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vfio/igd: Remove generation limitation for IGD passthrough

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Starting from Intel Core Ultra Series (Meteor Lake), Data Stolen Memory
has became a part of LMEMBAR (MMIO BAR2) [1][2], meaning that BDSM and
GGC register quirks are no longer needed on these platforms.

To support Meteor/Arrow/Lunar Lake and future IGD devices, remove the
generation limitation in IGD passthrough, and apply BDSM and GGC quirks
only to known Gen6-12 devices.

[1] https://edc.intel.com/content/www/us/en/design/publications/14th-generation-core-processors-cfg-and-mem-registers/d2-f0-processor-graphics-registers/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/i915/gem/i915_gem_stolen.c?h=v6.14#n142

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/20250505170305.23622-10-tomitamoeko@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
Tomita Moeko 2025-05-06 01:03:05 +08:00 • committed by Cédric Le Goater
parent 36e4047a9b
commit 7969cf4639
2 changed files with 27 additions and 37 deletions
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6
docs/igd-assign.txt
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@ -157,6 +157,12 @@ fw_cfg requirements on the VM firmware:
it's expected that this fw_cfg file is only relevant to a single PCI
class VGA device with Intel vendor ID, appearing at PCI bus address 00:02.0.
Starting from Meteor Lake, IGD devices access stolen memory via its MMIO
BAR2 (LMEMBAR) and removed the BDSM register in config space. There is
no need for guest firmware to allocate data stolen memory in guest address
space and write it to BDSM register. Value of this fw_cfg file is 0 in
such case.
Upstream Seabios has OpRegion and BDSM (pre-Gen11 device only) support.
However, the support is not accepted by upstream EDK2/OVMF. A recommended
solution is to create a virtual OpRom with following DXE drivers: