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    SubjectRe: [PATCH v1 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD
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    On 3/30/21 8:10 AM, Dave Hansen wrote:
    > On 3/30/21 8:00 AM, Andi Kleen wrote:
    >>>> + /* MWAIT is not supported in TDX platform, so suppress it */
    >>>> + setup_clear_cpu_cap(X86_FEATURE_MWAIT);
    >>> In fact, MWAIT bit returned by CPUID instruction is zero for TD guest. This
    >>> is enforced by SEAM module.
    >> Good point.
    >>> Do we still need to safeguard it by setup_clear_cpu_cap() here?
    >> I guess it doesn't hurt to do it explicitly.
    >
    > If this MWAIT behavior (clearing the CPUID bit) is part of the guest
    > architecture, then it would also be appropriate to WARN() rather than
    > silently clearing the X86_FEATURE bit.
    Makes sense. It will be useful to find the problem with TDX Module.
    >

    --
    Sathyanarayanan Kuppuswamy
    Linux Kernel Developer

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