From: Krzysztof Kozlowski <krzk@xxxxxxxxxx> [ Upstream commit 929a343b858612100cb09443a8aaa20d4a4706d3 ] The VFIO_AP uses ap_driver_register() (and deregister) functions implemented in ap_bus.c (compiled into ap.o). However the ap.o will be built only if CONFIG_ZCRYPT is selected. This was not visible before commit e93a1695d7fb ("iommu: Enable compile testing for some of drivers") because the CONFIG_VFIO_AP depends on CONFIG_S390_AP_IOMMU which depends on the missing CONFIG_ZCRYPT. After adding COMPILE_TEST, it is possible to select a configuration with VFIO_AP and S390_AP_IOMMU but without the ZCRYPT. Add proper dependency to the VFIO_AP to fix build errors: ERROR: modpost: "ap_driver_register" [drivers/s390/crypto/vfio_ap.ko] undefined! ERROR: modpost: "ap_driver_unregister" [drivers/s390/crypto/vfio_ap.ko] undefined! Reported-by: kernel test robot <lkp@xxxxxxxxx> Fixes: e93a1695d7fb ("iommu: Enable compile testing for some of drivers") Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx> Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/s390/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index c7d7ede6300c5..4907a5149a8a3 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -769,6 +769,7 @@ config VFIO_AP def_tristate n prompt "VFIO support for AP devices" depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM + depends on ZCRYPT help This driver grants access to Adjunct Processor (AP) devices via the VFIO mediated device interface. -- 2.25.1