Re: [PATCH] firmware: arm_scmi: Fix virtio transport Kconfig dependency

[Cristian Marussi <cristian.marussi@arm.com>]

On Mon, Aug 16, 2021 at 04:30:10PM +0200, Arnd Bergmann wrote:
> On Mon, Aug 16, 2021 at 4:16 PM Cristian Marussi
> <cristian.marussi@arm.com> wrote:
> >
> > ARM_SCMI_TRANSPORT_VIRTIO is a 'bool' Kconfig used to include support for
> > the SCMI virtio transport inside the core SCMI stack; a bare transport
> > dependency attached here to this option, though, cannot be properly
> > propagated to the parent ARM_SCMI_PROTOCOL option and, as a result, it is
> > currently possible to configure a Kernel where SCMI core is builtin
> > and includes support for virtio while VirtIO core is =m.
> > This allowed combination breaks linking:
> >
> >         ARM_SCMI_PROTOCOL=y
> >         ARM_SCMI_TRANSPORT_VIRTIO=y
> >         VIRTIO=m
> >
> > Bind the dependency in ARM_SCMI_TRANSPORT_VIRTIO to the chosen kind of
> > compilation of ARM_SCMI_PROTOCOL.
> >
> > Reported-by: kernel test robot <lkp@intel.com>
> > Suggested-by: Arnd Bergmann <arnd@kernel.org>
> > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> 

Hi,

> The description looks good
> 
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> 
> > @@ -68,7 +68,7 @@ config ARM_SCMI_TRANSPORT_SMC
> >
> >  config ARM_SCMI_TRANSPORT_VIRTIO
> >         bool "SCMI transport based on VirtIO"
> > -       depends on VIRTIO
> > +       depends on VIRTIO=y || VIRTIO=ARM_SCMI_PROTOCOL
> >         select ARM_SCMI_HAVE_TRANSPORT
> >         select ARM_SCMI_HAVE_MSG
> 
> Looking at this again, I noticed that this still needs the explicit
> 'depends on VIRTIO' line you removed, otherwise the prompt
> pops up when both VIRTIO and ARM_SCMI_PROTOCOL
> are disabled.

I checked this (VIRTIO=n with ARM_SCMI_PROTOCOL=n) and
ARM_SCMI_TRANSPORT_VIRTIO menu does not popup because the whole
menuconfig section under ARM_SCMI_PROTOCOL is already guarded by:

if ARM_SCMI_PROTOCOL

config ARM_SCMI_TRANSPORT_VIRTIO
...

endif

...if this was what you meant.

Thanks,
Cristian