Re: [PATCH v2 14/15] drm/i915/uapi: forbid ALLOC_GPU_ONLY for error capture

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On 2/10/22 13:13, Matthew Auld wrote:
> On platforms where there might be non-mappable LMEM, force userspace to
> mark the buffers with the correct hint. When dumping the BO contents
> during capture we need CPU access. Note this only applies to buffers
> that can be placed in LMEM, and also doesn't impact DG1.
>
> v2(Reported-by: kernel test robot <lkp@intel.com>):
>    - Also update the function signature on !CONFIG_DRM_I915_CAPTURE_ERROR
>      builds.
>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 13 ++++++++++---
>   1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index 498b458fd784..017f928cbcaf 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -1965,7 +1965,7 @@ eb_find_first_request_added(struct i915_execbuffer *eb)
>   #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
>   
>   /* Stage with GFP_KERNEL allocations before we enter the signaling critical path */
> -static void eb_capture_stage(struct i915_execbuffer *eb)
> +static int eb_capture_stage(struct i915_execbuffer *eb)
>   {
>   	const unsigned int count = eb->buffer_count;
>   	unsigned int i = count, j;
> @@ -1978,6 +1978,9 @@ static void eb_capture_stage(struct i915_execbuffer *eb)
>   		if (!(flags & EXEC_OBJECT_CAPTURE))
>   			continue;
>   
> +		if (vma->obj->flags & I915_BO_ALLOC_GPU_ONLY)
> +			return -EINVAL;

With suitable adjustment regarding how we define the ALLOC_GPU_ONLY flag..

/Thomas