KVM: x86/mmu: pull computation of kvm_mmu_role_regs to kvm_init_mmu

The init_kvm_*mmu functions, with the exception of shadow NPT,
do not need to know the full values of CR0/CR4/EFER; they only
need to know the bits that make up the "role".  This cleanup
however will take quite a few incremental steps.  As a start,
pull the common computation of the struct kvm_mmu_role_regs
into their caller: all of them extract the struct from the vcpu
as the very first step.
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

@@ -4821,12 +4821,12 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
 	return role;
 }
 
-static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
+static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
+			     const struct kvm_mmu_role_regs *regs)
 {
 	struct kvm_mmu *context = &vcpu->arch.root_mmu;
-	struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
 	union kvm_mmu_role new_role =
-		kvm_calc_tdp_mmu_root_page_role(vcpu, &regs, false);
+		kvm_calc_tdp_mmu_root_page_role(vcpu, regs, false);
 
 	if (new_role.as_u64 == context->mmu_role.as_u64)
 		return;
@@ -4840,7 +4840,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
 	context->get_guest_pgd = get_cr3;
 	context->get_pdptr = kvm_pdptr_read;
 	context->inject_page_fault = kvm_inject_page_fault;
-	context->root_level = role_regs_to_root_level(&regs);
+	context->root_level = role_regs_to_root_level(regs);
 
 	if (!is_cr0_pg(context))
 		context->gva_to_gpa = nonpaging_gva_to_gpa;
@@ -5009,12 +5009,12 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
 }
 EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);
 
-static void init_kvm_softmmu(struct kvm_vcpu *vcpu)
+static void init_kvm_softmmu(struct kvm_vcpu *vcpu,
+			     const struct kvm_mmu_role_regs *regs)
 {
 	struct kvm_mmu *context = &vcpu->arch.root_mmu;
-	struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
 
-	kvm_init_shadow_mmu(vcpu, &regs);
+	kvm_init_shadow_mmu(vcpu, regs);
 
 	context->get_guest_pgd     = get_cr3;
 	context->get_pdptr         = kvm_pdptr_read;
@@ -5038,10 +5038,10 @@ kvm_calc_nested_mmu_role(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *
 	return role;
 }
 
-static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
+static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu,
+				const struct kvm_mmu_role_regs *regs)
 {
-	struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
-	union kvm_mmu_role new_role = kvm_calc_nested_mmu_role(vcpu, &regs);
+	union kvm_mmu_role new_role = kvm_calc_nested_mmu_role(vcpu, regs);
 	struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
 
 	if (new_role.as_u64 == g_context->mmu_role.as_u64)
@@ -5081,12 +5081,14 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 
 void kvm_init_mmu(struct kvm_vcpu *vcpu)
 {
+	struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
+
 	if (mmu_is_nested(vcpu))
-		init_kvm_nested_mmu(vcpu);
+		init_kvm_nested_mmu(vcpu, &regs);
 	else if (tdp_enabled)
-		init_kvm_tdp_mmu(vcpu);
+		init_kvm_tdp_mmu(vcpu, &regs);
 	else
-		init_kvm_softmmu(vcpu);
+		init_kvm_softmmu(vcpu, &regs);
 }
 EXPORT_SYMBOL_GPL(kvm_init_mmu);