[PATCH v2 2/3] drm/i915: Split i915_gem_init_stolen()
Wayne Boyer
wayne.boyer at intel.com
Tue Sep 20 19:16:47 UTC 2022
On 9/16/22 10:36 AM, Lucas De Marchi wrote:
> Add some helpers: adjust_stolen(), request_smem_stolen_() and
> init_reserved_stolen() that are now called by i915_gem_init_stolen() to
> initialize each part of the Data Stolen Memory region.
>
> Main goal is to split the reserved part within the stolen, also known as
> WOPCM, as its calculation changes often per platform and is a big source
> of confusion when handling stolen memory.
>
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
> index 3665f9b035bb..6edf4e374f54 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
> @@ -77,22 +77,26 @@ void i915_gem_stolen_remove_node(struct drm_i915_private *i915,
> mutex_unlock(&i915->mm.stolen_lock);
> }
>
> -static int i915_adjust_stolen(struct drm_i915_private *i915,
> - struct resource *dsm)
> +static bool valid_stolen_size(struct resource *dsm)
> +{
> + return dsm->start != 0 && dsm->end > dsm->start;
> +}
> +
> +static int adjust_stolen(struct drm_i915_private *i915,
> + struct resource *dsm)
> {
> struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
> struct intel_uncore *uncore = ggtt->vm.gt->uncore;
> - struct resource *r;
>
> - if (dsm->start == 0 || dsm->end <= dsm->start)
> + if (!valid_stolen_size(dsm))
> return -EINVAL;
>
> /*
> + * Make sure we don't clobber the GTT if it's within stolen memory
> + *
> * TODO: We have yet too encounter the case where the GTT wasn't at the
nit: as long as you're updating this comment block, s/too/to/
Otherwise,
Reviewed-by: Wayne Boyer <wayne.boyer at intel.com>
> * end of stolen. With that assumption we could simplify this.
> */
> -
> - /* Make sure we don't clobber the GTT if it's within stolen memory */
> if (GRAPHICS_VER(i915) <= 4 &&
> !IS_G33(i915) && !IS_PINEVIEW(i915) && !IS_G4X(i915)) {
> struct resource stolen[2] = {*dsm, *dsm};
> @@ -131,10 +135,20 @@ static int i915_adjust_stolen(struct drm_i915_private *i915,
> }
> }
>
> + if (!valid_stolen_size(dsm))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int request_smem_stolen(struct drm_i915_private *i915,
> + struct resource *dsm)
> +{
> + struct resource *r;
> +
> /*
> - * With stolen lmem, we don't need to check if the address range
> - * overlaps with the non-stolen system memory range, since lmem is local
> - * to the gpu.
> + * With stolen lmem, we don't need to request system memory for the
> + * address range since it's local to the gpu.
> */
> if (HAS_LMEM(i915))
> return 0;
> @@ -392,39 +406,22 @@ static void icl_get_stolen_reserved(struct drm_i915_private *i915,
> }
> }
>
> -static int i915_gem_init_stolen(struct intel_memory_region *mem)
> +/*
> + * Initialize i915->dsm_reserved to contain the reserved space within the Data
> + * Stolen Memory. This is a range on the top of DSM that is reserved, not to
> + * be used by driver, so must be excluded from the region passed to the
> + * allocator later. In the spec this is also called as WOPCM.
> + *
> + * Our expectation is that the reserved space is at the top of the stolen
> + * region, as it has been the case for every platform, and *never* at the
> + * bottom, so the calculation here can be simplified.
> + */
> +static int init_reserved_stolen(struct drm_i915_private *i915)
> {
> - struct drm_i915_private *i915 = mem->i915;
> struct intel_uncore *uncore = &i915->uncore;
> resource_size_t reserved_base, stolen_top;
> - resource_size_t reserved_total, reserved_size;
> -
> - mutex_init(&i915->mm.stolen_lock);
> -
> - if (intel_vgpu_active(i915)) {
> - drm_notice(&i915->drm,
> - "%s, disabling use of stolen memory\n",
> - "iGVT-g active");
> - return 0;
> - }
> -
> - if (i915_vtd_active(i915) && GRAPHICS_VER(i915) < 8) {
> - drm_notice(&i915->drm,
> - "%s, disabling use of stolen memory\n",
> - "DMAR active");
> - return 0;
> - }
> -
> - if (resource_size(&mem->region) == 0)
> - return 0;
> -
> - i915->dsm = mem->region;
> -
> - if (i915_adjust_stolen(i915, &i915->dsm))
> - return 0;
> -
> - GEM_BUG_ON(i915->dsm.start == 0);
> - GEM_BUG_ON(i915->dsm.end <= i915->dsm.start);
> + resource_size_t reserved_size;
> + int ret = 0;
>
> stolen_top = i915->dsm.end + 1;
> reserved_base = stolen_top;
> @@ -455,17 +452,16 @@ static int i915_gem_init_stolen(struct intel_memory_region *mem)
> &reserved_base, &reserved_size);
> }
>
> - /*
> - * Our expectation is that the reserved space is at the top of the
> - * stolen region and *never* at the bottom. If we see !reserved_base,
> - * it likely means we failed to read the registers correctly.
> - */
> + /* No reserved stolen */
> + if (reserved_base == stolen_top)
> + goto bail_out;
> +
> if (!reserved_base) {
> drm_err(&i915->drm,
> "inconsistent reservation %pa + %pa; ignoring\n",
> &reserved_base, &reserved_size);
> - reserved_base = stolen_top;
> - reserved_size = 0;
> + ret = -EINVAL;
> + goto bail_out;
> }
>
> i915->dsm_reserved =
> @@ -475,19 +471,55 @@ static int i915_gem_init_stolen(struct intel_memory_region *mem)
> drm_err(&i915->drm,
> "Stolen reserved area %pR outside stolen memory %pR\n",
> &i915->dsm_reserved, &i915->dsm);
> + ret = -EINVAL;
> + goto bail_out;
> + }
> +
> + return 0;
> +
> +bail_out:
> + i915->dsm_reserved =
> + (struct resource)DEFINE_RES_MEM(reserved_base, 0);
> +
> + return ret;
> +}
> +
> +static int i915_gem_init_stolen(struct intel_memory_region *mem)
> +{
> + struct drm_i915_private *i915 = mem->i915;
> +
> + mutex_init(&i915->mm.stolen_lock);
> +
> + if (intel_vgpu_active(i915)) {
> + drm_notice(&i915->drm,
> + "%s, disabling use of stolen memory\n",
> + "iGVT-g active");
> + return 0;
> + }
> +
> + if (i915_vtd_active(i915) && GRAPHICS_VER(i915) < 8) {
> + drm_notice(&i915->drm,
> + "%s, disabling use of stolen memory\n",
> + "DMAR active");
> return 0;
> }
>
> + if (adjust_stolen(i915, &mem->region))
> + return 0;
> +
> + if (request_smem_stolen(i915, &mem->region))
> + return 0;
> +
> + i915->dsm = mem->region;
> +
> + if (init_reserved_stolen(i915))
> + return 0;
> +
> /* Exclude the reserved region from driver use */
> - mem->region.end = reserved_base - 1;
> + mem->region.end = i915->dsm_reserved.start - 1;
> mem->io_size = min(mem->io_size, resource_size(&mem->region));
>
> - /* It is possible for the reserved area to end before the end of stolen
> - * memory, so just consider the start. */
> - reserved_total = stolen_top - reserved_base;
> -
> - i915->stolen_usable_size =
> - resource_size(&i915->dsm) - reserved_total;
> + i915->stolen_usable_size = resource_size(&mem->region);
>
> drm_dbg(&i915->drm,
> "Memory reserved for graphics device: %lluK, usable: %lluK\n",
> @@ -759,11 +791,6 @@ static int init_stolen_lmem(struct intel_memory_region *mem)
> if (GEM_WARN_ON(resource_size(&mem->region) == 0))
> return -ENODEV;
>
> - /*
> - * TODO: For stolen lmem we mostly just care about populating the dsm
> - * related bits and setting up the drm_mm allocator for the range.
> - * Perhaps split up i915_gem_init_stolen() for this.
> - */
> err = i915_gem_init_stolen(mem);
> if (err)
> return err;
>
--
--
Wayne Boyer
Graphics Software Engineer
VTT-OSGC Platform Enablement
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