rc = -EAGAIN; + ptep = gmap_pte_op_walk(gmap, gaddr, &ptl); + if (ptep) { + pte = *ptep; + if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) { + address = pte_val(pte) & PAGE_MASK; + address += gaddr & ~PAGE_MASK; + *val = *(unsigned long *)__va(address); + set_pte(ptep, set_pte_bit(*ptep, __pgprot(_PAGE_YOUNG))); + /* Do *NOT* clear the _PAGE_INVALID bit! */ + rc = 0; + } + gmap_pte_op_end(ptep, ptl); + } + if (!rc) + break; + vmaddr = __gmap_translate(gmap, gaddr); + if (IS_ERR_VALUE(vmaddr)) { + rc = vmaddr; + break; + } + rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, PROT_READ); + if (rc) + break; + } + return rc; +} +EXPORT_SYMBOL_GPL(gmap_read_table); + +/** + * gmap_insert_rmap - add a rmap to the host_to_rmap radix tree + * @sg: pointer to the shadow guest address space structure + * @vmaddr: vm address associated with the rmap + * @rmap: pointer to the rmap structure + * + * Called with the sg->guest_table_lock + */ +static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr, + struct gmap_rmap *rmap) +{ + struct gmap_rmap *temp; + void __rcu **slot; + + BUG_ON(!gmap_is_shadow(sg)); + slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT); + if (slot) { + rmap->next = radix_tree_deref_slot_protected(slot, + &sg->guest_table_lock); + for (temp = rmap->next; temp; temp = temp->next) { + if (temp->raddr == rmap->raddr) { + kfree(rmap); + return; + } + } + radix_tree_replace_slot(&sg->host_to_rmap, slot, rmap); + } else { + rmap->next = NULL; + radix_tree_insert(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT, + rmap); + } +} + +/** + * gmap_protect_rmap - restrict access rights to memory (RO) and create an rmap + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow gmap + * @paddr: address in the parent guest address space + * @len: length of the memory area to protect + * + * Returns 0 if successfully protected and the rmap was created, -ENOMEM + * if out of memory and -EFAULT if paddr is invalid. + */ +static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr, + unsigned long paddr, unsigned long len) +{ + struct gmap *parent; + struct gmap_rmap *rmap; + unsigned long vmaddr; + spinlock_t *ptl; + pte_t *ptep; + int rc; + + BUG_ON(!gmap_is_shadow(sg)); + parent = sg->parent; + while (len) { + vmaddr = __gmap_translate(parent, paddr); + if (IS_ERR_VALUE(vmaddr)) + return vmaddr; + rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT); + if (!rmap) + return -ENOMEM; + rmap->raddr = raddr; + rc = radix_tree_preload(GFP_KERNEL_ACCOUNT); + if (rc) { + kfree(rmap); + return rc; + } + rc = -EAGAIN; + ptep = gmap_pte_op_walk(parent, paddr, &ptl); + if (ptep) { + spin_lock(&sg->guest_table_lock); + rc = ptep_force_prot(parent->mm, paddr, ptep, PROT_READ, + PGSTE_VSIE_BIT); + if (!rc) + gmap_insert_rmap(sg, vmaddr, rmap); + spin_unlock(&sg->guest_table_lock); + gmap_pte_op_end(ptep, ptl); + } + radix_tree_preload_end(); + if (rc) { + kfree(rmap); + rc = gmap_pte_op_fixup(parent, paddr, vmaddr, PROT_READ); + if (rc) + return rc; + continue; + } + paddr += PAGE_SIZE; + len -= PAGE_SIZE; + } + return 0; +} + +#define _SHADOW_RMAP_MASK 0x7 +#define _SHADOW_RMAP_REGION1 0x5 +#define _SHADOW_RMAP_REGION2 0x4 +#define _SHADOW_RMAP_REGION3 0x3 +#define _SHADOW_RMAP_SEGMENT 0x2 +#define _SHADOW_RMAP_PGTABLE 0x1 + +/** + * gmap_idte_one - invalidate a single region or segment table entry + * @asce: region or segment table *origin* + table-type bits + * @vaddr: virtual address to identify the table entry to flush + * + * The invalid bit of a single region or segment table entry is set + * and the associated TLB entries depending on the entry are flushed. + * The table-type of the @asce identifies the portion of the @vaddr + * that is used as the invalidation index. + */ +static inline void gmap_idte_one(unsigned long asce, unsigned long vaddr) +{ + asm volatile( + " idte %0,0,%1" + : : "a" (asce), "a" (vaddr) : "cc", "memory"); +} + +/** + * gmap_unshadow_page - remove a page from a shadow page table + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow guest address space + * + * Called with the sg->guest_table_lock + */ +static void gmap_unshadow_page(struct gmap *sg, unsigned long raddr) +{ + unsigned long *table; + + BUG_ON(!gmap_is_shadow(sg)); + table = gmap_table_walk(sg, raddr, 0); /* get page table pointer */ + if (!table || *table & _PAGE_INVALID) + return; + gmap_call_notifier(sg, raddr, raddr + _PAGE_SIZE - 1); + ptep_unshadow_pte(sg->mm, raddr, (pte_t *) table); +} + +/** + * __gmap_unshadow_pgt - remove all entries from a shadow page table + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow guest address space + * @pgt: pointer to the start of a shadow page table + * + * Called with the sg->guest_table_lock + */ +static void __gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr, + unsigned long *pgt) +{ + int i; + + BUG_ON(!gmap_is_shadow(sg)); + for (i = 0; i < _PAGE_ENTRIES; i++, raddr += _PAGE_SIZE) + pgt[i] = _PAGE_INVALID; +} + +/** + * gmap_unshadow_pgt - remove a shadow page table from a segment entry + * @sg: pointer to the shadow guest address space structure + * @raddr: address in the shadow guest address space + * + * Called with the sg->guest_table_lock + */ +static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr) +{ + unsigned long *ste; + phys_addr_t sto, pgt; + struct page *page; + + BUG_ON(!gmap_is_shadow(sg)); + ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */ + if (!ste || !(*ste & _SEGMENT_ENTRY_ORIGIN)) + return; + gmap_call_notifier(sg, raddr, raddr + _SEGMENT_SIZE - 1); + sto = __pa(ste - ((raddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT)); + gmap_idte_one(sto | _ASCE_TYPE_SEGMENT, raddr); + pgt = *ste & _SEGMENT_ENTRY_ORIGIN; + *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); +} + +/** + * __gmap_unshadow_sgt - remove all entries from a shadow segment table + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow guest address space + * @sgt: pointer to the start of a shadow segment table + * + * Called with the sg->guest_table_lock + */ +static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr, + unsigned long *sgt) +{ + struct page *page; + phys_addr_t pgt; + int i; + + BUG_ON(!gmap_is_shadow(sg)); + for (i = 0; i < _CRST_ENTRIES; i++, raddr += _SEGMENT_SIZE) { + if (!(sgt[i] & _SEGMENT_ENTRY_ORIGIN)) + continue; + pgt = sgt[i] & _REGION_ENTRY_ORIGIN; + 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); + } +} + +/** + * gmap_unshadow_sgt - remove a shadow segment table from a region-3 entry + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow guest address space + * + * Called with the shadow->guest_table_lock + */ +static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr) +{ + unsigned long r3o, *r3e; + phys_addr_t sgt; + struct page *page; + + BUG_ON(!gmap_is_shadow(sg)); + r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */ + if (!r3e || !(*r3e & _REGION_ENTRY_ORIGIN)) + return; + gmap_call_notifier(sg, raddr, raddr + _REGION3_SIZE - 1); + r3o = (unsigned long) (r3e - ((raddr & _REGION3_INDEX) >> _REGION3_SHIFT)); + gmap_idte_one(__pa(r3o) | _ASCE_TYPE_REGION3, raddr); + sgt = *r3e & _REGION_ENTRY_ORIGIN; + *r3e = _REGION3_ENTRY_EMPTY; + __gmap_unshadow_sgt(sg, raddr, __va(sgt)); + /* Free segment table */ + page = phys_to_page(sgt); + list_del(&page->lru); + __free_pages(page, CRST_ALLOC_ORDER); +} + +/** + * __gmap_unshadow_r3t - remove all entries from a shadow region-3 table + * @sg: pointer to the shadow guest address space structure + * @raddr: address in the shadow guest address space + * @r3t: pointer to the start of a shadow region-3 table + * + * Called with the sg->guest_table_lock + */ +static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr, + unsigned long *r3t) +{ + struct page *page; + phys_addr_t sgt; + int i; + + BUG_ON(!gmap_is_shadow(sg)); + for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION3_SIZE) { + if (!(r3t[i] & _REGION_ENTRY_ORIGIN)) + continue; + sgt = r3t[i] & _REGION_ENTRY_ORIGIN; + r3t[i] = _REGION3_ENTRY_EMPTY; + __gmap_unshadow_sgt(sg, raddr, __va(sgt)); + /* Free segment table */ + page = phys_to_page(sgt); + list_del(&page->lru); + __free_pages(page, CRST_ALLOC_ORDER); + } +} + +/** + * gmap_unshadow_r3t - remove a shadow region-3 table from a region-2 entry + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow guest address space + * + * Called with the sg->guest_table_lock + */ +static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr) +{ + unsigned long r2o, *r2e; + phys_addr_t r3t; + struct page *page; + + BUG_ON(!gmap_is_shadow(sg)); + r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */ + if (!r2e || !(*r2e & _REGION_ENTRY_ORIGIN)) + return; + gmap_call_notifier(sg, raddr, raddr + _REGION2_SIZE - 1); + r2o = (unsigned long) (r2e - ((raddr & _REGION2_INDEX) >> _REGION2_SHIFT)); + gmap_idte_one(__pa(r2o) | _ASCE_TYPE_REGION2, raddr); + r3t = *r2e & _REGION_ENTRY_ORIGIN; + *r2e = _REGION2_ENTRY_EMPTY; + __gmap_unshadow_r3t(sg, raddr, __va(r3t)); + /* Free region 3 table */ + page = phys_to_page(r3t); + list_del(&page->lru); + __free_pages(page, CRST_ALLOC_ORDER); +} + +/** + * __gmap_unshadow_r2t - remove all entries from a shadow region-2 table + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow guest address space + * @r2t: pointer to the start of a shadow region-2 table + * + * Called with the sg->guest_table_lock + */ +static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr, + unsigned long *r2t) +{ + phys_addr_t r3t; + struct page *page; + int i; + + BUG_ON(!gmap_is_shadow(sg)); + for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION2_SIZE) { + if (!(r2t[i] & _REGION_ENTRY_ORIGIN)) + continue; + r3t = r2t[i] & _REGION_ENTRY_ORIGIN; + r2t[i] = _REGION2_ENTRY_EMPTY; + __gmap_unshadow_r3t(sg, raddr, __va(r3t)); + /* Free region 3 table */ + page = phys_to_page(r3t); + list_del(&page->lru); + __free_pages(page, CRST_ALLOC_ORDER); + } +} + +/** + * gmap_unshadow_r2t - remove a shadow region-2 table from a region-1 entry + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow guest address space + * + * Called with the sg->guest_table_lock + */ +static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr) +{ + unsigned long r1o, *r1e; + struct page *page; + phys_addr_t r2t; + + BUG_ON(!gmap_is_shadow(sg)); + r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */ + if (!r1e || !(*r1e & _REGION_ENTRY_ORIGIN)) + return; + gmap_call_notifier(sg, raddr, raddr + _REGION1_SIZE - 1); + r1o = (unsigned long) (r1e - ((raddr & _REGION1_INDEX) >> _REGION1_SHIFT)); + gmap_idte_one(__pa(r1o) | _ASCE_TYPE_REGION1, raddr); + r2t = *r1e & _REGION_ENTRY_ORIGIN; + *r1e = _REGION1_ENTRY_EMPTY; + __gmap_unshadow_r2t(sg, raddr, __va(r2t)); + /* Free region 2 table */ + page = phys_to_page(r2t); + list_del(&page->lru); + __free_pages(page, CRST_ALLOC_ORDER); +} + +/** + * __gmap_unshadow_r1t - remove all entries from a shadow region-1 table + * @sg: pointer to the shadow guest address space structure + * @raddr: rmap address in the shadow guest address space + * @r1t: pointer to the start of a shadow region-1 table + * + * Called with the shadow->guest_table_lock + */ +static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr, + unsigned long *r1t) +{ + unsigned long asce; + struct page *page; + phys_addr_t r2t; + int i; + + BUG_ON(!gmap_is_shadow(sg)); + asce = __pa(r1t) | _ASCE_TYPE_REGION1; + for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION1_SIZE) { + if (!(r1t[i] & _REGION_ENTRY_ORIGIN)) + continue; + r2t = r1t[i] & _REGION_ENTRY_ORIGIN; + __gmap_unshadow_r2t(sg, raddr, __va(r2t)); + /* Clear entry and flush translation r1t -> r2t */ + gmap_idte_one(asce, raddr); + r1t[i] = _REGION1_ENTRY_EMPTY; + /* Free region 2 table */ + page = phys_to_page(r2t); + list_del(&page->lru); + __free_pages(page, CRST_ALLOC_ORDER); + } +} + +/** + * gmap_unshadow - remove a shadow page table completely + * @sg: pointer to the shadow guest address space structure + * + * Called with sg->guest_table_lock + */ +static void gmap_unshadow(struct gmap *sg) +{ + unsigned long *table; + + BUG_ON(!gmap_is_shadow(sg)); + if (sg->removed) + return; + sg->removed = 1; + gmap_call_notifier(sg, 0, -1UL); + gmap_flush_tlb(sg); + table = __va(sg->asce & _ASCE_ORIGIN); + switch (sg->asce & _ASCE_TYPE_MASK) { + case _ASCE_TYPE_REGION1: + __gmap_unshadow_r1t(sg, 0, table); + break; + case _ASCE_TYPE_REGION2: + __gmap_unshadow_r2t(sg, 0, table); + break; + case _ASCE_TYPE_REGION3: + __gmap_unshadow_r3t(sg, 0, table); + break; + case _ASCE_TYPE_SEGMENT: + __gmap_unshadow_sgt(sg, 0, table); + break; + } +} + +/** + * gmap_find_shadow - find a specific asce in the list of shadow tables + * @parent: pointer to the parent gmap + * @asce: ASCE for which the shadow table is created + * @edat_level: edat level to be used for the shadow translation + * + * Returns the pointer to a gmap if a shadow table with the given asce is + * already available, ERR_PTR(-EAGAIN) if another one is just being created, + * otherwise NULL + */ +static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce, + int edat_level) +{ + struct gmap *sg; + + list_for_each_entry(sg, &parent->children, list) { + if (sg->orig_asce != asce || sg->edat_level != edat_level || + sg->removed) + continue; + if (!sg->initialized) + return ERR_PTR(-EAGAIN); + refcount_inc(&sg->ref_count); + return sg; + } + return NULL; +} + +/** + * gmap_shadow_valid - check if a shadow guest address space matches the + * given properties and is still valid + * @sg: pointer to the shadow guest address space structure + * @asce: ASCE for which the shadow table is requested + * @edat_level: edat level to be used for the shadow translation + * + * Returns 1 if the gmap shadow is still valid and matches the given + * properties, the caller can continue using it. Returns 0 otherwise, the + * caller has to request a new shadow gmap in this case. + * + */ +int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level) +{ + if (sg->removed) + return 0; + return sg->orig_asce == asce && sg->edat_level == edat_level; +} +EXPORT_SYMBOL_GPL(gmap_shadow_valid); + +/** + * gmap_shadow - create/find a shadow guest address space + * @parent: pointer to the parent gmap + * @asce: ASCE for which the shadow table is created + * @edat_level: edat level to be used for the shadow translation + * + * The pages of the top level page table referred by the asce parameter + * will be set to read-only and marked in the PGSTEs of the kvm process. + * The shadow table will be removed automatically on any change to the + * PTE mapping for the source table. + * + * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory, + * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the + * parent gmap table could not be protected. + */ +struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, + int edat_level) +{ + struct gmap *sg, *new; + unsigned long limit; + int rc; + + BUG_ON(parent->mm->context.allow_gmap_hpage_1m); + BUG_ON(gmap_is_shadow(parent)); + spin_lock(&parent->shadow_lock); + sg = gmap_find_shadow(parent, asce, edat_level); + spin_unlock(&parent->shadow_lock); + if (sg) + return sg; + /* Create a new shadow gmap */ + limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11)); + if (asce & _ASCE_REAL_SPACE) + limit = -1UL; + new = gmap_alloc(limit); + if (!new) + return ERR_PTR(-ENOMEM); + new->mm = parent->mm; + new->parent = gmap_get(parent); + new->orig_asce = asce; + new->edat_level = edat_level; + new->initialized = false; + spin_lock(&parent->shadow_lock); + /* Recheck if another CPU created the same shadow */ + sg = gmap_find_shadow(parent, asce, edat_level); + if (sg) { + spin_unlock(&parent->shadow_lock); + gmap_free(new); + return sg; + } + if (asce & _ASCE_REAL_SPACE) { + /* only allow one real-space gmap shadow */ + list_for_each_entry(sg, &parent->children, list) { + if (sg->orig_asce & _ASCE_REAL_SPACE) { + spin_lock(&sg->guest_table_lock); + gmap_unshadow(sg); + spin_unlock(&sg->guest_table_lock); + list_del(&sg->list); + gmap_put(sg); + break; + } + } + } + refcount_set(&new->ref_count, 2); + list_add(&new->list, &parent->children); + if (asce & _ASCE_REAL_SPACE) { + /* nothing to protect, return right away */ + new->initialized = true; + spin_unlock(&parent->shadow_lock); + return new; + } + spin_unlock(&parent->shadow_lock); + /* protect after insertion, so it will get properly invalidated */ + mmap_read_lock(parent->mm); + rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN, + ((asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE, + PROT_READ, GMAP_NOTIFY_SHADOW); + mmap_read_unlock(parent->mm); + spin_lock(&parent->shadow_lock); + new->initialized = true; + if (rc) { + list_del(&new->list); + gmap_free(new); + new = ERR_PTR(rc); + } + spin_unlock(&parent->shadow_lock); + return new; +} +EXPORT_SYMBOL_GPL(gmap_shadow); + +/** + * gmap_shadow_r2t - create an empty shadow region 2 table + * @sg: pointer to the shadow guest address space structure + * @saddr: faulting address in the shadow gmap + * @r2t: parent gmap address of the region 2 table to get shadowed + * @fake: r2t references contiguous guest memory block, not a r2t + * + * The r2t parameter specifies the address of the source table. The + * four pages of the source table are made read-only in the parent gmap + * address space. A write to the source table area @r2t will automatically + * remove the shadow r2 table and all of its descendants. + * + * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the + * shadow table structure is incomplete, -ENOMEM if out of memory and + * -EFAULT if an address in the parent gmap could not be resolved. + * + * Called with sg->mm->mmap_lock in read. + */ +int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t, + int fake) +{ + unsigned long raddr, origin, offset, len; + unsigned long *table; + phys_addr_t s_r2t; + struct page *page; + int rc; + + BUG_ON(!gmap_is_shadow(sg)); + /* Allocate a shadow region second table */ + page = gmap_alloc_crst(); + if (!page) + return -ENOMEM; + page->index = r2t & _REGION_ENTRY_ORIGIN; + if (fake) + page->index |= GMAP_SHADOW_FAKE_TABLE; + s_r2t = page_to_phys(page); + /* Install shadow region second table */ + spin_lock(&sg->guest_table_lock); + table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */ + if (!table) { + rc = -EAGAIN; /* Race with unshadow */ + goto out_free; + } + if (!(*table & _REGION_ENTRY_INVALID)) { + rc = 0; /* Already established */ + goto out_free; + } else if (*table & _REGION_ENTRY_ORIGIN) { + rc = -EAGAIN; /* Race with shadow */ + goto out_free; + } + crst_table_init(__va(s_r2t), _REGION2_ENTRY_EMPTY); + /* mark as invalid as long as the parent table is not protected */ + *table = s_r2t | _REGION_ENTRY_LENGTH | + _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID; + if (sg->edat_level >= 1) + *table |= (r2t & _REGION_ENTRY_PROTECT); + list_add(&page->lru, &sg->crst_list); + if (fake) { + /* nothing to protect for fake tables */ + *table &= ~_REGION_ENTRY_INVALID; + spin_unlock(&sg->guest_table_lock); + return 0; + } + spin_unlock(&sg->guest_table_lock); + /* Make r2t read-only in parent gmap page table */ + raddr = (saddr & _REGION1_MASK) | _SHADOW_RMAP_REGION1; + origin = r2t & _REGION_ENTRY_ORIGIN; + offset = ((r2t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE; + len = ((r2t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset; + rc = gmap_protect_rmap(sg, raddr, origin + offset, len); + spin_lock(&sg->guest_table_lock); + if (!rc) { + table = gmap_table_walk(sg, saddr, 4); + if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r2t) + rc = -EAGAIN; /* Race with unshadow */ + else + *table &= ~_REGION_ENTRY_INVALID; + } else { + gmap_unshadow_r2t(sg, raddr); + } + spin_unlock(&sg->guest_table_lock); + return rc; +out_free: + spin_unlock(&sg->guest_table_lock); + __free_pages(page, CRST_ALLOC_ORDER); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_shadow_r2t); + +/** + * gmap_shadow_r3t - create a shadow region 3 table + * @sg: pointer to the shadow guest address space structure + * @saddr: faulting address in the shadow gmap + * @r3t: parent gmap address of the region 3 table to get shadowed + * @fake: r3t references contiguous guest memory block, not a r3t + * + * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the + * shadow table structure is incomplete, -ENOMEM if out of memory and + * -EFAULT if an address in the parent gmap could not be resolved. + * + * Called with sg->mm->mmap_lock in read. + */ +int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t, + int fake) +{ + unsigned long raddr, origin, offset, len; + unsigned long *table; + phys_addr_t s_r3t; + struct page *page; + int rc; + + BUG_ON(!gmap_is_shadow(sg)); + /* Allocate a shadow region second table */ + page = gmap_alloc_crst(); + if (!page) + return -ENOMEM; + page->index = r3t & _REGION_ENTRY_ORIGIN; + if (fake) + page->index |= GMAP_SHADOW_FAKE_TABLE; + s_r3t = page_to_phys(page); + /* Install shadow region second table */ + spin_lock(&sg->guest_table_lock); + table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */ + if (!table) { + rc = -EAGAIN; /* Race with unshadow */ + goto out_free; + } + if (!(*table & _REGION_ENTRY_INVALID)) { + rc = 0; /* Already established */ + goto out_free; + } else if (*table & _REGION_ENTRY_ORIGIN) { + rc = -EAGAIN; /* Race with shadow */ + goto out_free; + } + crst_table_init(__va(s_r3t), _REGION3_ENTRY_EMPTY); + /* mark as invalid as long as the parent table is not protected */ + *table = s_r3t | _REGION_ENTRY_LENGTH | + _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID; + if (sg->edat_level >= 1) + *table |= (r3t & _REGION_ENTRY_PROTECT); + list_add(&page->lru, &sg->crst_list); + if (fake) { + /* nothing to protect for fake tables */ + *table &= ~_REGION_ENTRY_INVALID; + spin_unlock(&sg->guest_table_lock); + return 0; + } + spin_unlock(&sg->guest_table_lock); + /* Make r3t read-only in parent gmap page table */ + raddr = (saddr & _REGION2_MASK) | _SHADOW_RMAP_REGION2; + origin = r3t & _REGION_ENTRY_ORIGIN; + offset = ((r3t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE; + len = ((r3t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset; + rc = gmap_protect_rmap(sg, raddr, origin + offset, len); + spin_lock(&sg->guest_table_lock); + if (!rc) { + table = gmap_table_walk(sg, saddr, 3); + if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r3t) + rc = -EAGAIN; /* Race with unshadow */ + else + *table &= ~_REGION_ENTRY_INVALID; + } else { + gmap_unshadow_r3t(sg, raddr); + } + spin_unlock(&sg->guest_table_lock); + return rc; +out_free: + spin_unlock(&sg->guest_table_lock); + __free_pages(page, CRST_ALLOC_ORDER); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_shadow_r3t); + +/** + * gmap_shadow_sgt - create a shadow segment table + * @sg: pointer to the shadow guest address space structure + * @saddr: faulting address in the shadow gmap + * @sgt: parent gmap address of the segment table to get shadowed + * @fake: sgt references contiguous guest memory block, not a sgt + * + * Returns: 0 if successfully shadowed or already shadowed, -EAGAIN if the + * shadow table structure is incomplete, -ENOMEM if out of memory and + * -EFAULT if an address in the parent gmap could not be resolved. + * + * Called with sg->mm->mmap_lock in read. + */ +int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt, + int fake) +{ + unsigned long raddr, origin, offset, len; + unsigned long *table; + phys_addr_t s_sgt; + struct page *page; + int rc; + + BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE)); + /* Allocate a shadow segment table */ + page = gmap_alloc_crst(); + if (!page) + return -ENOMEM; + page->index = sgt & _REGION_ENTRY_ORIGIN; + if (fake) + page->index |= GMAP_SHADOW_FAKE_TABLE; + s_sgt = page_to_phys(page); + /* Install shadow region second table */ + spin_lock(&sg->guest_table_lock); + table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */ + if (!table) { + rc = -EAGAIN; /* Race with unshadow */ + goto out_free; + } + if (!(*table & _REGION_ENTRY_INVALID)) { + rc = 0; /* Already established */ + goto out_free; + } else if (*table & _REGION_ENTRY_ORIGIN) { + rc = -EAGAIN; /* Race with shadow */ + goto out_free; + } + crst_table_init(__va(s_sgt), _SEGMENT_ENTRY_EMPTY); + /* mark as invalid as long as the parent table is not protected */ + *table = s_sgt | _REGION_ENTRY_LENGTH | + _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID; + if (sg->edat_level >= 1) + *table |= sgt & _REGION_ENTRY_PROTECT; + list_add(&page->lru, &sg->crst_list); + if (fake) { + /* nothing to protect for fake tables */ + *table &= ~_REGION_ENTRY_INVALID; + spin_unlock(&sg->guest_table_lock); + return 0; + } + spin_unlock(&sg->guest_table_lock); + /* Make sgt read-only in parent gmap page table */ + raddr = (saddr & _REGION3_MASK) | _SHADOW_RMAP_REGION3; + origin = sgt & _REGION_ENTRY_ORIGIN; + offset = ((sgt & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE; + len = ((sgt & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset; + rc = gmap_protect_rmap(sg, raddr, origin + offset, len); + spin_lock(&sg->guest_table_lock); + if (!rc) { + table = gmap_table_walk(sg, saddr, 2); + if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_sgt) + rc = -EAGAIN; /* Race with unshadow */ + else + *table &= ~_REGION_ENTRY_INVALID; + } else { + gmap_unshadow_sgt(sg, raddr); + } + spin_unlock(&sg->guest_table_lock); + return rc; +out_free: + spin_unlock(&sg->guest_table_lock); + __free_pages(page, CRST_ALLOC_ORDER); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_shadow_sgt); + +/** + * gmap_shadow_pgt_lookup - find a shadow page table + * @sg: pointer to the shadow guest address space structure + * @saddr: the address in the shadow aguest address space + * @pgt: parent gmap address of the page table to get shadowed + * @dat_protection: if the pgtable is marked as protected by dat + * @fake: pgt references contiguous guest memory block, not a pgtable + * + * Returns 0 if the shadow page table was found and -EAGAIN if the page + * table was not found. + * + * Called with sg->mm->mmap_lock in read. + */ +int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr, + unsigned long *pgt, int *dat_protection, + int *fake) +{ + unsigned long *table; + struct page *page; + int rc; + + BUG_ON(!gmap_is_shadow(sg)); + spin_lock(&sg->guest_table_lock); + table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */ + if (table && !(*table & _SEGMENT_ENTRY_INVALID)) { + /* Shadow page tables are full pages (pte+pgste) */ + page = pfn_to_page(*table >> PAGE_SHIFT); + *pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE; + *dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT); + *fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE); + rc = 0; + } else { + rc = -EAGAIN; + } + spin_unlock(&sg->guest_table_lock); + return rc; + +} +EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup); + +/** + * gmap_shadow_pgt - instantiate a shadow page table + * @sg: pointer to the shadow guest address space structure + * @saddr: faulting address in the shadow gmap + * @pgt: parent gmap address of the page table to get shadowed + * @fake: pgt references contiguous guest memory block, not a pgtable + * + * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the + * shadow table structure is incomplete, -ENOMEM if out of memory, + * -EFAULT if an address in the parent gmap could not be resolved and + * + * Called with gmap->mm->mmap_lock in read + */ +int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt, + int fake) +{ + unsigned long raddr, origin; + unsigned long *table; + struct page *page; + 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) + return -ENOMEM; + page->index = pgt & _SEGMENT_ENTRY_ORIGIN; + if (fake) + page->index |= GMAP_SHADOW_FAKE_TABLE; + s_pgt = page_to_phys(page); + /* Install shadow page table */ + spin_lock(&sg->guest_table_lock); + table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */ + if (!table) { + rc = -EAGAIN; /* Race with unshadow */ + goto out_free; + } + if (!(*table & _SEGMENT_ENTRY_INVALID)) { + rc = 0; /* Already established */ + goto out_free; + } else if (*table & _SEGMENT_ENTRY_ORIGIN) { + rc = -EAGAIN; /* Race with shadow */ + goto out_free; + } + /* 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); + if (fake) { + /* nothing to protect for fake tables */ + *table &= ~_SEGMENT_ENTRY_INVALID; + spin_unlock(&sg->guest_table_lock); + return 0; + } + spin_unlock(&sg->guest_table_lock); + /* Make pgt read-only in parent gmap page table (not the pgste) */ + raddr = (saddr & _SEGMENT_MASK) | _SHADOW_RMAP_SEGMENT; + origin = pgt & _SEGMENT_ENTRY_ORIGIN & PAGE_MASK; + rc = gmap_protect_rmap(sg, raddr, origin, PAGE_SIZE); + spin_lock(&sg->guest_table_lock); + if (!rc) { + table = gmap_table_walk(sg, saddr, 1); + if (!table || (*table & _SEGMENT_ENTRY_ORIGIN) != s_pgt) + rc = -EAGAIN; /* Race with unshadow */ + else + *table &= ~_SEGMENT_ENTRY_INVALID; + } else { + gmap_unshadow_pgt(sg, raddr); + } + spin_unlock(&sg->guest_table_lock); + return rc; +out_free: + spin_unlock(&sg->guest_table_lock); + page_table_free_pgste(page); + return rc; + +} +EXPORT_SYMBOL_GPL(gmap_shadow_pgt); + +/** + * gmap_shadow_page - create a shadow page mapping + * @sg: pointer to the shadow guest address space structure + * @saddr: faulting address in the shadow gmap + * @pte: pte in parent gmap address space to get shadowed + * + * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the + * shadow table structure is incomplete, -ENOMEM if out of memory and + * -EFAULT if an address in the parent gmap could not be resolved. + * + * Called with sg->mm->mmap_lock in read. + */ +int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte) +{ + struct gmap *parent; + struct gmap_rmap *rmap; + unsigned long vmaddr, paddr; + spinlock_t *ptl; + pte_t *sptep, *tptep; + int prot; + int rc; + + BUG_ON(!gmap_is_shadow(sg)); + parent = sg->parent; + prot = (pte_val(pte) & _PAGE_PROTECT) ? PROT_READ : PROT_WRITE; + + rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT); + if (!rmap) + return -ENOMEM; + rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE; + + while (1) { + paddr = pte_val(pte) & PAGE_MASK; + vmaddr = __gmap_translate(parent, paddr); + if (IS_ERR_VALUE(vmaddr)) { + rc = vmaddr; + break; + } + rc = radix_tree_preload(GFP_KERNEL_ACCOUNT); + if (rc) + break; + rc = -EAGAIN; + sptep = gmap_pte_op_walk(parent, paddr, &ptl); + if (sptep) { + spin_lock(&sg->guest_table_lock); + /* Get page table pointer */ + tptep = (pte_t *) gmap_table_walk(sg, saddr, 0); + if (!tptep) { + spin_unlock(&sg->guest_table_lock); + gmap_pte_op_end(sptep, ptl); + radix_tree_preload_end(); + break; + } + rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte); + if (rc > 0) { + /* Success and a new mapping */ + gmap_insert_rmap(sg, vmaddr, rmap); + rmap = NULL; + rc = 0; + } + gmap_pte_op_end(sptep, ptl); + spin_unlock(&sg->guest_table_lock); + } + radix_tree_preload_end(); + if (!rc) + break; + rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot); + if (rc) + break; + } + kfree(rmap); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_shadow_page); + +/* + * gmap_shadow_notify - handle notifications for shadow gmap + * + * Called with sg->parent->shadow_lock. + */ +static void gmap_shadow_notify(struct gmap *sg, unsigned long vmaddr, + unsigned long gaddr) +{ + struct gmap_rmap *rmap, *rnext, *head; + unsigned long start, end, bits, raddr; + + BUG_ON(!gmap_is_shadow(sg)); + + spin_lock(&sg->guest_table_lock); + if (sg->removed) { + spin_unlock(&sg->guest_table_lock); + return; + } + /* Check for top level table */ + start = sg->orig_asce & _ASCE_ORIGIN; + end = start + ((sg->orig_asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE; + if (!(sg->orig_asce & _ASCE_REAL_SPACE) && gaddr >= start && + gaddr < end) { + /* The complete shadow table has to go */ + gmap_unshadow(sg); + spin_unlock(&sg->guest_table_lock); + list_del(&sg->list); + gmap_put(sg); + return; + } + /* Remove the page table tree from on specific entry */ + head = radix_tree_delete(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT); + gmap_for_each_rmap_safe(rmap, rnext, head) { + bits = rmap->raddr & _SHADOW_RMAP_MASK; + raddr = rmap->raddr ^ bits; + switch (bits) { + case _SHADOW_RMAP_REGION1: + gmap_unshadow_r2t(sg, raddr); + break; + case _SHADOW_RMAP_REGION2: + gmap_unshadow_r3t(sg, raddr); + break; + case _SHADOW_RMAP_REGION3: + gmap_unshadow_sgt(sg, raddr); + break; + case _SHADOW_RMAP_SEGMENT: + gmap_unshadow_pgt(sg, raddr); + break; + case _SHADOW_RMAP_PGTABLE: + gmap_unshadow_page(sg, raddr); + break; + } + kfree(rmap); + } + spin_unlock(&sg->guest_table_lock); +} + +/** + * ptep_notify - call all invalidation callbacks for a specific pte. + * @mm: pointer to the process mm_struct + * @vmaddr: virtual address in the process address space + * @pte: pointer to the page table entry + * @bits: bits from the pgste that caused the notify call + * + * This function is assumed to be called with the page table lock held + * for the pte to notify. + */ +void ptep_notify(struct mm_struct *mm, unsigned long vmaddr, + pte_t *pte, unsigned long bits) +{ + unsigned long offset, gaddr = 0; + unsigned long *table; + struct gmap *gmap, *sg, *next; + + offset = ((unsigned long) pte) & (255 * sizeof(pte_t)); + offset = offset * (PAGE_SIZE / sizeof(pte_t)); + rcu_read_lock(); + list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) { + spin_lock(&gmap->guest_table_lock); + table = radix_tree_lookup(&gmap->host_to_guest, + vmaddr >> PMD_SHIFT); + if (table) + gaddr = __gmap_segment_gaddr(table) + offset; + spin_unlock(&gmap->guest_table_lock); + if (!table) + continue; + + if (!list_empty(&gmap->children) && (bits & PGSTE_VSIE_BIT)) { + spin_lock(&gmap->shadow_lock); + list_for_each_entry_safe(sg, next, + &gmap->children, list) + gmap_shadow_notify(sg, vmaddr, gaddr); + spin_unlock(&gmap->shadow_lock); + } + if (bits & PGSTE_IN_BIT) + gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1); + } + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(ptep_notify); + +static void pmdp_notify_gmap(struct gmap *gmap, pmd_t *pmdp, + unsigned long gaddr) +{ + set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN))); + gmap_call_notifier(gmap, gaddr, gaddr + HPAGE_SIZE - 1); +} + +/** + * gmap_pmdp_xchg - exchange a gmap pmd with another + * @gmap: pointer to the guest address space structure + * @pmdp: pointer to the pmd entry + * @new: replacement entry + * @gaddr: the affected guest address + * + * This function is assumed to be called with the guest_table_lock + * held. + */ +static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *pmdp, pmd_t new, + unsigned long gaddr) +{ + gaddr &= HPAGE_MASK; + pmdp_notify_gmap(gmap, pmdp, gaddr); + new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_GMAP_IN)); + if (MACHINE_HAS_TLB_GUEST) + __pmdp_idte(gaddr, (pmd_t *)pmdp, IDTE_GUEST_ASCE, gmap->asce, + IDTE_GLOBAL); + else if (MACHINE_HAS_IDTE) + __pmdp_idte(gaddr, (pmd_t *)pmdp, 0, 0, IDTE_GLOBAL); + else + __pmdp_csp(pmdp); + set_pmd(pmdp, new); +} + +static void gmap_pmdp_clear(struct mm_struct *mm, unsigned long vmaddr, + int purge) +{ + pmd_t *pmdp; + struct gmap *gmap; + unsigned long gaddr; + + rcu_read_lock(); + list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) { + spin_lock(&gmap->guest_table_lock); + pmdp = (pmd_t *)radix_tree_delete(&gmap->host_to_guest, + vmaddr >> PMD_SHIFT); + if (pmdp) { + gaddr = __gmap_segment_gaddr((unsigned long *)pmdp); + pmdp_notify_gmap(gmap, pmdp, gaddr); + WARN_ON(pmd_val(*pmdp) & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE | + _SEGMENT_ENTRY_GMAP_UC)); + if (purge) + __pmdp_csp(pmdp); + set_pmd(pmdp, __pmd(_SEGMENT_ENTRY_EMPTY)); + } + spin_unlock(&gmap->guest_table_lock); + } + rcu_read_unlock(); +} + +/** + * gmap_pmdp_invalidate - invalidate all affected guest pmd entries without + * flushing + * @mm: pointer to the process mm_struct + * @vmaddr: virtual address in the process address space + */ +void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr) +{ + gmap_pmdp_clear(mm, vmaddr, 0); +} +EXPORT_SYMBOL_GPL(gmap_pmdp_invalidate); + +/** + * gmap_pmdp_csp - csp all affected guest pmd entries + * @mm: pointer to the process mm_struct + * @vmaddr: virtual address in the process address space + */ +void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr) +{ + gmap_pmdp_clear(mm, vmaddr, 1); +} +EXPORT_SYMBOL_GPL(gmap_pmdp_csp); + +/** + * gmap_pmdp_idte_local - invalidate and clear a guest pmd entry + * @mm: pointer to the process mm_struct + * @vmaddr: virtual address in the process address space + */ +void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr) +{ + unsigned long *entry, gaddr; + struct gmap *gmap; + pmd_t *pmdp; + + rcu_read_lock(); + list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) { + spin_lock(&gmap->guest_table_lock); + entry = radix_tree_delete(&gmap->host_to_guest, + vmaddr >> PMD_SHIFT); + if (entry) { + pmdp = (pmd_t *)entry; + gaddr = __gmap_segment_gaddr(entry); + pmdp_notify_gmap(gmap, pmdp, gaddr); + WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE | + _SEGMENT_ENTRY_GMAP_UC)); + if (MACHINE_HAS_TLB_GUEST) + __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE, + gmap->asce, IDTE_LOCAL); + else if (MACHINE_HAS_IDTE) + __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_LOCAL); + *entry = _SEGMENT_ENTRY_EMPTY; + } + spin_unlock(&gmap->guest_table_lock); + } + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(gmap_pmdp_idte_local); + +/** + * gmap_pmdp_idte_global - invalidate and clear a guest pmd entry + * @mm: pointer to the process mm_struct + * @vmaddr: virtual address in the process address space + */ +void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr) +{ + unsigned long *entry, gaddr; + struct gmap *gmap; + pmd_t *pmdp; + + rcu_read_lock(); + list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) { + spin_lock(&gmap->guest_table_lock); + entry = radix_tree_delete(&gmap->host_to_guest, + vmaddr >> PMD_SHIFT); + if (entry) { + pmdp = (pmd_t *)entry; + gaddr = __gmap_segment_gaddr(entry); + pmdp_notify_gmap(gmap, pmdp, gaddr); + WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE | + _SEGMENT_ENTRY_GMAP_UC)); + if (MACHINE_HAS_TLB_GUEST) + __pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE, + gmap->asce, IDTE_GLOBAL); + else if (MACHINE_HAS_IDTE) + __pmdp_idte(gaddr, pmdp, 0, 0, IDTE_GLOBAL); + else + __pmdp_csp(pmdp); + *entry = _SEGMENT_ENTRY_EMPTY; + } + spin_unlock(&gmap->guest_table_lock); + } + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(gmap_pmdp_idte_global); + +/** + * gmap_test_and_clear_dirty_pmd - test and reset segment dirty status + * @gmap: pointer to guest address space + * @pmdp: pointer to the pmd to be tested + * @gaddr: virtual address in the guest address space + * + * This function is assumed to be called with the guest_table_lock + * held. + */ +static bool gmap_test_and_clear_dirty_pmd(struct gmap *gmap, pmd_t *pmdp, + unsigned long gaddr) +{ + if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID) + return false; + + /* Already protected memory, which did not change is clean */ + if (pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT && + !(pmd_val(*pmdp) & _SEGMENT_ENTRY_GMAP_UC)) + return false; + + /* Clear UC indication and reset protection */ + set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_UC))); + gmap_protect_pmd(gmap, gaddr, pmdp, PROT_READ, 0); + return true; +} + +/** + * gmap_sync_dirty_log_pmd - set bitmap based on dirty status of segment + * @gmap: pointer to guest address space + * @bitmap: dirty bitmap for this pmd + * @gaddr: virtual address in the guest address space + * @vmaddr: virtual address in the host address space + * + * This function is assumed to be called with the guest_table_lock + * held. + */ +void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long bitmap[4], + unsigned long gaddr, unsigned long vmaddr) +{ + int i; + pmd_t *pmdp; + pte_t *ptep; + spinlock_t *ptl; + + pmdp = gmap_pmd_op_walk(gmap, gaddr); + if (!pmdp) + return; + + if (pmd_large(*pmdp)) { + if (gmap_test_and_clear_dirty_pmd(gmap, pmdp, gaddr)) + bitmap_fill(bitmap, _PAGE_ENTRIES); + } else { + for (i = 0; i < _PAGE_ENTRIES; i++, vmaddr += PAGE_SIZE) { + ptep = pte_alloc_map_lock(gmap->mm, pmdp, vmaddr, &ptl); + if (!ptep) + continue; + if (ptep_test_and_clear_uc(gmap->mm, vmaddr, ptep)) + set_bit(i, bitmap); + pte_unmap_unlock(ptep, ptl); + } + } + gmap_pmd_op_end(gmap, pmdp); +} +EXPORT_SYMBOL_GPL(gmap_sync_dirty_log_pmd); + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static int thp_split_walk_pmd_entry(pmd_t *pmd, unsigned long addr, + unsigned long end, struct mm_walk *walk) +{ + struct vm_area_struct *vma = walk->vma; + + split_huge_pmd(vma, pmd, addr); + return 0; +} + +static const struct mm_walk_ops thp_split_walk_ops = { + .pmd_entry = thp_split_walk_pmd_entry, + .walk_lock = PGWALK_WRLOCK_VERIFY, +}; + +static inline void thp_split_mm(struct mm_struct *mm) +{ + struct vm_area_struct *vma; + VMA_ITERATOR(vmi, mm, 0); + + for_each_vma(vmi, vma) { + vm_flags_mod(vma, VM_NOHUGEPAGE, VM_HUGEPAGE); + walk_page_vma(vma, &thp_split_walk_ops, NULL); + } + mm->def_flags |= VM_NOHUGEPAGE; +} +#else +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) +{ + struct mm_struct *mm = current->mm; + + /* Do we have pgstes? if yes, we are done */ + if (mm_has_pgste(mm)) + return 0; + /* Fail if the page tables are 2K */ + if (!mm_alloc_pgste(mm)) + return -EINVAL; + mmap_write_lock(mm); + 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); + +int gmap_mark_unmergeable(void) +{ + /* + * 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. + */ + return ksm_disable(current->mm); +} +EXPORT_SYMBOL_GPL(gmap_mark_unmergeable); + +/* + * Enable storage key handling from now on and initialize the storage + * keys with the default key. + */ +static int __s390_enable_skey_pte(pte_t *pte, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + /* Clear storage key */ + ptep_zap_key(walk->mm, addr, pte); + return 0; +} + +/* + * Give a chance to schedule after setting a key to 256 pages. + * We only hold the mm lock, which is a rwsem and the kvm srcu. + * Both can sleep. + */ +static int __s390_enable_skey_pmd(pmd_t *pmd, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + cond_resched(); + return 0; +} + +static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr, + unsigned long hmask, unsigned long next, + struct mm_walk *walk) +{ + pmd_t *pmd = (pmd_t *)pte; + unsigned long start, end; + struct page *page = pmd_page(*pmd); + + /* + * The write check makes sure we do not set a key on shared + * memory. This is needed as the walker does not differentiate + * between actual guest memory and the process executable or + * shared libraries. + */ + if (pmd_val(*pmd) & _SEGMENT_ENTRY_INVALID || + !(pmd_val(*pmd) & _SEGMENT_ENTRY_WRITE)) + return 0; + + start = pmd_val(*pmd) & HPAGE_MASK; + end = start + HPAGE_SIZE - 1; + __storage_key_init_range(start, end); + set_bit(PG_arch_1, &page->flags); + cond_resched(); + return 0; +} + +static const struct mm_walk_ops enable_skey_walk_ops = { + .hugetlb_entry = __s390_enable_skey_hugetlb, + .pte_entry = __s390_enable_skey_pte, + .pmd_entry = __s390_enable_skey_pmd, + .walk_lock = PGWALK_WRLOCK, +}; + +int s390_enable_skey(void) +{ + struct mm_struct *mm = current->mm; + int rc = 0; + + mmap_write_lock(mm); + if (mm_uses_skeys(mm)) + goto out_up; + + mm->context.uses_skeys = 1; + rc = gmap_mark_unmergeable(); + if (rc) { + mm->context.uses_skeys = 0; + goto out_up; + } + walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL); + +out_up: + mmap_write_unlock(mm); + return rc; +} +EXPORT_SYMBOL_GPL(s390_enable_skey); + +/* + * Reset CMMA state, make all pages stable again. + */ +static int __s390_reset_cmma(pte_t *pte, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + ptep_zap_unused(walk->mm, addr, pte, 1); + return 0; +} + +static const struct mm_walk_ops reset_cmma_walk_ops = { + .pte_entry = __s390_reset_cmma, + .walk_lock = PGWALK_WRLOCK, +}; + +void s390_reset_cmma(struct mm_struct *mm) +{ + mmap_write_lock(mm); + walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL); + mmap_write_unlock(mm); +} +EXPORT_SYMBOL_GPL(s390_reset_cmma); + +#define GATHER_GET_PAGES 32 + +struct reset_walk_state { + unsigned long next; + unsigned long count; + unsigned long pfns[GATHER_GET_PAGES]; +}; + +static int s390_gather_pages(pte_t *ptep, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + struct reset_walk_state *p = walk->private; + pte_t pte = READ_ONCE(*ptep); + + if (pte_present(pte)) { + /* we have a reference from the mapping, take an extra one */ + get_page(phys_to_page(pte_val(pte))); + p->pfns[p->count] = phys_to_pfn(pte_val(pte)); + p->next = next; + p->count++; + } + return p->count >= GATHER_GET_PAGES; +} + +static const struct mm_walk_ops gather_pages_ops = { + .pte_entry = s390_gather_pages, + .walk_lock = PGWALK_RDLOCK, +}; + +/* + * Call the Destroy secure page UVC on each page in the given array of PFNs. + * Each page needs to have an extra reference, which will be released here. + */ +void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns) +{ + unsigned long i; + + for (i = 0; i < count; i++) { + /* we always have an extra reference */ + uv_destroy_owned_page(pfn_to_phys(pfns[i])); + /* get rid of the extra reference */ + put_page(pfn_to_page(pfns[i])); + cond_resched(); + } +} +EXPORT_SYMBOL_GPL(s390_uv_destroy_pfns); + +/** + * __s390_uv_destroy_range - Call the destroy secure page UVC on each page + * in the given range of the given address space. + * @mm: the mm to operate on + * @start: the start of the range + * @end: the end of the range + * @interruptible: if not 0, stop when a fatal signal is received + * + * Walk the given range of the given address space and call the destroy + * secure page UVC on each page. Optionally exit early if a fatal signal is + * pending. + * + * Return: 0 on success, -EINTR if the function stopped before completing + */ +int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start, + unsigned long end, bool interruptible) +{ + struct reset_walk_state state = { .next = start }; + int r = 1; + + while (r > 0) { + state.count = 0; + mmap_read_lock(mm); + r = walk_page_range(mm, state.next, end, &gather_pages_ops, &state); + mmap_read_unlock(mm); + cond_resched(); + s390_uv_destroy_pfns(state.count, state.pfns); + if (interruptible && fatal_signal_pending(current)) + return -EINTR; + } + return 0; +} +EXPORT_SYMBOL_GPL(__s390_uv_destroy_range); + +/** + * s390_unlist_old_asce - Remove the topmost level of page tables from the + * list of page tables of the gmap. + * @gmap: the gmap whose table is to be removed + * + * On s390x, KVM keeps a list of all pages containing the page tables of the + * gmap (the CRST list). This list is used at tear down time to free all + * pages that are now not needed anymore. + * + * This function removes the topmost page of the tree (the one pointed to by + * the ASCE) from the CRST list. + * + * This means that it will not be freed when the VM is torn down, and needs + * to be handled separately by the caller, unless a leak is actually + * intended. Notice that this function will only remove the page from the + * list, the page will still be used as a top level page table (and ASCE). + */ +void s390_unlist_old_asce(struct gmap *gmap) +{ + struct page *old; + + old = virt_to_page(gmap->table); + spin_lock(&gmap->guest_table_lock); + list_del(&old->lru); + /* + * Sometimes the topmost page might need to be "removed" multiple + * times, for example if the VM is rebooted into secure mode several + * times concurrently, or if s390_replace_asce fails after calling + * s390_remove_old_asce and is attempted again later. In that case + * the old asce has been removed from the list, and therefore it + * will not be freed when the VM terminates, but the ASCE is still + * in use and still pointed to. + * A subsequent call to replace_asce will follow the pointer and try + * to remove the same page from the list again. + * Therefore it's necessary that the page of the ASCE has valid + * pointers, so list_del can work (and do nothing) without + * dereferencing stale or invalid pointers. + */ + INIT_LIST_HEAD(&old->lru); + spin_unlock(&gmap->guest_table_lock); +} +EXPORT_SYMBOL_GPL(s390_unlist_old_asce); + +/** + * s390_replace_asce - Try to replace the current ASCE of a gmap with a copy + * @gmap: the gmap whose ASCE needs to be replaced + * + * If the ASCE is a SEGMENT type then this function will return -EINVAL, + * otherwise the pointers in the host_to_guest radix tree will keep pointing + * to the wrong pages, causing use-after-free and memory corruption. + * If the allocation of the new top level page table fails, the ASCE is not + * replaced. + * In any case, the old ASCE is always removed from the gmap CRST list. + * Therefore the caller has to make sure to save a pointer to it + * beforehand, unless a leak is actually intended. + */ +int s390_replace_asce(struct gmap *gmap) +{ + unsigned long asce; + struct page *page; + void *table; + + s390_unlist_old_asce(gmap); + + /* Replacing segment type ASCEs would cause serious issues */ + if ((gmap->asce & _ASCE_TYPE_MASK) == _ASCE_TYPE_SEGMENT) + return -EINVAL; + + page = gmap_alloc_crst(); + if (!page) + return -ENOMEM; + page->index = 0; + table = page_to_virt(page); + memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT)); + + /* + * The caller has to deal with the old ASCE, but here we make sure + * the new one is properly added to the CRST list, so that + * it will be freed when the VM is torn down. + */ + spin_lock(&gmap->guest_table_lock); + list_add(&page->lru, &gmap->crst_list); + spin_unlock(&gmap->guest_table_lock); + + /* Set new table origin while preserving existing ASCE control bits */ + asce = (gmap->asce & ~_ASCE_ORIGIN) | __pa(table); + WRITE_ONCE(gmap->asce, asce); + WRITE_ONCE(gmap->mm->context.gmap_asce, asce); + WRITE_ONCE(gmap->table, table); + + return 0; +} +EXPORT_SYMBOL_GPL(s390_replace_asce); |