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kvm: Fix page ageing bugs

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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 <andreslc@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Andres Lagar-Cavilla
2014-09-22 14:54:42 -07:00
committed by Paolo Bonzini
parent 8a9522d2fe
commit 5712846808
16 changed files with 71 additions and 41 deletions
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mm/mmu_notifier.c
+3 -2
View File
@@ -107,7 +107,8 @@ void __mmu_notifier_release(struct mm_struct *mm)
* existed or not.
*/
int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
unsigned long address)
unsigned long start,
unsigned long end)
{
struct mmu_notifier *mn;
int young = 0, id;
@@ -115,7 +116,7 @@ int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
if (mn->ops->clear_flush_young)
young |= mn->ops->clear_flush_young(mn, mm, address);
young |= mn->ops->clear_flush_young(mn, mm, start, end);
}
srcu_read_unlock(&srcu, id);