On 2/13/2018 10:25 AM, Paolo Bonzini wrote: > On 08/02/2018 23:58, Tom Lendacky wrote: >> +bool kvm_valid_msr_feature(u32 msr, u64 data) >> +{ >> + unsigned int i; >> + >> + for (i = 0; i < num_msr_based_features; i++) { >> + struct kvm_msr_based_features *m = msr_based_features + i; >> + >> + if (msr != m->msr) >> + continue; >> + >> + /* Make sure not trying to change unsupported bits */ >> + return (data & ~m->mask) ? false : true; >> + } >> + >> + return false; >> +} >> +EXPORT_SYMBOL_GPL(kvm_valid_msr_feature); >> + > > This is probably unnecessary too (the allowed values are a bit more > complicated for, you just guessed it, VMX capability MSRs) and you can > just check bits other than LFENCE in svm_set_msr. The whole routine or just the bit checking? I can see still needing the check to be sure the "feature" is present. Thanks, Tom > > Paolo >