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From:   Jim Mattson <jmattson@google.com>
Date:   Tue, 27 Aug 2019 10:09:52 -0700
Message-ID: <CALMp9eRqT1VpD25cp4yyr8oVLV8vzES_uki_Xuqs-_ghGsZy8A@mail.gmail.com>
Subject: Re: [PATCH 1/3] KVM: x86: hyper-v: don't crash on KVM_GET_SUPPORTED_HV_CPUID
 when kvm_intel.nested is disabled
To:     Vitaly Kuznetsov <vkuznets@redhat.com>
Cc:     kvm list <kvm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Joerg Roedel <joro@8bytes.org>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Roman Kagan <rkagan@virtuozzo.com>
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On Tue, Aug 27, 2019 at 9:04 AM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
> If kvm_intel is loaded with nested=0 parameter an attempt to perform
> KVM_GET_SUPPORTED_HV_CPUID results in OOPS as nested_get_evmcs_version hook
> in kvm_x86_ops is NULL (we assign it in nested_vmx_hardware_setup() and
> this only happens in case nested is enabled).
>
> Check that kvm_x86_ops->nested_get_evmcs_version is not NULL before
> calling it. With this, we can remove the stub from svm as it is no
> longer needed.
>
> Fixes: e2e871ab2f02 ("x86/kvm/hyper-v: Introduce nested_get_evmcs_version() helper")
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>