Re: [PATCH v10 04/11] x86/tdx: Add TDX support to intel_cc_platform_has()

[Sathyanarayanan Kuppuswamy]

On 10/14/21 12:12 AM, Thomas Gleixner wrote:
> On Fri, Oct 08 2021 at 22:37, Kuppuswamy Sathyanarayanan wrote:
> >   
> > -static bool __maybe_unused intel_cc_platform_has(enum cc_attr attr)
> > +static bool intel_cc_platform_has(enum cc_attr attr)
> >   {
> >   #ifdef CONFIG_INTEL_TDX_GUEST
> > -	return false;
> > +	switch (attr) {
> > +	case CC_ATTR_GUEST_TDX:
> > +		return is_tdx_guest();
> This function is only called when is_tdx_guest() is true. So
> is_tdx_guest() has to be called again to make sure?


Agree. In future, if intel_cc_platform_has() is used in non-tdx case then
we can add is_tdx_guest() back there. For now it is redundant
as you have mentioned. I will remove it in next version.

> Also the ifdeffery can just go away simply because the compiler will
> discard this function when CONFIG_INTEL_TDX_GUEST=n due to:
Agree. I will remove it.
> > +#ifdef CONFIG_INTEL_TDX_GUEST
> > +
> > +bool is_tdx_guest(void);
> > +void __init tdx_early_init(void);
> > +
> > +#else
> > +
> > +static inline bool is_tdx_guest(void) { return false; }
> > +static inline void tdx_early_init(void) { };
> > +
> > +#endif /* CONFIG_INTEL_TDX_GUEST */
> Thanks,
>
>          tglx

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer