linux-kernel - Re: [PATCH v2 06/14] x86/sev: Drop redundant and potentially misleading 'sev

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Message-ID: <966c10b2-e3b7-8036-271f-6fff8a4029ce@amd.com>
Date:   Thu, 14 Jan 2021 11:54:24 -0600
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Borislav Petkov <bp@...e.de>,
        Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v2 06/14] x86/sev: Drop redundant and potentially
 misleading 'sev_enabled'

On 1/13/21 6:37 PM, Sean Christopherson wrote:
> Drop the sev_enabled flag and switch its one user over to sev_active().
> sev_enabled was made redundant with the introduction of sev_status in
> commit b57de6cd1639 ("x86/sev-es: Add SEV-ES Feature Detection").
> sev_enabled and sev_active() are guaranteed to be equivalent, as each is
> true iff 'sev_status & MSR_AMD64_SEV_ENABLED' is true, and are only ever
> written in tandem (ignoring compressed boot's version of sev_status).
> 
> Removing sev_enabled avoids confusion over whether it refers to the guest
> or the host, and will also allow KVM to usurp "sev_enabled" for its own
> purposes.
> 
> No functional change intended.
> 
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@....com>

> ---
>   arch/x86/include/asm/mem_encrypt.h |  1 -
>   arch/x86/mm/mem_encrypt.c          | 12 +++++-------
>   arch/x86/mm/mem_encrypt_identity.c |  1 -
>   3 files changed, 5 insertions(+), 9 deletions(-)
>