Re: [tip:x86/mm] x86/mm: Add support for early encryption/decryption of memory

[Dave Hansen]

On 10/26/2017 06:05 AM, Tom Lendacky wrote:
>>>
>>> +static void __init __sme_early_enc_dec(resource_size_t paddr,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ unsigned long size, bool enc)
>>> +{
>>> +ÂÂÂ void *src, *dst;
>>> +ÂÂÂ size_t len;
>>> +
>>> +ÂÂÂ if (!sme_me_mask)
>>> +ÂÂÂÂÂÂÂ return;
>>> +
>>> +ÂÂÂ local_flush_tlb();
>>> +ÂÂÂ wbinvd();
>>
>> What is this TLB flush for? WBINVD is mentioned in "Volume 2, Section
>> 7.10.8", but TLB flushes are not. Is it OK that this does not flush
>> global pages?
> 
> The local_flush_tlb() is not needed and can be removed. I had that in
> there from early development and testing and just missed removing it.
> I can queue up a patch to delete it and remove the ambiguity with this
> routine and the APM document.

Cool, I was just doing a little audit of those TLB flushes and this one
stuck out at me.  It would be great if it can be removed.