KVM: MMU: do not update slot bitmap if spte is nonpresent
Xiao Guangrong [Mon, 11 Jul 2011 19:22:01 +0000 (03:22 +0800)]
Set slot bitmap only if the spte is present

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/mmu.c

index 03323dc..02c839f 100644 (file)
@@ -743,9 +743,6 @@ static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
        struct kvm_mmu_page *sp;
        unsigned long *rmapp;
 
-       if (!is_rmap_spte(*spte))
-               return 0;
-
        sp = page_header(__pa(spte));
        kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
        rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
@@ -2087,11 +2084,13 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
        if (!was_rmapped && is_large_pte(*sptep))
                ++vcpu->kvm->stat.lpages;
 
-       page_header_update_slot(vcpu->kvm, sptep, gfn);
-       if (!was_rmapped) {
-               rmap_count = rmap_add(vcpu, sptep, gfn);
-               if (rmap_count > RMAP_RECYCLE_THRESHOLD)
-                       rmap_recycle(vcpu, sptep, gfn);
+       if (is_shadow_present_pte(*sptep)) {
+               page_header_update_slot(vcpu->kvm, sptep, gfn);
+               if (!was_rmapped) {
+                       rmap_count = rmap_add(vcpu, sptep, gfn);
+                       if (rmap_count > RMAP_RECYCLE_THRESHOLD)
+                               rmap_recycle(vcpu, sptep, gfn);
+               }
        }
        kvm_release_pfn_clean(pfn);
        if (speculative) {