From: Honglei Huang <[email protected]>

Add MMU notifier event handling and garbage collection infrastructure:
- amdgpu_svm_range_remove: unmap pages and remove from gpusvm
- amdgpu_svm_range_notifier_event_begin: zap PTEs on notifier events
- amdgpu_svm_gc_enqueue: queue range for deferred removal with
  pending page bounds tracking
- amdgpu_svm_gc_add_range: mark range unmapped and enqueue for GC
- amdgpu_svm_range_notifier_event_end: DMA unmap and GC on MMU_UNMAP
- amdgpu_svm_range_invalidate_interval: cursor-based PTE clearing
  across notifiers/ranges with boundary-crossing range removal
- amdgpu_svm_range_dequeue_locked: dequeue work item with atomic
  pending state transfer
- range_try_dequeue: conditional dequeue for reference release
- amdgpu_svm_range_put_if_dequeued: release range ref after dequeue

Signed-off-by: Honglei Huang <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c | 228 ++++++++++++++++++
 1 file changed, 228 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c
index c733d611d..49240c704 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c
@@ -486,3 +486,231 @@ amdgpu_svm_range_map_interval(struct amdgpu_svm *svm,
        return 0;
 }
 
+void amdgpu_svm_range_remove(struct amdgpu_svm *svm,
+                            struct amdgpu_svm_range *range,
+                            struct drm_gpusvm_ctx *ctx)
+{
+       struct drm_gpusvm_range *base = &range->base;
+
+       amdgpu_svm_assert_locked(svm);
+
+       if (!base->pages.flags.unmapped && !base->pages.flags.partial_unmap)
+               drm_gpusvm_range_unmap_pages(&svm->gpusvm, base, ctx);
+
+       range_invalidate_gpu_mapping(range);
+       drm_gpusvm_range_remove(&svm->gpusvm, base);
+}
+
+static bool
+amdgpu_svm_range_notifier_event_begin(struct amdgpu_svm *svm,
+                                     struct drm_gpusvm_range *range,
+                                     const struct mmu_notifier_range 
*mmu_range)
+{
+       struct amdgpu_svm_range *svm_range = to_amdgpu_svm_range(range);
+
+       amdgpu_svm_assert_in_notifier(svm);
+
+       AMDGPU_SVM_RANGE_DEBUG(svm_range, "NOTIFIER");
+
+       if (range->pages.flags.unmapped || !svm_range->gpu_mapped)
+               return false;
+
+       AMDGPU_SVM_RANGE_DEBUG(svm_range, "NOTIFIER - EXECUTE");
+
+       amdgpu_svm_range_zap_ptes(svm, svm_range, mmu_range);
+       range_invalidate_gpu_mapping(svm_range);
+
+       return true;
+}
+
+static void
+amdgpu_svm_gc_enqueue(struct amdgpu_svm *svm,
+                     struct amdgpu_svm_range *range,
+                     unsigned long start_page, unsigned long last_page)
+{
+       if (atomic_read(&svm->exiting))
+               return;
+
+       spin_lock(&svm->work_lock);
+       if (!range->in_queue) {
+               drm_gpusvm_range_get(&range->base);
+               range->in_queue = true;
+       }
+
+       range->pending_start_page = min(range->pending_start_page, start_page);
+       range->pending_last_page = max(range->pending_last_page, last_page);
+       if (range->pending_ops == AMDGPU_SVM_RANGE_OP_NONE)
+               list_add_tail(&range->work_node, &svm->gc.list);
+       range->pending_ops |= AMDGPU_SVM_RANGE_OP_UNMAP;
+       spin_unlock(&svm->work_lock);
+
+       queue_work(svm->gc.wq, &svm->gc.work);
+}
+
+static void
+amdgpu_svm_gc_add_range(struct amdgpu_svm *svm,
+                       struct amdgpu_svm_range *svm_range,
+                       const struct mmu_notifier_range *mmu_range)
+{
+       unsigned long start_page = max(drm_gpusvm_range_start(&svm_range->base),
+                                      mmu_range->start) >> PAGE_SHIFT;
+       unsigned long last_page = (min(drm_gpusvm_range_end(&svm_range->base),
+                                      mmu_range->end) >> PAGE_SHIFT) - 1;
+
+       AMDGPU_SVM_RANGE_DEBUG(svm_range, "GARBAGE COLLECTOR ADD");
+
+       drm_gpusvm_range_set_unmapped(&svm_range->base, mmu_range);
+       amdgpu_svm_gc_enqueue(svm, svm_range, start_page, last_page);
+}
+
+static void
+amdgpu_svm_range_notifier_event_end(struct amdgpu_svm *svm,
+                                   struct drm_gpusvm_range *range,
+                                   const struct mmu_notifier_range *mmu_range)
+{
+       struct drm_gpusvm_ctx ctx = { .in_notifier = true, };
+
+       amdgpu_svm_assert_in_notifier(svm);
+
+       drm_gpusvm_range_unmap_pages(&svm->gpusvm, range, &ctx);
+       if (mmu_range->event == MMU_NOTIFY_UNMAP)
+               amdgpu_svm_gc_add_range(svm, to_amdgpu_svm_range(range),
+                                       mmu_range);
+}
+
+int
+amdgpu_svm_range_invalidate_interval(struct amdgpu_svm *svm,
+                                    unsigned long start_page,
+                                    unsigned long last_page)
+{
+       unsigned long start = start_page << PAGE_SHIFT;
+       unsigned long end = (last_page + 1) << PAGE_SHIFT;
+       struct drm_gpusvm_notifier *notifier, *next_notifier;
+       struct drm_gpusvm_ctx ctx = { .in_notifier = false };
+       struct drm_exec exec;
+       struct dma_fence *fence = NULL;
+       bool needs_flush = false;
+       unsigned int flags;
+       int ret;
+
+       amdgpu_svm_assert_locked(svm);
+
+       ret = amdgpu_svm_range_lock_vm_pd(svm, &exec, true);
+       if (ret)
+               return ret;
+
+       drm_gpusvm_for_each_notifier_safe(notifier, next_notifier, &svm->gpusvm,
+                                         start, end) {
+               struct drm_gpusvm_range *range, *next_range;
+
+               drm_gpusvm_for_each_range_safe(range, next_range, notifier,
+                                              start, end) {
+                       struct amdgpu_svm_range *svm_range = 
to_amdgpu_svm_range(range);
+                       unsigned long range_start = 
drm_gpusvm_range_start(range);
+                       unsigned long range_end = drm_gpusvm_range_end(range);
+                       unsigned long rs = range_start >> PAGE_SHIFT;
+                       unsigned long rl = (range_end >> PAGE_SHIFT) - 1;
+                       bool crosses_boundary = start > range_start || end < 
range_end;
+
+                       if (svm_range->gpu_mapped) {
+                               AMDGPU_SVM_RANGE_DEBUG(svm_range, 
crosses_boundary ? "ATTR DESTROY" :
+                                                                               
"ATTR ZAP PTE");
+
+                               flags = memalloc_noreclaim_save();
+                               ret = amdgpu_vm_update_range(svm->adev, 
svm->vm, false, true, true,
+                                                                       false, 
NULL, rs, rl, 0, 0, 0, NULL, NULL, &fence);
+                               memalloc_noreclaim_restore(flags);
+
+                               if (!ret && fence) {
+                                       dma_fence_wait(fence, false);
+                                       dma_fence_put(fence);
+                                       fence = NULL;
+                               }
+
+                               if (ret) {
+                                       AMDGPU_SVM_TRACE(
+                                               "attr invalidate PTE clear 
failed: ret=%d [0x%lx-0x%lx]\n",
+                                               ret, rs, rl);
+                                       drm_exec_fini(&exec);
+                                       return ret;
+                               }
+                               needs_flush = true;
+                       }
+
+                       if (crosses_boundary) {
+                               /* remove the ranges crosses boundary to let 
GPU fault create new ranges
+                                * bounded by the updated attr_range boundaries.
+                                */
+                               amdgpu_svm_range_remove(svm, svm_range, &ctx);
+                       } else {
+                               range_invalidate_gpu_mapping(svm_range);
+                       }
+               }
+       }
+
+       drm_exec_fini(&exec);
+
+       if (needs_flush)
+               svm->flush_tlb(svm);
+
+       AMDGPU_SVM_TRACE("attr invalidate done [0x%lx-0x%lx]-0x%lx 
needs_flush=%d\n",
+                        start_page, last_page, last_page - start_page + 1,
+                        needs_flush ? 1 : 0);
+
+       return 0;
+}
+
+bool
+amdgpu_svm_range_dequeue_locked(struct amdgpu_svm *svm,
+                                       struct list_head *work_list,
+                                       struct amdgpu_svm_range_op_ctx *op_ctx)
+{
+       struct amdgpu_svm_range *range;
+
+       lockdep_assert_held(&svm->work_lock);
+
+       range = list_first_entry_or_null(work_list, struct amdgpu_svm_range,
+                                       work_node);
+       if (!range)
+               return false;
+
+       list_del_init(&range->work_node);
+
+       op_ctx->range = range;
+       op_ctx->start_page = range->pending_start_page;
+       op_ctx->last_page = range->pending_last_page;
+       op_ctx->pending_ops = range->pending_ops;
+
+       range->pending_start_page = ULONG_MAX;
+       range->pending_last_page = 0;
+       range->pending_ops = AMDGPU_SVM_RANGE_OP_NONE;
+
+       return true;
+}
+
+static bool
+range_try_dequeue(struct amdgpu_svm_range *range)
+{
+       if (!range->in_queue)
+               return false;
+
+       if (range->pending_ops != AMDGPU_SVM_RANGE_OP_NONE)
+               return false;
+
+       range->in_queue = false;
+       return true;
+}
+
+void
+amdgpu_svm_range_put_if_dequeued(struct amdgpu_svm *svm,
+                                    struct amdgpu_svm_range *range)
+{
+       bool dequeue;
+
+       spin_lock(&svm->work_lock);
+       dequeue = range_try_dequeue(range);
+       spin_unlock(&svm->work_lock);
+
+       if (dequeue)
+               drm_gpusvm_range_put(&range->base);
+}
-- 
2.34.1

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