From a0bf4f149bbfa2e31b5f4172c817afdb7b986733 Mon Sep 17 00:00:00 2001 From: Dominik Dingel Date: Mon, 24 Mar 2014 14:27:58 +0100 Subject: [PATCH] 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 Acked-by: Martin Schwidefsky Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/pgtable.h | 2 ++ arch/s390/mm/pgtable.c | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index b2c630df0ca57..fcba5e03839f5 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 1ddf975352a07..ea4a31b959900 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)