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|
/*
* KVM guest address space mapping code
*
* Copyright IBM Corp. 2007, 2016
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/kernel.h>
#include <linux/mm.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 <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/gmap.h>
#include <asm/tlb.h>
/**
* gmap_alloc - allocate and initialize a guest address space
* @mm: pointer to the parent mm_struct
* @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 < (1UL << 31)) {
limit = (1UL << 31) - 1;
atype = _ASCE_TYPE_SEGMENT;
etype = _SEGMENT_ENTRY_EMPTY;
} else if (limit < (1UL << 42)) {
limit = (1UL << 42) - 1;
atype = _ASCE_TYPE_REGION3;
etype = _REGION3_ENTRY_EMPTY;
} else if (limit < (1UL << 53)) {
limit = (1UL << 53) - 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);
if (!gmap)
goto out;
INIT_LIST_HEAD(&gmap->crst_list);
INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL);
INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC);
spin_lock_init(&gmap->guest_table_lock);
atomic_set(&gmap->ref_count, 1);
page = alloc_pages(GFP_KERNEL, 2);
if (!page)
goto out_free;
page->index = 0;
list_add(&page->lru, &gmap->crst_list);
table = (unsigned long *) page_to_phys(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;
gmap = gmap_alloc(limit);
if (!gmap)
return NULL;
gmap->mm = mm;
spin_lock(&mm->context.gmap_lock);
list_add_rcu(&gmap->list, &mm->context.gmap_list);
spin_unlock(&mm->context.gmap_lock);
return gmap;
}
EXPORT_SYMBOL_GPL(gmap_create);
static void gmap_flush_tlb(struct gmap *gmap)
{
if (MACHINE_HAS_IDTE)
__tlb_flush_asce(gmap->mm, 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 **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);
}
/**
* gmap_free - free a guest address space
* @gmap: pointer to the guest address space structure
*/
static void gmap_free(struct gmap *gmap)
{
struct page *page, *next;
/* Free all segment & region tables. */
list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
__free_pages(page, 2);
gmap_radix_tree_free(&gmap->guest_to_host);
gmap_radix_tree_free(&gmap->host_to_guest);
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)
{
atomic_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 (atomic_dec_return(&gmap->ref_count) == 0)
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)
{
/* Flush tlb. */
gmap_flush_tlb(gmap);
/* Remove gmap from the pre-mm list */
spin_lock(&gmap->mm->context.gmap_lock);
list_del_rcu(&gmap->list);
spin_unlock(&gmap->mm->context.gmap_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_alloc_table is assumed to be called with mmap_sem 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 = alloc_pages(GFP_KERNEL, 2);
if (!page)
return -ENOMEM;
new = (unsigned long *) page_to_phys(page);
crst_table_init(new, init);
spin_lock(&gmap->mm->page_table_lock);
if (*table & _REGION_ENTRY_INVALID) {
list_add(&page->lru, &gmap->crst_list);
*table = (unsigned long) new | _REGION_ENTRY_LENGTH |
(*table & _REGION_ENTRY_TYPE_MASK);
page->index = gaddr;
page = NULL;
}
spin_unlock(&gmap->mm->page_table_lock);
if (page)
__free_pages(page, 2);
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, mask;
offset = (unsigned long) entry / sizeof(unsigned long);
offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
page = virt_to_page((void *)((unsigned long) entry & mask));
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;
spin_lock(&gmap->guest_table_lock);
entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
if (entry) {
flush = (*entry != _SEGMENT_ENTRY_INVALID);
*entry = _SEGMENT_ENTRY_INVALID;
}
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;
if ((to | len) & (PMD_SIZE - 1))
return -EINVAL;
if (len == 0 || to + len < to)
return -EINVAL;
flush = 0;
down_write(&gmap->mm->mmap_sem);
for (off = 0; off < len; off += PMD_SIZE)
flush |= __gmap_unmap_by_gaddr(gmap, to + off);
up_write(&gmap->mm->mmap_sem);
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;
if ((from | to | len) & (PMD_SIZE - 1))
return -EINVAL;
if (len == 0 || from + len < from || to + len < to ||
from + len - 1 > TASK_MAX_SIZE || to + len - 1 > gmap->asce_end)
return -EINVAL;
flush = 0;
down_write(&gmap->mm->mmap_sem);
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;
}
up_write(&gmap->mm->mmap_sem);
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_sem of the mm that belongs to the address space must be held
* when this function gets called.
*/
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);
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;
down_read(&gmap->mm->mmap_sem);
rc = __gmap_translate(gmap, gaddr);
up_read(&gmap->mm->mmap_sem);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_translate);
/**
* gmap_unlink - disconnect a page table from the gmap shadow tables
* @gmap: pointer to guest mapping meta data structure
* @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();
}
/**
* 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_sem 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;
pud_t *pud;
pmd_t *pmd;
int rc;
/* Create higher level tables in the gmap page table */
table = gmap->table;
if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
table += (gaddr >> 53) & 0x7ff;
if ((*table & _REGION_ENTRY_INVALID) &&
gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
gaddr & 0xffe0000000000000UL))
return -ENOMEM;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
}
if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
table += (gaddr >> 42) & 0x7ff;
if ((*table & _REGION_ENTRY_INVALID) &&
gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
gaddr & 0xfffffc0000000000UL))
return -ENOMEM;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
}
if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
table += (gaddr >> 31) & 0x7ff;
if ((*table & _REGION_ENTRY_INVALID) &&
gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
gaddr & 0xffffffff80000000UL))
return -ENOMEM;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
}
table += (gaddr >> 20) & 0x7ff;
/* Walk the parent mm page table */
mm = gmap->mm;
pgd = pgd_offset(mm, vmaddr);
VM_BUG_ON(pgd_none(*pgd));
pud = pud_offset(pgd, vmaddr);
VM_BUG_ON(pud_none(*pud));
pmd = pmd_offset(pud, vmaddr);
VM_BUG_ON(pmd_none(*pmd));
/* large pmds cannot yet be handled */
if (pmd_large(*pmd))
return -EFAULT;
/* Link gmap segment table entry location to page table. */
rc = radix_tree_preload(GFP_KERNEL);
if (rc)
return rc;
ptl = pmd_lock(mm, pmd);
spin_lock(&gmap->guest_table_lock);
if (*table == _SEGMENT_ENTRY_INVALID) {
rc = radix_tree_insert(&gmap->host_to_guest,
vmaddr >> PMD_SHIFT, table);
if (!rc)
*table = pmd_val(*pmd);
} else
rc = 0;
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;
down_read(&gmap->mm->mmap_sem);
retry:
unlocked = false;
vmaddr = __gmap_translate(gmap, gaddr);
if (IS_ERR_VALUE(vmaddr)) {
rc = vmaddr;
goto out_up;
}
if (fixup_user_fault(current, gmap->mm, vmaddr, fault_flags,
&unlocked)) {
rc = -EFAULT;
goto out_up;
}
/*
* In the case that fixup_user_fault unlocked the mmap_sem 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:
up_read(&gmap->mm->mmap_sem);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_fault);
/*
* this function is assumed to be called with mmap_sem held
*/
void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
{
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;
/* 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;
down_read(&gmap->mm->mmap_sem);
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);
size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
zap_page_range(vma, vmaddr, size, NULL);
}
up_read(&gmap->mm->mmap_sem);
}
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
*
* Returns a table pointer for the given guest address.
*/
static inline unsigned long *gmap_table_walk(struct gmap *gmap,
unsigned long gaddr)
{
unsigned long *table;
table = gmap->table;
switch (gmap->asce & _ASCE_TYPE_MASK) {
case _ASCE_TYPE_REGION1:
table += (gaddr >> 53) & 0x7ff;
if (*table & _REGION_ENTRY_INVALID)
return NULL;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
/* Fallthrough */
case _ASCE_TYPE_REGION2:
table += (gaddr >> 42) & 0x7ff;
if (*table & _REGION_ENTRY_INVALID)
return NULL;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
/* Fallthrough */
case _ASCE_TYPE_REGION3:
table += (gaddr >> 31) & 0x7ff;
if (*table & _REGION_ENTRY_INVALID)
return NULL;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
/* Fallthrough */
case _ASCE_TYPE_SEGMENT:
table += (gaddr >> 20) & 0x7ff;
}
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;
/* Walk the gmap page table, lock and get pte pointer */
table = gmap_table_walk(gmap, gaddr);
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
*
* 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)
{
struct mm_struct *mm = gmap->mm;
bool unlocked = false;
if (fixup_user_fault(current, mm, vmaddr, FAULT_FLAG_WRITE, &unlocked))
return -EFAULT;
if (unlocked)
/* lost mmap_sem, 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
* @ptl: pointer to the spinlock pointer
*/
static void gmap_pte_op_end(spinlock_t *ptl)
{
spin_unlock(ptl);
}
/**
* 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)
{
unsigned long vmaddr;
spinlock_t *ptl;
pte_t *ptep;
int rc = 0;
if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK))
return -EINVAL;
if (!MACHINE_HAS_ESOP && prot == PROT_READ)
return -EINVAL;
down_read(&gmap->mm->mmap_sem);
while (len) {
rc = -EAGAIN;
ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
if (ptep) {
rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot);
gmap_pte_op_end(ptl);
}
if (rc) {
vmaddr = __gmap_translate(gmap, gaddr);
if (IS_ERR_VALUE(vmaddr)) {
rc = vmaddr;
break;
}
rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr);
if (rc)
break;
continue;
}
gaddr += PAGE_SIZE;
len -= PAGE_SIZE;
}
up_read(&gmap->mm->mmap_sem);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_mprotect_notify);
/**
* ptep_notify - call all invalidation callbacks for a specific pte.
* @mm: pointer to the process mm_struct
* @addr: virtual address in the process address space
* @pte: pointer to the page table entry
*
* 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 offset, gaddr;
unsigned long *table;
struct gmap *gmap;
offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
offset = offset * (4096 / 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)
gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1);
}
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(ptep_notify);
static inline void thp_split_mm(struct mm_struct *mm)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
struct vm_area_struct *vma;
unsigned long addr;
for (vma = mm->mmap; vma != NULL; vma = vma->vm_next) {
for (addr = vma->vm_start;
addr < vma->vm_end;
addr += PAGE_SIZE)
follow_page(vma, addr, FOLL_SPLIT);
vma->vm_flags &= ~VM_HUGEPAGE;
vma->vm_flags |= VM_NOHUGEPAGE;
}
mm->def_flags |= VM_NOHUGEPAGE;
#endif
}
/*
* 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;
down_write(&mm->mmap_sem);
mm->context.has_pgste = 1;
/* split thp mappings and disable thp for future mappings */
thp_split_mm(mm);
up_write(&mm->mmap_sem);
return 0;
}
EXPORT_SYMBOL_GPL(s390_enable_sie);
/*
* Enable storage key handling from now on and initialize the storage
* keys with the default key.
*/
static int __s390_enable_skey(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
/*
* Remove all zero page mappings,
* after establishing a policy to forbid zero page mappings
* following faults for that page will get fresh anonymous pages
*/
if (is_zero_pfn(pte_pfn(*pte)))
ptep_xchg_direct(walk->mm, addr, pte, __pte(_PAGE_INVALID));
/* Clear storage key */
ptep_zap_key(walk->mm, addr, pte);
return 0;
}
int s390_enable_skey(void)
{
struct mm_walk walk = { .pte_entry = __s390_enable_skey };
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
int rc = 0;
down_write(&mm->mmap_sem);
if (mm_use_skey(mm))
goto out_up;
mm->context.use_skey = 1;
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
MADV_UNMERGEABLE, &vma->vm_flags)) {
mm->context.use_skey = 0;
rc = -ENOMEM;
goto out_up;
}
}
mm->def_flags &= ~VM_MERGEABLE;
walk.mm = mm;
walk_page_range(0, TASK_SIZE, &walk);
out_up:
up_write(&mm->mmap_sem);
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;
}
void s390_reset_cmma(struct mm_struct *mm)
{
struct mm_walk walk = { .pte_entry = __s390_reset_cmma };
down_write(&mm->mmap_sem);
walk.mm = mm;
walk_page_range(0, TASK_SIZE, &walk);
up_write(&mm->mmap_sem);
}
EXPORT_SYMBOL_GPL(s390_reset_cmma);
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