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From:   Jim Mattson <jmattson@google.com>
Date:   Mon, 11 May 2020 16:51:54 -0700
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Subject: Re: [PATCH v3 3/3] KVM: x86: Move MPK feature detection to common code
To:     Babu Moger <babu.moger@amd.com>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Thomas Gleixner <tglx@linutronix.de>,
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On Mon, May 11, 2020 at 4:33 PM Babu Moger <babu.moger@amd.com> wrote:
>
> Both Intel and AMD support (MPK) Memory Protection Key feature.
> Move the feature detection from VMX to the common code. It should
> work for both the platforms now.
>
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
>  arch/x86/kvm/cpuid.c   |    4 +++-
>  arch/x86/kvm/vmx/vmx.c |    4 ----
>  2 files changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 901cd1fdecd9..3da7d6ea7574 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -278,6 +278,8 @@ void kvm_set_cpu_caps(void)
>  #ifdef CONFIG_X86_64
>         unsigned int f_gbpages = F(GBPAGES);
>         unsigned int f_lm = F(LM);
> +       /* PKU is not yet implemented for shadow paging. */
> +       unsigned int f_pku = tdp_enabled ? F(PKU) : 0;

I think we still want to require that OSPKE be set on the host before
exposing PKU to the guest.