HOWTO Debian Jessie 8 pci_stub config to hide PCI devices from device modules

# If you have to hide a PCI device like a GPU, you can use pci_stub

# to get the PCI port of your PCI device you can use lspci

   lspci

#     ...
#     01:00.0 VGA compatible controller: NVIDIA Corporation GK110 
#     [GeForce GTX 780] (rev a1)#     01:00.1 Audio device: NVIDIA Corporation GK110 HDMI Audio (rev a1)
#     ...

# the GPU use the PCI Slot 01:00.0 and 01:00.1 for the Nvidia Audio device
# NOTE: It's important to passthrough both devices to the virtual machine.

# for pci_stub, we need the IDs, with "lspci -n" we see this IDs

   lspci
#     ...
#     01:00.0 0300: 10de:1004 (rev a1)
#     01:00.1 0403: 10de:0e1a (rev a1)
#     ...


# Use the grub cmdline for pci_stub initializations

sudo nano /etc/default/grub

# change GRUB_CMDLINE_LINUX_DEFAULT
# from "quiet" to
# "quiet intel_iommu=on pci_stub.ids=10de:1004,10de:0e1a"
# after save start update-grub

   sudo update-grub2

# Add pci_stub to the end of /etc/initramfs-tools/modules and update the initramfs

    sudo update-initramfs -u

# After this the pci_stub kernel line parameter is working.

# Now reboot and the given devices will not working until you wont this.