Re: [PATCHv2 01/29] x86/tdx: Detect running as a TDX guest in early boot

[Thomas Gleixner]

Kirill,

On Mon, Jan 24 2022 at 18:01, Kirill A. Shutemov wrote:

Just a nitpick...

> +static bool tdx_guest_detected __ro_after_init;
> +
> +bool is_tdx_guest(void)
> +{
> +	return tdx_guest_detected;
> +}
> +
> +void __init tdx_early_init(void)
> +{
> +	u32 eax, sig[3];
> +
> +	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2],  &sig[1]);
> +
> +	if (memcmp(TDX_IDENT, sig, 12))
> +		return;
> +
> +	tdx_guest_detected = true;
> +
> +	setup_force_cpu_cap(X86_FEATURE_TDX_GUEST);

So with that we have two ways to detect a TDX guest:

   - tdx_guest_detected

   - X86_FEATURE_TDX_GUEST

Shouldn't X86_FEATURE_TDX_GUEST be good enough?

Thanks,

        tglx