3 files changed, 38 insertions, 0 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 90f01169c8f0..9d8c4bb68a81 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1471,6 +1471,41 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
         vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
 }
 
+static void mmu_sync_children(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+}
+
+static void mmu_sync_roots(struct kvm_vcpu *vcpu)
+{
+        int i;
+        struct kvm_mmu_page *sp;
+
+        if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
+                return;
+        if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
+                hpa_t root = vcpu->arch.mmu.root_hpa;
+                sp = page_header(root);
+                mmu_sync_children(vcpu, sp);
+                return;
+        }
+        for (i = 0; i < 4; ++i) {
+                hpa_t root = vcpu->arch.mmu.pae_root[i];
+
+                if (root) {
+                        root &= PT64_BASE_ADDR_MASK;
+                        sp = page_header(root);
+                        mmu_sync_children(vcpu, sp);
+                }
+        }
+}
+
+void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
+{
+        spin_lock(&vcpu->kvm->mmu_lock);
+        mmu_sync_roots(vcpu);
+        spin_unlock(&vcpu->kvm->mmu_lock);
+}
+
 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
 {
         return vaddr;
@@ -1715,6 +1750,7 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
         spin_lock(&vcpu->kvm->mmu_lock);
         kvm_mmu_free_some_pages(vcpu);
         mmu_alloc_roots(vcpu);
+        mmu_sync_roots(vcpu);
         spin_unlock(&vcpu->kvm->mmu_lock);
         kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
         kvm_mmu_flush_tlb(vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 08edeabf15e6..88e6d9abbd2b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -594,6 +594,7 @@ EXPORT_SYMBOL_GPL(kvm_set_cr4);
 void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 {
         if (cr3 == vcpu->arch.cr3 && !pdptrs_changed(vcpu)) {
+                kvm_mmu_sync_roots(vcpu);
                 kvm_mmu_flush_tlb(vcpu);
                 return;
         }
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 8bad9bd9b37e..475d8ab83bff 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -584,6 +584,7 @@ int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva);
 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
 int kvm_mmu_load(struct kvm_vcpu *vcpu);
 void kvm_mmu_unload(struct kvm_vcpu *vcpu);
+void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu);
 
 int kvm_emulate_hypercall(struct kvm_vcpu *vcpu);