linux-kernel - Re: [PATCH 03/62] x86/cpufeatures: Add SEV-ES CPU feature

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Message-ID: <20200213065130.GC31799@zn.tnic>
Date:   Thu, 13 Feb 2020 07:51:30 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Joerg Roedel <joro@...tes.org>
Cc:     x86@...nel.org, hpa@...or.com, Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Hellstrom <thellstrom@...are.com>,
        Jiri Slaby <jslaby@...e.cz>,
        Dan Williams <dan.j.williams@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Juergen Gross <jgross@...e.com>,
        Kees Cook <keescook@...omium.org>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        Joerg Roedel <jroedel@...e.de>
Subject: Re: [PATCH 03/62] x86/cpufeatures: Add SEV-ES CPU feature

On Tue, Feb 11, 2020 at 02:51:57PM +0100, Joerg Roedel wrote:
> From: Tom Lendacky <thomas.lendacky@....com>
> 
> Add CPU feature detection for Secure Encrypted Virtualization with
> Encrypted State. This feature enhances SEV by also encrypting the
> guest register state, making it in-accessible to the hypervisor.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
> Signed-off-by: Joerg Roedel <jroedel@...e.de>
> ---
>  arch/x86/include/asm/cpufeatures.h | 1 +
>  arch/x86/kernel/cpu/amd.c          | 4 +++-
>  arch/x86/kernel/cpu/scattered.c    | 1 +
>  3 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index f3327cb56edf..26e4ee209f7b 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -285,6 +285,7 @@
>  #define X86_FEATURE_CQM_MBM_LOCAL	(11*32+ 3) /* LLC Local MBM monitoring */
>  #define X86_FEATURE_FENCE_SWAPGS_USER	(11*32+ 4) /* "" LFENCE in user entry SWAPGS path */
>  #define X86_FEATURE_FENCE_SWAPGS_KERNEL	(11*32+ 5) /* "" LFENCE in kernel entry SWAPGS path */
> +#define X86_FEATURE_SEV_ES		(11*32+ 6) /* AMD Secure Encrypted Virtualization - Encrypted State */

Let's put this in word 8 which is for virt flags. X86_FEATURE_SEV could
go there too but that should be a separate patch anyway, if at all.

>  /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
>  #define X86_FEATURE_AVX512_BF16		(12*32+ 5) /* AVX512 BFLOAT16 instructions */
> diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> index ac83a0fef628..aad2223862ef 100644
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -580,7 +580,7 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)
>  	 *	      If BIOS has not enabled SME then don't advertise the
>  	 *	      SME feature (set in scattered.c).
>  	 *   For SEV: If BIOS has not enabled SEV then don't advertise the
> -	 *            SEV feature (set in scattered.c).
> +	 *            SEV and SEV_ES feature (set in scattered.c).
>  	 *
>  	 *   In all cases, since support for SME and SEV requires long mode,
>  	 *   don't advertise the feature under CONFIG_X86_32.
> @@ -611,6 +611,8 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)
>  		setup_clear_cpu_cap(X86_FEATURE_SME);
>  clear_sev:
>  		setup_clear_cpu_cap(X86_FEATURE_SEV);
> +		setup_clear_cpu_cap(X86_FEATURE_SEV);

X86_FEATURE_SEV twice? Because once didn't stick?

:-)

-- 
Regards/Gruss,
    Boris.

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