What were you trying to do that didn't work?
guest cannot power off with the iommu and iothread enabled 

qemu-kvm-9.1.0-6.el10

kernel-6.12.0-31.el10.x86_64

edk2-20240524-12.el10

How reproducible:
100%

Steps to reproduce

1.boot vm with virtio-blk assigned iothread and intel-iommu

-object '{"qom-type":"iothread","id":"iothread1"}' \
-device '{"driver":"virtio-blk-pci","iommu_platform":true,"ats":true,"iothread":"iothread1","bus":"pci.4","addr":"0x0","drive":"libvirt-1-format","id":"virtio-disk0","bootindex":1}' \

-device '{"driver":"intel-iommu","id":"iommu0","intremap":"on","caching-mode":true,"eim":"on","device-iotlb":true}' \

2.shutdown vm with shutdown -h now

Expected results
vm shutdown successfully 

Actual results
fail to shutdown