KVM: MMU: Make set_cr3 a function pointer in kvm_mmu

This is necessary to implement Nested Nested Paging. As a
side effect this allows some cleanups in the SVM nested
paging code.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -236,6 +236,7 @@ struct kvm_pio_request {
  */
 struct kvm_mmu {
 	void (*new_cr3)(struct kvm_vcpu *vcpu);
+	void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long root);
 	int (*page_fault)(struct kvm_vcpu *vcpu, gva_t gva, u32 err);
 	void (*free)(struct kvm_vcpu *vcpu);
 	gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t gva, u32 access,

arch/x86/kvm/mmu.c

@@ -2714,6 +2714,7 @@ static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
 	context->shadow_root_level = kvm_x86_ops->get_tdp_level();
 	context->root_hpa = INVALID_PAGE;
 	context->direct_map = true;
+	context->set_cr3 = kvm_x86_ops->set_cr3;
 
 	if (!is_paging(vcpu)) {
 		context->gva_to_gpa = nonpaging_gva_to_gpa;
@@ -2753,6 +2754,7 @@ static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
 
 	vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
 	vcpu->arch.mmu.base_role.cr0_wp  = is_write_protection(vcpu);
+	vcpu->arch.mmu.set_cr3           = kvm_x86_ops->set_cr3;
 
 	return r;
 }
@@ -2796,7 +2798,7 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
 	if (r)
 		goto out;
 	/* set_cr3() should ensure TLB has been flushed */
-	kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
+	vcpu->arch.mmu.set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
 out:
 	return r;
 }