Hi Michael, On Sat, 11 Jul 2026 18:31:15 +0000 Michael Kelley <[email protected]> wrote:
> One new thought: Have you considered the hibernate/resume > cycle? Does anything need to be done with the pvIOMMU to > make it functional again after resume? I see that the Intel and > AMD IOMMU drivers have suspend and resume functions. I > don't know enough about the Hyper-V pvIOMMU to know if it > might also need suspend and resume functions. I don't think the Hyper-V pvIOMMU guest driver needs the same kind of suspend/resume handling as a hardware IOMMU driver. Unlike VT-d or AMD IOMMU, the guest driver does not own physical IOMMU registers, root tables, command queues, or translation enable state that must be saved and reprogrammed on resume. For nested translation, the guest does own the stage-1 I/O page tables, but those are normal guest memory. They survive S3 as system RAM. The guest driver still needs to issue the normal pvIOMMU invalidations when it changes S1 mappings, but suspend/resume by itself does not modify the S1 page tables and should not require a special flush. The important contract is on the Hyper-V side: Hyper-V owns translation enable/disable and must prevent device DMA while translation state is not valid. Thanks, Jacob
