Subject: Re: [PATCH 03/13] x86/HV: Add new hvcall guest address host visibility support

From: Dave Hansen <[email-masked]>
Date: Thu, 29 Jul 2021 09:05:34 -0700

On 7/29/21 8:02 AM, Tianyu Lan wrote:
>>
> 
> There is x86_hyper_type to identify hypervisor type and we may check
> this variable after checking X86_FEATURE_HYPERVISOR.
> 
> static inline bool hv_is_isolation_supported(void)
> {
>     if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
>         return 0;
> 
>         if (x86_hyper_type != X86_HYPER_MS_HYPERV)
>                 return 0;
> 
>     // out of line function call:
>     return __hv_is_isolation_supported();
> }   

Looks fine.  You just might want to use this existing helper:

static inline bool hypervisor_is_type(enum x86_hypervisor_type type)
{
        return x86_hyper_type == type;
}