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authorIzik Eidus <ieidus@redhat.com>2009-09-23 18:47:16 (GMT)
committerAvi Kivity <avi@redhat.com>2009-10-04 15:04:48 (GMT)
commitacb66dd051d0834c8b36d147ff83a8d39da0fe0b (patch)
tree20c5fb817e34ddca6dd4ec20ce70613eba5b10d1
parent6a54435560efdab1a08f429a954df4d6c740bddf (diff)
downloadlinux-fsl-qoriq-acb66dd051d0834c8b36d147ff83a8d39da0fe0b.tar.xz
KVM: MMU: dont hold pagecount reference for mapped sptes pages
When using mmu notifiers, we are allowed to remove the page count reference tooken by get_user_pages to a specific page that is mapped inside the shadow page tables. This is needed so we can balance the pagecount against mapcount checking. (Right now kvm increase the pagecount and does not increase the mapcount when mapping page into shadow page table entry, so when comparing pagecount against mapcount, you have no reliable result.) Signed-off-by: Izik Eidus <ieidus@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
-rw-r--r--arch/x86/kvm/mmu.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index eca41ae..6c67b23 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -634,9 +634,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
if (*spte & shadow_accessed_mask)
kvm_set_pfn_accessed(pfn);
if (is_writeble_pte(*spte))
- kvm_release_pfn_dirty(pfn);
- else
- kvm_release_pfn_clean(pfn);
+ kvm_set_pfn_dirty(pfn);
rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], sp->role.level);
if (!*rmapp) {
printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
@@ -1877,8 +1875,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
page_header_update_slot(vcpu->kvm, sptep, gfn);
if (!was_rmapped) {
rmap_count = rmap_add(vcpu, sptep, gfn);
- if (!is_rmap_spte(*sptep))
- kvm_release_pfn_clean(pfn);
+ kvm_release_pfn_clean(pfn);
if (rmap_count > RMAP_RECYCLE_THRESHOLD)
rmap_recycle(vcpu, sptep, gfn);
} else {