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From: Jim Mattson <jmattson@google.com>
Date: Thu, 13 Jun 2024 12:28:32 -0700
Message-ID: <CALMp9eSw65i8SpjPKxcu=g8dTRRR+eXLuj5rQNfeJjeTNNQJAw@mail.gmail.com>
Subject: Re: [PATCH] KVM: nVMX: Update VMCS12_REVISION comment to state it
 should never change
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org, linux-kernel@vger.kernel.org
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On Thu, Jun 13, 2024 at 12:01=E2=80=AFPM Sean Christopherson <seanjc@google=
.com> wrote:
>
> Rewrite the comment above VMCS12_REVISION to unequivocally state that the
> ID must never change.  KVM_{G,S}ET_NESTED_STATE have been officially
> supported for some time now, i.e. changing VMCS12_REVISION would break
> userspace.
>
> Opportunistically add a blurb to the CHECK_OFFSET() comment to make it
> explicitly clear that new fields are allowed, i.e. that the restriction
> on the layout is all about backwards compatibility.
>
> No functional change intended.
>
> Cc: Jim Mattson <jmattson@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>