How can I check if IOMMU is enabled in my kernel module?

Is there an API for it?

I’ve searched in

• https://github.com/torvalds/linux/blob/master/arch/x86/kernel/pci-dma.c
• https://github.com/torvalds/linux/blob/933069701c1b507825b514317d4edd5d3fd9d417/include/linux/of_iommu.h

but no luck.