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linux_dsm_epyc7002/arch/s390/mm/pgtable.c
Janosch Frank 55531b7431 KVM: s390: Add storage key facility interpretation control 
Up to now we always expected to have the storage key facility
available for our (non-VSIE) KVM guests. For huge page support, we
need to be able to disable it, so let's introduce that now.

We add the use_skf variable to manage KVM storage key facility
usage. Also we rename use_skey in the mm context struct to uses_skeys
to make it more clear that it is an indication that the vm actively
uses storage keys.

Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2018-05-17 09:00:41 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2007, 2011
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <linux/swapops.h>
#include <linux/sysctl.h>
#include <linux/ksm.h>
#include <linux/mman.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/page-states.h>
static inline void ptep_ipte_local(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, int nodat)
{
unsigned long opt, asce;
if (MACHINE_HAS_TLB_GUEST) {
opt = 0;
asce = READ_ONCE(mm->context.gmap_asce);
if (asce == 0UL || nodat)
opt |= IPTE_NODAT;
if (asce != -1UL) {
asce = asce ? : mm->context.asce;
opt |= IPTE_GUEST_ASCE;
}
__ptep_ipte(addr, ptep, opt, asce, IPTE_LOCAL);
} else {
__ptep_ipte(addr, ptep, 0, 0, IPTE_LOCAL);
}
}
static inline void ptep_ipte_global(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, int nodat)
{
unsigned long opt, asce;
if (MACHINE_HAS_TLB_GUEST) {
opt = 0;
asce = READ_ONCE(mm->context.gmap_asce);
if (asce == 0UL || nodat)
opt |= IPTE_NODAT;
if (asce != -1UL) {
asce = asce ? : mm->context.asce;
opt |= IPTE_GUEST_ASCE;
}
__ptep_ipte(addr, ptep, opt, asce, IPTE_GLOBAL);
} else {
__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
}
}
static inline pte_t ptep_flush_direct(struct mm_struct *mm,
unsigned long addr, pte_t *ptep,
int nodat)
{
pte_t old;
old = *ptep;
if (unlikely(pte_val(old) & _PAGE_INVALID))
return old;
atomic_inc(&mm->context.flush_count);
if (MACHINE_HAS_TLB_LC &&
cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
ptep_ipte_local(mm, addr, ptep, nodat);
else
ptep_ipte_global(mm, addr, ptep, nodat);
atomic_dec(&mm->context.flush_count);
return old;
}
static inline pte_t ptep_flush_lazy(struct mm_struct *mm,
unsigned long addr, pte_t *ptep,
int nodat)
{
pte_t old;
old = *ptep;
if (unlikely(pte_val(old) & _PAGE_INVALID))
return old;
atomic_inc(&mm->context.flush_count);
if (cpumask_equal(&mm->context.cpu_attach_mask,
cpumask_of(smp_processor_id()))) {
pte_val(*ptep) |= _PAGE_INVALID;
mm->context.flush_mm = 1;
} else
ptep_ipte_global(mm, addr, ptep, nodat);
atomic_dec(&mm->context.flush_count);
return old;
}
static inline pgste_t pgste_get_lock(pte_t *ptep)
{
unsigned long new = 0;
#ifdef CONFIG_PGSTE
unsigned long old;
asm(
" lg %0,%2\n"
"0: lgr %1,%0\n"
" nihh %0,0xff7f\n" /* clear PCL bit in old */
" oihh %1,0x0080\n" /* set PCL bit in new */
" csg %0,%1,%2\n"
" jl 0b\n"
: "=&d" (old), "=&d" (new), "=Q" (ptep[PTRS_PER_PTE])
: "Q" (ptep[PTRS_PER_PTE]) : "cc", "memory");
#endif
return __pgste(new);
}
static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste)
{
#ifdef CONFIG_PGSTE
asm(
" nihh %1,0xff7f\n" /* clear PCL bit */
" stg %1,%0\n"
: "=Q" (ptep[PTRS_PER_PTE])
: "d" (pgste_val(pgste)), "Q" (ptep[PTRS_PER_PTE])
: "cc", "memory");
#endif
}
static inline pgste_t pgste_get(pte_t *ptep)
{
unsigned long pgste = 0;
#ifdef CONFIG_PGSTE
pgste = *(unsigned long *)(ptep + PTRS_PER_PTE);
#endif
return __pgste(pgste);
}
static inline void pgste_set(pte_t *ptep, pgste_t pgste)
{
#ifdef CONFIG_PGSTE
*(pgste_t *)(ptep + PTRS_PER_PTE) = pgste;
#endif
}
static inline pgste_t pgste_update_all(pte_t pte, pgste_t pgste,
struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
unsigned long address, bits, skey;
if (!mm_uses_skeys(mm) || pte_val(pte) & _PAGE_INVALID)
return pgste;
address = pte_val(pte) & PAGE_MASK;
skey = (unsigned long) page_get_storage_key(address);
bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
/* Transfer page changed & referenced bit to guest bits in pgste */
pgste_val(pgste) |= bits << 48; /* GR bit & GC bit */
/* Copy page access key and fetch protection bit to pgste */
pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
pgste_val(pgste) |= (skey & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
#endif
return pgste;
}
static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry,
struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
unsigned long address;
unsigned long nkey;
if (!mm_uses_skeys(mm) || pte_val(entry) & _PAGE_INVALID)
return;
VM_BUG_ON(!(pte_val(*ptep) & _PAGE_INVALID));
address = pte_val(entry) & PAGE_MASK;
/*
* Set page access key and fetch protection bit from pgste.
* The guest C/R information is still in the PGSTE, set real
* key C/R to 0.
*/
nkey = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
nkey |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
page_set_storage_key(address, nkey, 0);
#endif
}
static inline pgste_t pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry)
{
#ifdef CONFIG_PGSTE
if ((pte_val(entry) & _PAGE_PRESENT) &&
(pte_val(entry) & _PAGE_WRITE) &&
!(pte_val(entry) & _PAGE_INVALID)) {
if (!MACHINE_HAS_ESOP) {
/*
* Without enhanced suppression-on-protection force
* the dirty bit on for all writable ptes.
*/
pte_val(entry) |= _PAGE_DIRTY;
pte_val(entry) &= ~_PAGE_PROTECT;
}
if (!(pte_val(entry) & _PAGE_PROTECT))
/* This pte allows write access, set user-dirty */
pgste_val(pgste) |= PGSTE_UC_BIT;
}
#endif
*ptep = entry;
return pgste;
}
static inline pgste_t pgste_pte_notify(struct mm_struct *mm,
unsigned long addr,
pte_t *ptep, pgste_t pgste)
{
#ifdef CONFIG_PGSTE
unsigned long bits;
bits = pgste_val(pgste) & (PGSTE_IN_BIT | PGSTE_VSIE_BIT);
if (bits) {
pgste_val(pgste) ^= bits;
ptep_notify(mm, addr, ptep, bits);
}
#endif
return pgste;
}
static inline pgste_t ptep_xchg_start(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
pgste_t pgste = __pgste(0);
if (mm_has_pgste(mm)) {
pgste = pgste_get_lock(ptep);
pgste = pgste_pte_notify(mm, addr, ptep, pgste);
}
return pgste;
}
static inline pte_t ptep_xchg_commit(struct mm_struct *mm,
unsigned long addr, pte_t *ptep,
pgste_t pgste, pte_t old, pte_t new)
{
if (mm_has_pgste(mm)) {
if (pte_val(old) & _PAGE_INVALID)
pgste_set_key(ptep, pgste, new, mm);
if (pte_val(new) & _PAGE_INVALID) {
pgste = pgste_update_all(old, pgste, mm);
if ((pgste_val(pgste) & _PGSTE_GPS_USAGE_MASK) ==
_PGSTE_GPS_USAGE_UNUSED)
pte_val(old) |= _PAGE_UNUSED;
}
pgste = pgste_set_pte(ptep, pgste, new);
pgste_set_unlock(ptep, pgste);
} else {
*ptep = new;
}
return old;
}
pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t new)
{
pgste_t pgste;
pte_t old;
int nodat;
preempt_disable();
pgste = ptep_xchg_start(mm, addr, ptep);
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
old = ptep_flush_direct(mm, addr, ptep, nodat);
old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
preempt_enable();
return old;
}
EXPORT_SYMBOL(ptep_xchg_direct);
pte_t ptep_xchg_lazy(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t new)
{
pgste_t pgste;
pte_t old;
int nodat;
preempt_disable();
pgste = ptep_xchg_start(mm, addr, ptep);
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
old = ptep_flush_lazy(mm, addr, ptep, nodat);
old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
preempt_enable();
return old;
}
EXPORT_SYMBOL(ptep_xchg_lazy);
pte_t ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
pgste_t pgste;
pte_t old;
int nodat;
preempt_disable();
pgste = ptep_xchg_start(mm, addr, ptep);
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
old = ptep_flush_lazy(mm, addr, ptep, nodat);
if (mm_has_pgste(mm)) {
pgste = pgste_update_all(old, pgste, mm);
pgste_set(ptep, pgste);
}
return old;
}
EXPORT_SYMBOL(ptep_modify_prot_start);
void ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
pgste_t pgste;
if (!MACHINE_HAS_NX)
pte_val(pte) &= ~_PAGE_NOEXEC;
if (mm_has_pgste(mm)) {
pgste = pgste_get(ptep);
pgste_set_key(ptep, pgste, pte, mm);
pgste = pgste_set_pte(ptep, pgste, pte);
pgste_set_unlock(ptep, pgste);
} else {
*ptep = pte;
}
preempt_enable();
}
EXPORT_SYMBOL(ptep_modify_prot_commit);
static inline void pmdp_idte_local(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
if (MACHINE_HAS_TLB_GUEST)
__pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_LOCAL);
else
__pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL);
}
static inline void pmdp_idte_global(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
if (MACHINE_HAS_TLB_GUEST)
__pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_GLOBAL);
else if (MACHINE_HAS_IDTE)
__pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
else
__pmdp_csp(pmdp);
}
static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
pmd_t old;
old = *pmdp;
if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
return old;
atomic_inc(&mm->context.flush_count);
if (MACHINE_HAS_TLB_LC &&
cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
pmdp_idte_local(mm, addr, pmdp);
else
pmdp_idte_global(mm, addr, pmdp);
atomic_dec(&mm->context.flush_count);
return old;
}
static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
pmd_t old;
old = *pmdp;
if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
return old;
atomic_inc(&mm->context.flush_count);
if (cpumask_equal(&mm->context.cpu_attach_mask,
cpumask_of(smp_processor_id()))) {
pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
mm->context.flush_mm = 1;
} else {
pmdp_idte_global(mm, addr, pmdp);
}
atomic_dec(&mm->context.flush_count);
return old;
}
pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t new)
{
pmd_t old;
preempt_disable();
old = pmdp_flush_direct(mm, addr, pmdp);
*pmdp = new;
preempt_enable();
return old;
}
EXPORT_SYMBOL(pmdp_xchg_direct);
pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t new)
{
pmd_t old;
preempt_disable();
old = pmdp_flush_lazy(mm, addr, pmdp);
*pmdp = new;
preempt_enable();
return old;
}
EXPORT_SYMBOL(pmdp_xchg_lazy);
static inline void pudp_idte_local(struct mm_struct *mm,
unsigned long addr, pud_t *pudp)
{
if (MACHINE_HAS_TLB_GUEST)
__pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_LOCAL);
else
__pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
}
static inline void pudp_idte_global(struct mm_struct *mm,
unsigned long addr, pud_t *pudp)
{
if (MACHINE_HAS_TLB_GUEST)
__pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_GLOBAL);
else if (MACHINE_HAS_IDTE)
__pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
else
/*
* Invalid bit position is the same for pmd and pud, so we can
* re-use _pmd_csp() here
*/
__pmdp_csp((pmd_t *) pudp);
}
static inline pud_t pudp_flush_direct(struct mm_struct *mm,
unsigned long addr, pud_t *pudp)
{
pud_t old;
old = *pudp;
if (pud_val(old) & _REGION_ENTRY_INVALID)
return old;
atomic_inc(&mm->context.flush_count);
if (MACHINE_HAS_TLB_LC &&
cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
pudp_idte_local(mm, addr, pudp);
else
pudp_idte_global(mm, addr, pudp);
atomic_dec(&mm->context.flush_count);
return old;
}
pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
pud_t *pudp, pud_t new)
{
pud_t old;
preempt_disable();
old = pudp_flush_direct(mm, addr, pudp);
*pudp = new;
preempt_enable();
return old;
}
EXPORT_SYMBOL(pudp_xchg_direct);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable)
{
struct list_head *lh = (struct list_head *) pgtable;
assert_spin_locked(pmd_lockptr(mm, pmdp));
/* FIFO */
if (!pmd_huge_pte(mm, pmdp))
INIT_LIST_HEAD(lh);
else
list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
pmd_huge_pte(mm, pmdp) = pgtable;
}
pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
{
struct list_head *lh;
pgtable_t pgtable;
pte_t *ptep;
assert_spin_locked(pmd_lockptr(mm, pmdp));
/* FIFO */
pgtable = pmd_huge_pte(mm, pmdp);
lh = (struct list_head *) pgtable;
if (list_empty(lh))
pmd_huge_pte(mm, pmdp) = NULL;
else {
pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
list_del(lh);
}
ptep = (pte_t *) pgtable;
pte_val(*ptep) = _PAGE_INVALID;
ptep++;
pte_val(*ptep) = _PAGE_INVALID;
return pgtable;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#ifdef CONFIG_PGSTE
void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t entry)
{
pgste_t pgste;
/* the mm_has_pgste() check is done in set_pte_at() */
preempt_disable();
pgste = pgste_get_lock(ptep);
pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
pgste_set_key(ptep, pgste, entry, mm);
pgste = pgste_set_pte(ptep, pgste, entry);
pgste_set_unlock(ptep, pgste);
preempt_enable();
}
void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
pgste_t pgste;
preempt_disable();
pgste = pgste_get_lock(ptep);
pgste_val(pgste) |= PGSTE_IN_BIT;
pgste_set_unlock(ptep, pgste);
preempt_enable();
}
/**
* ptep_force_prot - change access rights of a locked pte
* @mm: pointer to the process mm_struct
* @addr: virtual address in the guest address space
* @ptep: pointer to the page table entry
* @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
* @bit: pgste bit to set (e.g. for notification)
*
* Returns 0 if the access rights were changed and -EAGAIN if the current
* and requested access rights are incompatible.
*/
int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, int prot, unsigned long bit)
{
pte_t entry;
pgste_t pgste;
int pte_i, pte_p, nodat;
pgste = pgste_get_lock(ptep);
entry = *ptep;
/* Check pte entry after all locks have been acquired */
pte_i = pte_val(entry) & _PAGE_INVALID;
pte_p = pte_val(entry) & _PAGE_PROTECT;
if ((pte_i && (prot != PROT_NONE)) ||
(pte_p && (prot & PROT_WRITE))) {
pgste_set_unlock(ptep, pgste);
return -EAGAIN;
}
/* Change access rights and set pgste bit */
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
if (prot == PROT_NONE && !pte_i) {
ptep_flush_direct(mm, addr, ptep, nodat);
pgste = pgste_update_all(entry, pgste, mm);
pte_val(entry) |= _PAGE_INVALID;
}
if (prot == PROT_READ && !pte_p) {
ptep_flush_direct(mm, addr, ptep, nodat);
pte_val(entry) &= ~_PAGE_INVALID;
pte_val(entry) |= _PAGE_PROTECT;
}
pgste_val(pgste) |= bit;
pgste = pgste_set_pte(ptep, pgste, entry);
pgste_set_unlock(ptep, pgste);
return 0;
}
int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
pte_t *sptep, pte_t *tptep, pte_t pte)
{
pgste_t spgste, tpgste;
pte_t spte, tpte;
int rc = -EAGAIN;
if (!(pte_val(*tptep) & _PAGE_INVALID))
return 0; /* already shadowed */
spgste = pgste_get_lock(sptep);
spte = *sptep;
if (!(pte_val(spte) & _PAGE_INVALID) &&
!((pte_val(spte) & _PAGE_PROTECT) &&
!(pte_val(pte) & _PAGE_PROTECT))) {
pgste_val(spgste) |= PGSTE_VSIE_BIT;
tpgste = pgste_get_lock(tptep);
pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
(pte_val(pte) & _PAGE_PROTECT);
/* don't touch the storage key - it belongs to parent pgste */
tpgste = pgste_set_pte(tptep, tpgste, tpte);
pgste_set_unlock(tptep, tpgste);
rc = 1;
}
pgste_set_unlock(sptep, spgste);
return rc;
}
void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
{
pgste_t pgste;
int nodat;
pgste = pgste_get_lock(ptep);
/* notifier is called by the caller */
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
ptep_flush_direct(mm, saddr, ptep, nodat);
/* don't touch the storage key - it belongs to parent pgste */
pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
pgste_set_unlock(ptep, pgste);
}
static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
{
if (!non_swap_entry(entry))
dec_mm_counter(mm, MM_SWAPENTS);
else if (is_migration_entry(entry)) {
struct page *page = migration_entry_to_page(entry);
dec_mm_counter(mm, mm_counter(page));
}
free_swap_and_cache(entry);
}
void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, int reset)
{
unsigned long pgstev;
pgste_t pgste;
pte_t pte;
/* Zap unused and logically-zero pages */
preempt_disable();
pgste = pgste_get_lock(ptep);
pgstev = pgste_val(pgste);
pte = *ptep;
if (!reset && pte_swap(pte) &&
((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
(pgstev & _PGSTE_GPS_ZERO))) {
ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
pte_clear(mm, addr, ptep);
}
if (reset)
pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
pgste_set_unlock(ptep, pgste);
preempt_enable();
}
void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
unsigned long ptev;
pgste_t pgste;
/* Clear storage key ACC and F, but set R/C */
preempt_disable();
pgste = pgste_get_lock(ptep);
pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
ptev = pte_val(*ptep);
if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
pgste_set_unlock(ptep, pgste);
preempt_enable();
}
/*
* Test and reset if a guest page is dirty
*/
bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr)
{
spinlock_t *ptl;
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pgste_t pgste;
pte_t *ptep;
pte_t pte;
bool dirty;
int nodat;
pgd = pgd_offset(mm, addr);
p4d = p4d_alloc(mm, pgd, addr);
if (!p4d)
return false;
pud = pud_alloc(mm, p4d, addr);
if (!pud)
return false;
pmd = pmd_alloc(mm, pud, addr);
if (!pmd)
return false;
/* We can't run guests backed by huge pages, but userspace can
* still set them up and then try to migrate them without any
* migration support.
*/
if (pmd_large(*pmd))
return true;
ptep = pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (unlikely(!ptep))
return false;
pgste = pgste_get_lock(ptep);
dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
pgste_val(pgste) &= ~PGSTE_UC_BIT;
pte = *ptep;
if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
pgste = pgste_pte_notify(mm, addr, ptep, pgste);
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
ptep_ipte_global(mm, addr, ptep, nodat);
if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
pte_val(pte) |= _PAGE_PROTECT;
else
pte_val(pte) |= _PAGE_INVALID;
*ptep = pte;
}
pgste_set_unlock(ptep, pgste);
spin_unlock(ptl);
return dirty;
}
EXPORT_SYMBOL_GPL(test_and_clear_guest_dirty);
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char key, bool nq)
{
unsigned long keyul;
spinlock_t *ptl;
pgste_t old, new;
pte_t *ptep;
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep))
return -EFAULT;
new = old = pgste_get_lock(ptep);
pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
PGSTE_ACC_BITS | PGSTE_FP_BIT);
keyul = (unsigned long) key;
pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
unsigned long address, bits, skey;
address = pte_val(*ptep) & PAGE_MASK;
skey = (unsigned long) page_get_storage_key(address);
bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
/* Set storage key ACC and FP */
page_set_storage_key(address, skey, !nq);
/* Merge host changed & referenced into pgste */
pgste_val(new) |= bits << 52;
}
/* changing the guest storage key is considered a change of the page */
if ((pgste_val(new) ^ pgste_val(old)) &
(PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
pgste_val(new) |= PGSTE_UC_BIT;
pgste_set_unlock(ptep, new);
pte_unmap_unlock(ptep, ptl);
return 0;
}
EXPORT_SYMBOL(set_guest_storage_key);
/**
* Conditionally set a guest storage key (handling csske).
* oldkey will be updated when either mr or mc is set and a pointer is given.
*
* Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
* storage key was updated and -EFAULT on access errors.
*/
int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char key, unsigned char *oldkey,
bool nq, bool mr, bool mc)
{
unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
int rc;
/* we can drop the pgste lock between getting and setting the key */
if (mr | mc) {
rc = get_guest_storage_key(current->mm, addr, &tmp);
if (rc)
return rc;
if (oldkey)
*oldkey = tmp;
if (!mr)
mask |= _PAGE_REFERENCED;
if (!mc)
mask |= _PAGE_CHANGED;
if (!((tmp ^ key) & mask))
return 0;
}
rc = set_guest_storage_key(current->mm, addr, key, nq);
return rc < 0 ? rc : 1;
}
EXPORT_SYMBOL(cond_set_guest_storage_key);
/**
* Reset a guest reference bit (rrbe), returning the reference and changed bit.
*
* Returns < 0 in case of error, otherwise the cc to be reported to the guest.
*/
int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
{
spinlock_t *ptl;
pgste_t old, new;
pte_t *ptep;
int cc = 0;
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep))
return -EFAULT;
new = old = pgste_get_lock(ptep);
/* Reset guest reference bit only */
pgste_val(new) &= ~PGSTE_GR_BIT;
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
/* Merge real referenced bit into host-set */
pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
}
/* Reflect guest's logical view, not physical */
cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
/* Changing the guest storage key is considered a change of the page */
if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
pgste_val(new) |= PGSTE_UC_BIT;
pgste_set_unlock(ptep, new);
pte_unmap_unlock(ptep, ptl);
return cc;
}
EXPORT_SYMBOL(reset_guest_reference_bit);
int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char *key)
{
spinlock_t *ptl;
pgste_t pgste;
pte_t *ptep;
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep))
return -EFAULT;
pgste = pgste_get_lock(ptep);
*key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
if (!(pte_val(*ptep) & _PAGE_INVALID))
*key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK);
/* Reflect guest's logical view, not physical */
*key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
pgste_set_unlock(ptep, pgste);
pte_unmap_unlock(ptep, ptl);
return 0;
}
EXPORT_SYMBOL(get_guest_storage_key);
/**
* pgste_perform_essa - perform ESSA actions on the PGSTE.
* @mm: the memory context. It must have PGSTEs, no check is performed here!
* @hva: the host virtual address of the page whose PGSTE is to be processed
* @orc: the specific action to perform, see the ESSA_SET_* macros.
* @oldpte: the PTE will be saved there if the pointer is not NULL.
* @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
*
* Return: 1 if the page is to be added to the CBRL, otherwise 0,
* or < 0 in case of error. -EINVAL is returned for invalid values
* of orc, -EFAULT for invalid addresses.
*/
int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
unsigned long *oldpte, unsigned long *oldpgste)
{
unsigned long pgstev;
spinlock_t *ptl;
pgste_t pgste;
pte_t *ptep;
int res = 0;
WARN_ON_ONCE(orc > ESSA_MAX);
if (unlikely(orc > ESSA_MAX))
return -EINVAL;
ptep = get_locked_pte(mm, hva, &ptl);
if (unlikely(!ptep))
return -EFAULT;
pgste = pgste_get_lock(ptep);
pgstev = pgste_val(pgste);
if (oldpte)
*oldpte = pte_val(*ptep);
if (oldpgste)
*oldpgste = pgstev;
switch (orc) {
case ESSA_GET_STATE:
break;
case ESSA_SET_STABLE:
pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
pgstev |= _PGSTE_GPS_USAGE_STABLE;
break;
case ESSA_SET_UNUSED:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_UNUSED;
if (pte_val(*ptep) & _PAGE_INVALID)
res = 1;
break;
case ESSA_SET_VOLATILE:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
if (pte_val(*ptep) & _PAGE_INVALID)
res = 1;
break;
case ESSA_SET_POT_VOLATILE:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
break;
}
if (pgstev & _PGSTE_GPS_ZERO) {
pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
break;
}
if (!(pgstev & PGSTE_GC_BIT)) {
pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
res = 1;
break;
}
break;
case ESSA_SET_STABLE_RESIDENT:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_STABLE;
/*
* Since the resident state can go away any time after this
* call, we will not make this page resident. We can revisit
* this decision if a guest will ever start using this.
*/
break;
case ESSA_SET_STABLE_IF_RESIDENT:
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_STABLE;
}
break;
case ESSA_SET_STABLE_NODAT:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
break;
default:
/* we should never get here! */
break;
}
/* If we are discarding a page, set it to logical zero */
if (res)
pgstev |= _PGSTE_GPS_ZERO;
pgste_val(pgste) = pgstev;
pgste_set_unlock(ptep, pgste);
pte_unmap_unlock(ptep, ptl);
return res;
}
EXPORT_SYMBOL(pgste_perform_essa);
/**
* set_pgste_bits - set specific PGSTE bits.
* @mm: the memory context. It must have PGSTEs, no check is performed here!
* @hva: the host virtual address of the page whose PGSTE is to be processed
* @bits: a bitmask representing the bits that will be touched
* @value: the values of the bits to be written. Only the bits in the mask
* will be written.
*
* Return: 0 on success, < 0 in case of error.
*/
int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
unsigned long bits, unsigned long value)
{
spinlock_t *ptl;
pgste_t new;
pte_t *ptep;
ptep = get_locked_pte(mm, hva, &ptl);
if (unlikely(!ptep))
return -EFAULT;
new = pgste_get_lock(ptep);
pgste_val(new) &= ~bits;
pgste_val(new) |= value & bits;
pgste_set_unlock(ptep, new);
pte_unmap_unlock(ptep, ptl);
return 0;
}
EXPORT_SYMBOL(set_pgste_bits);
/**
* get_pgste - get the current PGSTE for the given address.
* @mm: the memory context. It must have PGSTEs, no check is performed here!
* @hva: the host virtual address of the page whose PGSTE is to be processed
* @pgstep: will be written with the current PGSTE for the given address.
*
* Return: 0 on success, < 0 in case of error.
*/
int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
{
spinlock_t *ptl;
pte_t *ptep;
ptep = get_locked_pte(mm, hva, &ptl);
if (unlikely(!ptep))
return -EFAULT;
*pgstep = pgste_val(pgste_get(ptep));
pte_unmap_unlock(ptep, ptl);
return 0;
}
EXPORT_SYMBOL(get_pgste);
#endif
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