KVM: x86: Get vcpu->arch.apic_base directly and drop kvm_get_apic_base()

Access KVM's emulated APIC base MSR value directly instead of bouncing
through a helper, as there is no reason to add a layer of indirection, and
there are other MSRs with a "set" but no "get", e.g. EFER.

No functional change intended.

Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20241009181742.1128779-4-seanjc@google.com
Link: https://lore.kernel.org/r/20241101183555.1794700-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/lapic.h

@@ -117,7 +117,6 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
 		struct kvm_lapic_irq *irq, int *r, struct dest_map *dest_map);
 void kvm_apic_send_ipi(struct kvm_lapic *apic, u32 icr_low, u32 icr_high);
 
-u64 kvm_get_apic_base(struct kvm_vcpu *vcpu);
 int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 int kvm_apic_get_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);
 int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);

arch/x86/kvm/x86.c

@@ -668,14 +668,9 @@ static void drop_user_return_notifiers(void)
 		kvm_on_user_return(&msrs->urn);
 }
 
-u64 kvm_get_apic_base(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.apic_base;
-}
-
 enum lapic_mode kvm_get_apic_mode(struct kvm_vcpu *vcpu)
 {
-	return kvm_apic_mode(kvm_get_apic_base(vcpu));
+	return kvm_apic_mode(vcpu->arch.apic_base);
 }
 EXPORT_SYMBOL_GPL(kvm_get_apic_mode);
 
@@ -4315,7 +4310,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		msr_info->data = 1 << 24;
 		break;
 	case MSR_IA32_APICBASE:
-		msr_info->data = kvm_get_apic_base(vcpu);
+		msr_info->data = vcpu->arch.apic_base;
 		break;
 	case APIC_BASE_MSR ... APIC_BASE_MSR + 0xff:
 		return kvm_x2apic_msr_read(vcpu, msr_info->index, &msr_info->data);
@@ -10173,7 +10168,7 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu)
 
 	kvm_run->if_flag = kvm_x86_call(get_if_flag)(vcpu);
 	kvm_run->cr8 = kvm_get_cr8(vcpu);
-	kvm_run->apic_base = kvm_get_apic_base(vcpu);
+	kvm_run->apic_base = vcpu->arch.apic_base;
 
 	kvm_run->ready_for_interrupt_injection =
 		pic_in_kernel(vcpu->kvm) ||
@@ -11725,7 +11720,7 @@ static void __get_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
 	sregs->cr4 = kvm_read_cr4(vcpu);
 	sregs->cr8 = kvm_get_cr8(vcpu);
 	sregs->efer = vcpu->arch.efer;
-	sregs->apic_base = kvm_get_apic_base(vcpu);
+	sregs->apic_base = vcpu->arch.apic_base;
 }
 
 static void __get_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)