[Qemu-discuss] IOMMU in kernel command line, still getting "No IOMMU found. Unable to assign device "(null)"I

[Kevin Wilson]

Hello,
I have IOMMU in the kernel command line on a server which supports Virt-d:

cat /proc/cmdline | grep -i iommu
BOOT_IMAGE=...intel_iommu=on iommu=pt

Now when I try to start a KVM VM with qemu-system-x86_64 without any
PCI device assignment it starts ok, and I can work with this VM just
fine.

But when I try to add PCI device assignment to a VF (of a nic) in the
qemu command line and launch an image, it failed with this message:

qemu-system-x86_64: -device pci-assign,host=05:00.0:  No IOMMU found.
Unable to assign device "(null)"

Why do I get this error, any ideas?

I want to add that when running:
virt-host-validate
I get everything righ:
  QEMU: Checking for hardware virtualization
      : PASS
  QEMU: Checking for device /dev/kvm
      : PASS
  QEMU: Checking for device /dev/vhost-net
      : PASS
  QEMU: Checking for device /dev/net/tun
      : PASS
   LXC: Checking for Linux >= 2.6.26
      : PASS

And when running dmesg | grep -i iommu I get:
...
Jan 10 11:22:56 host1 kernel: [    0.000000] Intel-IOMMU: enabled
...
I did enabled virt-d in bios, and from what I know, if I failed to do
so, then according to all I know I would not get anything
as output of "dmesg | grep -i iommu" and also virt-host-validate

So what can be the reason the "IOMMMU failed" message ?

Regards,
Kevin