Re: [PATCH v10 08/16] KVM: guest_memfd: Allow host to map guest_memfd pages

[Vlastimil Babka <vbabka@suse.cz>]

On 5/27/25 20:02, Fuad Tabba wrote:
> This patch enables support for shared memory in guest_memfd, including
> mapping that memory at the host userspace. This support is gated by the
> configuration option KVM_GMEM_SHARED_MEM, and toggled by the guest_memfd
> flag GUEST_MEMFD_FLAG_SUPPORT_SHARED, which can be set when creating a
> guest_memfd instance.
> 
> Co-developed-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Fuad Tabba <tabba@google.com>

<snip>

> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index 559c93ad90be..df225298ab10 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -128,3 +128,8 @@ config HAVE_KVM_ARCH_GMEM_PREPARE
>  config HAVE_KVM_ARCH_GMEM_INVALIDATE
>         bool
>         depends on KVM_GMEM
> +
> +config KVM_GMEM_SHARED_MEM
> +       select KVM_GMEM
> +       bool
> +       prompt "Enable support for non-private (shared) memory in guest_memfd"

Due to this "prompt" line, the toggle for this appears on the front page on
make menuconfig, or is asked during make oldconfig etc.
Seems not intended, no other options in this Kconfig have prompts, and the
later patch selects this option. So the prompt should be removed, otherwise
it's a Linus yelling hazard :)