1 files changed, 251 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
new file mode 100644
index 000000000000..2dadcfe43d03
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
@@ -0,0 +1,251 @@
+/*
+ * Copyright 2014 Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ */
+/*
+ * Authors:
+ *    Christian König <christian.koenig@amd.com>
+ */
+
+/**
+ * DOC: MMU Notifier
+ *
+ * For coherent userptr handling registers an MMU notifier to inform the driver
+ * about updates on the page tables of a process.
+ *
+ * When somebody tries to invalidate the page tables we block the update until
+ * all operations on the pages in question are completed, then those pages are
+ * marked as accessed and also dirty if it wasn't a read only access.
+ *
+ * New command submissions using the userptrs in question are delayed until all
+ * page table invalidation are completed and we once more see a coherent process
+ * address space.
+ */
+
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <drm/drm.h>
+
+#include "amdgpu.h"
+#include "amdgpu_amdkfd.h"
+#include "amdgpu_hmm.h"
+
+#define MAX_WALK_BYTE	(2UL << 30)
+
+/**
+ * amdgpu_hmm_invalidate_gfx - callback to notify about mm change
+ *
+ * @mni: the range (mm) is about to update
+ * @range: details on the invalidation
+ * @cur_seq: Value to pass to mmu_interval_set_seq()
+ *
+ * Block for operations on BOs to finish and mark pages as accessed and
+ * potentially dirty.
+ */
+static bool amdgpu_hmm_invalidate_gfx(struct mmu_interval_notifier *mni,
+				      const struct mmu_notifier_range *range,
+				      unsigned long cur_seq)
+{
+	struct amdgpu_bo *bo = container_of(mni, struct amdgpu_bo, notifier);
+	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+	long r;
+
+	if (!mmu_notifier_range_blockable(range))
+		return false;
+
+	mutex_lock(&adev->notifier_lock);
+
+	mmu_interval_set_seq(mni, cur_seq);
+
+	r = dma_resv_wait_timeout(bo->tbo.base.resv, DMA_RESV_USAGE_BOOKKEEP,
+				  false, MAX_SCHEDULE_TIMEOUT);
+	mutex_unlock(&adev->notifier_lock);
+	if (r <= 0)
+		DRM_ERROR("(%ld) failed to wait for user bo\n", r);
+	return true;
+}
+
+static const struct mmu_interval_notifier_ops amdgpu_hmm_gfx_ops = {
+	.invalidate = amdgpu_hmm_invalidate_gfx,
+};
+
+/**
+ * amdgpu_hmm_invalidate_hsa - callback to notify about mm change
+ *
+ * @mni: the range (mm) is about to update
+ * @range: details on the invalidation
+ * @cur_seq: Value to pass to mmu_interval_set_seq()
+ *
+ * We temporarily evict the BO attached to this range. This necessitates
+ * evicting all user-mode queues of the process.
+ */
+static bool amdgpu_hmm_invalidate_hsa(struct mmu_interval_notifier *mni,
+				      const struct mmu_notifier_range *range,
+				      unsigned long cur_seq)
+{
+	struct amdgpu_bo *bo = container_of(mni, struct amdgpu_bo, notifier);
+
+	if (!mmu_notifier_range_blockable(range))
+		return false;
+
+	amdgpu_amdkfd_evict_userptr(mni, cur_seq, bo->kfd_bo);
+
+	return true;
+}
+
+static const struct mmu_interval_notifier_ops amdgpu_hmm_hsa_ops = {
+	.invalidate = amdgpu_hmm_invalidate_hsa,
+};
+
+/**
+ * amdgpu_hmm_register - register a BO for notifier updates
+ *
+ * @bo: amdgpu buffer object
+ * @addr: userptr addr we should monitor
+ *
+ * Registers a mmu_notifier for the given BO at the specified address.
+ * Returns 0 on success, -ERRNO if anything goes wrong.
+ */
+int amdgpu_hmm_register(struct amdgpu_bo *bo, unsigned long addr)
+{
+	if (bo->kfd_bo)
+		return mmu_interval_notifier_insert(&bo->notifier, current->mm,
+						    addr, amdgpu_bo_size(bo),
+						    &amdgpu_hmm_hsa_ops);
+	return mmu_interval_notifier_insert(&bo->notifier, current->mm, addr,
+					    amdgpu_bo_size(bo),
+					    &amdgpu_hmm_gfx_ops);
+}
+
+/**
+ * amdgpu_hmm_unregister - unregister a BO for notifier updates
+ *
+ * @bo: amdgpu buffer object
+ *
+ * Remove any registration of mmu notifier updates from the buffer object.
+ */
+void amdgpu_hmm_unregister(struct amdgpu_bo *bo)
+{
+	if (!bo->notifier.mm)
+		return;
+	mmu_interval_notifier_remove(&bo->notifier);
+	bo->notifier.mm = NULL;
+}
+
+int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
+			       uint64_t start, uint64_t npages, bool readonly,
+			       void *owner, struct page **pages,
+			       struct hmm_range **phmm_range)
+{
+	struct hmm_range *hmm_range;
+	unsigned long end;
+	unsigned long timeout;
+	unsigned long i;
+	unsigned long *pfns;
+	int r = 0;
+
+	hmm_range = kzalloc(sizeof(*hmm_range), GFP_KERNEL);
+	if (unlikely(!hmm_range))
+		return -ENOMEM;
+
+	pfns = kvmalloc_array(npages, sizeof(*pfns), GFP_KERNEL);
+	if (unlikely(!pfns)) {
+		r = -ENOMEM;
+		goto out_free_range;
+	}
+
+	hmm_range->notifier = notifier;
+	hmm_range->default_flags = HMM_PFN_REQ_FAULT;
+	if (!readonly)
+		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
+	hmm_range->hmm_pfns = pfns;
+	hmm_range->start = start;
+	end = start + npages * PAGE_SIZE;
+	hmm_range->dev_private_owner = owner;
+
+	do {
+		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, end);
+
+		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
+			hmm_range->start, hmm_range->end);
+
+		/* Assuming 512MB takes maxmium 1 second to fault page address */
+		timeout = max((hmm_range->end - hmm_range->start) >> 29, 1UL);
+		timeout *= HMM_RANGE_DEFAULT_TIMEOUT;
+		timeout = jiffies + msecs_to_jiffies(timeout);
+
+retry:
+		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
+		r = hmm_range_fault(hmm_range);
+		if (unlikely(r)) {
+			/*
+			 * FIXME: This timeout should encompass the retry from
+			 * mmu_interval_read_retry() as well.
+			 */
+			if (r == -EBUSY && !time_after(jiffies, timeout))
+				goto retry;
+			goto out_free_pfns;
+		}
+
+		if (hmm_range->end == end)
+			break;
+		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
+		hmm_range->start = hmm_range->end;
+		schedule();
+	} while (hmm_range->end < end);
+
+	hmm_range->start = start;
+	hmm_range->hmm_pfns = pfns;
+
+	/*
+	 * Due to default_flags, all pages are HMM_PFN_VALID or
+	 * hmm_range_fault() fails. FIXME: The pages cannot be touched outside
+	 * the notifier_lock, and mmu_interval_read_retry() must be done first.
+	 */
+	for (i = 0; pages && i < npages; i++)
+		pages[i] = hmm_pfn_to_page(pfns[i]);
+
+	*phmm_range = hmm_range;
+
+	return 0;
+
+out_free_pfns:
+	kvfree(pfns);
+out_free_range:
+	kfree(hmm_range);
+
+	return r;
+}
+
+bool amdgpu_hmm_range_get_pages_done(struct hmm_range *hmm_range)
+{
+	bool r;
+
+	r = mmu_interval_read_retry(hmm_range->notifier,
+				    hmm_range->notifier_seq);
+	kvfree(hmm_range->hmm_pfns);
+	kfree(hmm_range);
+
+	return r;
+}