Re: [PATCH v5 06/12] x86/tdx: Get TD execution environment information via TDINFO

[Sean Christopherson <seanjc@google.com>]

On Wed, Aug 04, 2021, Kuppuswamy Sathyanarayanan wrote:
> diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
> index 287564990f21..3973e81751ba 100644
> --- a/arch/x86/kernel/tdx.c
> +++ b/arch/x86/kernel/tdx.c
> @@ -8,6 +8,14 @@
>  
>  #include <asm/tdx.h>
>  
> +/* TDX Module call Leaf IDs */
> +#define TDINFO				1
> +
> +static struct {
> +	unsigned int gpa_width;
> +	unsigned long attributes;
> +} td_info __ro_after_init;
> +
>  /*
>   * Wrapper for standard use of __tdx_hypercall with BUG_ON() check
>   * for TDCALL error.
> @@ -54,6 +62,19 @@ bool tdx_prot_guest_has(unsigned long flag)
>  }
>  EXPORT_SYMBOL_GPL(tdx_prot_guest_has);
>  
> +static void tdg_get_info(void)

I've already made my dislike of "tdg" abundantly clear, but I will keep on complaining
so long as y'all keep sending patches with "tdx" and "tdg" interspersed without any
obvious method to the madness.

Also, a function with "get" in the name that returns a void and fills in a global
struct that's is a bit misleading.  

> +{
> +	u64 ret;
> +	struct tdx_module_output out = {0};
> +
> +	ret = __tdx_module_call(TDINFO, 0, 0, 0, 0, &out);
> +
> +	BUG_ON(ret);
> +
> +	td_info.gpa_width = out.rcx & GENMASK(5, 0);
> +	td_info.attributes = out.rdx;
> +}
> +
>  void __init tdx_early_init(void)
>  {
>  	if (!cpuid_has_tdx_guest())
> @@ -61,5 +82,7 @@ void __init tdx_early_init(void)
>  
>  	setup_force_cpu_cap(X86_FEATURE_TDX_GUEST);
>  
> +	tdg_get_info();
> +
>  	pr_info("Guest initialized\n");
>  }
> -- 
> 2.25.1
>