linux-kernel - Re: [RFC PATCH v1 03/18] x86: Secure Memory Encryption (SME) support

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Date:	Tue, 22 Mar 2016 14:03:54 +0100
From:	Pavel Machek <pavel@....cz>
To:	Tom Lendacky <thomas.lendacky@....com>
Cc:	linux-arch@...r.kernel.org, linux-efi@...r.kernel.org,
	kvm@...r.kernel.org, linux-doc@...r.kernel.org, x86@...nel.org,
	linux-kernel@...r.kernel.org, kasan-dev@...glegroups.com,
	linux-mm@...ck.org, iommu@...ts.linux-foundation.org,
	Radim Krčmář <rkrcmar@...hat.com>,
	Arnd Bergmann <arnd@...db.de>,
	Jonathan Corbet <corbet@....net>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	Joerg Roedel <joro@...tes.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>,
	Alexander Potapenko <glider@...gle.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Dmitry Vyukov <dvyukov@...gle.com>
Subject: Re: [RFC PATCH v1 03/18] x86: Secure Memory Encryption (SME) support

On Tue 2016-04-26 17:56:26, Tom Lendacky wrote:
> Provide support for Secure Memory Encryption (SME). This initial support
> defines the memory encryption mask as a variable for quick access and an
> accessor for retrieving the number of physical addressing bits lost if
> SME is enabled.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
> ---
>  arch/x86/include/asm/mem_encrypt.h |   37 ++++++++++++++++++++++++++++++++++++
>  arch/x86/kernel/Makefile           |    2 ++
>  arch/x86/kernel/mem_encrypt.S      |   29 ++++++++++++++++++++++++++++
>  arch/x86/kernel/x8664_ksyms_64.c   |    6 ++++++
>  4 files changed, 74 insertions(+)
>  create mode 100644 arch/x86/include/asm/mem_encrypt.h
>  create mode 100644 arch/x86/kernel/mem_encrypt.S
> 
> index 0000000..ef7f325
> --- /dev/null
> +++ b/arch/x86/kernel/mem_encrypt.S
> @@ -0,0 +1,29 @@
> +/*
> + * AMD Memory Encryption Support
> + *
> + * Copyright (C) 2016 Advanced Micro Devices, Inc.
> + *
> + * Author: Tom Lendacky <thomas.lendacky@....com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/linkage.h>
> +
> +	.text
> +	.code64
> +ENTRY(sme_get_me_loss)
> +	xor	%rax, %rax
> +	mov	sme_me_loss(%rip), %al
> +	ret
> +ENDPROC(sme_get_me_loss)

Does this really need to be implemented in assembly?


-- 
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