KVM: x86: Unpack msr_data structure prior to calling kvm_apic_set_base()

Pass in the new value and "host initiated" as separate parameters to
kvm_apic_set_base(), as forcing the KVM_SET_SREGS path to declare and fill
an msr_data structure is awkward and kludgy, e.g. __set_sregs_common()
doesn't even bother to set the proper MSR index.

No functional change intended.

Suggested-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20241101183555.1794700-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/lapic.c

@@ -2628,23 +2628,23 @@ static void __kvm_apic_set_base(struct kvm_vcpu *vcpu, u64 value)
 	}
 }
 
-int kvm_apic_set_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
+int kvm_apic_set_base(struct kvm_vcpu *vcpu, u64 value, bool host_initiated)
 {
 	enum lapic_mode old_mode = kvm_get_apic_mode(vcpu);
-	enum lapic_mode new_mode = kvm_apic_mode(msr_info->data);
+	enum lapic_mode new_mode = kvm_apic_mode(value);
 	u64 reserved_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu) | 0x2ff |
 		(guest_cpuid_has(vcpu, X86_FEATURE_X2APIC) ? 0 : X2APIC_ENABLE);
 
-	if ((msr_info->data & reserved_bits) != 0 || new_mode == LAPIC_MODE_INVALID)
+	if ((value & reserved_bits) != 0 || new_mode == LAPIC_MODE_INVALID)
 		return 1;
-	if (!msr_info->host_initiated) {
+	if (!host_initiated) {
 		if (old_mode == LAPIC_MODE_X2APIC && new_mode == LAPIC_MODE_XAPIC)
 			return 1;
 		if (old_mode == LAPIC_MODE_DISABLED && new_mode == LAPIC_MODE_X2APIC)
 			return 1;
 	}
 
-	__kvm_apic_set_base(vcpu, msr_info->data);
+	__kvm_apic_set_base(vcpu, value);
 	kvm_recalculate_apic_map(vcpu->kvm);
 	return 0;
 }

arch/x86/kvm/lapic.h

@@ -115,7 +115,7 @@ 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);
 
-int kvm_apic_set_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
+int kvm_apic_set_base(struct kvm_vcpu *vcpu, u64 value, bool host_initiated);
 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);
 int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu);

arch/x86/kvm/x86.c

@@ -3863,7 +3863,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_MTRRdefType:
 		return kvm_mtrr_set_msr(vcpu, msr, data);
 	case MSR_IA32_APICBASE:
-		return kvm_apic_set_base(vcpu, msr_info);
+		return kvm_apic_set_base(vcpu, data, msr_info->host_initiated);
 	case APIC_BASE_MSR ... APIC_BASE_MSR + 0xff:
 		return kvm_x2apic_msr_write(vcpu, msr, data);
 	case MSR_IA32_TSC_DEADLINE:
@@ -11870,16 +11870,13 @@ static bool kvm_is_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
 static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs,
 		int *mmu_reset_needed, bool update_pdptrs)
 {
-	struct msr_data apic_base_msr;
 	int idx;
 	struct desc_ptr dt;
 
 	if (!kvm_is_valid_sregs(vcpu, sregs))
 		return -EINVAL;
 
-	apic_base_msr.data = sregs->apic_base;
-	apic_base_msr.host_initiated = true;
-	if (kvm_apic_set_base(vcpu, &apic_base_msr))
+	if (kvm_apic_set_base(vcpu, sregs->apic_base, true))
 		return -EINVAL;
 
 	if (vcpu->arch.guest_state_protected)