[Intel-gfx] [PATCH v3] drm/i915: Enable guest i915 full ppgtt functionality

[Joonas Lahtinen]

On ma, 2017-05-22 at 16:19 +0800, Tina Zhang wrote:
> Enable the guest i915 full ppgtt functionality when host can provide this
> capability. vgt_caps is introduced to guest i915 driver to get the vgpu
> capabilities from the device model. VGT_CPAS_FULL_PPGTT is one of the
> capabilities type to let guest i915 dirver know that the guest i915 full
> ppgtt is supported by device model.
> 
> Changes since v1:
> - Use u32 instead of uint32_t (Joonas)
> - Move VGT_CAPS_FULL_PPGTT introduction to this patch and use #define
>   instead of enum (Joonas)
> - Rewrite the vgpu full ppgtt capability checking logic. (Joonas)
> - Some coding style refine. (Joonas)
> 
> Changes since v2:
> - Divide the whole patch set into two separate patch series, with one
>   patch in i915 side to check guest i915 full ppgtt capability and enable
>   it when this capability is supported by the device model, and the other
>   one in gvt side which fixs the blocking issue and enables the device
>   model to provide the capability to guest. And this patch focuses on guest
>   i915 side. (Joonas)
> - Change the title from "introduce vgt_caps to pvinfo" to
>   "Enable guest i915 full ppgtt functionality". (Tina)
> 
> Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Signed-off-by: Tina Zhang <tina.zhang at intel.com>

I just noticed there is INTEL_VGT_IF_VERSION when I was looking to make
sure that vgt_if is zeroed. Neither the version is incremented nor do I
see VGT_PVINFO_PAGE getting zeroed.

What measures are in place to make sure running a new i915 under older
DOM0 won't result in corruption?

The dependencies between i915 and gvt are rather tricky, so we'd need
INTEL_VGT_IF_VERSION minor increment and also a one line change
(zeroing of the new caps register) from gvt code to the same patch,
otherwise bisecting will break.

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation