On Tue, Jul 07, 2026 at 07:48:14AM -0700, Jacob Pan wrote: > Hi Mukesh, > > On Mon, 6 Jul 2026 17:08:50 -0700 > Mukesh R <[email protected]> wrote: > > > From: Mukesh R <[email protected]> > > To: Yu Zhang <[email protected]>, > > [email protected], [email protected], > > [email protected], [email protected], > > [email protected] Cc: [email protected], [email protected], > > [email protected], [email protected], [email protected], > > [email protected], [email protected], [email protected], > > [email protected], [email protected], [email protected], > > [email protected], [email protected], [email protected], [email protected], > > [email protected], [email protected], > > [email protected], [email protected] > > Subject: Re: [PATCH v2 3/4] iommu/hyperv: Add para-virtualized IOMMU > > support for Hyper-V guest Date: Mon, 6 Jul 2026 17:08:50 -0700 > > User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 > > Thunderbird/91.13.1 > > > > On 7/2/26 09:05, 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. > > > > > > 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/iommu.c | 620 > > > ++++++++++++++++++++++++++++++++ drivers/iommu/hyperv/iommu.h | > > > 51 +++ 7 files changed, 697 insertions(+) > > > create mode 100644 drivers/iommu/hyperv/Kconfig > > > create mode 100644 drivers/iommu/hyperv/iommu.c > > > > Hey Jacob, > > > > You had suggested I rename iommu.c to iommu-root.c (I called it > > hv-iommu-root.c eventually), so this needs to be renamed also, > > right? > > yes, I agree. I feel it is clearer to name it hv-iommu-guest.c since > this is a guest only driver. >
hv-iommu-guest.c sounds good to me. :) B.R. Yu
