[libvirt-users] Trouble passing PCI device in isolated IOMMU group

I'm attempting PCI-passthrough from host to guest on an HP ProLiant 380P, which has an outdated BIOS (2014), but it does support VT-d. I'm running CentOS 7, kernel 3.10.0-862.9.1.el7.x86_64. I have an Intel 82580 NIC installed with 4 ports. Each of these ports is in its own IOMMU group (I enabled SR-IOV at the BIOS, which might be the reason they show up separately) After detaching and adding a 'hostdev' device with the appropriate pci address, I attempt to start my VM. I get " failed to set iommu for container: Operation not permitted". As recommended here ( http://vfio.blogspot.com/2014/08/vfiovga-faq.html) I parsed dmesg in an attempt to find: ------------------- No interrupt remapping support. Use the module param "allow_unsafe_interrupts" to enable VFIO IOMMU support on this platform ------------------- ...but nothing similar exists in my logs. Since this device is showing up in its own IOMMU group, I assume ACS override won't get me any further. In any case, it is not an option for me to leave ACS override on. I can turn it on for testing, the server is not currently in production. Any idea why this could be failing?