linux-kernel - Re: [PATCH 2/3] KVM: nVMX: fix wrong condition for SPEC_CTRL and PRED

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Message-ID: <CALMp9eSbH67rm2vDnuaCjSU0JRsZxT1cW2qoyWQREV_iSAVaTw@mail.gmail.com>
Date:   Wed, 21 Feb 2018 16:07:35 -0800
From:   Jim Mattson <jmattson@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kvm list <kvm@...r.kernel.org>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Radim Krčmář <rkrcmar@...hat.com>,
        KarimAllah Ahmed <karahmed@...zon.de>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>, stable@...r.kernel.org
Subject: Re: [PATCH 2/3] KVM: nVMX: fix wrong condition for SPEC_CTRL and
 PRED_CMD MSRs

On Wed, Feb 21, 2018 at 1:41 PM, Paolo Bonzini <pbonzini@...hat.com> wrote:
> We need to change the default all-1s bitmap if the MSRs are _not_
> intercepted.  However, the code was disabling the intercept when it was
> _enabled_ in the VMCS01.  This is not causing bigger trouble,
> because vmx_vcpu_run checks the VMCS02's MSR bitmap and would do the
> right thing even if fed garbage... but it's obviously a bug and it can
> cause extra MSR reads and writes when running nested guests.
>
> Fixes: d28b387fb74da95d69d2615732f50cceb38e9a4d
> Fixes: 15d45071523d89b3fb7372e2135fbd72f6af9506
> Cc: x86@...nel.org
> Cc: Radim Krčmář <rkrcmar@...hat.com>
> Cc: KarimAllah Ahmed <karahmed@...zon.de>
> Cc: David Woodhouse <dwmw@...zon.co.uk>
> Cc: Jim Mattson <jmattson@...gle.com>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Ingo Molnar <mingo@...nel.org>
> Cc: stable@...r.kernel.org
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>

Wasn't this already fixed by 206587a9fb76 ("X86/nVMX: Properly set
spec_ctrl and pred_cmd before merging MSRs")?