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SubjectRe: [PATCH 1/2] KVM: VMX: Don't expose unrestricted_guest is enabled if ept is disabled
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On 09/10/2017 00:35, Jim Mattson wrote:
> If it were me, I'd apply De Morgan to that expression, but the logic looks fine.
>
> Reviewed-by: Jim Mattson <jmattson@google.com>

I'm okay with the way Wanpeng wrote it, but as a follow up this:

if (!cpu_has_vmx_ept() ||
!cpu_has_vmx_ept_4levels() ||
!cpu_has_vmx_ept_mt_wb()) {
enable_ept = 0;
enable_unrestricted_guest = 0;
enable_ept_ad_bits = 0;
}

can be reduced to just "enable_ept = 0".

Paolo

> On Sat, Oct 7, 2017 at 7:35 PM, Wanpeng Li <kernellwp@gmail.com> wrote:
>> From: Wanpeng Li <wanpeng.li@hotmail.com>
>>
>> SDM mentioned:
>>
>> "If either the “unrestricted guest” VM-execution control or the “mode-based
>> execute control for EPT” VM- execution control is 1, the “enable EPT”
>> VM-execution control must also be 1."
>>
>> However, we can still observe unrestricted_guest is Y after inserting the kvm-intel.ko
>> w/ ept=N. It depends on later starts a guest in order that the function
>> vmx_compute_secondary_exec_control() can be executed, then both the module parameter
>> and exec control fields will be amended.
>>
>> This patch fixes it by amending module parameter immediately during vmcs data setup.
>>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Radim Krčmář <rkrcmar@redhat.com>
>> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
>> ---
>> arch/x86/kvm/vmx.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 244e366..3e664ca 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -6737,7 +6737,7 @@ static __init int hardware_setup(void)
>> if (!cpu_has_vmx_ept_ad_bits() || !enable_ept)
>> enable_ept_ad_bits = 0;
>>
>> - if (!cpu_has_vmx_unrestricted_guest())
>> + if (!cpu_has_vmx_unrestricted_guest() || !enable_ept)
>> enable_unrestricted_guest = 0;
>>
>> if (!cpu_has_vmx_flexpriority())
>> --
>> 2.7.4
>>

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