Re: [PATCH v3 0/9] vfio/igd: Detect IGD by OpRegion and enable OpRegion automatically

["Cédric Le Goater" <clg@redhat.com>]

On 5/5/25 19:02, Tomita Moeko wrote:
> As proposed in a previous discussion [1], detect IGD devices based on
> whether it has VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION exposed by kernel
> and enables OpRegion access by default. This enables out-of-the-box
> display output support for IGD passthrough without having to manually
> set x-igd-opregion=on, which probably saves effort for libvirt users.
> 
> This patchset also limits legacy mode to Gen6-9 devices, as Intel no
> longer provides CSM support and VBIOS on newer IGD, and Seabios does not
> support setting up the 64 bit BDSM register on Gen 11+ devices. Exposing
> VGA ranges to guests by default on platforms without VGA mode support is
> undesirable.
> 
> Additionally, as we enables OpRegion on IGD devices by default, and
> Intel removes the BDSM register from Meteor Lake [2]. There seems to be
> no extra register quirks rather than OpRegion required on newer devices.
> To support them (and probably future devices), the generation limit is
> removed, with BDSM quirk only applied to known Gen 6-12 devices.
> 
> Note: I have not been able to test this on Meteor Lake or newer
> platforms due to lack of hardware.
> 
> 
> [1] https://lore.kernel.org/qemu-devel/20250325172239.27926-1-tomitamoeko@gmail.com
> [2] https://edc.intel.com/content/www/us/en/design/publications/14th-generation-core-processors-cfg-and-mem-registers/d2-f0-processor-graphics-registers/
> 
> 
> Changelog:
> v3:
> * Addressed a nit in patch #8
> Link: https://lore.kernel.org/qemu-devel/20250428161004.35613-1-tomitamoeko@gmail.com
> v2:
> * Removed "Allow hotplugging with OpRegion enabled", hotplugging is
>    always forbidden.
> * Test device is not hotplugged and get opregion in a single function.
> * Update documentation along with code changes.
> * Minor code style fixes.
> Link: https://lore.kernel.org/qemu-devel/20250421163112.21316-1-tomitamoeko@gmail.com
> 
> 
> Tomita Moeko (9):
>    vfio/igd: Restrict legacy mode to Gen6-9 devices
>    vfio/igd: Always emulate ASLS (OpRegion) register
>    vfio/igd: Detect IGD device by OpRegion
>    vfio/igd: Check vendor and device ID on GVT-g mdev
>    vfio/igd: Check OpRegion support on GVT-g mdev
>    vfio/igd: Enable OpRegion by default
>    vfio/igd: Allow overriding GMS with 0xf0 to 0xfe on Gen9+
>    vfio/igd: Only emulate GGC register when x-igd-gms is set
>    vfio/igd: Remove generation limitation for IGD passthrough
> 
>   docs/igd-assign.txt |  11 ++-
>   hw/vfio/igd.c       | 220 ++++++++++++++++++++++++++------------------
>   hw/vfio/pci.c       |   2 +-
>   3 files changed, 138 insertions(+), 95 deletions(-)
> 


Applied to vfio-next.

Thanks,

C.