On 11/3/22 19:35, Sean Christopherson wrote:
It's technically required. IA32_FEAT_CTL and thus KVM_INTEL depends on any of CPU_SUP_{INTEL,CENATUR,ZHAOXIN}, but init_ia32_feat_ctl() is invoked if and only if the actual CPU type matches one of the aforementioned CPU_SUP_*.E.g. running a kernel built with CONFIG_CPU_SUP_INTEL=y CONFIG_CPU_SUP_AMD=y # CONFIG_CPU_SUP_HYGON is not set # CONFIG_CPU_SUP_CENTAUR is not set # CONFIG_CPU_SUP_ZHAOXIN is not set on a Cenatur or Zhaoxin CPU will leave X86_FEATURE_VMX set but not set X86_FEATURE_MSR_IA32_FEAT_CTL. If VMX isn't enabled in MSR_IA32_FEAT_CTL, KVM will get unexpected #UDs when trying to enable VMX.
Oh, I see. Perhaps X86_FEATURE_VMX and X86_FEATURE_SGX should be moved to one of the software words instead of using cpuid. Nothing that you should care about for this series though.
Paolo
