Re: [PATCH v10 22/28] KVM: nVMX: Restrict event data VMCS fields to FRED-supported hosts

[Binbin Wu]

On 9/12/2026 5:36 AM, Sohil Mehta wrote:
> From: Xin Li <xin@xxxxxxxxx>
> 
> Prevent L1 from accessing the ORIGINAL_EVENT_DATA and INJECTED_EVENT_DATA
> VMCS fields via VMREAD or VMWRITE when FRED support is disabled or not
> present in KVM.

I think the change log should tell why the patch only restricts event data
fields.

> 
> Signed-off-by: Xin Li <xin@xxxxxxxxx>
> Signed-off-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>
> ---
> v10:
>  - Split out of "KVM: nVMX: Guard SHADOW_FIELD_R[OW] macros with VMX
>    feature checks" and renamed (Sean).
> ---
>  arch/x86/kvm/vmx/vmcs12.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/kvm/vmx/vmcs12.c b/arch/x86/kvm/vmx/vmcs12.c
> index 837cb3d568c3..67c730e31465 100644
> --- a/arch/x86/kvm/vmx/vmcs12.c
> +++ b/arch/x86/kvm/vmx/vmcs12.c
> @@ -222,6 +222,9 @@ static __init bool cpu_has_vmcs12_field(unsigned int idx)
>  	case HOST_SSP:
>  	case HOST_INTR_SSP_TABLE:
>  		return cpu_has_load_cet_ctrl();
> +	VMCS12_CASE64(ORIGINAL_EVENT_DATA):
> +	VMCS12_CASE64(INJECTED_EVENT_DATA):
> +		return cpu_has_vmx_fred();
>  
>  	/* KVM always emulates PML and the VMX preemption timer in software. */
>  	case GUEST_PML_INDEX: