[Intel-gfx] [PATCH 4/9] drm/i915: Introduce host graphics memory partition for GVT-g

[Chris Wilson]

On Tue, May 17, 2016 at 04:19:04AM -0400, Zhi Wang wrote:
> From: Bing Niu <bing.niu at intel.com>
> 
> This patch introduces host graphics memory partition when GVT-g
> is enabled.
> 
> Under GVT-g, i915 host driver only owned limited graphics resources,
> others are managed by GVT-g resource allocator and kept for other vGPUs.

Strong justification required for why the user is expected to get these
right via module parameters.

> +/*
> + * Under GVT-g, i915 host driver only owned limited graphics resources,
> + * others are managed by GVT-g resource allocator and kept for other vGPUs.
> + *
> + * For graphics memory space partition, a typical layout looks like:
> + *
> + * +-------+-----------------------+------+-----------------------+
> + * |* Host |   *GVT-g Resource     |* Host|   *GVT-g Resource     |
> + * | Owned |   Allocator Managed   | Owned|   Allocator Managed   |
> + * |       |                       |      |                       |
> + * +---------------+-------+----------------------+-------+-------+
> + * |       |       |       |       |      |       |       |       |
> + * | i915  | vm 1  | vm 2  | vm 3  | i915 | vm 1  | vm 2  | vm 3  |
> + * |       |       |       |       |      |       |       |       |
> + * +-------+-------+-------+--------------+-------+-------+-------+
> + * |           Aperture            |            Hidden            |
> + * +-------------------------------+------------------------------+
> + * |                       GGTT memory space                      |
> + * +--------------------------------------------------------------+
> + */
>  struct i915_gvt {
>  	void *gvt;
> +	u64 low_gm_size;
> +	u64 high_gm_size;
>  };
>  
>  struct i915_virtual_gpu {
> diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
> index 5312816..9382f04 100644
> --- a/drivers/gpu/drm/i915/i915_vgpu.c
> +++ b/drivers/gpu/drm/i915/i915_vgpu.c
> @@ -189,13 +189,24 @@ int intel_vgt_balloon(struct drm_i915_private *dev_priv)
>  	unsigned long unmappable_base, unmappable_size, unmappable_end;
>  	int ret;
>  
> -	if (!intel_vgpu_active(dev_priv))
> +	if (!intel_vgpu_active(dev_priv) && !intel_gvt_active(dev_priv))
>  		return 0;
>  
> -	mappable_base = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.base));
> -	mappable_size = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.size));
> -	unmappable_base = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.base));
> -	unmappable_size = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.size));
> +	if (intel_gvt_active(dev_priv)) {
> +		mappable_base = 0;
> +		mappable_size = dev_priv->gvt.low_gm_size;
> +		unmappable_base = dev_priv->ggtt.mappable_end;
> +		unmappable_size = dev_priv->gvt.high_gm_size;
> +	} else if (intel_vgpu_active(dev_priv)) {
> +		mappable_base = I915_READ(
> +				vgtif_reg(avail_rs.mappable_gmadr.base));
> +		mappable_size = I915_READ(
> +				vgtif_reg(avail_rs.mappable_gmadr.size));
> +		unmappable_base = I915_READ(
> +				vgtif_reg(avail_rs.nonmappable_gmadr.base));
> +		unmappable_size = I915_READ(
> +				vgtif_reg(avail_rs.nonmappable_gmadr.size));
> +	}
else
	return 0;

and lose the early return.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre