Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20181205191956.31480-1-ehabkost@redhat.com>
In-Reply-To: <20181205191956.31480-1-ehabkost@redhat.com>
From:   Jim Mattson <jmattson@google.com>
Date:   Wed, 5 Dec 2018 11:36:54 -0800
Message-ID: <CALMp9eRZtRb-tUSwomtPg7BCrY4dzny9HMVr+SvanAw3hdN7Dg@mail.gmail.com>
Subject: Re: [PATCH] kvm: x86: Report STIBP on GET_SUPPORTED_CPUID
To:     Eduardo Habkost <ehabkost@redhat.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        kvm list <kvm@vger.kernel.org>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        KarimAllah Ahmed <karahmed@amazon.de>,
        David Woodhouse <dwmw2@infradead.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Dec 5, 2018 at 11:19 AM Eduardo Habkost <ehabkost@redhat.com> wrote:
>
> Months ago, we have added code to allow direct access to MSR_IA32_SPEC_CTRL
> to the guest, which makes STIBP available to guests.  This was implemented
> by commits d28b387fb74d ("KVM/VMX: Allow direct access to
> MSR_IA32_SPEC_CTRL") and b2ac58f90540 ("KVM/SVM: Allow direct access to
> MSR_IA32_SPEC_CTRL").
>
> However, we never updated GET_SUPPORTED_CPUID to let userspace know that
> STIBP can be enabled in CPUID.  Fix that by updating
> kvm_cpuid_8000_0008_ebx_x86_features and kvm_cpuid_7_0_edx_x86_features.
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>