[Intel-gfx] [PATCH 03/21] drm/i915/gtt: Check va range against vm size

[Joonas Lahtinen]

On pe, 2015-05-22 at 20:04 +0300, Mika Kuoppala wrote:
> Check the allocation area against the known end
> of address space instead of against fixed value.
> 
> v2: Return ENODEV on internal bugs (Chris)
> 
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 1a5ad4c..76de781 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -756,9 +756,6 @@ static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
>  
>  	WARN_ON(!bitmap_empty(new_pds, GEN8_LEGACY_PDPES));
>  
> -	/* FIXME: upper bound must not overflow 32 bits  */
> -	WARN_ON((start + length) > (1ULL << 32));
> -
>  	gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
>  		if (pd)
>  			continue;
> @@ -857,7 +854,10 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
>  	 * actually use the other side of the canonical address space.
>  	 */
>  	if (WARN_ON(start + length < start))
> -		return -ERANGE;
> +		return -ENODEV;
> +
> +	if (WARN_ON(start + length > ppgtt->base.total))
> +		return -ENODEV;
>  
>  	ret = alloc_gen8_temp_bitmaps(&new_page_dirs, &new_page_tables);
>  	if (ret)
> @@ -1341,7 +1341,7 @@ static void gen6_initialize_pt(struct i915_address_space *vm,
>  }
>  
>  static int gen6_alloc_va_range(struct i915_address_space *vm,
> -			       uint64_t start, uint64_t length)
> +			       uint64_t start_in, uint64_t length_in)
>  {
>  	DECLARE_BITMAP(new_page_tables, I915_PDES);
>  	struct drm_device *dev = vm->dev;
> @@ -1349,11 +1349,15 @@ static int gen6_alloc_va_range(struct i915_address_space *vm,
>  	struct i915_hw_ppgtt *ppgtt =
>  				container_of(vm, struct i915_hw_ppgtt, base);
>  	struct i915_page_table *pt;
> -	const uint32_t start_save = start, length_save = length;
> +	uint32_t start, length, start_save, length_save;
>  	uint32_t pde, temp;
>  	int ret;
>  
> -	WARN_ON(upper_32_bits(start));
> +	if (WARN_ON(start_in + length_in > ppgtt->base.total))
> +		return -ENODEV;
> +
> +	start = start_save = start_in;
> +	length = length_save = length_in;

Why is it not enough just to change the WARN_ON test?

>  
>  	bitmap_zero(new_page_tables, I915_PDES);
>