Kevin, On Sun, Dec 12 2021 at 01:56, Kevin Tian wrote: >> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >> All I can find is drivers/iommu/virtio-iommu.c but I can't find anything >> vIR related there. > > Well, virtio-iommu is a para-virtualized vIOMMU implementations. > > In reality there are also fully emulated vIOMMU implementations (e.g. > Qemu fully emulates Intel/AMD/ARM IOMMUs). In those configurations > the IR logic in existing iommu drivers just apply: > > drivers/iommu/intel/irq_remapping.c > drivers/iommu/amd/iommu.c thanks for the explanation. So that's a full IOMMU emulation. I was more expecting a paravirtualized lightweight one. Thanks, tglx