Re: [PATCH v5 4/5] iommu/hyperv: Add para-virtualized IOMMU support for Hyper-V guest

[Easwar Hariharan]

On 9/29/2026 14:25, Jacob Pan wrote:
> Hi Jason,
> 
> On Tue, 29 Sep 2026 17:04:47 -0300
> Jason Gunthorpe <j...@nvidia.com> wrote:
> 
>>> +config HYPERV_PVIOMMU
>>> +   bool "Microsoft Hyper-V para-virtualized IOMMU driver for
>>> Linux guests"
>>> +   depends on X86_64 && HYPERV
>>> +   select IOMMU_API
>>> +   select GENERIC_PT
>>> +   select IOMMU_PT
>>> +   select IOMMU_PT_X86_64
>>> +   select IOMMU_IOVA  
>>
>> Should this be IOMMU_DMA ?
> 
> I agree. I guess we should also delete "select IOMMU_API", since
> IOMMU_DMA selects both.
> 
> Noticed vt-d driver has the same option, maybe it should also
> be changed. Baolu, is that due to historical reasons?
> 
> config INTEL_IOMMU
>       bool "Support for Intel IOMMU using DMA Remapping Devices"
>       depends on PCI_MSI && ACPI && X86
>       select IOMMU_API
>       select GENERIC_PT
>       select IOMMU_PT
>       select IOMMU_PT_X86_64
>       select IOMMU_PT_VTDSS
>       select IOMMU_IOVA

FWIW, AMD also has the same...

config AMD_IOMMU
        bool "AMD IOMMU support"
        select SWIOTLB
        select PCI_MSI
        select PCI_ATS
        select PCI_PRI
        select PCI_PASID
        select IRQ_MSI_LIB
        select MMU_NOTIFIER
        select IOMMU_API
        select IOMMU_IOVA

but ARM doesn't, and doesn't select IOMMU_DMA either.

:confused:

Thanks,
Easwar (he/him)