drm/amdkfd: Optimize svm range map to GPU with XNACK on

With XNACK on if svm_range_set_attr set the range access or
access_in_place attribute, we don't call svm_range_validate_and_map to
update GPU mapping. This avoids prefaulting the range pages on system
memory if the range is not prefetch to VRAM and not mapped to GPUs.
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdkfd/kfd_svm.c

@@ -735,7 +735,9 @@ svm_range_apply_attrs(struct kfd_process *p, struct svm_range *prange,
 		case KFD_IOCTL_SVM_ATTR_ACCESS:
 		case KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE:
 		case KFD_IOCTL_SVM_ATTR_NO_ACCESS:
-			*update_mapping = true;
+			if (!p->xnack_enabled)
+				*update_mapping = true;
+
 			gpuidx = kfd_process_gpuidx_from_gpuid(p,
 							       attrs[i].value);
 			if (attrs[i].type == KFD_IOCTL_SVM_ATTR_NO_ACCESS) {