KVM: nSVM: split kvm_init_shadow_npt_mmu() from kvm_init_shadow_mmu()

As a preparatory change for moving kvm_mmu_new_pgd() from
nested_prepare_vmcb_save() to nested_svm_init_mmu_context() split
kvm_init_shadow_npt_mmu() from kvm_init_shadow_mmu(). This also makes
the code look more like nVMX (kvm_init_shadow_ept_mmu()).

No functional change intended.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200710141157.1640173-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu.h

@@ -57,7 +57,8 @@ void
 reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context);
 
 void kvm_init_mmu(struct kvm_vcpu *vcpu, bool reset_roots);
-void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer);
+void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer,
+			     gpa_t nested_cr3);
 void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
 			     bool accessed_dirty, gpa_t new_eptp);
 bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu);

arch/x86/kvm/mmu/mmu.c

@@ -4918,14 +4918,10 @@ kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu, bool base_only)
 	return role;
 }
 
-void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer)
+static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4,
+				    u32 efer, union kvm_mmu_role new_role)
 {
 	struct kvm_mmu *context = vcpu->arch.mmu;
-	union kvm_mmu_role new_role =
-		kvm_calc_shadow_mmu_root_page_role(vcpu, false);
-
-	if (new_role.as_u64 == context->mmu_role.as_u64)
-		return;
 
 	if (!(cr0 & X86_CR0_PG))
 		nonpaging_init_context(vcpu, context);
@@ -4939,7 +4935,28 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer)
 	context->mmu_role.as_u64 = new_role.as_u64;
 	reset_shadow_zero_bits_mask(vcpu, context);
 }
-EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
+
+static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer)
+{
+	struct kvm_mmu *context = vcpu->arch.mmu;
+	union kvm_mmu_role new_role =
+		kvm_calc_shadow_mmu_root_page_role(vcpu, false);
+
+	if (new_role.as_u64 != context->mmu_role.as_u64)
+		shadow_mmu_init_context(vcpu, cr0, cr4, efer, new_role);
+}
+
+void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer,
+			     gpa_t nested_cr3)
+{
+	struct kvm_mmu *context = vcpu->arch.mmu;
+	union kvm_mmu_role new_role =
+		kvm_calc_shadow_mmu_root_page_role(vcpu, false);
+
+	if (new_role.as_u64 != context->mmu_role.as_u64)
+		shadow_mmu_init_context(vcpu, cr0, cr4, efer, new_role);
+}
+EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
 
 static union kvm_mmu_role
 kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty,

arch/x86/kvm/svm/nested.c

@@ -87,7 +87,8 @@ static void nested_svm_init_mmu_context(struct kvm_vcpu *vcpu)
 	WARN_ON(mmu_is_nested(vcpu));
 
 	vcpu->arch.mmu = &vcpu->arch.guest_mmu;
-	kvm_init_shadow_mmu(vcpu, X86_CR0_PG, hsave->save.cr4, hsave->save.efer);
+	kvm_init_shadow_npt_mmu(vcpu, X86_CR0_PG, hsave->save.cr4, hsave->save.efer,
+				svm->nested.ctl.nested_cr3);
 	vcpu->arch.mmu->get_guest_pgd     = nested_svm_get_tdp_cr3;
 	vcpu->arch.mmu->get_pdptr         = nested_svm_get_tdp_pdptr;
 	vcpu->arch.mmu->inject_page_fault = nested_svm_inject_npf_exit;