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KVM: s390: Clear storage keys
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page_table_reset_pgste() already does a complete page table walk to
reset the pgste. Enhance it to initialize the storage keys to
PAGE_DEFAULT_KEY if requested by the caller. This will be used
for lazy storage key handling. Also provide an empty stub for
!CONFIG_PGSTE

Lets adopt the current code (diag 308) to not clear the keys.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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Dominik Dingel authored and Christian Borntraeger committed Apr 22, 2014
1 parent 65eef33 commit d4cb113
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Showing 3 changed files with 37 additions and 15 deletions.
3 changes: 2 additions & 1 deletion arch/s390/include/asm/pgalloc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,8 @@ unsigned long *page_table_alloc(struct mm_struct *, unsigned long);
void page_table_free(struct mm_struct *, unsigned long *);
void page_table_free_rcu(struct mmu_gather *, unsigned long *);

void page_table_reset_pgste(struct mm_struct *, unsigned long, unsigned long);
void page_table_reset_pgste(struct mm_struct *, unsigned long, unsigned long,
bool init_skey);
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned long key, bool nq);

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6 changes: 3 additions & 3 deletions arch/s390/kvm/diag.c
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Original file line number Diff line number Diff line change
Expand Up @@ -169,15 +169,15 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
switch (subcode) {
case 0:
case 1:
page_table_reset_pgste(current->mm, 0, TASK_SIZE);
page_table_reset_pgste(current->mm, 0, TASK_SIZE, false);
return -EOPNOTSUPP;
case 3:
vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
page_table_reset_pgste(current->mm, 0, TASK_SIZE);
page_table_reset_pgste(current->mm, 0, TASK_SIZE, false);
break;
case 4:
vcpu->run->s390_reset_flags = 0;
page_table_reset_pgste(current->mm, 0, TASK_SIZE);
page_table_reset_pgste(current->mm, 0, TASK_SIZE, false);
break;
default:
return -EOPNOTSUPP;
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43 changes: 32 additions & 11 deletions arch/s390/mm/pgtable.c
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Original file line number Diff line number Diff line change
Expand Up @@ -883,8 +883,8 @@ static inline void page_table_free_pgste(unsigned long *table)
__free_page(page);
}

static inline unsigned long page_table_reset_pte(struct mm_struct *mm,
pmd_t *pmd, unsigned long addr, unsigned long end)
static inline unsigned long page_table_reset_pte(struct mm_struct *mm, pmd_t *pmd,
unsigned long addr, unsigned long end, bool init_skey)
{
pte_t *start_pte, *pte;
spinlock_t *ptl;
Expand All @@ -895,15 +895,31 @@ static inline unsigned long page_table_reset_pte(struct mm_struct *mm,
do {
pgste = pgste_get_lock(pte);
pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
if (init_skey) {
unsigned long address;

pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT |
PGSTE_GR_BIT | PGSTE_GC_BIT);

/* skip invalid and not writable pages */
if (pte_val(*pte) & _PAGE_INVALID ||
!(pte_val(*pte) & _PAGE_WRITE)) {
pgste_set_unlock(pte, pgste);
continue;
}

address = pte_val(*pte) & PAGE_MASK;
page_set_storage_key(address, PAGE_DEFAULT_KEY, 1);
}
pgste_set_unlock(pte, pgste);
} while (pte++, addr += PAGE_SIZE, addr != end);
pte_unmap_unlock(start_pte, ptl);

return addr;
}

static inline unsigned long page_table_reset_pmd(struct mm_struct *mm,
pud_t *pud, unsigned long addr, unsigned long end)
static inline unsigned long page_table_reset_pmd(struct mm_struct *mm, pud_t *pud,
unsigned long addr, unsigned long end, bool init_skey)
{
unsigned long next;
pmd_t *pmd;
Expand All @@ -913,14 +929,14 @@ static inline unsigned long page_table_reset_pmd(struct mm_struct *mm,
next = pmd_addr_end(addr, end);
if (pmd_none_or_clear_bad(pmd))
continue;
next = page_table_reset_pte(mm, pmd, addr, next);
next = page_table_reset_pte(mm, pmd, addr, next, init_skey);
} while (pmd++, addr = next, addr != end);

return addr;
}

static inline unsigned long page_table_reset_pud(struct mm_struct *mm,
pgd_t *pgd, unsigned long addr, unsigned long end)
static inline unsigned long page_table_reset_pud(struct mm_struct *mm, pgd_t *pgd,
unsigned long addr, unsigned long end, bool init_skey)
{
unsigned long next;
pud_t *pud;
Expand All @@ -930,14 +946,14 @@ static inline unsigned long page_table_reset_pud(struct mm_struct *mm,
next = pud_addr_end(addr, end);
if (pud_none_or_clear_bad(pud))
continue;
next = page_table_reset_pmd(mm, pud, addr, next);
next = page_table_reset_pmd(mm, pud, addr, next, init_skey);
} while (pud++, addr = next, addr != end);

return addr;
}

void page_table_reset_pgste(struct mm_struct *mm,
unsigned long start, unsigned long end)
void page_table_reset_pgste(struct mm_struct *mm, unsigned long start,
unsigned long end, bool init_skey)
{
unsigned long addr, next;
pgd_t *pgd;
Expand All @@ -949,7 +965,7 @@ void page_table_reset_pgste(struct mm_struct *mm,
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
next = page_table_reset_pud(mm, pgd, addr, next);
next = page_table_reset_pud(mm, pgd, addr, next, init_skey);
} while (pgd++, addr = next, addr != end);
up_read(&mm->mmap_sem);
}
Expand Down Expand Up @@ -1011,6 +1027,11 @@ static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
return NULL;
}

void page_table_reset_pgste(struct mm_struct *mm, unsigned long start,
unsigned long end, bool init_skey)
{
}

static inline void page_table_free_pgste(unsigned long *table)
{
}
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