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| author | Dominik Dingel <dingel@linux.vnet.ibm.com> | 2014-01-14 17:10:17 (GMT) |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-04-22 07:36:25 (GMT) |
| commit | 934bc131efc3e4be6a52f7dd6c4dbf99635e381a (patch) | |
| tree | 67b5df8e42e7db5f1f59f7d851b97923b5336678 /arch/s390 | |
| parent | d4cb11340be6a1613d40d2b546cb111ea2547066 (diff) | |
| download | linux-934bc131efc3e4be6a52f7dd6c4dbf99635e381a.tar.xz | |
KVM: s390: Allow skeys to be enabled for the current process
Introduce a new function s390_enable_skey(), which enables storage key
handling via setting the use_skey flag in the mmu context.
This function is only useful within the context of kvm.
Note that enabling storage keys will cause a one-time hickup when
walking the page table; however, it saves us special effort for cases
like clear reset while making it possible for us to be architecture
conform.
s390_enable_skey() takes the page table lock to prevent reseting
storage keys triggered from multiple vcpus.
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>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 1 | ||||
| -rw-r--r-- | arch/s390/mm/pgtable.c | 23 |
2 files changed, 24 insertions, 0 deletions
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index e88e9f6..51b002b 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1747,6 +1747,7 @@ static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset) extern int vmem_add_mapping(unsigned long start, unsigned long size); extern int vmem_remove_mapping(unsigned long start, unsigned long size); extern int s390_enable_sie(void); +extern void s390_enable_skey(void); /* * No page table caches to initialise diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index be80f55..02a8607 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -1378,6 +1378,29 @@ int s390_enable_sie(void) } EXPORT_SYMBOL_GPL(s390_enable_sie); +/* + * Enable storage key handling from now on and initialize the storage + * keys with the default key. + */ +void s390_enable_skey(void) +{ + /* + * To avoid races between multiple vcpus, ending in calling + * page_table_reset twice or more, + * the page_table_lock is taken for serialization. + */ + spin_lock(¤t->mm->page_table_lock); + if (mm_use_skey(current->mm)) { + spin_unlock(¤t->mm->page_table_lock); + return; + } + + current->mm->context.use_skey = 1; + spin_unlock(¤t->mm->page_table_lock); + page_table_reset_pgste(current->mm, 0, TASK_SIZE, true); +} +EXPORT_SYMBOL_GPL(s390_enable_skey); + #ifdef CONFIG_TRANSPARENT_HUGEPAGE int pmdp_clear_flush_young(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp) |