Re: [PATCH] iommu/s390: tolerate repeat attach_dev calls

[Matthew Rosato]

On 5/19/22 2:29 PM, Matthew Rosato wrote:
> Since commit 0286300e6045 ("iommu: iommu_group_claim_dma_owner() must
> always assign a domain") s390-iommu will get called to allocate multiple
> unmanaged iommu domains for a vfio-pci device -- however the current
> s390-iommu logic tolerates only one.  Recognize that multiple domains can
> be allocated and handle switching between DMA or different iommu domain
> tables during attach_dev.
>
> Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
> ---

Tested in conjuction with

https://lore.kernel.org/kvm/0-v1-9cfc47edbcd4+13546-vfio_dma_owner_fix_jgg@xxxxxxxxxx/

Along with that patch, vfio{-pci,-ap,-ccw} on s390x for -next seem happy 
again.