Re: [RFC PATCH v7 17/37] x86/apic: Unionize apic regs for 32bit/64bit access w/o type casting

[Huang, Kai]

> +struct apic_page {
> +	union {
> +		u64     regs64[PAGE_SIZE / 8];
> +		u32     regs[PAGE_SIZE / 4];
> +		u8      bytes[PAGE_SIZE];
> +	};
> +} __aligned(PAGE_SIZE);

The 'bytes' field is never used.  Should it be removed?

> +
>  static inline u32 apic_get_reg(void *regs, int reg)
>  {
> -	return *((u32 *) (regs + reg));
> +	struct apic_page *ap = regs;
> +
> +	return ap->regs[reg / 4];
>  }
>  
>  static inline void apic_set_reg(void *regs, int reg, u32 val)
>  {
> -	*((u32 *) (regs + reg)) = val;
> +	struct apic_page *ap = regs;
> +
> +	ap->regs[reg / 4] = val;
>  }
>  
>  static __always_inline u64 apic_get_reg64(void *regs, int reg)
>  {
> +	struct apic_page *ap = regs;
> +
>  	BUILD_BUG_ON(reg != APIC_ICR);
> -	return *((u64 *) (regs + reg));
> +
> +	return ap->regs64[reg / 8];
>  }
>  
>  static __always_inline void apic_set_reg64(void *regs, int reg, u64 val)
>  {
> +	struct apic_page *ap = regs;
> +
>  	BUILD_BUG_ON(reg != APIC_ICR);
> -	*((u64 *) (regs + reg)) = val;
> +	ap->regs64[reg / 8] = val;
>  }
>  
>  static inline void apic_clear_vector(int vec, void *bitmap)