Re: [RFC v7 09/26] vfio: Force nested if iommu requires it

[Kunkun Jiang]

Hi Eric,
> @@ -1668,6 +1679,14 @@ static int vfio_connect_container(VFIOGroup *group, 
> AddressSpace *as,
>      VFIOContainer *container;
>      int ret, fd;
>      VFIOAddressSpace *space;
> +    IOMMUMemoryRegion *iommu_mr;
> +    bool nested = false;
> +
> +    if (as != &address_space_memory && memory_region_is_iommu(as->root)) {
> +        iommu_mr = IOMMU_MEMORY_REGION(as->root);
> +        memory_region_iommu_get_attr(iommu_mr, IOMMU_ATTR_VFIO_NESTED,
> +                                     (void *)&nested);
> +    }
>  
>      space = vfio_get_address_space(as);
Is the condition "as != &address_space_memory" needed to determine whether
a vIOMMU is in place? I think "memory_region_is_iommu(as->root)" is enough.

Looking forward to your reply.:)

Thanks,

Kunkun Jiang