Re: [PATCH v4 00/10] vfio/igd: Enable legacy mode on more devices

[Cédric Le Goater]

On 12/6/24 13:27, Tomita Moeko wrote:
> This patchset extends the support of legacy mode igd passthrough to
> all Intel Gen 11 and 12 devices (including Ice Lake, Jasper Lake,
> Rocket Lake, Alder Lake and Raptor Lake), and emulates GGC register
> in MMIO BAR0 for better compatibiltiy (It is tested Windows and GOP
> driver will read this MMIO register).
>
> It also replaces magic numbers with macros to improve readability,
> and aligns behavior (BDSM registor mirroring and GGMS calculation for
> gen7) with i915 driver to avoid possible issues.
>
> The x-igd-gms option removed in 971ca22f041b ("vfio/igd: don't set
> stolen memory size to zero") is also added back so that data stolen
> memory size can be specified for guest. It is tested that GMS may
> related to framebuffer size, a small GMS value may cause display issues
> like blackscreen. It can be changed by DVMT Pre-allocated option in
> host BIOS, but not all BIOS comes with this option. Having it in QEMU
> helps resolves such issues.
>
> This patchset was verified on Intel i9-12900K CPU(UHD 770, 8086:4680)
> with custom OVMF firmware [1] and IntelGopDriver extracted from host
> bios. IGD device works well in both Windows and Linux guests, and
> scored 726 in 3DMark Time Spy Graphics on Windows guest.
>
> [1] https://github.com/tomitamoeko/edk2/commits/igd-pt-adl/
>
> Btw, IO BAR4 seems never be used by guest, and it the IO BAR itself
> is not working on Gen11+ devices in my experiments. There is no hints
> about that in old commit message and mailing list. It would be greatly
> appreciated if someone shares the background.
>
> Changelog:
> v4:
> * Move "vfio/igd: fix GTT stolen memory size calculation for gen 8+" to
>    the first.
> Link: 
> 20241205105535.30498-1-tomitamoeko@gmail.com/">https://lore.kernel.org/qemu-devel/20241205105535.30498-1-tomitamoeko@gmail.com/

A v4 was not necessary for just this change. Anyhow, It seems the
series is ready and an overall 'Acked-by' from Alex or Corvin would
be appreciated before applying to vfio-next.


Thanks,

C.




> v3:
> * Added new patch to fix GTT stolen memory size calculation for gen 8+
>    devicess.
> * Fixed quirk index in "vfio/igd: add macro for declaring mirrored
>    registers"
> * Fixed condition in "vfio/igd: add x-igd-gms option back to set DSM
>    region size for guest"
> * Updated comments and commit message.
> Link: 
> 20241203133548.38252-1-tomitamoeko@gmail.com/">https://lore.kernel.org/qemu-devel/20241203133548.38252-1-tomitamoeko@gmail.com/
>
> v2:
> * Droped "vfio/igd: fix GTT stolen memory size calculation for gen 7".
> * Fixed conditions when calculating GGMS size.
> * Added Gemini Lake and Comet Lake device ids.
> * Splited mirroring register declaration macro into a new patch.
> * Minor fixes.
> Link: 
> 20241201160938.44355-1-tomitamoeko@gmail.com/">https://lore.kernel.org/qemu-devel/20241201160938.44355-1-tomitamoeko@gmail.com/
>
> Tomita Moeko (10):
>    vfio/igd: fix GTT stolen memory size calculation for gen 8+
>    vfio/igd: remove unsupported device ids
>    vfio/igd: align generation with i915 kernel driver
>    vfio/igd: canonicalize memory size calculations
>    vfio/igd: add Gemini Lake and Comet Lake device ids
>    vfio/igd: add Alder/Raptor/Rocket/Ice/Jasper Lake device ids
>    vfio/igd: add macro for declaring mirrored registers
>    vfio/igd: emulate GGC register in mmio bar0
>    vfio/igd: emulate BDSM in mmio bar0 for gen 6-10 devices
>    vfio/igd: add x-igd-gms option back to set DSM region size for guest
>
>   hw/vfio/igd.c | 262 +++++++++++++++++++++++++++++++-------------------
>   1 file changed, 165 insertions(+), 97 deletions(-)