Re: [PATCH v6 18/43] KVM: Move KVM_VM_MEMORY_ATTRIBUTES config definition to x86

[Fuad Tabba]

On Thu, 7 May 2026 at 21:22, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@xxxxxxxxxx> wrote:
>
> From: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> Bury KVM_VM_MEMORY_ATTRIBUTES in x86 to discourage other architectures
> from adding support for per-VM memory attributes, because tracking private
> vs. shared memory on a per-VM basis is now deprecated in favor of tracking
> on a per-guest_memfd basis, and no other memory attributes are on the
> horizon.
>
> This will also allow modifying KVM_VM_MEMORY_ATTRIBUTES to be
> user-selectable (in x86) without creating weirdness in KVM's Kconfigs.
> Now that guest_memfd support memory attributes, it's entirely possible to
> run x86 CoCo VMs without support for KVM_VM_MEMORY_ATTRIBUTES.
>
> Leave the code itself in common KVM so that it's trivial to undo this
> change if new per-VM attributes do come along.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>

Reviewed-by: Fuad Tabba <tabba@xxxxxxxxxx>

Cheers,
/fuad
> ---
>  arch/x86/kvm/Kconfig | 4 ++++
>  virt/kvm/Kconfig     | 4 ----
>  2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index 26f6afd51bbdc..b6d65ee664d0f 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -80,6 +80,10 @@ config KVM_WERROR
>
>           If in doubt, say "N".
>
> +config KVM_VM_MEMORY_ATTRIBUTES
> +       select KVM_MEMORY_ATTRIBUTES
> +       bool
> +
>  config KVM_SW_PROTECTED_VM
>         bool "Enable support for KVM software-protected VMs"
>         depends on EXPERT
> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index e371e079e2c50..663de6421eda2 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -103,10 +103,6 @@ config KVM_MMU_LOCKLESS_AGING
>  config KVM_MEMORY_ATTRIBUTES
>         bool
>
> -config KVM_VM_MEMORY_ATTRIBUTES
> -       select KVM_MEMORY_ATTRIBUTES
> -       bool
> -
>  config KVM_GUEST_MEMFD
>         select XARRAY_MULTI
>         select KVM_MEMORY_ATTRIBUTES
>
> --
> 2.54.0.563.g4f69b47b94-goog
>
>