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From:   Erdem Aktas <erdemaktas@google.com>
Date:   Wed, 11 Jan 2023 14:02:58 -0800
Message-ID: <CAAYXXYwQ_qBbug85QgMMN376FSZqoZypbTm9Gzc9wgY88AxX+w@mail.gmail.com>
Subject: Re: [PATCH v10 005/108] KVM: TDX: Initialize the TDX module when
 loading the KVM intel kernel module
To:     isaku.yamahata@intel.com
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        isaku.yamahata@gmail.com, Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Sagi Shahar <sagis@google.com>,
        David Matlack <dmatlack@google.com>
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On Sat, Oct 29, 2022 at 11:24 PM <isaku.yamahata@intel.com> wrote:
>
> From: Isaku Yamahata <isaku.yamahata@intel.com>

> +int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops)
> +{
> +       int r;
> +
> +       if (!enable_ept) {
> +               pr_warn("Cannot enable TDX with EPT disabled\n");
> +               return -EINVAL;
> +       }
> +
> +       /* MOVDIR64B instruction is needed. */
> +       if (!static_cpu_has(X86_FEATURE_MOVDIR64B)) {
> +               pr_warn("Cannot enable TDX with MOVDIR64B supported ");
> +               return -ENODEV;
> +       }
> +
> +       /* TDX requires VMX. */
> +       r = vmxon_all();
> +       if (!r)
> +               r = tdx_module_setup();
> +       vmxoff_all();

if few CPUs have VMX enabled, this will disable VMX in all of them.
Depending on what enabled VMX on those CPUs, would this not cause
kernel crashes/problems?