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Commit a0bf4f14 authored by Dominik Dingel's avatar Dominik Dingel Committed by Christian Borntraeger
Browse files

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: default avatarDominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 0a61b222

arch/s390/include/asm/pgtable.h

+2 −0
Original line number Diff line number Diff line
@@ -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 *);

arch/s390/mm/pgtable.c

+21 −0
Original line number Diff line number Diff line
@@ -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)