Re: [RFC PATCH v4 05/28] x86: Add Secure Memory Encryption (SME) support

[Borislav Petkov]

On Thu, Feb 16, 2017 at 09:43:07AM -0600, Tom Lendacky wrote:
> Add support for Secure Memory Encryption (SME). This initial support
> provides a Kconfig entry to build the SME support into the kernel and
> defines the memory encryption mask that will be used in subsequent
> patches to mark pages as encrypted.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
>  arch/x86/Kconfig                   |   22 +++++++++++++++++++
>  arch/x86/include/asm/mem_encrypt.h |   42 ++++++++++++++++++++++++++++++++++++
>  arch/x86/mm/Makefile               |    1 +
>  arch/x86/mm/mem_encrypt.c          |   21 ++++++++++++++++++
>  include/linux/mem_encrypt.h        |   37 ++++++++++++++++++++++++++++++++
>  5 files changed, 123 insertions(+)
>  create mode 100644 arch/x86/include/asm/mem_encrypt.h
>  create mode 100644 arch/x86/mm/mem_encrypt.c
>  create mode 100644 include/linux/mem_encrypt.h
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index f8fbfc5..a3b8c71 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1395,6 +1395,28 @@ config X86_DIRECT_GBPAGES
>  	  supports them), so don't confuse the user by printing
>  	  that we have them enabled.
>  
> +config AMD_MEM_ENCRYPT
> +	bool "AMD Secure Memory Encryption (SME) support"
> +	depends on X86_64 && CPU_SUP_AMD
> +	---help---
> +	  Say yes to enable support for the encryption of system memory.
> +	  This requires an AMD processor that supports Secure Memory
> +	  Encryption (SME).
> +
> +config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
> +	bool "Activate AMD Secure Memory Encryption (SME) by default"
> +	default y
> +	depends on AMD_MEM_ENCRYPT
> +	---help---
> +	  Say yes to have system memory encrypted by default if running on
> +	  an AMD processor that supports Secure Memory Encryption (SME).
> +
> +	  If set to Y, then the encryption of system memory can be
> +	  deactivated with the mem_encrypt=off command line option.
> +
> +	  If set to N, then the encryption of system memory can be
> +	  activated with the mem_encrypt=on command line option.

Good.

-- 
Regards/Gruss,
    Boris.

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