KVM: x86: Change lapic regs base address to void pointer

Change APIC base address from "char *" to "void *" in KVM
lapic's set/get helper functions. Pointer arithmetic for "void *"
and "char *" operate identically. With "void *" there is less
of a chance of doing the wrong thing, e.g. neglecting to cast and
reading a byte instead of the desired APIC register size.

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/20250709033242.267892-6-Neeraj.Upadhyay@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: neerajupadhya

arch/x86/kvm/lapic.c

@@ -79,7 +79,7 @@ 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 __kvm_lapic_set_reg(char *regs, int reg_off, u32 val)
+static inline void __kvm_lapic_set_reg(void *regs, int reg_off, u32 val)
 {
 	*((u32 *) (regs + reg_off)) = val;
 }
@@ -89,7 +89,7 @@ static inline void kvm_lapic_set_reg(struct kvm_lapic *apic, int reg_off, u32 va
 	__kvm_lapic_set_reg(apic->regs, reg_off, val);
 }
 
-static __always_inline u64 __kvm_lapic_get_reg64(char *regs, int reg)
+static __always_inline u64 __kvm_lapic_get_reg64(void *regs, int reg)
 {
 	BUILD_BUG_ON(reg != APIC_ICR);
 	return *((u64 *) (regs + reg));
@@ -100,7 +100,7 @@ static __always_inline u64 kvm_lapic_get_reg64(struct kvm_lapic *apic, int reg)
 	return __kvm_lapic_get_reg64(apic->regs, reg);
 }
 
-static __always_inline void __kvm_lapic_set_reg64(char *regs, int reg, u64 val)
+static __always_inline void __kvm_lapic_set_reg64(void *regs, int reg, u64 val)
 {
 	BUILD_BUG_ON(reg != APIC_ICR);
 	*((u64 *) (regs + reg)) = val;

arch/x86/kvm/lapic.h

@@ -165,7 +165,7 @@ static inline void kvm_lapic_set_irr(int vec, struct kvm_lapic *apic)
 	apic->irr_pending = true;
 }
 
-static inline u32 __kvm_lapic_get_reg(char *regs, int reg_off)
+static inline u32 __kvm_lapic_get_reg(void *regs, int reg_off)
 {
 	return *((u32 *) (regs + reg_off));
 }