virtualbox.org

I'm running a W10 host with W10 and Linux guests. What would be the use-case or advantage of turning on IOMMU for the host? Anything to be gained?

Searching the PDF of the manual for 6.1.12 shows no mention of IOMMU. In 6.0.14's manual, IOMMU is mentioned in the context of PCI-passthrough on Linux hosts.

PCI Passthrough was removed in 6.1.x and was never active in Windows hosts, so if you're on 6.1.x or WIndows, IOMMU will do nothing, apparently.

6.0.x & earlier used it for PCI-passthrough on Linux hosts, which didn't work well or at all for PCIe-passthrough, according to the devs, and didn't help the guest when trying a video pass-through, according to forum guru PerryG.

JustinH wrote:What would be the use-case or advantage of turning on IOMMU for the host? Anything to be gained?

None, and no. That's why the feature only ever existed as an experiment on one host OS and was then dropped.