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Subject: Re: [tip:x86/mm] x86/mm: Add support for early encryption/decryption
 of memory
To: arnd@arndb.de, aryabinin@virtuozzo.com, dvyukov@google.com,
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References: <f9968e9432cd6c4b57ef245729be04ff18852225.1500319216.git.thomas.lendacky@amd.com>
 <tip-7f8b7e7f4ccbbd1fb8badddfabd28c955aea87b4@git.kernel.org>
From: Dave Hansen <dave.hansen@intel.com>
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Date: Wed, 25 Oct 2017 10:34:57 -0700
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On 07/18/2017 03:51 AM, tip-bot for Tom Lendacky wrote:
> +/*
> + * This routine does not change the underlying encryption setting of the
> + * page(s) that map this memory. It assumes that eventually the memory is
> + * meant to be accessed as either encrypted or decrypted but the contents
> + * are currently not in the desired state.
> + *
> + * This routine follows the steps outlined in the AMD64 Architecture
> + * Programmer's Manual Volume 2, Section 7.10.8 Encrypt-in-Place.
> + */
> +static void __init __sme_early_enc_dec(resource_size_t paddr,
> +				       unsigned long size, bool enc)
> +{
> +	void *src, *dst;
> +	size_t len;
> +
> +	if (!sme_me_mask)
> +		return;
> +
> +	local_flush_tlb();
> +	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?