Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> writes:
> Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
>
>> For stolen pages, since it is verboten to access them directly on many
>> architectures, we have to read them through the GTT aperture. If they
>> are not accessible through the aperture, then we have to abort.
>>
>> This was complicated by
>>
>> commit 8b6124a633d8095b0c8364f585edff9c59568a96
>> Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>> Date: Thu Jan 30 14:38:16 2014 +0000
>>
>> drm/i915: Don't access snooped pages through the GTT (even for error capture)
>>
>> and the desire to use stolen memory for ringbuffers, contexts and
>> batches in the future.
>>
>> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/gpu/drm/i915/i915_gpu_error.c | 50 ++++++++++++++++++++++-------------
>> 1 file changed, 31 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
>> index 35e70d5..6d280c07 100644
>> --- a/drivers/gpu/drm/i915/i915_gpu_error.c
>> +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
>> @@ -561,10 +561,11 @@ static struct drm_i915_error_object *
>> i915_error_object_create_sized(struct drm_i915_private *dev_priv,
>> struct drm_i915_gem_object *src,
>> struct i915_address_space *vm,
>> - const int num_pages)
>> + int num_pages)
>> {
>> struct drm_i915_error_object *dst;
>> - int i;
>> + bool use_ggtt;
>> + int i = 0;
>> u32 reloc_offset;
>>
>> if (src == NULL || src->pages == NULL)
>> @@ -574,8 +575,32 @@ i915_error_object_create_sized(struct drm_i915_private *dev_priv,
>> if (dst == NULL)
>> return NULL;
>>
>> - reloc_offset = dst->gtt_offset = i915_gem_obj_offset(src, vm);
>> - for (i = 0; i < num_pages; i++) {
>> + dst->gtt_offset = i915_gem_obj_offset(src, vm);
>> +
>> + reloc_offset = dst->gtt_offset;
>> + use_ggtt = (src->cache_level == I915_CACHE_NONE &&
>
> Take this cache level check out so that we end up doing the
> snoopable check for non stolen objects too?
This _is_ the snoopable check for non stolen objects.
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> -Mika
>
>> + i915_is_ggtt(vm) &&
>> + src->has_global_gtt_mapping &&
>> + reloc_offset + num_pages * PAGE_SIZE <= dev_priv->gtt.mappable_end);
>> +
>> + /* Cannot access stolen address directly, try to use the aperture */
>> + if (src->stolen) {
>> + use_ggtt = true;
>> +
>> + if (!src->has_global_gtt_mapping)
>> + goto unwind;
>> +
>> + reloc_offset = i915_gem_obj_ggtt_offset(src);
>> + if (reloc_offset + num_pages * PAGE_SIZE > dev_priv->gtt.mappable_end)
>> + goto unwind;
>> + }
>> +
>> + /* Cannot access snooped pages through the aperture */
>> + if (use_ggtt && src->cache_level != I915_CACHE_NONE && !HAS_LLC(dev_priv->dev))
>> + goto unwind;
>> +
>> + dst->page_count = num_pages;
>> + while (num_pages--) {
>> unsigned long flags;
>> void *d;
>>
>> @@ -584,10 +609,7 @@ i915_error_object_create_sized(struct drm_i915_private *dev_priv,
>> goto unwind;
>>
>> local_irq_save(flags);
>> - if (src->cache_level == I915_CACHE_NONE &&
>> - reloc_offset < dev_priv->gtt.mappable_end &&
>> - src->has_global_gtt_mapping &&
>> - i915_is_ggtt(vm)) {
>> + if (use_ggtt) {
>> void __iomem *s;
>>
>> /* Simply ignore tiling or any overlapping fence.
>> @@ -599,14 +621,6 @@ i915_error_object_create_sized(struct drm_i915_private *dev_priv,
>> reloc_offset);
>> memcpy_fromio(d, s, PAGE_SIZE);
>> io_mapping_unmap_atomic(s);
>> - } else if (src->stolen) {
>> - unsigned long offset;
>> -
>> - offset = dev_priv->mm.stolen_base;
>> - offset += src->stolen->start;
>> - offset += i << PAGE_SHIFT;
>> -
>> - memcpy_fromio(d, (void __iomem *) offset, PAGE_SIZE);
>> } else {
>> struct page *page;
>> void *s;
>> @@ -623,11 +637,9 @@ i915_error_object_create_sized(struct drm_i915_private *dev_priv,
>> }
>> local_irq_restore(flags);
>>
>> - dst->pages[i] = d;
>> -
>> + dst->pages[i++] = d;
>> reloc_offset += PAGE_SIZE;
>> }
>> - dst->page_count = num_pages;
>>
>> return dst;
>>
>> --
>> 1.9.1
>>
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