KVM: Replace reads of vcpu->arch.cr3 by an accessor

This allows us to keep cr3 in the VMCS, later on.

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a2127f8..e558795 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2727,13 +2727,13 @@
 
 static void paging_new_cr3(struct kvm_vcpu *vcpu)
 {
-	pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
+	pgprintk("%s: cr3 %lx\n", __func__, kvm_read_cr3(vcpu));
 	mmu_free_roots(vcpu);
 }
 
 static unsigned long get_cr3(struct kvm_vcpu *vcpu)
 {
-	return vcpu->arch.cr3;
+	return kvm_read_cr3(vcpu);
 }
 
 static void inject_page_fault(struct kvm_vcpu *vcpu,
@@ -3637,7 +3637,7 @@
 
 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
 {
-	(void)kvm_set_cr3(vcpu, vcpu->arch.cr3);
+	(void)kvm_set_cr3(vcpu, kvm_read_cr3(vcpu));
 	return 1;
 }