Re: [PATCH v2 1/3] iommufd/viommu: Allow associating a KVM VM fd with a vIOMMU

Aneesh Kumar K.V
2026-03-16T05:49:37Z

Nicolin Chen <nicolinc@nvidia.com> writes:

> On Mon, Mar 09, 2026 at 04:47:02PM +0530, Aneesh Kumar K.V (Arm) wrote:
>> Add optional KVM association to IOMMU_VIOMMU_ALLOC by introducing
>> IOMMU_VIOMMU_KVM_FD and iommu_viommu_alloc::kvm_vm_fd.
>>
>> When the flag is set, iommufd validates that kvm_vm_fd refers to a KVM
>> VM file and stores a referenced struct file in the vIOMMU object, so
>> later iommufd operations can safely resolve the owning VM.
>>
>> This is preparatory plumbing for subsequent patches that bind TDI state
>> to the associated KVM VM.
>>
>> The patch also switch file_is_kvm from EXPORT_SYMBOL_FOR_KVM_INTERNAL to
>> EXPORT_SYMBOL_GPL so that iommu module can use that.
>
> struct vfio_device has the kvm pointer already. So, I think it
> could be forwarded from VFIO side v.s. via userspace ioctl.
>
> Shammer had two patches before and Jason partially reviewed. I
> took those for a side project but haven't sent anywhere. Would
> you please check if they for you?
>
> https://github.com/nicolinc/iommufd/commits/wip/viommu_kvm
>

I will use these patches and add additional patches on top of it.

-aneesh