[Intel-gfx] [PATCH v2 3/8] drm/i915: reserve stolen for LMEM region

[Chris Wilson]

Quoting Matthew Auld (2021-01-26 15:12:54)
> From: CQ Tang <cq.tang at intel.com>
> 
> The lmem region needs to remove the stolen part, which should just be a
> case of snipping it off the end.
> 
> Signed-off-by: CQ Tang <cq.tang at intel.com>
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_region_lmem.c | 12 ++++++++----
>  drivers/gpu/drm/i915/i915_reg.h             |  2 ++
>  2 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_region_lmem.c b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
> index b676dc67dc2a..4da808e35ecb 100644
> --- a/drivers/gpu/drm/i915/gt/intel_region_lmem.c
> +++ b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
> @@ -141,17 +141,20 @@ intel_gt_setup_fake_lmem(struct intel_gt *gt)
>  static struct intel_memory_region *setup_lmem(struct intel_gt *gt)
>  {
>         struct drm_i915_private *i915 = gt->i915;
> +       struct intel_uncore *uncore = &i915->uncore;

gt->uncore

(See the plan is starting to come together!)

>         struct pci_dev *pdev = i915->drm.pdev;
>         struct intel_memory_region *mem;
>         resource_size_t io_start;
> -       resource_size_t size;
> +       resource_size_t lmem_size;
> +
> +       /* Stolen starts from GSMBASE on DG1 */
> +       lmem_size = intel_uncore_read64(uncore, GEN12_GSMBASE);
>  
>         io_start = pci_resource_start(pdev, 2);
> -       size = pci_resource_len(pdev, 2);

Trust nobody, certainly not the HW. Check that lmem_size is < size.
-Chris