Add viommu support
We don't support viommu, so the guest kernel hung when trying to access the virtiofs-mount directory with viommu enabled.
Libkrun seems to have a patch. Sergio is planning to propose it to upstream linux kernel. That will use iommu if available, otherwise it falls back to swiommu in case of confidential computing setup.
Tracking: https://bugzilla.redhat.com/show_bug.cgi?id=1976676
Related: https://bugzilla.redhat.com/show_bug.cgi?id=1812886