Re: [PATCH v8 05/11] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions

[Borislav Petkov]

On Mon, Oct 04, 2021 at 07:51:59PM -0700, Kuppuswamy Sathyanarayanan wrote:
> diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
> index ad3ff5925153..d5fc2904facf 100644
> --- a/arch/x86/kernel/tdx.c
> +++ b/arch/x86/kernel/tdx.c
> @@ -27,6 +27,29 @@ static void __init is_tdx_guest_init(void)
>  	is_tdx_guest = !memcmp("IntelTDX    ", sig, 12);
>  }
>  
> +/*
> + * Wrapper for standard use of __tdx_hypercall with BUG_ON() check
> + * for TDCALL error.
> + */
> +static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14,
> +				 u64 r15, struct tdx_hypercall_output *out)
> +{
> +	struct tdx_hypercall_output outl = {0};

Why do you need to clear this when, if used, it will get completely
overwritten in __tdx_hypercall()?

-- 
Regards/Gruss,
    Boris.

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