diff options
| author | Dominik Dingel <dingel@linux.vnet.ibm.com> | 2014-03-24 14:27:58 +0100 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-04-22 09:36:27 +0200 |
| commit | a0bf4f149bbfa2e31b5f4172c817afdb7b986733 (patch) | |
| tree | ed16368e498daaf4451241b5c734368a31986b1e | |
| parent | 0a61b222df75a6a69dc34816f7db2f61fee8c935 (diff) | |
KVM: s390/mm: new gmap_test_and_clear_dirty function
For live migration kvm needs to test and clear the dirty bit of guest pages.
That for is ptep_test_and_clear_user_dirty, to be sure we are not racing with
other code, we protect the pte. This needs to be done within
the architecture memory management code.
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>
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 2 | ||||
| -rw-r--r-- | arch/s390/mm/pgtable.c | 21 |
2 files changed, 23 insertions, 0 deletions
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index b2c630df0ca..fcba5e03839 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -838,6 +838,8 @@ unsigned long __gmap_fault(unsigned long address, struct gmap *); unsigned long gmap_fault(unsigned long address, struct gmap *); void gmap_discard(unsigned long from, unsigned long to, struct gmap *); void __gmap_zap(unsigned long address, struct gmap *); +bool gmap_test_and_clear_dirty(unsigned long address, struct gmap *); + void gmap_register_ipte_notifier(struct gmap_notifier *); void gmap_unregister_ipte_notifier(struct gmap_notifier *); diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 1ddf975352a..ea4a31b9599 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -1401,6 +1401,27 @@ void s390_enable_skey(void) } EXPORT_SYMBOL_GPL(s390_enable_skey); +/* + * Test and reset if a guest page is dirty + */ +bool gmap_test_and_clear_dirty(unsigned long address, struct gmap *gmap) +{ + pte_t *pte; + spinlock_t *ptl; + bool dirty = false; + + pte = get_locked_pte(gmap->mm, address, &ptl); + if (unlikely(!pte)) + return false; + + if (ptep_test_and_clear_user_dirty(gmap->mm, address, pte)) + dirty = true; + + spin_unlock(ptl); + return dirty; +} +EXPORT_SYMBOL_GPL(gmap_test_and_clear_dirty); + #ifdef CONFIG_TRANSPARENT_HUGEPAGE int pmdp_clear_flush_young(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp) |