KVM: x86: Move "apicv_active" into "struct kvm_lapic"

Move the per-vCPU apicv_active flag into KVM's local APIC instance.
APICv is fully dependent on an in-kernel local APIC, but that's not at
all clear when reading the current code due to the flag being stored in
the generic kvm_vcpu_arch struct.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220614230548.3852141-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -663,7 +663,6 @@ struct kvm_vcpu_arch {
 	u64 efer;
 	u64 apic_base;
 	struct kvm_lapic *apic;    /* kernel irqchip context */
-	bool apicv_active;
 	bool load_eoi_exitmap_pending;
 	DECLARE_BITMAP(ioapic_handled_vectors, 256);
 	unsigned long apic_attention;

arch/x86/kvm/lapic.c

@@ -519,14 +519,11 @@ static inline int apic_find_highest_irr(struct kvm_lapic *apic)
 
 static inline void apic_clear_irr(int vec, struct kvm_lapic *apic)
 {
-	struct kvm_vcpu *vcpu;
+	if (unlikely(apic->apicv_active)) {
-
-	vcpu = apic->vcpu;
-
-	if (unlikely(vcpu->arch.apicv_active)) {
 		/* need to update RVI */
 		kvm_lapic_clear_vector(vec, apic->regs + APIC_IRR);
-		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
+		static_call_cond(kvm_x86_hwapic_irr_update)(apic->vcpu,
+							    apic_find_highest_irr(apic));
 	} else {
 		apic->irr_pending = false;
 		kvm_lapic_clear_vector(vec, apic->regs + APIC_IRR);
@@ -543,19 +540,15 @@ EXPORT_SYMBOL_GPL(kvm_apic_clear_irr);
 
 static inline void apic_set_isr(int vec, struct kvm_lapic *apic)
 {
-	struct kvm_vcpu *vcpu;
-
 	if (__apic_test_and_set_vector(vec, apic->regs + APIC_ISR))
 		return;
 
-	vcpu = apic->vcpu;
-
 	/*
 	 * With APIC virtualization enabled, all caching is disabled
 	 * because the processor can modify ISR under the hood.  Instead
 	 * just set SVI.
 	 */
-	if (unlikely(vcpu->arch.apicv_active))
+	if (unlikely(apic->apicv_active))
 		static_call_cond(kvm_x86_hwapic_isr_update)(vec);
 	else {
 		++apic->isr_count;
@@ -590,12 +583,9 @@ static inline int apic_find_highest_isr(struct kvm_lapic *apic)
 
 static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
 {
-	struct kvm_vcpu *vcpu;
 	if (!__apic_test_and_clear_vector(vec, apic->regs + APIC_ISR))
 		return;
 
-	vcpu = apic->vcpu;
-
 	/*
 	 * We do get here for APIC virtualization enabled if the guest
 	 * uses the Hyper-V APIC enlightenment.  In this case we may need
@@ -603,7 +593,7 @@ static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
 	 * on the other hand isr_count and highest_isr_cache are unused
 	 * and must be left alone.
 	 */
-	if (unlikely(vcpu->arch.apicv_active))
+	if (unlikely(apic->apicv_active))
 		static_call_cond(kvm_x86_hwapic_isr_update)(apic_find_highest_isr(apic));
 	else {
 		--apic->isr_count;
@@ -1584,7 +1574,7 @@ static bool lapic_timer_int_injected(struct kvm_vcpu *vcpu)
 		int vec = reg & APIC_VECTOR_MASK;
 		void *bitmap = apic->regs + APIC_ISR;
 
-		if (vcpu->arch.apicv_active)
+		if (apic->apicv_active)
 			bitmap = apic->regs + APIC_IRR;
 
 		if (apic_test_vector(vec, bitmap))
@@ -1701,7 +1691,7 @@ static void apic_timer_expired(struct kvm_lapic *apic, bool from_timer_fn)
 	if (apic_lvtt_tscdeadline(apic) || ktimer->hv_timer_in_use)
 		ktimer->expired_tscdeadline = ktimer->tscdeadline;
 
-	if (!from_timer_fn && vcpu->arch.apicv_active) {
+	if (!from_timer_fn && apic->apicv_active) {
 		WARN_ON(kvm_get_running_vcpu() != vcpu);
 		kvm_apic_inject_pending_timer_irqs(apic);
 		return;
@@ -2379,7 +2369,7 @@ void kvm_apic_update_apicv(struct kvm_vcpu *vcpu)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
 
-	if (vcpu->arch.apicv_active) {
+	if (apic->apicv_active) {
 		/* irr_pending is always true when apicv is activated. */
 		apic->irr_pending = true;
 		apic->isr_count = 1;
@@ -2454,7 +2444,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 
 	vcpu->arch.pv_eoi.msr_val = 0;
 	apic_update_ppr(apic);
-	if (vcpu->arch.apicv_active) {
+	if (apic->apicv_active) {
 		static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
 		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, -1);
 		static_call_cond(kvm_x86_hwapic_isr_update)(-1);
@@ -2734,7 +2724,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
 	kvm_lapic_set_reg(apic, APIC_TMCCT, 0);
 	kvm_apic_update_apicv(vcpu);
 	apic->highest_isr_cache = -1;
-	if (vcpu->arch.apicv_active) {
+	if (apic->apicv_active) {
 		static_call_cond(kvm_x86_apicv_post_state_restore)(vcpu);
 		static_call_cond(kvm_x86_hwapic_irr_update)(vcpu, apic_find_highest_irr(apic));
 		static_call_cond(kvm_x86_hwapic_isr_update)(apic_find_highest_isr(apic));

arch/x86/kvm/lapic.h

@@ -48,6 +48,7 @@ struct kvm_lapic {
 	struct kvm_timer lapic_timer;
 	u32 divide_count;
 	struct kvm_vcpu *vcpu;
+	bool apicv_active;
 	bool sw_enabled;
 	bool irr_pending;
 	bool lvt0_in_nmi_mode;
@@ -204,7 +205,7 @@ static inline int apic_x2apic_mode(struct kvm_lapic *apic)
 
 static inline bool kvm_vcpu_apicv_active(struct kvm_vcpu *vcpu)
 {
-	return vcpu->arch.apic && vcpu->arch.apicv_active;
+	return vcpu->arch.apic && vcpu->arch.apic->apicv_active;
 }
 
 static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)

arch/x86/kvm/svm/svm.c

@@ -3465,12 +3465,13 @@ void svm_complete_interrupt_delivery(struct kvm_vcpu *vcpu, int delivery_mode,
 				     int trig_mode, int vector)
 {
 	/*
-	 * vcpu->arch.apicv_active must be read after vcpu->mode.
+	 * apic->apicv_active must be read after vcpu->mode.
 	 * Pairs with smp_store_release in vcpu_enter_guest.
 	 */
 	bool in_guest_mode = (smp_load_acquire(&vcpu->mode) == IN_GUEST_MODE);
 
-	if (!READ_ONCE(vcpu->arch.apicv_active)) {
+	/* Note, this is called iff the local APIC is in-kernel. */
+	if (!READ_ONCE(vcpu->arch.apic->apicv_active)) {
 		/* Process the interrupt via inject_pending_event */
 		kvm_make_request(KVM_REQ_EVENT, vcpu);
 		kvm_vcpu_kick(vcpu);

arch/x86/kvm/vmx/vmx.c

@@ -4099,7 +4099,8 @@ static int vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector)
 	if (!r)
 		return 0;
 
-	if (!vcpu->arch.apicv_active)
+	/* Note, this is called iff the local APIC is in-kernel. */
+	if (!vcpu->arch.apic->apicv_active)
 		return -1;
 
 	if (pi_test_and_set_pir(vector, &vmx->pi_desc))

arch/x86/kvm/x86.c

@@ -9460,7 +9460,7 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu)
 	if (!lapic_in_kernel(vcpu))
 		return;
 
-	if (vcpu->arch.apicv_active)
+	if (vcpu->arch.apic->apicv_active)
 		return;
 
 	if (!vcpu->arch.apic->vapic_addr)
@@ -9913,6 +9913,7 @@ void kvm_make_scan_ioapic_request(struct kvm *kvm)
 
 void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
 {
+	struct kvm_lapic *apic = vcpu->arch.apic;
 	bool activate;
 
 	if (!lapic_in_kernel(vcpu))
@@ -9923,10 +9924,10 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
 
 	activate = kvm_vcpu_apicv_activated(vcpu);
 
-	if (vcpu->arch.apicv_active == activate)
+	if (apic->apicv_active == activate)
 		goto out;
 
-	vcpu->arch.apicv_active = activate;
+	apic->apicv_active = activate;
 	kvm_apic_update_apicv(vcpu);
 	static_call(kvm_x86_refresh_apicv_exec_ctrl)(vcpu);
 
@@ -9936,7 +9937,7 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
 	 * still active when the interrupt got accepted. Make sure
 	 * inject_pending_event() is called to check for that.
 	 */
-	if (!vcpu->arch.apicv_active)
+	if (!apic->apicv_active)
 		kvm_make_request(KVM_REQ_EVENT, vcpu);
 
 out:
@@ -11379,7 +11380,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 		 * will ensure the vCPU gets the correct state before VM-Entry.
 		 */
 		if (enable_apicv) {
-			vcpu->arch.apicv_active = true;
+			vcpu->arch.apic->apicv_active = true;
 			kvm_make_request(KVM_REQ_APICV_UPDATE, vcpu);
 		}
 	} else