drm/gpuvm: allow building as module

Currently, the DRM GPUVM does not have any core dependencies preventing
a module build.

Also, new features from subsequent patches require helpers (namely
drm_exec) which can be built as module.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230920144343.64830-3-dakr@redhat.com

drivers/gpu/drm/Kconfig

@@ -216,6 +216,13 @@ config DRM_EXEC
 	help
 	  Execution context for command submissions
 
+config DRM_GPUVM
+	tristate
+	depends on DRM
+	help
+	  GPU-VM representation providing helpers to manage a GPUs virtual
+	  address space
+
 config DRM_BUDDY
 	tristate
 	depends on DRM

drivers/gpu/drm/Makefile

@@ -45,7 +45,6 @@ drm-y := \
 	drm_vblank.o \
 	drm_vblank_work.o \
 	drm_vma_manager.o \
-	drm_gpuvm.o \
 	drm_writeback.o
 drm-$(CONFIG_DRM_LEGACY) += \
 	drm_agpsupport.o \
@@ -81,6 +80,7 @@ obj-$(CONFIG_DRM_PANEL_ORIENTATION_QUIRKS) += drm_panel_orientation_quirks.o
 #
 #
 obj-$(CONFIG_DRM_EXEC) += drm_exec.o
+obj-$(CONFIG_DRM_GPUVM) += drm_gpuvm.o
 
 obj-$(CONFIG_DRM_BUDDY) += drm_buddy.o
 

drivers/gpu/drm/drm_gpuvm.c

@@ -1723,3 +1723,6 @@ drm_gpuva_ops_free(struct drm_gpuvm *gpuvm,
 	kfree(ops);
 }
 EXPORT_SYMBOL_GPL(drm_gpuva_ops_free);
+
+MODULE_DESCRIPTION("DRM GPUVM");
+MODULE_LICENSE("GPL");

drivers/gpu/drm/nouveau/Kconfig

@@ -11,6 +11,7 @@ config DRM_NOUVEAU
 	select DRM_TTM
 	select DRM_TTM_HELPER
 	select DRM_EXEC
+	select DRM_GPUVM
 	select DRM_SCHED
 	select I2C
 	select I2C_ALGOBIT