[PATCH 3/3] drm/amdgpu: replace get_user_pages with HMM address mirror helpers v5

Yang, Philip Philip.Yang at amd.com
Wed Jan 2 20:10:16 UTC 2019


Hi Christian,

May you help review the CS parts related changes? I tested it using 
libdrm Userptr Test under X. Do you know other test applications which 
can stress the CS userptr path?

Thanks,
Philip

On 2018-12-14 4:25 p.m., Kuehling, Felix wrote:
> Except for the GEM and CS parts, the series is Reviewed-by: Felix
> Kuehling <Felix.Kuehling at amd.com>
> 
> Regards,
>    Felix
> 
> On 2018-12-14 4:10 p.m., Yang, Philip wrote:
>> Use HMM helper function hmm_vma_fault() to get physical pages backing
>> userptr and start CPU page table update track of those pages. Then use
>> hmm_vma_range_done() to check if those pages are updated before
>> amdgpu_cs_submit for gfx or before user queues are resumed for kfd.
>>
>> If userptr pages are updated, for gfx, amdgpu_cs_ioctl will restart
>> from scratch, for kfd, restore worker is rescheduled to retry.
>>
>> HMM simplify the CPU page table concurrent update check, so remove
>> guptasklock, mmu_invalidations, last_set_pages fields from
>> amdgpu_ttm_tt struct.
>>
>> HMM does not pin the page (increase page ref count), so remove related
>> operations like release_pages(), put_page(), mark_page_dirty().
>>
>> Change-Id: I2e8c0c6f0d8c21e5596a32d7fc91762778bc9e67
>> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h    |   1 -
>>   .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  |  95 +++------
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c   |   2 -
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h   |   3 +-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c        | 185 +++++++++---------
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c       |  14 +-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c        |  25 ++-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h        |   4 +-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c       | 168 ++++++----------
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h       |   4 +-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c        |   1 -
>>   11 files changed, 209 insertions(+), 293 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
>> index 70429f7aa9a8..717791d4fa45 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
>> @@ -62,7 +62,6 @@ struct kgd_mem {
>>   
>>   	atomic_t invalid;
>>   	struct amdkfd_process_info *process_info;
>> -	struct page **user_pages;
>>   
>>   	struct amdgpu_sync sync;
>>   
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> index be1ab43473c6..2897793600f7 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> @@ -582,28 +582,12 @@ static int init_user_pages(struct kgd_mem *mem, struct mm_struct *mm,
>>   		goto out;
>>   	}
>>   
>> -	/* If no restore worker is running concurrently, user_pages
>> -	 * should not be allocated
>> -	 */
>> -	WARN(mem->user_pages, "Leaking user_pages array");
>> -
>> -	mem->user_pages = kvmalloc_array(bo->tbo.ttm->num_pages,
>> -					   sizeof(struct page *),
>> -					   GFP_KERNEL | __GFP_ZERO);
>> -	if (!mem->user_pages) {
>> -		pr_err("%s: Failed to allocate pages array\n", __func__);
>> -		ret = -ENOMEM;
>> -		goto unregister_out;
>> -	}
>> -
>> -	ret = amdgpu_ttm_tt_get_user_pages(bo->tbo.ttm, mem->user_pages);
>> +	ret = amdgpu_ttm_tt_get_user_pages(bo->tbo.ttm, bo->tbo.ttm->pages);
>>   	if (ret) {
>>   		pr_err("%s: Failed to get user pages: %d\n", __func__, ret);
>> -		goto free_out;
>> +		goto unregister_out;
>>   	}
>>   
>> -	amdgpu_ttm_tt_set_user_pages(bo->tbo.ttm, mem->user_pages);
>> -
>>   	ret = amdgpu_bo_reserve(bo, true);
>>   	if (ret) {
>>   		pr_err("%s: Failed to reserve BO\n", __func__);
>> @@ -616,11 +600,7 @@ static int init_user_pages(struct kgd_mem *mem, struct mm_struct *mm,
>>   	amdgpu_bo_unreserve(bo);
>>   
>>   release_out:
>> -	if (ret)
>> -		release_pages(mem->user_pages, bo->tbo.ttm->num_pages);
>> -free_out:
>> -	kvfree(mem->user_pages);
>> -	mem->user_pages = NULL;
>> +	amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>>   unregister_out:
>>   	if (ret)
>>   		amdgpu_mn_unregister(bo);
>> @@ -679,7 +659,6 @@ static int reserve_bo_and_vm(struct kgd_mem *mem,
>>   	ctx->kfd_bo.priority = 0;
>>   	ctx->kfd_bo.tv.bo = &bo->tbo;
>>   	ctx->kfd_bo.tv.num_shared = 1;
>> -	ctx->kfd_bo.user_pages = NULL;
>>   	list_add(&ctx->kfd_bo.tv.head, &ctx->list);
>>   
>>   	amdgpu_vm_get_pd_bo(vm, &ctx->list, &ctx->vm_pd[0]);
>> @@ -743,7 +722,6 @@ static int reserve_bo_and_cond_vms(struct kgd_mem *mem,
>>   	ctx->kfd_bo.priority = 0;
>>   	ctx->kfd_bo.tv.bo = &bo->tbo;
>>   	ctx->kfd_bo.tv.num_shared = 1;
>> -	ctx->kfd_bo.user_pages = NULL;
>>   	list_add(&ctx->kfd_bo.tv.head, &ctx->list);
>>   
>>   	i = 0;
>> @@ -1371,15 +1349,6 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
>>   	list_del(&bo_list_entry->head);
>>   	mutex_unlock(&process_info->lock);
>>   
>> -	/* Free user pages if necessary */
>> -	if (mem->user_pages) {
>> -		pr_debug("%s: Freeing user_pages array\n", __func__);
>> -		if (mem->user_pages[0])
>> -			release_pages(mem->user_pages,
>> -					mem->bo->tbo.ttm->num_pages);
>> -		kvfree(mem->user_pages);
>> -	}
>> -
>>   	ret = reserve_bo_and_cond_vms(mem, NULL, BO_VM_ALL, &ctx);
>>   	if (unlikely(ret))
>>   		return ret;
>> @@ -1855,25 +1824,11 @@ static int update_invalid_user_pages(struct amdkfd_process_info *process_info,
>>   
>>   		bo = mem->bo;
>>   
>> -		if (!mem->user_pages) {
>> -			mem->user_pages =
>> -				kvmalloc_array(bo->tbo.ttm->num_pages,
>> -						 sizeof(struct page *),
>> -						 GFP_KERNEL | __GFP_ZERO);
>> -			if (!mem->user_pages) {
>> -				pr_err("%s: Failed to allocate pages array\n",
>> -				       __func__);
>> -				return -ENOMEM;
>> -			}
>> -		} else if (mem->user_pages[0]) {
>> -			release_pages(mem->user_pages, bo->tbo.ttm->num_pages);
>> -		}
>> -
>>   		/* Get updated user pages */
>>   		ret = amdgpu_ttm_tt_get_user_pages(bo->tbo.ttm,
>> -						   mem->user_pages);
>> +						   bo->tbo.ttm->pages);
>>   		if (ret) {
>> -			mem->user_pages[0] = NULL;
>> +			bo->tbo.ttm->pages[0] = NULL;
>>   			pr_info("%s: Failed to get user pages: %d\n",
>>   				__func__, ret);
>>   			/* Pretend it succeeded. It will fail later
>> @@ -1882,12 +1837,6 @@ static int update_invalid_user_pages(struct amdkfd_process_info *process_info,
>>   			 * stalled user mode queues.
>>   			 */
>>   		}
>> -
>> -		/* Mark the BO as valid unless it was invalidated
>> -		 * again concurrently
>> -		 */
>> -		if (atomic_cmpxchg(&mem->invalid, invalid, 0) != invalid)
>> -			return -EAGAIN;
>>   	}
>>   
>>   	return 0;
>> @@ -1917,7 +1866,8 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info)
>>   				     GFP_KERNEL);
>>   	if (!pd_bo_list_entries) {
>>   		pr_err("%s: Failed to allocate PD BO list entries\n", __func__);
>> -		return -ENOMEM;
>> +		ret = -ENOMEM;
>> +		goto out_no_mem;
>>   	}
>>   
>>   	INIT_LIST_HEAD(&resv_list);
>> @@ -1941,7 +1891,7 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info)
>>   	ret = ttm_eu_reserve_buffers(&ticket, &resv_list, false, &duplicates);
>>   	WARN(!list_empty(&duplicates), "Duplicates should be empty");
>>   	if (ret)
>> -		goto out;
>> +		goto out_free;
>>   
>>   	amdgpu_sync_create(&sync);
>>   
>> @@ -1967,10 +1917,8 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info)
>>   
>>   		bo = mem->bo;
>>   
>> -		/* Copy pages array and validate the BO if we got user pages */
>> -		if (mem->user_pages[0]) {
>> -			amdgpu_ttm_tt_set_user_pages(bo->tbo.ttm,
>> -						     mem->user_pages);
>> +		/* Validate the BO if we got user pages */
>> +		if (bo->tbo.ttm->pages[0]) {
>>   			amdgpu_bo_placement_from_domain(bo, mem->domain);
>>   			ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
>>   			if (ret) {
>> @@ -1979,16 +1927,16 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info)
>>   			}
>>   		}
>>   
>> -		/* Validate succeeded, now the BO owns the pages, free
>> -		 * our copy of the pointer array. Put this BO back on
>> -		 * the userptr_valid_list. If we need to revalidate
>> -		 * it, we need to start from scratch.
>> -		 */
>> -		kvfree(mem->user_pages);
>> -		mem->user_pages = NULL;
>>   		list_move_tail(&mem->validate_list.head,
>>   			       &process_info->userptr_valid_list);
>>   
>> +		/* Stop HMM track the userptr update. We dont check the return
>> +		 * value for concurrent CPU page table update because we will
>> +		 * reschedule the restore worker if process_info->evicted_bos
>> +		 * is updated.
>> +		 */
>> +		amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>> +
>>   		/* Update mapping. If the BO was not validated
>>   		 * (because we couldn't get user pages), this will
>>   		 * clear the page table entries, which will result in
>> @@ -2022,8 +1970,15 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info)
>>   	ttm_eu_backoff_reservation(&ticket, &resv_list);
>>   	amdgpu_sync_wait(&sync, false);
>>   	amdgpu_sync_free(&sync);
>> -out:
>> +out_free:
>>   	kfree(pd_bo_list_entries);
>> +out_no_mem:
>> +	list_for_each_entry_safe(mem, tmp_mem,
>> +				 &process_info->userptr_inval_list,
>> +				 validate_list.head) {
>> +		bo = mem->bo;
>> +		amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>> +	}
>>   
>>   	return ret;
>>   }
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
>> index 5c79da8e1150..3842183970cc 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
>> @@ -200,8 +200,6 @@ void amdgpu_bo_list_get_list(struct amdgpu_bo_list *list,
>>   
>>   		if (!bo->parent)
>>   			list_add_tail(&e->tv.head, &bucket[priority]);
>> -
>> -		e->user_pages = NULL;
>>   	}
>>   
>>   	/* Connect the sorted buckets in the output list. */
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
>> index 7c5f5d1601e6..4beab2de09b3 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
>> @@ -35,8 +35,7 @@ struct amdgpu_bo_list_entry {
>>   	struct ttm_validate_buffer	tv;
>>   	struct amdgpu_bo_va		*bo_va;
>>   	uint32_t			priority;
>> -	struct page			**user_pages;
>> -	int				user_invalidated;
>> +	bool				user_invalidated;
>>   };
>>   
>>   struct amdgpu_bo_list {
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> index 1c49b8266d69..e30e39fb7224 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> @@ -52,7 +52,6 @@ static int amdgpu_cs_user_fence_chunk(struct amdgpu_cs_parser *p,
>>   	p->uf_entry.tv.bo = &bo->tbo;
>>   	/* One for TTM and one for the CS job */
>>   	p->uf_entry.tv.num_shared = 2;
>> -	p->uf_entry.user_pages = NULL;
>>   
>>   	drm_gem_object_put_unlocked(gobj);
>>   
>> @@ -532,24 +531,19 @@ static int amdgpu_cs_list_validate(struct amdgpu_cs_parser *p,
>>   
>>   	list_for_each_entry(lobj, validated, tv.head) {
>>   		struct amdgpu_bo *bo = ttm_to_amdgpu_bo(lobj->tv.bo);
>> -		bool binding_userptr = false;
>>   		struct mm_struct *usermm;
>>   
>>   		usermm = amdgpu_ttm_tt_get_usermm(bo->tbo.ttm);
>>   		if (usermm && usermm != current->mm)
>>   			return -EPERM;
>>   
>> -		/* Check if we have user pages and nobody bound the BO already */
>> -		if (amdgpu_ttm_tt_userptr_needs_pages(bo->tbo.ttm) &&
>> -		    lobj->user_pages) {
>> +		if (amdgpu_ttm_tt_is_userptr(bo->tbo.ttm) &&
>> +		    lobj->user_invalidated) {
>>   			amdgpu_bo_placement_from_domain(bo,
>>   							AMDGPU_GEM_DOMAIN_CPU);
>>   			r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
>>   			if (r)
>>   				return r;
>> -			amdgpu_ttm_tt_set_user_pages(bo->tbo.ttm,
>> -						     lobj->user_pages);
>> -			binding_userptr = true;
>>   		}
>>   
>>   		if (p->evictable == lobj)
>> @@ -558,11 +552,6 @@ static int amdgpu_cs_list_validate(struct amdgpu_cs_parser *p,
>>   		r = amdgpu_cs_validate(p, bo);
>>   		if (r)
>>   			return r;
>> -
>> -		if (binding_userptr) {
>> -			kvfree(lobj->user_pages);
>> -			lobj->user_pages = NULL;
>> -		}
>>   	}
>>   	return 0;
>>   }
>> @@ -577,7 +566,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
>>   	struct amdgpu_bo *gds;
>>   	struct amdgpu_bo *gws;
>>   	struct amdgpu_bo *oa;
>> -	unsigned tries = 10;
>> +	struct list_head userpage_list;
>>   	int r;
>>   
>>   	INIT_LIST_HEAD(&p->validated);
>> @@ -586,7 +575,6 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
>>   	if (cs->in.bo_list_handle) {
>>   		if (p->bo_list)
>>   			return -EINVAL;
>> -
>>   		r = amdgpu_bo_list_get(fpriv, cs->in.bo_list_handle,
>>   				       &p->bo_list);
>>   		if (r)
>> @@ -613,79 +601,72 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
>>   	if (p->uf_entry.tv.bo && !ttm_to_amdgpu_bo(p->uf_entry.tv.bo)->parent)
>>   		list_add(&p->uf_entry.tv.head, &p->validated);
>>   
>> -	while (1) {
>> -		struct list_head need_pages;
>> +	r = ttm_eu_reserve_buffers(&p->ticket, &p->validated, true,
>> +				   &duplicates);
>> +	if (unlikely(r != 0)) {
>> +		if (r != -ERESTARTSYS)
>> +			DRM_ERROR("ttm_eu_reserve_buffers failed.\n");
>> +		goto out;
>> +	}
>>   
>> -		r = ttm_eu_reserve_buffers(&p->ticket, &p->validated, true,
>> -					   &duplicates);
>> -		if (unlikely(r != 0)) {
>> -			if (r != -ERESTARTSYS)
>> -				DRM_ERROR("ttm_eu_reserve_buffers failed.\n");
>> -			goto error_free_pages;
>> -		}
>> +	INIT_LIST_HEAD(&userpage_list);
>> +	amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
>> +		struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
>>   
>> -		INIT_LIST_HEAD(&need_pages);
>> -		amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
>> -			struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
>> +		list_del(&e->tv.head);
>> +		list_add(&e->tv.head, &userpage_list);
>> +		amdgpu_bo_unreserve(bo);
>> +	}
>>   
>> -			if (amdgpu_ttm_tt_userptr_invalidated(bo->tbo.ttm,
>> -				 &e->user_invalidated) && e->user_pages) {
>> +	/* Get userptr backing pages. If pages are updated after registered
>> +	 * in amdgpu_gem_userptr_ioctl(), amdgpu_cs_list_validate() will do
>> +	 * amdgpu_ttm_backend_bind() to flush and invalidate new pages
>> +	 */
>> +	if (!list_empty(&userpage_list)) {
>> +		/* Unreserve everything again, to avoid circular locking case
>> +		 * bo::reserve -> mmap->sem
>> +		 */
>> +		ttm_eu_backoff_reservation(&p->ticket, &p->validated);
>>   
>> -				/* We acquired a page array, but somebody
>> -				 * invalidated it. Free it and try again
>> -				 */
>> -				release_pages(e->user_pages,
>> -					      bo->tbo.ttm->num_pages);
>> -				kvfree(e->user_pages);
>> -				e->user_pages = NULL;
>> +		list_for_each_entry(e, &userpage_list, tv.head) {
>> +			struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
>> +			bool userpage_invalidated = false;
>> +			struct page **pages;
>> +			int i;
>> +
>> +			pages = kvmalloc_array(bo->tbo.ttm->num_pages,
>> +						sizeof(*pages),
>> +						GFP_KERNEL | __GFP_ZERO);
>> +			if (!pages) {
>> +				DRM_ERROR("calloc failure\n");
>> +				return -ENOMEM;
>>   			}
>>   
>> -			if (amdgpu_ttm_tt_userptr_needs_pages(bo->tbo.ttm) &&
>> -			    !e->user_pages) {
>> -				list_del(&e->tv.head);
>> -				list_add(&e->tv.head, &need_pages);
>> -
>> -				amdgpu_bo_unreserve(bo);
>> +			r = amdgpu_ttm_tt_get_user_pages(bo->tbo.ttm, pages);
>> +			if (r) {
>> +				kvfree(pages);
>> +				return r;
>>   			}
>> -		}
>>   
>> -		if (list_empty(&need_pages))
>> -			break;
>> -
>> -		/* Unreserve everything again. */
>> -		ttm_eu_backoff_reservation(&p->ticket, &p->validated);
>> -
>> -		/* We tried too many times, just abort */
>> -		if (!--tries) {
>> -			r = -EDEADLK;
>> -			DRM_ERROR("deadlock in %s\n", __func__);
>> -			goto error_free_pages;
>> +			for (i = 0; i < bo->tbo.ttm->num_pages; i++) {
>> +				if (bo->tbo.ttm->pages[i] != pages[i]) {
>> +					bo->tbo.ttm->pages[i] = pages[i];
>> +					userpage_invalidated = true;
>> +				}
>> +			}
>> +			e->user_invalidated = userpage_invalidated;
>> +			kvfree(pages);
>>   		}
>>   
>> -		/* Fill the page arrays for all userptrs. */
>> -		list_for_each_entry(e, &need_pages, tv.head) {
>> -			struct ttm_tt *ttm = e->tv.bo->ttm;
>> -
>> -			e->user_pages = kvmalloc_array(ttm->num_pages,
>> -							 sizeof(struct page*),
>> -							 GFP_KERNEL | __GFP_ZERO);
>> -			if (!e->user_pages) {
>> -				r = -ENOMEM;
>> -				DRM_ERROR("calloc failure in %s\n", __func__);
>> -				goto error_free_pages;
>> -			}
>> +		list_splice(&userpage_list, &p->validated);
>>   
>> -			r = amdgpu_ttm_tt_get_user_pages(ttm, e->user_pages);
>> -			if (r) {
>> -				DRM_ERROR("amdgpu_ttm_tt_get_user_pages failed.\n");
>> -				kvfree(e->user_pages);
>> -				e->user_pages = NULL;
>> -				goto error_free_pages;
>> -			}
>> +		r = ttm_eu_reserve_buffers(&p->ticket, &p->validated, true,
>> +					   &duplicates);
>> +		if (unlikely(r != 0)) {
>> +			if (r != -ERESTARTSYS)
>> +				DRM_ERROR("ttm_eu_reserve_buffers failed.\n");
>> +			goto out;
>>   		}
>> -
>> -		/* And try again. */
>> -		list_splice(&need_pages, &p->validated);
>>   	}
>>   
>>   	amdgpu_cs_get_threshold_for_moves(p->adev, &p->bytes_moved_threshold,
>> @@ -754,17 +735,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
>>   error_validate:
>>   	if (r)
>>   		ttm_eu_backoff_reservation(&p->ticket, &p->validated);
>> -
>> -error_free_pages:
>> -
>> -	amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
>> -		if (!e->user_pages)
>> -			continue;
>> -
>> -		release_pages(e->user_pages, e->tv.bo->ttm->num_pages);
>> -		kvfree(e->user_pages);
>> -	}
>> -
>> +out:
>>   	return r;
>>   }
>>   
>> @@ -1213,8 +1184,7 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
>>   	struct amdgpu_bo_list_entry *e;
>>   	struct amdgpu_job *job;
>>   	uint64_t seq;
>> -
>> -	int r;
>> +	int r = 0;
>>   
>>   	job = p->job;
>>   	p->job = NULL;
>> @@ -1223,15 +1193,21 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
>>   	if (r)
>>   		goto error_unlock;
>>   
>> -	/* No memory allocation is allowed while holding the mn lock */
>> +	/* No memory allocation is allowed while holding the mn lock.
>> +	 * p->mn is hold until amdgpu_cs_submit is finished and fence is added
>> +	 * to BOs.
>> +	 */
>>   	amdgpu_mn_lock(p->mn);
>> +
>> +	/* If userptr are updated after amdgpu_cs_parser_bos(), restart cs */
>>   	amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
>>   		struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
>>   
>> -		if (amdgpu_ttm_tt_userptr_needs_pages(bo->tbo.ttm)) {
>> -			r = -ERESTARTSYS;
>> -			goto error_abort;
>> -		}
>> +		r |= !amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>> +	}
>> +	if (r) {
>> +		r = -ERESTARTSYS;
>> +		goto error_abort;
>>   	}
>>   
>>   	job->owner = p->filp;
>> @@ -1278,14 +1254,20 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
>>   int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
>>   {
>>   	struct amdgpu_device *adev = dev->dev_private;
>> -	union drm_amdgpu_cs *cs = data;
>> -	struct amdgpu_cs_parser parser = {};
>> -	bool reserved_buffers = false;
>> +	union drm_amdgpu_cs *cs;
>> +	struct amdgpu_cs_parser parser;
>> +	bool reserved_buffers;
>> +	int tries = 10;
>>   	int i, r;
>>   
>>   	if (!adev->accel_working)
>>   		return -EBUSY;
>>   
>> +restart:
>> +	memset(&parser, 0, sizeof(parser));
>> +	cs = data;
>> +	reserved_buffers = false;
>> +
>>   	parser.adev = adev;
>>   	parser.filp = filp;
>>   
>> @@ -1327,6 +1309,15 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
>>   
>>   out:
>>   	amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
>> +
>> +	if (r == -ERESTARTSYS) {
>> +		if (!--tries) {
>> +			DRM_ERROR("Possible deadlock? Retry too many times\n");
>> +			return -EDEADLK;
>> +		}
>> +		goto restart;
>> +	}
>> +
>>   	return r;
>>   }
>>   
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> index f4f00217546e..92025993bfb1 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> @@ -336,26 +336,24 @@ int amdgpu_gem_userptr_ioctl(struct drm_device *dev, void *data,
>>   
>>   		r = amdgpu_bo_reserve(bo, true);
>>   		if (r)
>> -			goto free_pages;
>> +			goto user_pages_done;
>>   
>>   		amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
>>   		r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
>>   		amdgpu_bo_unreserve(bo);
>>   		if (r)
>> -			goto free_pages;
>> +			goto user_pages_done;
>>   	}
>>   
>>   	r = drm_gem_handle_create(filp, gobj, &handle);
>> -	/* drop reference from allocate - handle holds it now */
>> -	drm_gem_object_put_unlocked(gobj);
>>   	if (r)
>> -		return r;
>> +		goto user_pages_done;
>>   
>>   	args->handle = handle;
>> -	return 0;
>>   
>> -free_pages:
>> -	release_pages(bo->tbo.ttm->pages, bo->tbo.ttm->num_pages);
>> +user_pages_done:
>> +	if (args->flags & AMDGPU_GEM_USERPTR_VALIDATE)
>> +		amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>>   
>>   release_object:
>>   	drm_gem_object_put_unlocked(gobj);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> index 5d518d2bb9be..9d40f3001f3c 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> @@ -229,8 +229,6 @@ static void amdgpu_mn_invalidate_node(struct amdgpu_mn_node *node,
>>   			true, false, MAX_SCHEDULE_TIMEOUT);
>>   		if (r <= 0)
>>   			DRM_ERROR("(%ld) failed to wait for user bo\n", r);
>> -
>> -		amdgpu_ttm_tt_mark_user_pages(bo->tbo.ttm);
>>   	}
>>   }
>>   
>> @@ -513,3 +511,26 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
>>   	mutex_unlock(&adev->mn_lock);
>>   }
>>   
>> +/* flags used by HMM internal, not related to CPU/GPU PTE flags */
>> +static const uint64_t hmm_range_flags[HMM_PFN_FLAG_MAX] = {
>> +		(1 << 0), /* HMM_PFN_VALID */
>> +		(1 << 1), /* HMM_PFN_WRITE */
>> +		0 /* HMM_PFN_DEVICE_PRIVATE */
>> +};
>> +
>> +static const uint64_t hmm_range_values[HMM_PFN_VALUE_MAX] = {
>> +		0xfffffffffffffffeUL, /* HMM_PFN_ERROR */
>> +		0, /* HMM_PFN_NONE */
>> +		0xfffffffffffffffcUL /* HMM_PFN_SPECIAL */
>> +};
>> +
>> +void amdgpu_hmm_init_range(struct hmm_range *range)
>> +{
>> +	if (range) {
>> +		range->flags = hmm_range_flags;
>> +		range->values = hmm_range_values;
>> +		range->pfn_shift = PAGE_SHIFT;
>> +		range->pfns = NULL;
>> +		INIT_LIST_HEAD(&range->list);
>> +	}
>> +}
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>> index 0a51fd00021c..4803e216e174 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>> @@ -25,9 +25,10 @@
>>   #define __AMDGPU_MN_H__
>>   
>>   /*
>> - * MMU Notifier
>> + * HMM mirror
>>    */
>>   struct amdgpu_mn;
>> +struct hmm_range;
>>   
>>   enum amdgpu_mn_type {
>>   	AMDGPU_MN_TYPE_GFX,
>> @@ -41,6 +42,7 @@ struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
>>   				enum amdgpu_mn_type type);
>>   int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr);
>>   void amdgpu_mn_unregister(struct amdgpu_bo *bo);
>> +void amdgpu_hmm_init_range(struct hmm_range *range);
>>   #else
>>   static inline void amdgpu_mn_lock(struct amdgpu_mn *mn) {}
>>   static inline void amdgpu_mn_unlock(struct amdgpu_mn *mn) {}
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> index c91ec3101d00..70df6c68b4ed 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> @@ -43,6 +43,7 @@
>>   #include <linux/pagemap.h>
>>   #include <linux/debugfs.h>
>>   #include <linux/iommu.h>
>> +#include <linux/hmm.h>
>>   #include "amdgpu.h"
>>   #include "amdgpu_object.h"
>>   #include "amdgpu_trace.h"
>> @@ -705,11 +706,6 @@ static unsigned long amdgpu_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
>>   /*
>>    * TTM backend functions.
>>    */
>> -struct amdgpu_ttm_gup_task_list {
>> -	struct list_head	list;
>> -	struct task_struct	*task;
>> -};
>> -
>>   struct amdgpu_ttm_tt {
>>   	struct ttm_dma_tt	ttm;
>>   	u64			offset;
>> @@ -718,107 +714,97 @@ struct amdgpu_ttm_tt {
>>   	uint32_t		userflags;
>>   	spinlock_t              guptasklock;
>>   	struct list_head        guptasks;
>> -	atomic_t		mmu_invalidations;
>> -	uint32_t		last_set_pages;
>> +	struct hmm_range	range;
>>   };
>>   
>>   /**
>> - * amdgpu_ttm_tt_get_user_pages - Pin pages of memory pointed to by a USERPTR
>> - * pointer to memory
>> + * amdgpu_ttm_tt_get_user_pages - get device accessible pages that back user
>> + * memory and start HMM tracking CPU page table update
>>    *
>> - * Called by amdgpu_gem_userptr_ioctl() and amdgpu_cs_parser_bos().
>> - * This provides a wrapper around the get_user_pages() call to provide
>> - * device accessible pages that back user memory.
>> + * Calling function must call amdgpu_ttm_tt_userptr_range_done() once and only
>> + * once afterwards to stop HMM tracking
>>    */
>>   int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
>>   {
>>   	struct amdgpu_ttm_tt *gtt = (void *)ttm;
>>   	struct mm_struct *mm = gtt->usertask->mm;
>> -	unsigned int flags = 0;
>> -	unsigned pinned = 0;
>> -	int r;
>> +	unsigned long end = gtt->userptr + ttm->num_pages * PAGE_SIZE;
>> +	struct hmm_range *range = &gtt->range;
>> +	int r = 0, i;
>>   
>>   	if (!mm) /* Happens during process shutdown */
>>   		return -ESRCH;
>>   
>> -	if (!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY))
>> -		flags |= FOLL_WRITE;
>> +	amdgpu_hmm_init_range(range);
>>   
>>   	down_read(&mm->mmap_sem);
>>   
>> -	if (gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) {
>> -		/*
>> -		 * check that we only use anonymous memory to prevent problems
>> -		 * with writeback
>> -		 */
>> -		unsigned long end = gtt->userptr + ttm->num_pages * PAGE_SIZE;
>> -		struct vm_area_struct *vma;
>> +	range->vma = find_vma(mm, gtt->userptr);
>> +	if (!range_in_vma(range->vma, gtt->userptr, end))
>> +		r = -EFAULT;
>> +	else if ((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) &&
>> +		range->vma->vm_file)
>> +		r = -EPERM;
>> +	if (r)
>> +		goto out;
>>   
>> -		vma = find_vma(mm, gtt->userptr);
>> -		if (!vma || vma->vm_file || vma->vm_end < end) {
>> -			up_read(&mm->mmap_sem);
>> -			return -EPERM;
>> -		}
>> +	range->pfns = kvmalloc_array(ttm->num_pages, sizeof(uint64_t),
>> +				     GFP_KERNEL);
>> +	if (range->pfns == NULL) {
>> +		r = -ENOMEM;
>> +		goto out;
>>   	}
>> +	range->start = gtt->userptr;
>> +	range->end = end;
>>   
>> -	/* loop enough times using contiguous pages of memory */
>> -	do {
>> -		unsigned num_pages = ttm->num_pages - pinned;
>> -		uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;
>> -		struct page **p = pages + pinned;
>> -		struct amdgpu_ttm_gup_task_list guptask;
>> -
>> -		guptask.task = current;
>> -		spin_lock(&gtt->guptasklock);
>> -		list_add(&guptask.list, &gtt->guptasks);
>> -		spin_unlock(&gtt->guptasklock);
>> -
>> -		if (mm == current->mm)
>> -			r = get_user_pages(userptr, num_pages, flags, p, NULL);
>> -		else
>> -			r = get_user_pages_remote(gtt->usertask,
>> -					mm, userptr, num_pages,
>> -					flags, p, NULL, NULL);
>> +	range->pfns[0] = range->flags[HMM_PFN_VALID];
>> +	range->pfns[0] |= amdgpu_ttm_tt_is_readonly(ttm) ?
>> +				0 : range->flags[HMM_PFN_WRITE];
>> +	for (i = 1; i < ttm->num_pages; i++)
>> +		range->pfns[i] = range->pfns[0];
>>   
>> -		spin_lock(&gtt->guptasklock);
>> -		list_del(&guptask.list);
>> -		spin_unlock(&gtt->guptasklock);
>> -
>> -		if (r < 0)
>> -			goto release_pages;
>> +	/* This may trigger page table update */
>> +	r = hmm_vma_fault(range, true);
>> +	if (r)
>> +		goto out_free_pfns;
>>   
>> -		pinned += r;
>> +	up_read(&mm->mmap_sem);
>>   
>> -	} while (pinned < ttm->num_pages);
>> +	for (i = 0; i < ttm->num_pages; i++)
>> +		pages[i] = hmm_pfn_to_page(range, range->pfns[i]);
>>   
>> -	up_read(&mm->mmap_sem);
>>   	return 0;
>>   
>> -release_pages:
>> -	release_pages(pages, pinned);
>> +out_free_pfns:
>> +	kvfree(range->pfns);
>> +	range->pfns = NULL;
>> +out:
>>   	up_read(&mm->mmap_sem);
>>   	return r;
>>   }
>>   
>>   /**
>> - * amdgpu_ttm_tt_set_user_pages - Copy pages in, putting old pages as necessary.
>> + * amdgpu_ttm_tt_userptr_range_done - stop HMM track the CPU page table change
>> + * Check if the pages backing this ttm range have been invalidated
>>    *
>> - * Called by amdgpu_cs_list_validate(). This creates the page list
>> - * that backs user memory and will ultimately be mapped into the device
>> - * address space.
>> + * Returns: true if pages are still valid
>>    */
>> -void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page **pages)
>> +bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm)
>>   {
>>   	struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> -	unsigned i;
>> +	bool r = false;
>>   
>> -	gtt->last_set_pages = atomic_read(&gtt->mmu_invalidations);
>> -	for (i = 0; i < ttm->num_pages; ++i) {
>> -		if (ttm->pages[i])
>> -			put_page(ttm->pages[i]);
>> +	if (!gtt || !gtt->userptr)
>> +		return false;
>>   
>> -		ttm->pages[i] = pages ? pages[i] : NULL;
>> +	WARN_ONCE(!gtt->range.pfns, "No user pages to check\n");
>> +	if (gtt->range.pfns) {
>> +		r = hmm_vma_range_done(&gtt->range);
>> +		kvfree(gtt->range.pfns);
>> +		gtt->range.pfns = NULL;
>>   	}
>> +
>> +	return r;
>>   }
>>   
>>   /**
>> @@ -903,10 +889,9 @@ static void amdgpu_ttm_tt_unpin_userptr(struct ttm_tt *ttm)
>>   	/* unmap the pages mapped to the device */
>>   	dma_unmap_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction);
>>   
>> -	/* mark the pages as dirty */
>> -	amdgpu_ttm_tt_mark_user_pages(ttm);
>> -
>>   	sg_free_table(ttm->sg);
>> +
>> +	WARN_ONCE(gtt->range.pfns, "Missing get_user_page_done\n");
>>   }
>>   
>>   int amdgpu_ttm_gart_bind(struct amdgpu_device *adev,
>> @@ -1207,7 +1192,7 @@ static void amdgpu_ttm_tt_unpopulate(struct ttm_tt *ttm)
>>   	bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);
>>   
>>   	if (gtt && gtt->userptr) {
>> -		amdgpu_ttm_tt_set_user_pages(ttm, NULL);
>> +		memset(ttm->pages, 0, ttm->num_pages * sizeof(struct page *));
>>   		kfree(ttm->sg);
>>   		ttm->page_flags &= ~TTM_PAGE_FLAG_SG;
>>   		return;
>> @@ -1258,8 +1243,6 @@ int amdgpu_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
>>   
>>   	spin_lock_init(&gtt->guptasklock);
>>   	INIT_LIST_HEAD(&gtt->guptasks);
>> -	atomic_set(&gtt->mmu_invalidations, 0);
>> -	gtt->last_set_pages = 0;
>>   
>>   	return 0;
>>   }
>> @@ -1289,7 +1272,6 @@ bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt *ttm, unsigned long start,
>>   				  unsigned long end)
>>   {
>>   	struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> -	struct amdgpu_ttm_gup_task_list *entry;
>>   	unsigned long size;
>>   
>>   	if (gtt == NULL || !gtt->userptr)
>> @@ -1302,48 +1284,20 @@ bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt *ttm, unsigned long start,
>>   	if (gtt->userptr > end || gtt->userptr + size <= start)
>>   		return false;
>>   
>> -	/* Search the lists of tasks that hold this mapping and see
>> -	 * if current is one of them.  If it is return false.
>> -	 */
>> -	spin_lock(&gtt->guptasklock);
>> -	list_for_each_entry(entry, &gtt->guptasks, list) {
>> -		if (entry->task == current) {
>> -			spin_unlock(&gtt->guptasklock);
>> -			return false;
>> -		}
>> -	}
>> -	spin_unlock(&gtt->guptasklock);
>> -
>> -	atomic_inc(&gtt->mmu_invalidations);
>> -
>>   	return true;
>>   }
>>   
>>   /**
>> - * amdgpu_ttm_tt_userptr_invalidated - Has the ttm_tt object been invalidated?
>> + * amdgpu_ttm_tt_is_userptr - Have the pages backing by userptr?
>>    */
>> -bool amdgpu_ttm_tt_userptr_invalidated(struct ttm_tt *ttm,
>> -				       int *last_invalidated)
>> -{
>> -	struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> -	int prev_invalidated = *last_invalidated;
>> -
>> -	*last_invalidated = atomic_read(&gtt->mmu_invalidations);
>> -	return prev_invalidated != *last_invalidated;
>> -}
>> -
>> -/**
>> - * amdgpu_ttm_tt_userptr_needs_pages - Have the pages backing this ttm_tt object
>> - * been invalidated since the last time they've been set?
>> - */
>> -bool amdgpu_ttm_tt_userptr_needs_pages(struct ttm_tt *ttm)
>> +bool amdgpu_ttm_tt_is_userptr(struct ttm_tt *ttm)
>>   {
>>   	struct amdgpu_ttm_tt *gtt = (void *)ttm;
>>   
>>   	if (gtt == NULL || !gtt->userptr)
>>   		return false;
>>   
>> -	return atomic_read(&gtt->mmu_invalidations) != gtt->last_set_pages;
>> +	return true;
>>   }
>>   
>>   /**
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> index b5b2d101f7db..c5a1e78a09b1 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> @@ -102,7 +102,7 @@ int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo);
>>   int amdgpu_ttm_recover_gart(struct ttm_buffer_object *tbo);
>>   
>>   int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages);
>> -void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page **pages);
>> +bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm);
>>   void amdgpu_ttm_tt_mark_user_pages(struct ttm_tt *ttm);
>>   int amdgpu_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
>>   				     uint32_t flags);
>> @@ -112,7 +112,7 @@ bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt *ttm, unsigned long start,
>>   				  unsigned long end);
>>   bool amdgpu_ttm_tt_userptr_invalidated(struct ttm_tt *ttm,
>>   				       int *last_invalidated);
>> -bool amdgpu_ttm_tt_userptr_needs_pages(struct ttm_tt *ttm);
>> +bool amdgpu_ttm_tt_is_userptr(struct ttm_tt *ttm);
>>   bool amdgpu_ttm_tt_is_readonly(struct ttm_tt *ttm);
>>   uint64_t amdgpu_ttm_tt_pde_flags(struct ttm_tt *ttm, struct ttm_mem_reg *mem);
>>   uint64_t amdgpu_ttm_tt_pte_flags(struct amdgpu_device *adev, struct ttm_tt *ttm,
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> index e73d152659a2..1f8ab1a4fabc 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> @@ -619,7 +619,6 @@ void amdgpu_vm_get_pd_bo(struct amdgpu_vm *vm,
>>   	entry->tv.bo = &vm->root.base.bo->tbo;
>>   	/* One for the VM updates, one for TTM and one for the CS job */
>>   	entry->tv.num_shared = 3;
>> -	entry->user_pages = NULL;
>>   	list_add(&entry->tv.head, validated);
>>   }
>>   


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