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

[Fuad Tabba <tabba@google.com>]

Hi Vlastimil

On Thu, 5 Jun 2025 at 09:28, Vlastimil Babka <vbabka@suse.cz> wrote:
>
> 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 :)

Ack, and thanks for the reviews!

Cheers,
/fuad