On 8/11/2026 08:50, Yu Zhang wrote: > Add a para-virtualized IOMMU driver for Linux guests running on Hyper-V. > This driver implements stage-1 IO translation within the guest OS. > It integrates with the Linux IOMMU core, utilizing Hyper-V hypercalls > for: > - Capability discovery > - Domain allocation, configuration, and deallocation > - Device attachment and detachment > - IOTLB invalidation > > The driver constructs x86-compatible stage-1 IO page tables in the > guest memory using consolidated IO page table helpers. This allows > the guest to manage stage-1 translations independently of vendor- > specific drivers (like Intel VT-d or AMD IOMMU). > > Hyper-V consumes this stage-1 IO page table when a device domain is > created and configured, and nests it with the host's stage-2 IO page > tables, therefore eliminating the VM exits for guest IOMMU mapping > operations. For unmapping operations, VM exits to perform the IOTLB > flush are still unavoidable. > > Guest hibernation and resume are not supported by this initial > implementation. The guest-owned stage-1 page tables reside in guest > memory and are preserved in the hibernation image. However, the image > does not by itself preserve the Hyper-V device-domain objects or their > device attachments, and the current pvIOMMU interface does not define > whether or how Hyper-V restores that state. > > To identify a device in its hypercall interface, the driver looks up the > logical device ID prefix registered for the device's PCI domain (see the > logical device ID registry in hv_common.c) and combines it with the PCI > function number of the endpoint device. > > Co-developed-by: Wei Liu <[email protected]> > Signed-off-by: Wei Liu <[email protected]> > Co-developed-by: Easwar Hariharan <[email protected]> > Signed-off-by: Easwar Hariharan <[email protected]> > Signed-off-by: Yu Zhang <[email protected]> > --- > arch/x86/hyperv/hv_init.c | 4 + > arch/x86/include/asm/mshyperv.h | 4 + > drivers/iommu/Kconfig | 1 + > drivers/iommu/hyperv/Kconfig | 16 + > drivers/iommu/hyperv/Makefile | 1 + > drivers/iommu/hyperv/hv-iommu-guest.c | 632 ++++++++++++++++++++++++++ > drivers/iommu/hyperv/iommu.h | 50 ++ > 7 files changed, 708 insertions(+) > create mode 100644 drivers/iommu/hyperv/Kconfig > create mode 100644 drivers/iommu/hyperv/hv-iommu-guest.c > create mode 100644 drivers/iommu/hyperv/iommu.h > Seems like this is missing a change to MAINTAINERS. I'd suggest making a new section and adding both the IOMMU and Hyper-V lists. As it stands, the IOMMU list will get no notification of changes to this driver.
Thanks, Easwar (he/him)
