Re: [PATCH 2/3] KVM: x86: leave the legacy private attribute in for TDX and SEV

[Ackerley Tng]

Paolo Bonzini <pbonzini@xxxxxxxxxx> writes:

> As of today, and presumably as of Linux 7.4's release date, there
> is hardly any VMM that supports guest_memfd attributes.  Support the
> legacy VM attribute for private memory if SEV or TDX are requested;
> default it to disabled if only the software-protected VM is requested,
> since it is only used by guest_memfd selftests.
>
> While in-place conversion is the best option, it is way too
> early to enable it by default.
>

Reviewed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>

> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
>  arch/x86/kvm/Kconfig | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index 01a683a9042a..4f7d75ec8c40 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -80,6 +80,7 @@ config KVM_PRIVATE_MEMATTR_VM
>  	bool "Enable per-VM PRIVATE vs. SHARED attributes (for CoCo VMs)"
>  	depends on KVM_SW_PROTECTED_VM || KVM_INTEL_TDX || KVM_AMD_SEV
>  	select KVM_VM_MEMORY_ATTRIBUTES
> +	default KVM_INTEL_TDX || KVM_AMD_SEV
>  	help
>  	  Enable support for tracking PRIVATE vs. SHARED memory using per-VM
>  	  memory attributes.  Using per-VM attributes is deprecated in favor of
> @@ -87,7 +88,7 @@ config KVM_PRIVATE_MEMATTR_VM
>  	  CoCo VMs using a VMM that doesn't support guest_memfd memory
>  	  attributes.
>
> -	  If unsure, say N.
> +	  If unsure, say "Y".
>
>  config KVM_SW_PROTECTED_VM
>  	bool "Enable support for KVM software-protected VMs"
> --
> 2.52.0