Re: [PATCH 33/44] KVM: x86: Do VMX/SVM support checks directly in vendor code

[Huang, Kai]

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.