KVM: x86: Move kvm_intr_is_single_vcpu() to lapic.c

Move kvm_intr_is_single_vcpu() to lapic.c, drop its export, and make its
"fast" helper local to lapic.c.  kvm_intr_is_single_vcpu() is only usable
if the local APIC is in-kernel, i.e. it most definitely belongs in the
local APIC code.

No functional change intended.

Fixes: cf04ec3 ("KVM: x86: Dedup AVIC vs. PI code for identifying target vCPU")
Link: https://lore.kernel.org/r/20250919003303.1355064-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/include/asm/kvm_host.h

@@ -2401,9 +2401,6 @@ void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,
 bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu);
 bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu);
 
-bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
-			     struct kvm_vcpu **dest_vcpu);
-
 static inline bool kvm_irq_is_postable(struct kvm_lapic_irq *irq)
 {
 	/* We can only post Fixed and LowPrio IRQs */

arch/x86/kvm/irq.c

@@ -354,34 +354,6 @@ int kvm_set_routing_entry(struct kvm *kvm,
 	return 0;
 }
 
-bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
-			     struct kvm_vcpu **dest_vcpu)
-{
-	int r = 0;
-	unsigned long i;
-	struct kvm_vcpu *vcpu;
-
-	if (kvm_intr_is_single_vcpu_fast(kvm, irq, dest_vcpu))
-		return true;
-
-	kvm_for_each_vcpu(i, vcpu, kvm) {
-		if (!kvm_apic_present(vcpu))
-			continue;
-
-		if (!kvm_apic_match_dest(vcpu, NULL, irq->shorthand,
-					irq->dest_id, irq->dest_mode))
-			continue;
-
-		if (++r == 2)
-			return false;
-
-		*dest_vcpu = vcpu;
-	}
-
-	return r == 1;
-}
-EXPORT_SYMBOL_GPL(kvm_intr_is_single_vcpu);
-
 void kvm_scan_ioapic_irq(struct kvm_vcpu *vcpu, u32 dest_id, u16 dest_mode,
 			 u8 vector, unsigned long *ioapic_handled_vectors)
 {

arch/x86/kvm/lapic.c

@@ -1235,8 +1235,9 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
  *	   interrupt.
  * - Otherwise, use remapped mode to inject the interrupt.
  */
-bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
-			struct kvm_vcpu **dest_vcpu)
+static bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm,
+					 struct kvm_lapic_irq *irq,
+					 struct kvm_vcpu **dest_vcpu)
 {
 	struct kvm_apic_map *map;
 	unsigned long bitmap;
@@ -1263,6 +1264,34 @@ bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
 	return ret;
 }
 
+bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
+			     struct kvm_vcpu **dest_vcpu)
+{
+	int r = 0;
+	unsigned long i;
+	struct kvm_vcpu *vcpu;
+
+	if (kvm_intr_is_single_vcpu_fast(kvm, irq, dest_vcpu))
+		return true;
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		if (!kvm_apic_present(vcpu))
+			continue;
+
+		if (!kvm_apic_match_dest(vcpu, NULL, irq->shorthand,
+					irq->dest_id, irq->dest_mode))
+			continue;
+
+		if (++r == 2)
+			return false;
+
+		*dest_vcpu = vcpu;
+	}
+
+	return r == 1;
+}
+EXPORT_SYMBOL_GPL(kvm_intr_is_single_vcpu);
+
 int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 			     struct kvm_lapic_irq *irq, struct dest_map *dest_map)
 {

arch/x86/kvm/lapic.h

@@ -236,8 +236,8 @@ void kvm_wait_lapic_expire(struct kvm_vcpu *vcpu);
 void kvm_bitmap_or_dest_vcpus(struct kvm *kvm, struct kvm_lapic_irq *irq,
 			      unsigned long *vcpu_bitmap);
 
-bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
-			struct kvm_vcpu **dest_vcpu);
+bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
+			     struct kvm_vcpu **dest_vcpu);
 void kvm_lapic_switch_to_sw_timer(struct kvm_vcpu *vcpu);
 void kvm_lapic_switch_to_hv_timer(struct kvm_vcpu *vcpu);
 void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu);