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From:   Jim Mattson <jmattson@google.com>
Date:   Wed, 21 Aug 2019 12:47:35 -0700
Message-ID: <CALMp9eS=qsrOE2yaJAFZK6VhFEtkx2vjCQkYa8UMjeWYDOQQgg@mail.gmail.com>
Subject: Re: [PATCH 2/3] KVM: x86: always expose VIRT_SSBD to guests
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        kvm list <kvm@vger.kernel.org>, jmattson@redhat.com,
        Eduardo Habkost <ehabkost@redhat.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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On Wed, Aug 21, 2019 at 1:27 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> Even though it is preferrable to use SPEC_CTRL (represented by
> X86_FEATURE_AMD_SSBD) instead of VIRT_SPEC, VIRT_SPEC is always
> supported anyway because otherwise it would be impossible to
> migrate from old to new CPUs.  Make this apparent in the
> result of KVM_GET_SUPPORTED_CPUID as well.
>
> While at it, reuse X86_FEATURE_* constants for the SVM leaf too.
>
> However, we need to hide the bit on Intel processors, so move
> the setting to svm_set_supported_cpuid.
>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Reported-by: Eduardo Habkost <ehabkost@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>