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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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