[PATCH 1/2] KVM: VMX: Don't advertise EPT switching if EPT itself is not exposed

[PATCH 1/2] KVM: VMX: Don't advertise EPT switching if EPT itself is not exposed

[Wanpeng Li]

From: Wanpeng Li <wanpeng.li@hotmail.com>

EPT switching is advertised unconditionally since it is emulated, however, it can 
be treated as an extended feature for EPT, it should be not advertised if EPT itself
is not exposed. This patch fixes it.

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 | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c460b0b..3644540 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2842,8 +2842,9 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 		 * Advertise EPTP switching unconditionally
 		 * since we emulate it
 		 */
-		vmx->nested.nested_vmx_vmfunc_controls =
-			VMX_VMFUNC_EPTP_SWITCHING;
+		if (enable_ept)
+			vmx->nested.nested_vmx_vmfunc_controls =
+				VMX_VMFUNC_EPTP_SWITCHING;
 	}
 
 	/*
-- 
2.7.4

Re: [PATCH 1/2] KVM: VMX: Don't advertise EPT switching if EPT itself is not exposed

[Jim Mattson]

Does it still make sense to advertise "Enable VM Functions" in the
secondary processor-based VM-execution controls if we don't actually
support any VM Functions?

On Sat, Oct 14, 2017 at 7:31 PM, Wanpeng Li <kernellwp@gmail.com> wrote:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
>
> EPT switching is advertised unconditionally since it is emulated, however, it can
> be treated as an extended feature for EPT, it should be not advertised if EPT itself
> is not exposed. This patch fixes it.
>
> 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 | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index c460b0b..3644540 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2842,8 +2842,9 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
>                  * Advertise EPTP switching unconditionally
>                  * since we emulate it
>                  */
> -               vmx->nested.nested_vmx_vmfunc_controls =
> -                       VMX_VMFUNC_EPTP_SWITCHING;
> +               if (enable_ept)
> +                       vmx->nested.nested_vmx_vmfunc_controls =
> +                               VMX_VMFUNC_EPTP_SWITCHING;
>         }
>
>         /*
> --
> 2.7.4
>

Re: [PATCH 1/2] KVM: VMX: Don't advertise EPT switching if EPT itself is not exposed

[Wanpeng Li]

2017-10-17 1:16 GMT+08:00 Jim Mattson <jmattson@google.com>:
> Does it still make sense to advertise "Enable VM Functions" in the
> secondary processor-based VM-execution controls if we don't actually
> support any VM Functions?

Will do in v2. Thanks for your review.

Regards,
Wanpeng Li

>
> On Sat, Oct 14, 2017 at 7:31 PM, Wanpeng Li <kernellwp@gmail.com> wrote:
>> From: Wanpeng Li <wanpeng.li@hotmail.com>
>>
>> EPT switching is advertised unconditionally since it is emulated, however, it can
>> be treated as an extended feature for EPT, it should be not advertised if EPT itself
>> is not exposed. This patch fixes it.
>>
>> 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 | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index c460b0b..3644540 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -2842,8 +2842,9 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
>>                  * Advertise EPTP switching unconditionally
>>                  * since we emulate it
>>                  */
>> -               vmx->nested.nested_vmx_vmfunc_controls =
>> -                       VMX_VMFUNC_EPTP_SWITCHING;
>> +               if (enable_ept)
>> +                       vmx->nested.nested_vmx_vmfunc_controls =
>> +                               VMX_VMFUNC_EPTP_SWITCHING;
>>         }
>>
>>         /*
>> --
>> 2.7.4
>>