[RFC PATCH 17/28] drm/xe: Add SVM device memory mirroring

[Matthew Brost]

Add SVM device memory mirroring which enables device pages for
migration.

TODO: Hide this behind Kconfig

Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com
Signed-off-by: Oak Zeng <oak.zeng at intel.com>
Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_device_types.h |  8 ++++
 drivers/gpu/drm/xe/xe_svm.c          | 56 +++++++++++++++++++++++++++-
 drivers/gpu/drm/xe/xe_svm.h          |  3 ++
 drivers/gpu/drm/xe/xe_tile.c         |  5 +++
 4 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 4ecd620921a3..b4367efae55b 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -105,6 +105,14 @@ struct xe_mem_region {
 	resource_size_t actual_physical_size;
 	/** @mapping: pointer to VRAM mappable space */
 	void __iomem *mapping;
+	/** @pagemap: Used to remap device memory as ZONE_DEVICE */
+	struct dev_pagemap pagemap;
+	/**
+	 * @hpa_base: base host physical address
+	 *
+	 * This is generated when remap device memory as ZONE_DEVICE
+	 */
+	resource_size_t hpa_base;
 };
 
 /**
diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index 2339359a1d91..258a94e83e57 100644
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -21,6 +21,11 @@ static struct xe_vm *range_to_vm(struct drm_gpusvm_range *r)
 	return gpusvm_to_vm(r->gpusvm);
 }
 
+static void *xe_svm_devm_owner(struct xe_device *xe)
+{
+	return xe;
+}
+
 static struct drm_gpusvm_range *
 xe_svm_range_alloc(struct drm_gpusvm *gpusvm)
 {
@@ -285,8 +290,9 @@ int xe_svm_init(struct xe_vm *vm)
 		  xe_svm_garbage_collector_work_func);
 
 	return drm_gpusvm_init(&vm->svm.gpusvm, "Xe SVM", &vm->xe->drm,
-			       current->mm, NULL, 0, vm->size,
-			       SZ_512M, &gpusvm_ops, fault_chunk_sizes,
+			       current->mm, xe_svm_devm_owner(vm->xe), 0,
+			       vm->size, SZ_512M, &gpusvm_ops,
+			       fault_chunk_sizes,
 			       ARRAY_SIZE(fault_chunk_sizes));
 }
 
@@ -371,3 +377,49 @@ bool xe_svm_has_mapping(struct xe_vm *vm, u64 start, u64 end)
 {
 	return drm_gpusvm_has_mapping(&vm->svm.gpusvm, start, end);
 }
+
+/**
+ * xe_devm_add: Remap and provide memmap backing for device memory
+ * @tile: tile that the memory region belongs to
+ * @mr: memory region to remap
+ *
+ * This remap device memory to host physical address space and create
+ * struct page to back device memory
+ *
+ * Return: 0 on success standard error code otherwise
+ */
+int xe_devm_add(struct xe_tile *tile, struct xe_mem_region *mr)
+{
+	struct xe_device *xe = tile_to_xe(tile);
+	struct device *dev = &to_pci_dev(xe->drm.dev)->dev;
+	struct resource *res;
+	void *addr;
+	int ret;
+
+	res = devm_request_free_mem_region(dev, &iomem_resource,
+					   mr->usable_size);
+	if (IS_ERR(res)) {
+		ret = PTR_ERR(res);
+		return ret;
+	}
+
+	mr->pagemap.type = MEMORY_DEVICE_PRIVATE;
+	mr->pagemap.range.start = res->start;
+	mr->pagemap.range.end = res->end;
+	mr->pagemap.nr_range = 1;
+	mr->pagemap.ops = drm_gpusvm_pagemap_ops_get();
+	mr->pagemap.owner = xe_svm_devm_owner(xe);
+	addr = devm_memremap_pages(dev, &mr->pagemap);
+	if (IS_ERR(addr)) {
+		devm_release_mem_region(dev, res->start, resource_size(res));
+		ret = PTR_ERR(addr);
+		drm_err(&xe->drm, "Failed to remap tile %d memory, errno %d\n",
+				tile->id, ret);
+		return ret;
+	}
+	mr->hpa_base = res->start;
+
+	drm_info(&xe->drm, "Added tile %d memory [%llx-%llx] to devm, remapped to %pr\n",
+		 tile->id, mr->io_start, mr->io_start + mr->usable_size, res);
+	return 0;
+}
diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
index a4f764bcd835..f15df5c813f1 100644
--- a/drivers/gpu/drm/xe/xe_svm.h
+++ b/drivers/gpu/drm/xe/xe_svm.h
@@ -8,6 +8,7 @@
 
 #include "drm_gpusvm.h"
 
+struct xe_mem_region;
 struct xe_tile;
 struct xe_vm;
 struct xe_vma;
@@ -19,6 +20,8 @@ struct xe_svm_range {
 	u8 tile_invalidated;
 };
 
+int xe_devm_add(struct xe_tile *tile, struct xe_mem_region *mr);
+
 int xe_svm_init(struct xe_vm *vm);
 void xe_svm_fini(struct xe_vm *vm);
 
diff --git a/drivers/gpu/drm/xe/xe_tile.c b/drivers/gpu/drm/xe/xe_tile.c
index 15ea0a942f67..1c1b3d406f1e 100644
--- a/drivers/gpu/drm/xe/xe_tile.c
+++ b/drivers/gpu/drm/xe/xe_tile.c
@@ -10,6 +10,7 @@
 #include "xe_gt.h"
 #include "xe_migrate.h"
 #include "xe_sa.h"
+#include "xe_svm.h"
 #include "xe_tile.h"
 #include "xe_tile_sysfs.h"
 #include "xe_ttm_vram_mgr.h"
@@ -158,6 +159,7 @@ 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);
 	int err;
 
 	err = tile_ttm_mgr_init(tile);
@@ -170,6 +172,9 @@ int xe_tile_init_noalloc(struct xe_tile *tile)
 
 	xe_wa_apply_tile_workarounds(tile);
 
+	if (xe->info.has_usm && IS_DGFX(xe))
+		xe_devm_add(tile, &tile->mem.vram);
+
 	err = xe_tile_sysfs_init(tile);
 
 	return 0;
-- 
2.34.1