diff options
Diffstat (limited to 'arch/s390/mm')
-rw-r--r-- | arch/s390/mm/pgtable.c | 106 |
1 files changed, 79 insertions, 27 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 4324b87..fa286d0 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -506,12 +506,9 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr, pgste_t old, new; pte_t *ptep; - down_read(&mm->mmap_sem); ptep = get_locked_pte(mm, addr, &ptl); - if (unlikely(!ptep)) { - up_read(&mm->mmap_sem); + if (unlikely(!ptep)) return -EFAULT; - } new = old = pgste_get_lock(ptep); pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT | @@ -538,45 +535,100 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr, pgste_set_unlock(ptep, new); pte_unmap_unlock(ptep, ptl); - up_read(&mm->mmap_sem); return 0; } EXPORT_SYMBOL(set_guest_storage_key); -unsigned char get_guest_storage_key(struct mm_struct *mm, unsigned long addr) +/** + * 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) { - unsigned char key; spinlock_t *ptl; - pgste_t pgste; + pgste_t old, new; pte_t *ptep; + int cc = 0; - down_read(&mm->mmap_sem); ptep = get_locked_pte(mm, addr, &ptl); - if (unlikely(!ptep)) { - up_read(&mm->mmap_sem); + if (unlikely(!ptep)) return -EFAULT; - } - pgste = pgste_get_lock(ptep); - if (pte_val(*ptep) & _PAGE_INVALID) { - key = (pgste_val(pgste) & PGSTE_ACC_BITS) >> 56; - key |= (pgste_val(pgste) & PGSTE_FP_BIT) >> 56; - key |= (pgste_val(pgste) & PGSTE_GR_BIT) >> 48; - key |= (pgste_val(pgste) & PGSTE_GC_BIT) >> 48; - } else { - key = page_get_storage_key(pte_val(*ptep) & PAGE_MASK); + new = old = pgste_get_lock(ptep); + /* Reset guest reference bit only */ + pgste_val(new) &= ~PGSTE_GR_BIT; - /* Reflect guest's logical view, not physical */ - if (pgste_val(pgste) & PGSTE_GR_BIT) - key |= _PAGE_REFERENCED; - if (pgste_val(pgste) & PGSTE_GC_BIT) - key |= _PAGE_CHANGED; + 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 0; +} +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); - up_read(&mm->mmap_sem); - return key; + return 0; } EXPORT_SYMBOL(get_guest_storage_key); #endif |