What were you trying to do that didn't work?
as subject.
There should be some problematic if with iommu device present but without iommu_platform to virtio device, but balloon device works.

Please provide the package NVR for which bug is seen:
virtiofsd-1.13.0-1.el10.x86_64
qemu-kvm-9.1.0-11.el10.x86_64
edk2-ovmf-20241117-1.el10.noarch
seabios-bin-1.16.3-7.el10.noarch
kernel-6.12.0-36.el10.x86_64
kernel-6.12.0-41.el10.x86_64
swtpm-0.9.0-4.el10.x86_64
prewhql-0.1-275

How reproducible:
always

Steps to reproduce
1.start win2025 guest with intel-iommu device and other virtio device but without iommu_platform configured.
-device '

{"intremap": "on", "aw-bits": 48, "eim": "off", "driver": "intel-iommu"}

' \
-device '

{"id": "virtio_scsi_pci0", "driver": "virtio-scsi-pci", "bus": "pcie-root-port-2", "addr": "0x0"}

' \

-device '

{"driver": "virtio-net-pci", "mac": "9a:8d:fc:e1:ce:6c", "id": "idSva5bB", "netdev": "idpGF7mv", "bus": "pcie-root-port-3", "addr": "0x0"}

' \
-netdev '

{"id": "idpGF7mv", "type": "tap", "vhost": true}

' \

-device '

{"driver": "virtio-balloon-pci", "id": "balloon0", "bus": "pcie-root-port-4", "addr": "0x0"}

'
2. enable driver verifier with /standard flag. 

3. Check balloon device in device manager that DMA Remapping policy value is 2.

 

Expected results
All virtio devices don't work.

Actual results
Balloon works.
Netkvm doesn't work as expected.