KVM: x86/mmu: do not recompute root level from kvm_mmu_role_regs

The root_level can be found in the cpu_role (in fact the field
is superfluous and could be removed, but one thing at a time).
Since there is only one usage left of role_regs_to_root_level,
inline it into kvm_calc_cpu_role.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

@@ -245,19 +245,6 @@ static struct kvm_mmu_role_regs vcpu_to_role_regs(struct kvm_vcpu *vcpu)
 	return regs;
 }
 
-static int role_regs_to_root_level(const struct kvm_mmu_role_regs *regs)
-{
-	if (!____is_cr0_pg(regs))
-		return 0;
-	else if (____is_efer_lma(regs))
-		return ____is_cr4_la57(regs) ? PT64_ROOT_5LEVEL :
-					       PT64_ROOT_4LEVEL;
-	else if (____is_cr4_pae(regs))
-		return PT32E_ROOT_LEVEL;
-	else
-		return PT32_ROOT_LEVEL;
-}
-
 static inline bool kvm_available_flush_tlb_with_range(void)
 {
 	return kvm_x86_ops.tlb_remote_flush_with_range;
@@ -4768,7 +4755,14 @@ kvm_calc_cpu_role(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
 	role.base.smep_andnot_wp = ____is_cr4_smep(regs) && !____is_cr0_wp(regs);
 	role.base.smap_andnot_wp = ____is_cr4_smap(regs) && !____is_cr0_wp(regs);
 	role.base.has_4_byte_gpte = !____is_cr4_pae(regs);
-	role.base.level = role_regs_to_root_level(regs);
+
+	if (____is_efer_lma(regs))
+		role.base.level = ____is_cr4_la57(regs) ? PT64_ROOT_5LEVEL
+							: PT64_ROOT_4LEVEL;
+	else if (____is_cr4_pae(regs))
+		role.base.level = PT32E_ROOT_LEVEL;
+	else
+		role.base.level = PT32_ROOT_LEVEL;
 
 	role.ext.cr0_pg = 1;
 	role.ext.cr4_pae = ____is_cr4_pae(regs);
@@ -4860,7 +4854,7 @@ 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 = cpu_role.base.level;
 
 	if (!is_cr0_pg(context))
 		context->gva_to_gpa = nonpaging_gva_to_gpa;