[PATCH RESEND v11 10/13] um: nommu: a work around for MMU dependency to PCI driver

[Hajime Tazaki]

On Thu, 18 Sep 2025 17:30:22 +0900,
Johannes Berg wrote:
> 
> On Thu, 2025-09-18 at 16:39 +0900, Hajime Tazaki wrote:
> > The commit 8fe743b5eba0 ("PCI: Add CONFIG_MMU dependency") restricts the
> > PCI base driver to depend on MMU.  While nommu UML _can_ implement PCI
> > drivers over PCI devices (e.g., virtio-pci), the current nommu UML
> > doesn't implement it.
> > 
> > But without PCI drivers kunit complains as config for kunit
> > (arch_uml.config) defines the dependency to PCI drivers.
> > 
> > This commit fixes the issue of this compile failures when building PCI
> > drivers with nommu UML.  In particular, the fix is to undefine the
> > constant PCI_IOBASE to be able to bypass pci_unmap_iospace() call.
> 
> This doesn't make a lot of sense to me. Why would we even want to build
> PCI on NOMMU-UML if PCI in general is dependent on MMU now?
> 
> It's not like ARCH=um with PCI and NOMMU has any value even for testing
> if such a configuration cannot exist in reality?

totally understand your point.

now I see that we don't have to have this work around by using
--kconfig_add option to kunit.py.

# like --kconfig_add CONFIG_UML_PCI_OVER_VIRTIO=n (in addition to
  --kconfig_add CONFIG_MMU=n).

so I'll drop this patch in the next version.

thanks,
-- Hajime