drm/xe/svm: Implement prefetch support for SVM ranges

This commit adds prefetch support for SVM ranges, utilizing the
existing ioctl vm_bind functionality to achieve this.

v2: rebase

v3:
   - use xa_for_each() instead of manual loop
   - check range is valid and in preferred location before adding to
     xarray
   - Fix naming conventions
   - Fix return condition as -ENODATA instead of -EAGAIN (Matthew Brost)
   - Handle sparsely populated cpu vma range (Matthew Brost)

v4:
   - fix end address to find next cpu vma in case of -ENOENT

v5:
   - Move find next vma logic to drm gpusvm layer
   - Avoid mixing declaration and logic

v6:
  - Use new function names
  - Move eviction logic to prefetch_ranges

v7:
  - devmem_only assigned 0
  - nit address

v8:
  - initialize ctx with 0

Cc: Matthew Brost <matthew.brost@intel.com>
Acked-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250513040228.470682-15-himal.prasad.ghimiray@intel.com
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>

1 files changed, 45 insertions, 13 deletions

diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
index 4d248d06bfa5..c9c41fbe125c 100644
--- a/drivers/gpu/drm/xe/xe_pt.c
+++ b/drivers/gpu/drm/xe/xe_pt.c
@@ -1458,6 +1458,7 @@ 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;
+	unsigned long i;
 	int err;
 
 	err = xe_pt_pre_commit(pt_update);
@@ -1467,20 +1468,35 @@ static int xe_pt_svm_pre_commit(struct xe_migrate_pt_update *pt_update)
 	xe_svm_notifier_lock(vm);
 
 	list_for_each_entry(op, &vops->list, link) {
-		struct xe_svm_range *range = op->map_range.range;
+		struct xe_svm_range *range = NULL;
 
 		if (op->subop == XE_VMA_SUBOP_UNMAP_RANGE)
 			continue;
 
-		xe_svm_range_debug(range, "PRE-COMMIT");
+		if (op->base.op == DRM_GPUVA_OP_PREFETCH) {
+			xe_assert(vm->xe,
+				  xe_vma_is_cpu_addr_mirror(gpuva_to_vma(op->base.prefetch.va)));
+			xa_for_each(&op->prefetch_range.range, i, range) {
+				xe_svm_range_debug(range, "PRE-COMMIT");
 
-		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_range_debug(range, "PRE-COMMIT - RETRY");
+					xe_svm_notifier_unlock(vm);
+					return -ENODATA;
+				}
+			}
+		} else {
+			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);
+			range = op->map_range.range;
 
-		if (!xe_svm_range_pages_valid(range)) {
-			xe_svm_range_debug(range, "PRE-COMMIT - RETRY");
-			xe_svm_notifier_unlock(vm);
-			return -EAGAIN;
+			xe_svm_range_debug(range, "PRE-COMMIT");
+
+			if (!xe_svm_range_pages_valid(range)) {
+				xe_svm_range_debug(range, "PRE-COMMIT - RETRY");
+				xe_svm_notifier_unlock(vm);
+				return -EAGAIN;
+			}
 		}
 	}
 
@@ -2065,11 +2081,20 @@ static int op_prepare(struct xe_vm *vm,
 	{
 		struct xe_vma *vma = gpuva_to_vma(op->base.prefetch.va);
 
-		if (xe_vma_is_cpu_addr_mirror(vma))
-			break;
+		if (xe_vma_is_cpu_addr_mirror(vma)) {
+			struct xe_svm_range *range;
+			unsigned long i;
 
-		err = bind_op_prepare(vm, tile, pt_update_ops, vma, false);
-		pt_update_ops->wait_vm_kernel = true;
+			xa_for_each(&op->prefetch_range.range, i, range) {
+				err = bind_range_prepare(vm, tile, pt_update_ops,
+							 vma, range);
+				if (err)
+					return err;
+			}
+		} else {
+			err = bind_op_prepare(vm, tile, pt_update_ops, vma, false);
+			pt_update_ops->wait_vm_kernel = true;
+		}
 		break;
 	}
 	case DRM_GPUVA_OP_DRIVER:
@@ -2275,9 +2300,16 @@ static void op_commit(struct xe_vm *vm,
 	{
 		struct xe_vma *vma = gpuva_to_vma(op->base.prefetch.va);
 
-		if (!xe_vma_is_cpu_addr_mirror(vma))
+		if (xe_vma_is_cpu_addr_mirror(vma)) {
+			struct xe_svm_range *range = NULL;
+			unsigned long i;
+
+			xa_for_each(&op->prefetch_range.range, i, range)
+				range_present_and_invalidated_tile(vm, range, tile->id);
+		} else {
 			bind_op_commit(vm, tile, pt_update_ops, vma, fence,
 				       fence2, false);
+		}
 		break;
 	}
 	case DRM_GPUVA_OP_DRIVER: