[patch 10/13] KVM: MMU: sync roots on mmu reload

[Marcelo Tosatti <mtosatti@redhat.com>]

[-- Attachment #1: kvm-oos-hook-cr3 --]
[-- Type: text/plain, Size: 3099 bytes --]

Bring the pages for the root being switched to back in sync.

Index: kvm/arch/x86/kvm/mmu.c
===================================================================
--- kvm.orig/arch/x86/kvm/mmu.c
+++ kvm/arch/x86/kvm/mmu.c
@@ -1065,6 +1065,20 @@ static int kvm_unsync_page(struct kvm_vc
 		return mmu_unsync_page(vcpu, sp);
 }
 
+static int mmu_sync_root(struct kvm_vcpu *vcpu, struct kvm_mmu_page *root_sp)
+{
+	struct kvm_mmu_page *sp, *n;
+	int ret = 0;
+
+	list_for_each_entry_safe(sp, n, &root_sp->unsync_pages, oos_link) {
+		ret = 1;
+		kvm_sync_page(vcpu, sp);
+	}
+
+	OOS_ASSERT(list_empty(&root_sp->unsync_pages));
+	return ret;
+}
+
 static int set_shared_mmu_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 {
 	struct kvm_mmu_page *root_sp;
@@ -1075,6 +1089,8 @@ static int set_shared_mmu_page(struct kv
 			kvm_sync_page(vcpu, sp);
 	} else if (sp->root_gfn != -1) {
 		root_sp = kvm_mmu_lookup_page_root(vcpu, sp->root_gfn);
+		if (root_sp)
+			ret = mmu_sync_root(vcpu, root_sp);
 	}
 
 	sp->root_gfn = -1;
@@ -1716,6 +1732,37 @@ static void mmu_alloc_roots(struct kvm_v
 	vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
 }
 
+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_root(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_root(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;
@@ -1960,6 +2007,7 @@ 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);
Index: kvm/arch/x86/kvm/x86.c
===================================================================
--- kvm.orig/arch/x86/kvm/x86.c
+++ kvm/arch/x86/kvm/x86.c
@@ -582,6 +582,7 @@ 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;
 	}
Index: kvm/include/asm-x86/kvm_host.h
===================================================================
--- kvm.orig/include/asm-x86/kvm_host.h
+++ kvm/include/asm-x86/kvm_host.h
@@ -610,6 +610,7 @@ int kvm_mmu_unprotect_page_virt(struct k
 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);
 

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