Re: [PATCH 00/10] vfio/igd: Remove legacy mode

["Cédric Le Goater" <clg@redhat.com>]

Hello Tomita,

+Corvin

On 2/24/25 19:29, Tomita Moeko wrote:
> This patchset removes some legacy checks and converts the legacy mode
> implicitly enabled by BDF 00:02.0 into x-igd-* options, including:
> * Removing PCI ROM BAR and VGA IO/MMIO range check before applying quirk
> * Using unified x-igd-opregion option for OpRegion access.
> * Introducing new x-igd-lpc option for the LPC bridge / Host bridge ID
>    quirk. Currently this is only supported on i440fx.
> * Extending quirk support when IGD is not assigned to BDF 00:02.0
> 
> The first 2 patches of this patchset was taken from a previous one,
> details can be found at:
> https://lore.kernel.org/all/20250124191245.12464-1-tomitamoeko@gmail.com/
> 
> This patchest was mainly tested on Alder Lake UHD770, with Debian 12
> (kernel 6.1), Windows 11 (driver 32.0.101.6458) and Intel GOP driver
> 17.0.1081.

Did you try a Linux guest ?

Could you provide the QEMU command line please ? I would like to
reproduce on the AlderLake-S GT1 system I have access to.

Also, since you spent quite of lot time on IGD support, would you
mind adding a vfio-igd entry in the MAINTAINERS file and propose
your self as a maintainer ? The aim would be to keep you informed
of the proposed changes on the vfio-igd device, not to handle PRs.
  
> If the design is good to go, I will update the documentation also.

yes please.

> A open question is whether the old legacy mode behavior should be kept
> or not. Checking if all the condition of legacy mode were met and
> toggling correspoding options is more complicated then I expected :(
> Any ideas would be appreciated.

I will let Alex comment,

Thanks,

C.

  
> Tomita Moeko (10):
>    vfio/igd: Remove GTT write quirk in IO BAR 4
>    vfio/igd: Do not include GTT stolen size in etc/igd-bdsm-size
>    vfio/igd: Remove rombar check for legacy mode
>    vfio/igd: Remove implicit VGA access enabled by legacy mode
>    vfio/pci: Make vfio_populate_vga static
>    vfio/igd: Consolidate OpRegion initialization into a single function
>    vfio/igd: Move LPC bridge initialization to a separate function
>    vfio/pci: Add placeholder for device-specific config space quirks
>    vfio/igd: Refactor vfio_probe_igd_bar4_quirk into pci config quirk
>    vfio/igd: Replace legacy mode with options
> 
>   hw/vfio/igd.c        | 476 ++++++++++++++-----------------------------
>   hw/vfio/pci-quirks.c |  51 +----
>   hw/vfio/pci.c        |  33 +--
>   hw/vfio/pci.h        |  12 +-
>   4 files changed, 166 insertions(+), 406 deletions(-)
>