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authorAvi Kivity <avi@redhat.com>2010-06-06 14:31:27 +0300
committerAvi Kivity <avi@redhat.com>2010-08-02 06:40:17 +0300
commitbe38d276b0189fa86231fc311428622a1981ad62 (patch)
tree4706819e23ade99c43bb676830071da9bd2d0abd /arch/x86/kvm/paging_tmpl.h
parentdd180b3e90253cb4ca95d603a8c17413f8daec69 (diff)
KVM: MMU: Introduce drop_spte()
When we call rmap_remove(), we (almost) always immediately follow it by an __set_spte() to a nonpresent pte. Since we need to perform the two operations atomically, to avoid losing the dirty and accessed bits, introduce a helper drop_spte() and convert all call sites. The operation is still nonatomic at this point. Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm/paging_tmpl.h')
-rw-r--r--arch/x86/kvm/paging_tmpl.h13
1 files changed, 6 insertions, 7 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 59e750c1a26..796a325c7e5 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -353,8 +353,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
}
if (is_large_pte(*sptep)) {
- rmap_remove(vcpu->kvm, sptep);
- __set_spte(sptep, shadow_trap_nonpresent_pte);
+ drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
kvm_flush_remote_tlbs(vcpu->kvm);
}
@@ -516,12 +515,13 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
if (is_shadow_present_pte(*sptep)) {
- rmap_remove(vcpu->kvm, sptep);
if (is_large_pte(*sptep))
--vcpu->kvm->stat.lpages;
+ drop_spte(vcpu->kvm, sptep,
+ shadow_trap_nonpresent_pte);
need_flush = 1;
- }
- __set_spte(sptep, shadow_trap_nonpresent_pte);
+ } else
+ __set_spte(sptep, shadow_trap_nonpresent_pte);
break;
}
@@ -637,12 +637,11 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
!is_present_gpte(gpte) || !(gpte & PT_ACCESSED_MASK)) {
u64 nonpresent;
- rmap_remove(vcpu->kvm, &sp->spt[i]);
if (is_present_gpte(gpte) || !clear_unsync)
nonpresent = shadow_trap_nonpresent_pte;
else
nonpresent = shadow_notrap_nonpresent_pte;
- __set_spte(&sp->spt[i], nonpresent);
+ drop_spte(vcpu->kvm, &sp->spt[i], nonpresent);
continue;
}