From 57128468080a8b6ea452223036d3e417f748af55 Mon Sep 17 00:00:00 2001 From: Andres Lagar-Cavilla Date: Mon, 22 Sep 2014 14:54:42 -0700 Subject: kvm: Fix page ageing bugs 1. We were calling clear_flush_young_notify in unmap_one, but we are within an mmu notifier invalidate range scope. The spte exists no more (due to range_start) and the accessed bit info has already been propagated (due to kvm_pfn_set_accessed). Simply call clear_flush_young. 2. We clear_flush_young on a primary MMU PMD, but this may be mapped as a collection of PTEs by the secondary MMU (e.g. during log-dirty). This required expanding the interface of the clear_flush_young mmu notifier, so a lot of code has been trivially touched. 3. In the absence of shadow_accessed_mask (e.g. EPT A bit), we emulate the access bit by blowing the spte. This requires proper synchronizing with MMU notifier consumers, like every other removal of spte's does. Signed-off-by: Andres Lagar-Cavilla Acked-by: Rik van Riel Signed-off-by: Paolo Bonzini --- include/linux/mmu_notifier.h | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) (limited to 'include/linux/mmu_notifier.h') diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 27288692241e..88787bb4b3b9 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -57,10 +57,13 @@ struct mmu_notifier_ops { * pte. This way the VM will provide proper aging to the * accesses to the page through the secondary MMUs and not * only to the ones through the Linux pte. + * Start-end is necessary in case the secondary MMU is mapping the page + * at a smaller granularity than the primary MMU. */ int (*clear_flush_young)(struct mmu_notifier *mn, struct mm_struct *mm, - unsigned long address); + unsigned long start, + unsigned long end); /* * test_young is called to check the young/accessed bitflag in @@ -175,7 +178,8 @@ extern void mmu_notifier_unregister_no_release(struct mmu_notifier *mn, extern void __mmu_notifier_mm_destroy(struct mm_struct *mm); extern void __mmu_notifier_release(struct mm_struct *mm); extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm, - unsigned long address); + unsigned long start, + unsigned long end); extern int __mmu_notifier_test_young(struct mm_struct *mm, unsigned long address); extern void __mmu_notifier_change_pte(struct mm_struct *mm, @@ -194,10 +198,11 @@ static inline void mmu_notifier_release(struct mm_struct *mm) } static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm, - unsigned long address) + unsigned long start, + unsigned long end) { if (mm_has_notifiers(mm)) - return __mmu_notifier_clear_flush_young(mm, address); + return __mmu_notifier_clear_flush_young(mm, start, end); return 0; } @@ -255,7 +260,9 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) unsigned long ___address = __address; \ __young = ptep_clear_flush_young(___vma, ___address, __ptep); \ __young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \ - ___address); \ + ___address, \ + ___address + \ + PAGE_SIZE); \ __young; \ }) @@ -266,7 +273,9 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) unsigned long ___address = __address; \ __young = pmdp_clear_flush_young(___vma, ___address, __pmdp); \ __young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \ - ___address); \ + ___address, \ + ___address + \ + PMD_SIZE); \ __young; \ }) @@ -301,7 +310,8 @@ static inline void mmu_notifier_release(struct mm_struct *mm) } static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm, - unsigned long address) + unsigned long start, + unsigned long end) { return 0; } -- cgit v1.2.3