drm/xe: Add always_migrate_to_vram modparam

Used to show we can bounce memory multiple times which will happen once
a real migration policy is implemented. Can be removed once migration
policy is implemented.

v3:
 - Pull some changes into the previous patch (Thomas)
 - Better commit message (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/20250306012657.3505757-32-matthew.brost@intel.com

drivers/gpu/drm/xe/xe_module.c

@@ -29,6 +29,9 @@ struct xe_modparam xe_modparam = {
 module_param_named(svm_notifier_size, xe_modparam.svm_notifier_size, uint, 0600);
 MODULE_PARM_DESC(svm_notifier_size, "Set the svm notifier size(in MiB), must be power of 2");
 
+module_param_named(always_migrate_to_vram, xe_modparam.always_migrate_to_vram, bool, 0444);
+MODULE_PARM_DESC(always_migrate_to_vram, "Always migrate to VRAM on GPU fault");
+
 module_param_named_unsafe(force_execlist, xe_modparam.force_execlist, bool, 0444);
 MODULE_PARM_DESC(force_execlist, "Force Execlist submission");
 

drivers/gpu/drm/xe/xe_module.h

@@ -12,6 +12,7 @@
 struct xe_modparam {
 	bool force_execlist;
 	bool probe_display;
+	bool always_migrate_to_vram;
 	u32 force_vram_bar_size;
 	int guc_log_level;
 	char *guc_firmware_path;

drivers/gpu/drm/xe/xe_svm.c

@@ -822,6 +822,9 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
 	}
 	drm_exec_fini(&exec);
 
+	if (xe_modparam.always_migrate_to_vram)
+		range->skip_migrate = false;
+
 	dma_fence_wait(fence, false);
 	dma_fence_put(fence);