On Tue, Nov 15, 2022, Huang, Kai wrote:
> On Wed, 2022-11-02 at 23:19 +0000, Sean Christopherson wrote:
> > +static bool __init kvm_is_vmx_supported(void)
> > +{
> > + if (!cpu_has_vmx()) {
> > + pr_err("CPU doesn't support VMX\n");
> > + return false;
> > + }
> > +
> > + if (!boot_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
> > + !boot_cpu_has(X86_FEATURE_VMX)) {
> > + pr_err("VMX not enabled in MSR_IA32_FEAT_CTL\n");
> > + return false;
> > + }
> > +
> > + return true;
> > +}
> > +
> > static int __init vmx_check_processor_compat(void)
> > {
> > struct vmcs_config vmcs_conf;
> > struct vmx_capability vmx_cap;
> >
> > - if (!this_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
> > - !this_cpu_has(X86_FEATURE_VMX)) {
> > - pr_err("VMX is disabled on CPU %d\n", smp_processor_id());
> > + if (!kvm_is_vmx_supported())
> > return -EIO;
> > - }
> >
>
> Looks there's a functional change here -- the old code checks local cpu's
> feature bits but the new code always checks bsp's feature bits. Should have no
> problem I think, though.
Ouch. The bad check will defeat the purpose of doing compat checks. Nice catch!
