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Date:   Tue, 17 Aug 2021 19:54:15 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Brijesh Singh <brijesh.singh@amd.com>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
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        linux-crypto@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ard Biesheuvel <ardb@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        David Rientjes <rientjes@google.com>,
        Dov Murik <dovmurik@linux.ibm.com>,
        Tobin Feldman-Fitzthum <tobin@ibm.com>,
        Michael Roth <michael.roth@amd.com>,
        Vlastimil Babka <vbabka@suse.cz>, tony.luck@intel.com,
        npmccallum@redhat.com, brijesh.ksingh@gmail.com
Subject: Re: [PATCH Part1 RFC v4 16/36] KVM: SVM: define new SEV_FEATURES
 field in the VMCB Save State Area
Message-ID: <YRv3x/JeNjcJ4E8a@zn.tnic>
References: <20210707181506.30489-1-brijesh.singh@amd.com>
 <20210707181506.30489-17-brijesh.singh@amd.com>
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In-Reply-To: <20210707181506.30489-17-brijesh.singh@amd.com>
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On Wed, Jul 07, 2021 at 01:14:46PM -0500, Brijesh Singh wrote:
> The hypervisor uses the SEV_FEATURES field (offset 3B0h) in the Save State
> Area to control the SEV-SNP guest features such as SNPActive, vTOM,
> ReflectVC etc. An SEV-SNP guest can read the SEV_FEATURES fields through
> the SEV_STATUS MSR.
> 
> While at it, update the dump_vmcb() to log the VMPL level.
> 
> See APM2 Table 15-34 and B-4 for more details.
> 
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  arch/x86/include/asm/svm.h | 15 +++++++++++++--
>  arch/x86/kvm/svm/svm.c     |  4 ++--
>  2 files changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
> index 772e60efe243..ff614cdcf628 100644
> --- a/arch/x86/include/asm/svm.h
> +++ b/arch/x86/include/asm/svm.h
> @@ -212,6 +212,15 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
>  #define SVM_NESTED_CTL_SEV_ENABLE	BIT(1)
>  #define SVM_NESTED_CTL_SEV_ES_ENABLE	BIT(2)
>  
> +#define SVM_SEV_FEATURES_SNP_ACTIVE		BIT(0)
> +#define SVM_SEV_FEATURES_VTOM			BIT(1)
> +#define SVM_SEV_FEATURES_REFLECT_VC		BIT(2)
> +#define SVM_SEV_FEATURES_RESTRICTED_INJECTION	BIT(3)
> +#define SVM_SEV_FEATURES_ALTERNATE_INJECTION	BIT(4)
> +#define SVM_SEV_FEATURES_DEBUG_SWAP		BIT(5)
> +#define SVM_SEV_FEATURES_PREVENT_HOST_IBS	BIT(6)
> +#define SVM_SEV_FEATURES_BTB_ISOLATION		BIT(7)

Only some of those get used and only later. Please introduce only those
with the patch that adds usage.

Also,

s/SVM_SEV_FEATURES_/SVM_SEV_FEAT_/g

at least.

And by the way, why is this patch and the next 3 part of the guest set?
They look like they belong into the hypervisor set.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette