drm/xe: Add Xe SVM devmem_release GPU SVM vfunc

Implement with a simple BO put which releases the device memory.

v2:
 - Use new drm_gpusvm_devmem_ops
v3:
 - Better commit message (Thomas)
v4:
 - Use xe_bo_put_async (Thomas)

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250306012657.3505757-27-matthew.brost@intel.com

drivers/gpu/drm/xe/xe_svm.c

@@ -3,6 +3,7 @@
  * Copyright © 2024 Intel Corporation
  */
 
+#include "xe_bo.h"
 #include "xe_gt_tlb_invalidation.h"
 #include "xe_migrate.h"
 #include "xe_pt.h"
@@ -467,6 +468,13 @@ static struct xe_bo *to_xe_bo(struct drm_gpusvm_devmem *devmem_allocation)
 	return container_of(devmem_allocation, struct xe_bo, devmem_allocation);
 }
 
+static void xe_svm_devmem_release(struct drm_gpusvm_devmem *devmem_allocation)
+{
+	struct xe_bo *bo = to_xe_bo(devmem_allocation);
+
+	xe_bo_put_async(bo);
+}
+
 static u64 block_offset_to_pfn(struct xe_vram_region *vr, u64 offset)
 {
 	return PHYS_PFN(offset + vr->hpa_base);
@@ -502,6 +510,7 @@ static int xe_svm_populate_devmem_pfn(struct drm_gpusvm_devmem *devmem_allocatio
 
 __maybe_unused
 static const struct drm_gpusvm_devmem_ops gpusvm_devmem_ops = {
+	.devmem_release = xe_svm_devmem_release,
 	.populate_devmem_pfn = xe_svm_populate_devmem_pfn,
 	.copy_to_devmem = xe_svm_copy_to_devmem,
 	.copy_to_ram = xe_svm_copy_to_ram,