+ x86_platform.iommu_shutdown = intel_iommu_shutdown;
How about moving it to detect_intel_iommu() in drivers/iommu/dmar.c? And
Ok, makes sense to move it along with the init handler.
make sure that it's included with CONFIG_X86_64.
You mean CONFIG_X86 like the init that is already there?
#ifdef CONFIG_X86
if (!ret)
x86_init.iommu.iommu_init = intel_iommu_init;
#endif