drm/xe: Add (re)bind to SVM page fault handler

Add (re)bind to SVM page fault handler. To facilitate add support
function to VM layer which (re)binds a SVM range. Also teach PT layer to
understand (re)binds of SVM ranges.

v2:
 - Don't assert BO lock held for range binds
 - Use xe_svm_notifier_lock/unlock helper in xe_svm_close
 - Use drm_pagemap dma cursor
 - Take notifier lock in bind code to check range state
v3:
 - Use new GPU SVM range structure (Thomas)
 - Kernel doc (Thomas)
 - s/DRM_GPUVA_OP_USER/DRM_GPUVA_OP_DRIVER (Thomas)
v5:
 - Kernel doc (Thomas)
v6:
 - Only compile if CONFIG_DRM_GPUSVM selected (CI, Lucas)

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Tested-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250306012657.3505757-15-matthew.brost@intel.com

Author: mbrost05

drivers/gpu/drm/xe/xe_pt.c

@@ -608,6 +608,7 @@ static const struct xe_pt_walk_ops xe_pt_stage_bind_ops = {
  * range.
  * @tile: The tile we're building for.
  * @vma: The vma indicating the address range.
+ * @range: The range indicating the address range.
  * @entries: Storage for the update entries used for connecting the tree to
  * the main tree at commit time.
  * @num_entries: On output contains the number of @entries used.
@@ -623,6 +624,7 @@ static const struct xe_pt_walk_ops xe_pt_stage_bind_ops = {
  */
 static int
 xe_pt_stage_bind(struct xe_tile *tile, struct xe_vma *vma,
+		 struct xe_svm_range *range,
 		 struct xe_vm_pgtable_update *entries, u32 *num_entries)
 {
 	struct xe_device *xe = tile_to_xe(tile);
@@ -640,14 +642,38 @@ xe_pt_stage_bind(struct xe_tile *tile, struct xe_vma *vma,
 		.vm = xe_vma_vm(vma),
 		.tile = tile,
 		.curs = &curs,
-		.va_curs_start = xe_vma_start(vma),
+		.va_curs_start = range ? range->base.itree.start :
+			xe_vma_start(vma),
 		.vma = vma,
 		.wupd.entries = entries,
-		.needs_64K = (xe_vma_vm(vma)->flags & XE_VM_FLAG_64K) && is_devmem,
 	};
 	struct xe_pt *pt = xe_vma_vm(vma)->pt_root[tile->id];
 	int ret;
 
+	if (range) {
+		/* Move this entire thing to xe_svm.c? */
+		xe_svm_notifier_lock(xe_vma_vm(vma));
+		if (!xe_svm_range_pages_valid(range)) {
+			xe_svm_notifier_unlock(xe_vma_vm(vma));
+			return -EAGAIN;
+		}
+		if (xe_svm_range_has_dma_mapping(range)) {
+			xe_res_first_dma(range->base.dma_addr, 0,
+					 range->base.itree.last + 1 - range->base.itree.start,
+					 &curs);
+			is_devmem = xe_res_is_vram(&curs);
+		} else {
+			xe_assert(xe, false);
+		}
+		/*
+		 * Note, when unlocking the resource cursor dma addresses may become
+		 * stale, but the bind will be aborted anyway at commit time.
+		 */
+		xe_svm_notifier_unlock(xe_vma_vm(vma));
+	}
+
+	xe_walk.needs_64K = (xe_vma_vm(vma)->flags & XE_VM_FLAG_64K) && is_devmem;
+
 	/**
 	 * Default atomic expectations for different allocation scenarios are as follows:
 	 *
@@ -669,7 +695,7 @@ xe_pt_stage_bind(struct xe_tile *tile, struct xe_vma *vma,
 			 * gets migrated to LMEM, bind such allocations with
 			 * device atomics enabled.
 			 */
-			else if (is_devmem && !xe_bo_has_single_placement(bo))
+			else if (is_devmem)
 				xe_walk.default_pte |= XE_USM_PPGTT_PTE_AE;
 		} else {
 			xe_walk.default_pte |= XE_USM_PPGTT_PTE_AE;
@@ -685,15 +711,16 @@ xe_pt_stage_bind(struct xe_tile *tile, struct xe_vma *vma,
 
 	if (is_devmem) {
 		xe_walk.default_pte |= XE_PPGTT_PTE_DM;
-		xe_walk.dma_offset = vram_region_gpu_offset(bo->ttm.resource);
+		xe_walk.dma_offset = bo ? vram_region_gpu_offset(bo->ttm.resource) : 0;
 	}
 
 	if (!xe_vma_has_no_bo(vma) && xe_bo_is_stolen(bo))
 		xe_walk.dma_offset = xe_ttm_stolen_gpu_offset(xe_bo_device(bo));
 
-	xe_bo_assert_held(bo);
+	if (!range)
+		xe_bo_assert_held(bo);
 
-	if (!xe_vma_is_null(vma)) {
+	if (!xe_vma_is_null(vma) && !range) {
 		if (xe_vma_is_userptr(vma))
 			xe_res_first_sg(to_userptr_vma(vma)->userptr.sg, 0,
 					xe_vma_size(vma), &curs);
@@ -703,12 +730,14 @@ xe_pt_stage_bind(struct xe_tile *tile, struct xe_vma *vma,
 		else
 			xe_res_first_sg(xe_bo_sg(bo), xe_vma_bo_offset(vma),
 					xe_vma_size(vma), &curs);
-	} else {
+	} else if (!range) {
 		curs.size = xe_vma_size(vma);
 	}
 
-	ret = xe_pt_walk_range(&pt->base, pt->level, xe_vma_start(vma),
-			       xe_vma_end(vma), &xe_walk.base);
+	ret = xe_pt_walk_range(&pt->base, pt->level,
+			       range ? range->base.itree.start : xe_vma_start(vma),
+			       range ? range->base.itree.last + 1 : xe_vma_end(vma),
+			       &xe_walk.base);
 
 	*num_entries = xe_walk.wupd.num_used_entries;
 	return ret;
@@ -941,7 +970,7 @@ static void xe_pt_commit_prepare_locks_assert(struct xe_vma *vma)
 
 	lockdep_assert_held(&vm->lock);
 
-	if (!xe_vma_is_userptr(vma) && !xe_vma_is_null(vma))
+	if (!xe_vma_has_no_bo(vma))
 		dma_resv_assert_held(xe_vma_bo(vma)->ttm.base.resv);
 
 	xe_vm_assert_held(vm);
@@ -1057,12 +1086,13 @@ static void xe_pt_free_bind(struct xe_vm_pgtable_update *entries,
 
 static int
 xe_pt_prepare_bind(struct xe_tile *tile, struct xe_vma *vma,
+		   struct xe_svm_range *range,
 		   struct xe_vm_pgtable_update *entries, u32 *num_entries)
 {
 	int err;
 
 	*num_entries = 0;
-	err = xe_pt_stage_bind(tile, vma, entries, num_entries);
+	err = xe_pt_stage_bind(tile, vma, range, entries, num_entries);
 	if (!err)
 		xe_tile_assert(tile, *num_entries);
 
@@ -1168,6 +1198,8 @@ static int op_add_deps(struct xe_vm *vm, struct xe_vma_op *op,
 	case DRM_GPUVA_OP_PREFETCH:
 		err = vma_add_deps(gpuva_to_vma(op->base.prefetch.va), job);
 		break;
+	case DRM_GPUVA_OP_DRIVER:
+		break;
 	default:
 		drm_warn(&vm->xe->drm, "NOT POSSIBLE");
 	}
@@ -1372,6 +1404,34 @@ static int xe_pt_userptr_pre_commit(struct xe_migrate_pt_update *pt_update)
 	return err;
 }
 
+static int xe_pt_svm_pre_commit(struct xe_migrate_pt_update *pt_update)
+{
+	struct xe_vm *vm = pt_update->vops->vm;
+	struct xe_vma_ops *vops = pt_update->vops;
+	struct xe_vma_op *op;
+	int err;
+
+	err = xe_pt_pre_commit(pt_update);
+	if (err)
+		return err;
+
+	xe_svm_notifier_lock(vm);
+
+	list_for_each_entry(op, &vops->list, link) {
+		struct xe_svm_range *range = op->map_range.range;
+
+		xe_assert(vm->xe, xe_vma_is_cpu_addr_mirror(op->map_range.vma));
+		xe_assert(vm->xe, op->subop == XE_VMA_SUBOP_MAP_RANGE);
+
+		if (!xe_svm_range_pages_valid(range)) {
+			xe_svm_notifier_unlock(vm);
+			return -EAGAIN;
+		}
+	}
+
+	return 0;
+}
+
 struct invalidation_fence {
 	struct xe_gt_tlb_invalidation_fence base;
 	struct xe_gt *gt;
@@ -1665,12 +1725,12 @@ xe_pt_commit_prepare_unbind(struct xe_vma *vma,
 
 static void
 xe_pt_update_ops_rfence_interval(struct xe_vm_pgtable_update_ops *pt_update_ops,
-				 struct xe_vma *vma)
+				 u64 start, u64 end)
 {
+	u64 last;
 	u32 current_op = pt_update_ops->current_op;
 	struct xe_vm_pgtable_update_op *pt_op = &pt_update_ops->ops[current_op];
 	int i, level = 0;
-	u64 start, last;
 
 	for (i = 0; i < pt_op->num_entries; i++) {
 		const struct xe_vm_pgtable_update *entry = &pt_op->entries[i];
@@ -1680,8 +1740,8 @@ xe_pt_update_ops_rfence_interval(struct xe_vm_pgtable_update_ops *pt_update_ops,
 	}
 
 	/* Greedy (non-optimal) calculation but simple */
-	start = ALIGN_DOWN(xe_vma_start(vma), 0x1ull << xe_pt_shift(level));
-	last = ALIGN(xe_vma_end(vma), 0x1ull << xe_pt_shift(level)) - 1;
+	start = ALIGN_DOWN(start, 0x1ull << xe_pt_shift(level));
+	last = ALIGN(end, 0x1ull << xe_pt_shift(level)) - 1;
 
 	if (start < pt_update_ops->start)
 		pt_update_ops->start = start;
@@ -1723,15 +1783,17 @@ static int bind_op_prepare(struct xe_vm *vm, struct xe_tile *tile,
 	if (err)
 		return err;
 
-	err = xe_pt_prepare_bind(tile, vma, pt_op->entries,
+	err = xe_pt_prepare_bind(tile, vma, NULL, pt_op->entries,
 				 &pt_op->num_entries);
 	if (!err) {
 		xe_tile_assert(tile, pt_op->num_entries <=
 			       ARRAY_SIZE(pt_op->entries));
 		xe_vm_dbg_print_entries(tile_to_xe(tile), pt_op->entries,
 					pt_op->num_entries, true);
 
-		xe_pt_update_ops_rfence_interval(pt_update_ops, vma);
+		xe_pt_update_ops_rfence_interval(pt_update_ops,
+						 xe_vma_start(vma),
+						 xe_vma_end(vma));
 		++pt_update_ops->current_op;
 		pt_update_ops->needs_userptr_lock |= xe_vma_is_userptr(vma);
 
@@ -1765,6 +1827,48 @@ static int bind_op_prepare(struct xe_vm *vm, struct xe_tile *tile,
 	return err;
 }
 
+static int bind_range_prepare(struct xe_vm *vm, struct xe_tile *tile,
+			      struct xe_vm_pgtable_update_ops *pt_update_ops,
+			      struct xe_vma *vma, struct xe_svm_range *range)
+{
+	u32 current_op = pt_update_ops->current_op;
+	struct xe_vm_pgtable_update_op *pt_op = &pt_update_ops->ops[current_op];
+	int err;
+
+	xe_tile_assert(tile, xe_vma_is_cpu_addr_mirror(vma));
+
+	vm_dbg(&xe_vma_vm(vma)->xe->drm,
+	       "Preparing bind, with range [%lx...%lx)\n",
+	       range->base.itree.start, range->base.itree.last);
+
+	pt_op->vma = NULL;
+	pt_op->bind = true;
+	pt_op->rebind = BIT(tile->id) & range->tile_present;
+
+	err = xe_pt_prepare_bind(tile, vma, range, pt_op->entries,
+				 &pt_op->num_entries);
+	if (!err) {
+		xe_tile_assert(tile, pt_op->num_entries <=
+			       ARRAY_SIZE(pt_op->entries));
+		xe_vm_dbg_print_entries(tile_to_xe(tile), pt_op->entries,
+					pt_op->num_entries, true);
+
+		xe_pt_update_ops_rfence_interval(pt_update_ops,
+						 range->base.itree.start,
+						 range->base.itree.last + 1);
+		++pt_update_ops->current_op;
+		pt_update_ops->needs_svm_lock = true;
+
+		pt_op->vma = vma;
+		xe_pt_commit_prepare_bind(vma, pt_op->entries,
+					  pt_op->num_entries, pt_op->rebind);
+	} else {
+		xe_pt_cancel_bind(vma, pt_op->entries, pt_op->num_entries);
+	}
+
+	return err;
+}
+
 static int unbind_op_prepare(struct xe_tile *tile,
 			     struct xe_vm_pgtable_update_ops *pt_update_ops,
 			     struct xe_vma *vma)
@@ -1802,7 +1906,8 @@ static int unbind_op_prepare(struct xe_tile *tile,
 
 	xe_vm_dbg_print_entries(tile_to_xe(tile), pt_op->entries,
 				pt_op->num_entries, false);
-	xe_pt_update_ops_rfence_interval(pt_update_ops, vma);
+	xe_pt_update_ops_rfence_interval(pt_update_ops, xe_vma_start(vma),
+					 xe_vma_end(vma));
 	++pt_update_ops->current_op;
 	pt_update_ops->needs_userptr_lock |= xe_vma_is_userptr(vma);
 	pt_update_ops->needs_invalidation = true;
@@ -1872,6 +1977,15 @@ static int op_prepare(struct xe_vm *vm,
 		pt_update_ops->wait_vm_kernel = true;
 		break;
 	}
+	case DRM_GPUVA_OP_DRIVER:
+		if (op->subop == XE_VMA_SUBOP_MAP_RANGE) {
+			xe_assert(vm->xe, xe_vma_is_cpu_addr_mirror(op->map_range.vma));
+
+			err = bind_range_prepare(vm, tile, pt_update_ops,
+						 op->map_range.vma,
+						 op->map_range.range);
+		}
+		break;
 	default:
 		drm_warn(&vm->xe->drm, "NOT POSSIBLE");
 	}
@@ -2054,6 +2168,14 @@ static void op_commit(struct xe_vm *vm,
 				       fence2);
 		break;
 	}
+	case DRM_GPUVA_OP_DRIVER:
+	{
+		if (op->subop == XE_VMA_SUBOP_MAP_RANGE) {
+			op->map_range.range->tile_present |= BIT(tile->id);
+			op->map_range.range->tile_invalidated &= ~BIT(tile->id);
+		}
+		break;
+	}
 	default:
 		drm_warn(&vm->xe->drm, "NOT POSSIBLE");
 	}
@@ -2071,6 +2193,12 @@ static const struct xe_migrate_pt_update_ops userptr_migrate_ops = {
 	.pre_commit = xe_pt_userptr_pre_commit,
 };
 
+static const struct xe_migrate_pt_update_ops svm_migrate_ops = {
+	.populate = xe_vm_populate_pgtable,
+	.clear = xe_migrate_clear_pgtable_callback,
+	.pre_commit = xe_pt_svm_pre_commit,
+};
+
 /**
  * xe_pt_update_ops_run() - Run PT update operations
  * @tile: Tile of PT update operations
@@ -2096,7 +2224,9 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
 	struct xe_vma_op *op;
 	int err = 0, i;
 	struct xe_migrate_pt_update update = {
-		.ops = pt_update_ops->needs_userptr_lock ?
+		.ops = pt_update_ops->needs_svm_lock ?
+			&svm_migrate_ops :
+			pt_update_ops->needs_userptr_lock ?
 			&userptr_migrate_ops :
 			&migrate_ops,
 		.vops = vops,
@@ -2217,6 +2347,8 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
 				  &ifence->base.base, &mfence->base.base);
 	}
 
+	if (pt_update_ops->needs_svm_lock)
+		xe_svm_notifier_unlock(vm);
 	if (pt_update_ops->needs_userptr_lock)
 		up_read(&vm->userptr.notifier_lock);
 

drivers/gpu/drm/xe/xe_pt_types.h

@@ -104,6 +104,8 @@ struct xe_vm_pgtable_update_ops {
 	u32 num_ops;
 	/** @current_op: current operations */
 	u32 current_op;
+	/** @needs_svm_lock: Needs SVM lock */
+	bool needs_svm_lock;
 	/** @needs_userptr_lock: Needs userptr lock */
 	bool needs_userptr_lock;
 	/** @needs_invalidation: Needs invalidation */