diff options
| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2013-06-12 13:54:52 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2013-06-17 17:04:30 +0200 |
| commit | db70ccdfb9953b984f5b95d98c50d8da335bab59 (patch) | |
| tree | 0fcf0e279caf6c7b9652a7e6bc824fe926b893dd /arch/s390/mm/pgtable.c | |
| parent | 8915aa27d5efbb9185357175b0acf884325565f9 (diff) | |
KVM: s390: Provide function for setting the guest storage key
From time to time we need to set the guest storage key. Lets
provide a helper function that handles the changes with all the
right locking and checking.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/s390/mm/pgtable.c')
| -rw-r--r-- | arch/s390/mm/pgtable.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 1e0c438dbd65..44b145055f35 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -771,6 +771,54 @@ static inline void page_table_free_pgste(unsigned long *table) __free_page(page); } +int set_guest_storage_key(struct mm_struct *mm, unsigned long addr, + unsigned long key, bool nq) +{ + spinlock_t *ptl; + pgste_t old, new; + pte_t *ptep; + + down_read(&mm->mmap_sem); + ptep = get_locked_pte(current->mm, addr, &ptl); + if (unlikely(!ptep)) { + up_read(&mm->mmap_sem); + return -EFAULT; + } + + new = old = pgste_get_lock(ptep); + pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT | + PGSTE_ACC_BITS | PGSTE_FP_BIT); + pgste_val(new) |= (key & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48; + pgste_val(new) |= (key & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56; + if (!(pte_val(*ptep) & _PAGE_INVALID)) { + unsigned long address, bits; + unsigned char skey; + + address = pte_val(*ptep) & PAGE_MASK; + skey = page_get_storage_key(address); + bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED); + /* Set storage key ACC and FP */ + page_set_storage_key(address, + (key & (_PAGE_ACC_BITS | _PAGE_FP_BIT)), + !nq); + + /* Merge host changed & referenced into pgste */ + pgste_val(new) |= bits << 52; + /* Transfer skey changed & referenced bit to kvm user bits */ + pgste_val(new) |= bits << 45; /* PGSTE_UR_BIT & PGSTE_UC_BIT */ + } + /* 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); + up_read(&mm->mmap_sem); + return 0; +} +EXPORT_SYMBOL(set_guest_storage_key); + #else /* CONFIG_PGSTE */ static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm, |