What were you trying to do that didn't work?

Attach a filesystem device on x86_64.

Please provide the package NVR for which bug is seen:

libvirt-10.3.0-2

How reproducible:

100%

Steps to reproduce

1. Define a VM with shared memory and <boot order="1"/> in the bootable disk (don't use //os/boot).
2. Prepare xml

   # cat virtiofs.xml
   <filesystem type="mount" accessmode="passthrough"><target dir="mount_tag" /><source dir="/tmp" /><binary path="/usr/libexec/virtiofsd" /><boot order="2" /><driver type="virtiofs" /></filesystem>

3. Cold or hotplug the device

   # virsh attach-device vm virtiofs.xml --current

Expected results

Device attached successfully

Actual results

error: Failed to attach device from virtiofs.xml
error: unsupported configuration: setting virtiofs boot order is supported only with PCI bus

Additional information

1. Looks like this was introduced when fixing hotplug errors for ccw-addresses RHEL-22728
2. If a PCI address is defined in the virtiofs.xml, then the hot/coldplug still works
3. Using the virsh edit, the snippet can just be added, no validation error.