Messages in this thread | | | Subject | Re: [PATCH v1 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD | From | "Kuppuswamy, Sathyanarayanan" <> | Date | Tue, 30 Mar 2021 10:02:53 -0700 |
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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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