qemu/docs/igd-assign.txt

1 Intel Graphics Device (IGD) assignment with vfio-pci
4 IGD has two different modes for assignment using vfio-pci:
6 1) Universal Pass-Through (UPT) mode:
8    In this mode the IGD device is added as a *secondary* (ie. non-primary)
14    by Intel, does not support direct video output.  The intention is to use
16    or to use this mode in combination with guest-based remote access software,
18    theoretically has no device specific handling dependencies on vfio-pci or
19    the VM firmware.
32     * The VM firmware must support specific fw_cfg enablers for IGD
35       ISA/LPC bridge device (vfio-pci-igd-lpc-bridge) on the root bus at
44 may generate faults and errors upon re-binding to an IGD device after it
48 the driver_override option can be used to ensure that only vfio-pci can bind
49 to the device on the host[2], virsh nodedev-detach can be used to bind the
51 re-binding to i915, etc.  Also note that IGD is also typically the primary
53 blacklisting i915 or using pci-stub/vfio-pci to take ownership of IGD as a
55 It may therefore be necessary to use kernel boot options video=vesafb:off or
56 video=efifb:off (depending on host BIOS/UEFI) or these can be combined to
57 a catch-all, video=vesafb:off,efifb:off.  Error messages such as:
80 other graphics options and use "-nographic" and either "-vga none" or
81 "-nodefaults", along with adding the device using vfio-pci:
83     -device vfio-pci,host=00:02.0,id=hostdev0,bus=pci.0,addr=0x2
85 For UPT mode, retain the default emulated graphics and simply add the vfio-pci
88 users will need to manually edit the XML if using a tool like virt-manager
91 An experimental vfio-pci option also exists to enable OpRegion, and thus
93 "x-igd-opregion=on" to the vfio-pci device options for the IGD device.  As
96 be made non-experimental in the future, opening it to libvirt support.
100 Legacy mode IGD support imposes two fw_cfg requirements on the VM firmware:
102 1) "etc/igd-opregion"
109    recommended that firmware should make use of this fw_cfg entry for any
113 2) "etc/igd-bdsm-size"
115    This fw_cfg file contains an 8-byte, little endian integer indicating
117    Firmware must allocate a reserved memory below 4GB with required 1MB
129     as non-primary, other than the combination typically not working.  I only
133 [2] # echo "vfio-pci" > /sys/bus/pci/devices/0000:00:02.0/driver_override