[v2 13/31] drm/xe/svm: Introduce DRM_XE_SVM kernel config

[Oak Zeng <oak.zeng@intel.com>]

Introduce a DRM_XE_SVM kernel config entry for
xe svm feature. xe svm feature allows share
virtual address space between CPU and GPU program.

v1: Improve commit message (Thomas)
    Avoid using #if directive (Thomas)

Signed-off-by: Oak Zeng <oak.zeng@intel.com>
Co-developed-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@intel.com>
Cc: Brian Welty <brian.welty@intel.com>
---
 drivers/gpu/drm/xe/Kconfig   | 21 +++++++++++++++++++++
 drivers/gpu/drm/xe/xe_tile.c |  7 +++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/Kconfig b/drivers/gpu/drm/xe/Kconfig
index 449a1ecbc92a..0accb2cb81d6 100644
--- a/drivers/gpu/drm/xe/Kconfig
+++ b/drivers/gpu/drm/xe/Kconfig
@@ -84,6 +84,27 @@ config DRM_XE_FORCE_PROBE
 	  4571.
 
 	  Use "!*" to block the probe of the driver for all known devices.
+config DRM_XE_SVM
+	bool "Enable Shared Virtual Memory support in xe"
+	depends on DRM_XE
+	depends on ARCH_ENABLE_MEMORY_HOTPLUG
+	depends on ARCH_ENABLE_MEMORY_HOTREMOVE
+	depends on MEMORY_HOTPLUG
+	depends on MEMORY_HOTREMOVE
+	depends on ARCH_HAS_PTE_DEVMAP
+	depends on SPARSEMEM_VMEMMAP
+	depends on ZONE_DEVICE
+	depends on DEVICE_PRIVATE
+	depends on MMU
+	select HMM_MIRROR
+	select MMU_NOTIFIER
+	default y
+	help
+	  Choose this option if you want Shared Virtual Memory (SVM)
+	  support in xe. With SVM, virtual address space is shared
+	  between CPU and GPU. This means any virtual address such
+	  as malloc or mmap returns, variables on stack, or global
+	  memory pointers, can be used for GPU transparently.
 
 menu "drm/Xe Debugging"
 depends on DRM_XE
diff --git a/drivers/gpu/drm/xe/xe_tile.c b/drivers/gpu/drm/xe/xe_tile.c
index f1c4f9de51df..a1a436912fe3 100644
--- a/drivers/gpu/drm/xe/xe_tile.c
+++ b/drivers/gpu/drm/xe/xe_tile.c
@@ -159,9 +159,12 @@ static int tile_ttm_mgr_init(struct xe_tile *tile)
  */
 int xe_tile_init_noalloc(struct xe_tile *tile)
 {
-	struct xe_device *xe = tile_to_xe(tile);
+	struct xe_device __maybe_unused *xe;
 	int err;
 
+	if (IS_ENABLED(CONFIG_DRM_XE_SVM))
+		xe = tile_to_xe(tile);
+
 	xe_device_mem_access_get(tile_to_xe(tile));
 
 	err = tile_ttm_mgr_init(tile);
@@ -177,7 +180,7 @@ int xe_tile_init_noalloc(struct xe_tile *tile)
 
 	xe_tile_sysfs_init(tile);
 
-	if (xe->info.has_usm)
+	if (IS_ENABLED(CONFIG_DRM_XE_SVM) && xe->info.has_usm)
 		xe_devm_add(tile, &tile->mem.vram);
 err_mem_access:
 	xe_device_mem_access_put(tile_to_xe(tile));
-- 
2.26.3