KVM: x86/mmu: Add helper to generate mask of reserved HPA bits

Add a helper to generate the mask of reserved PA bits in the host.

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210204000117.3303214-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

@@ -4123,6 +4123,11 @@ static void reset_rsvds_bits_mask_ept(struct kvm_vcpu *vcpu,
 				    vcpu->arch.reserved_gpa_bits, execonly);
 }
 
+static inline u64 reserved_hpa_bits(void)
+{
+	return rsvd_bits(shadow_phys_bits, 63);
+}
+
 /*
  * the page table on host is the shadow page table for the page
  * table in guest or amd nested guest, its mmu features completely
@@ -4142,7 +4147,7 @@ reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
 	 */
 	shadow_zero_check = &context->shadow_zero_check;
 	__reset_rsvds_bits_mask(vcpu, shadow_zero_check,
-				rsvd_bits(shadow_phys_bits, 63),
+				reserved_hpa_bits(),
 				context->shadow_root_level, uses_nx,
 				guest_cpuid_has(vcpu, X86_FEATURE_GBPAGES),
 				is_pse(vcpu), true);
@@ -4179,14 +4184,13 @@ reset_tdp_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
 
 	if (boot_cpu_is_amd())
 		__reset_rsvds_bits_mask(vcpu, shadow_zero_check,
-					rsvd_bits(shadow_phys_bits, 63),
+					reserved_hpa_bits(),
 					context->shadow_root_level, false,
 					boot_cpu_has(X86_FEATURE_GBPAGES),
 					true, true);
 	else
 		__reset_rsvds_bits_mask_ept(shadow_zero_check,
-					    rsvd_bits(shadow_phys_bits, 63),
-					    false);
+					    reserved_hpa_bits(), false);
 
 	if (!shadow_me_mask)
 		return;
@@ -4206,7 +4210,7 @@ reset_ept_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
 				struct kvm_mmu *context, bool execonly)
 {
 	__reset_rsvds_bits_mask_ept(&context->shadow_zero_check,
-				    rsvd_bits(shadow_phys_bits, 63), execonly);
+				    reserved_hpa_bits(), execonly);
 }
 
 #define BYTE_MASK(access) \