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    SubjectRe: [PATCH v1 04/11] x86/x86: Add is_tdx_guest() interface
    On Tue, Jun 01, 2021 at 07:21:29PM -0700, Kuppuswamy Sathyanarayanan wrote:
    > +static int __ro_after_init tdx_guest = -1;
    > +
    > +static inline bool native_cpuid_has_tdx_guest(void)
    > +{
    > + u32 eax = TDX_CPUID_LEAF_ID, signature[3] = {0};
    > +
    > + if (native_cpuid_eax(0) < TDX_CPUID_LEAF_ID)
    > + return false;
    > +
    > + native_cpuid(&eax, &signature[0], &signature[1], &signature[2]);
    > +
    > + if (memcmp("IntelTDX ", signature, 12))
    > + return false;
    > +
    > + return true;

    As before,

    return !memcmp(...

    and then that function can return simply an int.


    > +}
    > +
    > +bool is_tdx_guest(void)

    If anything, this should be early_is_tdx_guest().

    > +{
    > + if (tdx_guest < 0)
    > + tdx_guest = native_cpuid_has_tdx_guest();
    > +
    > + return !!tdx_guest;
    > +}
    > +

    Applying: x86/x86: Add is_tdx_guest() interface
    .git/rebase-apply/patch:58: new blank line at EOF.
    +
    warning: 1 line adds whitespace errors.


    > diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
    > index 5b14b72e41c5..5e70617e9877 100644
    > --- a/arch/x86/kernel/tdx.c
    > +++ b/arch/x86/kernel/tdx.c
    > @@ -19,6 +19,12 @@ static inline bool cpuid_has_tdx_guest(void)
    > return true;
    > }
    >
    > +bool is_tdx_guest(void)
    > +{
    > + return static_cpu_has(X86_FEATURE_TDX_GUEST);
    > +}
    > +EXPORT_SYMBOL_GPL(is_tdx_guest);

    I don't like this is_tdx_guest() thing in kernel proper - what's wrong
    with

    prot_guest_has(PR_GUEST_TDX)

    ?

    Also, why is it exported, for kvm?

    Thx.

    --
    Regards/Gruss,
    Boris.

    https://people.kernel.org/tglx/notes-about-netiquette

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