diff options
| -rw-r--r-- | include/linux/mmu_notifier.h | 44 | ||||
| -rw-r--r-- | mm/mmu_notifier.c | 17 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 31 |
3 files changed, 92 insertions, 0 deletions
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 61cd67f4d788..a5b17137c683 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -66,6 +66,16 @@ struct mmu_notifier_ops { unsigned long end); /* + * clear_young is a lightweight version of clear_flush_young. Like the + * latter, it is supposed to test-and-clear the young/accessed bitflag + * in the secondary pte, but it may omit flushing the secondary tlb. + */ + int (*clear_young)(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, + unsigned long end); + + /* * test_young is called to check the young/accessed bitflag in * the secondary pte. This is used to know if the page is * frequently used without actually clearing the flag or tearing @@ -203,6 +213,9 @@ extern void __mmu_notifier_release(struct mm_struct *mm); extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm, unsigned long start, unsigned long end); +extern int __mmu_notifier_clear_young(struct mm_struct *mm, + 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, @@ -231,6 +244,15 @@ static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm, return 0; } +static inline int mmu_notifier_clear_young(struct mm_struct *mm, + unsigned long start, + unsigned long end) +{ + if (mm_has_notifiers(mm)) + return __mmu_notifier_clear_young(mm, start, end); + return 0; +} + static inline int mmu_notifier_test_young(struct mm_struct *mm, unsigned long address) { @@ -311,6 +333,28 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) __young; \ }) +#define ptep_clear_young_notify(__vma, __address, __ptep) \ +({ \ + int __young; \ + struct vm_area_struct *___vma = __vma; \ + unsigned long ___address = __address; \ + __young = ptep_test_and_clear_young(___vma, ___address, __ptep);\ + __young |= mmu_notifier_clear_young(___vma->vm_mm, ___address, \ + ___address + PAGE_SIZE); \ + __young; \ +}) + +#define pmdp_clear_young_notify(__vma, __address, __pmdp) \ +({ \ + int __young; \ + struct vm_area_struct *___vma = __vma; \ + unsigned long ___address = __address; \ + __young = pmdp_test_and_clear_young(___vma, ___address, __pmdp);\ + __young |= mmu_notifier_clear_young(___vma->vm_mm, ___address, \ + ___address + PMD_SIZE); \ + __young; \ +}) + #define ptep_clear_flush_notify(__vma, __address, __ptep) \ ({ \ unsigned long ___addr = __address & PAGE_MASK; \ diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 3b9b3d0741b2..5fbdd367bbed 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -123,6 +123,23 @@ int __mmu_notifier_clear_flush_young(struct mm_struct *mm, return young; } +int __mmu_notifier_clear_young(struct mm_struct *mm, + unsigned long start, + unsigned long end) +{ + struct mmu_notifier *mn; + int young = 0, id; + + id = srcu_read_lock(&srcu); + hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { + if (mn->ops->clear_young) + young |= mn->ops->clear_young(mn, mm, start, end); + } + srcu_read_unlock(&srcu, id); + + return young; +} + int __mmu_notifier_test_young(struct mm_struct *mm, unsigned long address) { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d8db2f8fce9c..268fc0a5a932 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -387,6 +387,36 @@ static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn, return young; } +static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, + unsigned long end) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + int young, idx; + + idx = srcu_read_lock(&kvm->srcu); + spin_lock(&kvm->mmu_lock); + /* + * Even though we do not flush TLB, this will still adversely + * affect performance on pre-Haswell Intel EPT, where there is + * no EPT Access Bit to clear so that we have to tear down EPT + * tables instead. If we find this unacceptable, we can always + * add a parameter to kvm_age_hva so that it effectively doesn't + * do anything on clear_young. + * + * Also note that currently we never issue secondary TLB flushes + * from clear_young, leaving this job up to the regular system + * cadence. If we find this inaccurate, we might come up with a + * more sophisticated heuristic later. + */ + young = kvm_age_hva(kvm, start, end); + spin_unlock(&kvm->mmu_lock); + srcu_read_unlock(&kvm->srcu, idx); + + return young; +} + static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn, struct mm_struct *mm, unsigned long address) @@ -419,6 +449,7 @@ static const struct mmu_notifier_ops kvm_mmu_notifier_ops = { .invalidate_range_start = kvm_mmu_notifier_invalidate_range_start, .invalidate_range_end = kvm_mmu_notifier_invalidate_range_end, .clear_flush_young = kvm_mmu_notifier_clear_flush_young, + .clear_young = kvm_mmu_notifier_clear_young, .test_young = kvm_mmu_notifier_test_young, .change_pte = kvm_mmu_notifier_change_pte, .release = kvm_mmu_notifier_release, |