Re: [RFC PATCH 0/5] hw/arm/virt: Add support for user-creatable nested SMMUv3

[Jason Gunthorpe]

On Thu, Feb 06, 2025 at 06:18:14PM +0000, Shameerali Kolothum Thodi wrote:

> > So even if you invent an iommu ID we cannot accept it as a handle to
> > create viommu in iommufd.
> 
> Creating the vIOMMU only happens when the user does a  cold/hot plug of
> a VFIO device. At that time Qemu checks whether the assigned id matches
> with whatever the kernel tell it. 

This is not hard up until the guest is started. If you boot a guest
without a backing viommu iommufd object then there will be some more
complexities.

Jason