Re: [PATCH] KVM: x86: add hint to skip hidden rdpkru under kvm_load_host_xsave_state

[Jon Kohler]

> On May 7, 2021, at 12:58 PM, Dave Hansen <dave.hansen@xxxxxxxxx> wrote:
> 
> On 5/7/21 9:52 AM, Paolo Bonzini wrote:
>> This can be optimized as well, can't it?  This means that the only case
>> that needs the rdpkru is in switch_fpu_finish, and __write_pkru can be
>> removed completely:
>> 
>> - do the rdpkru+wrpkru in switch_fpu_finish
>> 
>> - just use wrpkru in KVM
> 
> I was going to suggest exactly the same thing.  It doesn't require the
> compiler to be smart, and wrpkru() is available in the same header as
> __write_pkru().

Thanks Paolo, Dave. Good suggestion, I’ll work up a v2 and send it out.

> 
> I also detest the mysterious true/false arguments to functions where you
> have no clue what they're doing at the call site without comments.

Noted, my apologies. Thats a good point, I won’t make that mistake again.