Re: [PATCH v6 4/9] drm/i915: Introduce host graphics memory partition for GVT-g

[Joonas Lahtinen <joonas.lahtinen@linux.intel.com>]

On to, 2016-06-02 at 12:36 -0400, Zhi Wang wrote:
> From: Bing Niu <bing.niu@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.
> 
> v6:
> 
> - Remove kernel parameters used to configure GGTT owned by host. (Chris)
> - Other coding style comments from Chris.
> - Add more comments for reviewer.
> 
> v3:
> 
> - Remove fence partition, will use i915 fence stealing in future.(Kevin)
> - Santinize GVT host gm kernel parameters. (Joonas)
> 
> v2:
> - Address all coding-style comments from Joonas previously.
> - Fix errors and warnning reported by checkpatch.pl. (Joonas)
> - Move the graphs into the header files. (Daniel)
> 
> Signed-off-by: Bing Niu <bing.niu@intel.com>
> Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_vgpu.c | 23 +++++++++++++++++------
>  drivers/gpu/drm/i915/intel_gvt.h | 25 +++++++++++++++++++++++++
>  2 files changed, 42 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
> index 5312816..0d891a3 100644
> --- a/drivers/gpu/drm/i915/i915_vgpu.c
> +++ b/drivers/gpu/drm/i915/i915_vgpu.c
> @@ -189,14 +189,25 @@ 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_gvt_active(dev_priv)) {
> +		/* Retrieve GGTT partition information from macros */
> +		mappable_base = 0;
> +		mappable_size = INTEL_GVT_HOST_LOW_GM_SIZE;
> +		unmappable_base = dev_priv->ggtt.mappable_end;
> +		unmappable_size = INTEL_GVT_HOST_HIGH_GM_SIZE;
> +	} else if (intel_vgpu_active(dev_priv)) {
> +		/* Retrieve GGTT partition information from PVINFO */
> +		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;
>  
> -	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));
> -
>  	mappable_end = mappable_base + mappable_size;
>  	unmappable_end = unmappable_base + unmappable_size;
>  
> diff --git a/drivers/gpu/drm/i915/intel_gvt.h b/drivers/gpu/drm/i915/intel_gvt.h
> index b9b361b..f0b9aac 100644
> --- a/drivers/gpu/drm/i915/intel_gvt.h
> +++ b/drivers/gpu/drm/i915/intel_gvt.h
> @@ -24,6 +24,31 @@
>  #ifndef _INTEL_GVT_H_
>  #define _INTEL_GVT_H_
>  
> +/*
> + * 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                      |
> + * +--------------------------------------------------------------+
> + */
> +
> +/* GGTT memory space owned by host */
> +#define INTEL_GVT_HOST_LOW_GM_SIZE (96 * 1024 * 1024)
> +#define INTEL_GVT_HOST_HIGH_GM_SIZE (384 * 1024 * 1024)

Might be worth a comment where these numbers come from, with that;

Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

> +
>  #ifdef CONFIG_DRM_I915_GVT
>  #include "gvt/gvt.h"
>  extern int intel_gvt_init(struct drm_i915_private *dev_priv);
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation
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