Hi Thomas,
On Mon, 8 Sept 2025 at 09:04, Thomas Weißschuh thomas.weissschuh@linutronix.de wrote:
Various KUnit tests require PCI infrastructure to work. All normal platforms enable PCI by default, but UML does not. Enabling PCI from .kunitconfig files is problematic as it would not be portable. So in commit 6fc3a8636a7b ("kunit: tool: Enable virtio/PCI by default on UML") PCI was enabled by way of CONFIG_UML_PCI_OVER_VIRTIO=y. However CONFIG_UML_PCI_OVER_VIRTIO requires additional configuration of CONFIG_UML_PCI_OVER_VIRTIO_DEVICE_ID or will otherwise trigger a WARN() in virtio_pcidev_init(). However there is no one correct value for UML_PCI_OVER_VIRTIO_DEVICE_ID which could be used by default.
This warning is confusing when debugging test failures.
On the other hand, the functionality of CONFIG_UML_PCI_OVER_VIRTIO is not used at all, given that it is completely non-functional as indicated by the WARN() in question. Instead it is only used as a way to enable CONFIG_UML_PCI which itself is not directly configurable.
Instead of going through CONFIG_UML_PCI_OVER_VIRTIO, introduce a custom configuration option which enables CONFIG_UML_PCI without triggering warnings or building dead code.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de Reviewed-by: Johannes Berg johannes@sipsolutions.net
Thanks for your patch!
--- a/lib/kunit/Kconfig +++ b/lib/kunit/Kconfig @@ -106,4 +106,11 @@ config KUNIT_DEFAULT_TIMEOUT If unsure, the default timeout of 300 seconds is suitable for most cases.
+config KUNIT_UML_PCI
Where is the consumer of this symbol?
bool "KUnit UML PCI Support"depends on UMLselect UML_PCIhelpEnables the PCI subsystem on UML for use by KUnit tests.endif # KUNIT diff --git a/tools/testing/kunit/configs/arch_uml.config b/tools/testing/kunit/configs/arch_uml.config index 54ad8972681a2cc724e6122b19407188910b9025..28edf816aa70e6f408d9486efff8898df79ee090 100644 --- a/tools/testing/kunit/configs/arch_uml.config +++ b/tools/testing/kunit/configs/arch_uml.config @@ -1,8 +1,7 @@ # Config options which are added to UML builds by default
-# Enable virtio/pci, as a lot of tests require it. -CONFIG_VIRTIO_UML=y -CONFIG_UML_PCI_OVER_VIRTIO=y +# Enable pci, as a lot of tests require it. +CONFIG_KUNIT_UML_PCI=y
# Enable FORTIFY_SOURCE for wider checking. CONFIG_FORTIFY_SOURCE=y
Gr{oetje,eeting}s,
Geert