As the presence of OpRegion is used to detect IGD device now, and
guest driver usually depends on OpRegion to work. Enable OpRegion
on IGD devices by default for out-of-the-box passthrough experience
(except pre-boot display output), especially for libvirt users.
Example of IGD passthrough with libvirt:
<hostdev mode="subsystem" type="pci" managed="yes">
<source>
<address domain="0x0000" bus="0x00" slot="0x02" function="0x0"/>
</source>
<rom file="/path/to/igd/rom"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x0"/>
</hostdev>
Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
Reviewed-by: Corvin Köhne <c.koehne@beckhoff.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250505170305.23622-7-tomitamoeko@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Document the usage modes, host primary graphics considerations, usage,
and fw_cfg ABI required for IGD assignment with vfio.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
