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>
Intel only provides legacy VBIOS for IGD up to Gen9, and there is no
CSM support on later devices. Additionally, Seabios can only handle
32-bit BDSM register used until Gen9. Since legacy mode requires VGA
capability, restrict it to Gen6 through Gen9 devices.
Link: https://lore.kernel.org/qemu-devel/20250325172239.27926-1-tomitamoeko@gmail.com/T/
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/20250505170305.23622-2-tomitamoeko@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
A previous change made the OpRegion and LPC quirks independent of the
existing legacy mode, update the documentation accordingly. More related
topics, like creating EFI Option ROM of IGD for OVMF, how to solve the
VFIO_DMA_MAP Invalid Argument warning, as well as details on IGD memory
internals, are also added.
Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250313150339.358621-1-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>
