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
