Check region type first before casting the memory region
to IOMMUMemoryRegion. Otherwise QEMU will abort with below
error message when casting non-IOMMU memory region:
vhost_iommu_region_add: Object 0x561f28bce4f0 is not an
instance of type qemu:iommu-memory-region
Fixes: cb1efcf462a2 ("iommu: Add IOMMU index argument to notifier APIs")
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
388a86df9c