x86/apic: KVM: Move lapic get/set helpers to common code

Move the apic_get_reg(), apic_set_reg(), apic_get_reg64() and
apic_set_reg64() helper functions to apic.h in order to reuse them in the
Secure AVIC guest APIC driver in later patches to read/write registers
from/to the APIC backing page.

No functional change intended.

Signed-off-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250709033242.267892-12-Neeraj.Upadhyay@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: neerajupadhya

arch/x86/include/asm/apic.h

@@ -525,6 +525,28 @@ static inline int apic_find_highest_vector(void *bitmap)
 	return -1;
 }
 
+static inline u32 apic_get_reg(void *regs, int reg_off)
+{
+	return *((u32 *) (regs + reg_off));
+}
+
+static inline void apic_set_reg(void *regs, int reg_off, u32 val)
+{
+	*((u32 *) (regs + reg_off)) = val;
+}
+
+static __always_inline u64 apic_get_reg64(void *regs, int reg)
+{
+	BUILD_BUG_ON(reg != APIC_ICR);
+	return *((u64 *) (regs + reg));
+}
+
+static __always_inline void apic_set_reg64(void *regs, int reg, u64 val)
+{
+	BUILD_BUG_ON(reg != APIC_ICR);
+	*((u64 *) (regs + reg)) = val;
+}
+
 /*
  * Warm reset vector position:
  */

arch/x86/kvm/lapic.c

@@ -77,33 +77,16 @@ module_param(lapic_timer_advance, bool, 0444);
 static int kvm_lapic_msr_read(struct kvm_lapic *apic, u32 reg, u64 *data);
 static int kvm_lapic_msr_write(struct kvm_lapic *apic, u32 reg, u64 data);
 
-static inline void apic_set_reg(void *regs, int reg_off, u32 val)
-{
-	*((u32 *) (regs + reg_off)) = val;
-}
-
 static inline void kvm_lapic_set_reg(struct kvm_lapic *apic, int reg_off, u32 val)
 {
 	apic_set_reg(apic->regs, reg_off, val);
 }
 
-static __always_inline u64 apic_get_reg64(void *regs, int reg)
-{
-	BUILD_BUG_ON(reg != APIC_ICR);
-	return *((u64 *) (regs + reg));
-}
-
 static __always_inline u64 kvm_lapic_get_reg64(struct kvm_lapic *apic, int reg)
 {
 	return apic_get_reg64(apic->regs, reg);
 }
 
-static __always_inline void apic_set_reg64(void *regs, int reg, u64 val)
-{
-	BUILD_BUG_ON(reg != APIC_ICR);
-	*((u64 *) (regs + reg)) = val;
-}
-
 static __always_inline void kvm_lapic_set_reg64(struct kvm_lapic *apic,
 						int reg, u64 val)
 {

arch/x86/kvm/lapic.h

@@ -4,6 +4,8 @@
 
 #include <kvm/iodev.h>
 
+#include <asm/apic.h>
+
 #include <linux/kvm_host.h>
 
 #include "hyperv.h"
@@ -165,11 +167,6 @@ static inline void kvm_lapic_set_irr(int vec, struct kvm_lapic *apic)
 	apic->irr_pending = true;
 }
 
-static inline u32 apic_get_reg(void *regs, int reg_off)
-{
-	return *((u32 *) (regs + reg_off));
-}
-
 static inline u32 kvm_lapic_get_reg(struct kvm_lapic *apic, int reg_off)
 {
 	return apic_get_reg(apic->regs, reg_off);