Merge tag 'drm-rust-next-2025-11-18' of https://gitlab.freedesktop.org/drm/rust/kernel into drm-next

Cross-subsystem Changes:

Rust
  - Make slice::as_flattened usable on all supported versions of rustc.
  - Add FromBytes::from_bytes_prefix() method.

Core Changes:

  - Update Tyr in MAINTAINERS file.
  - Remove redundant device ptr from Rust GEM object.
  - Change how AlwaysRefCounted is implemented for GEM objects.
  - Add deferred vm_bo cleanup to GPUVM and use it in Panthor.

Driver Changes:

Nova Core
  - Introduction of bitfield! macro, with support for different storage sizes
    and custom visibility.
  - Introduction of safe converters between integer types for which the
    conversion is lossless.
  - GSP initialized up to fully booted state on Ampere.
  - Use more future-proof register for GPU identification.
  - Various simplifications and optimizations.

Nova
  - Select NOVA_CORE.
  - Depend on CONFIG_64BIT.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/aRxtJC0D1pQUepF4@google.com

Author: airlied

Documentation/gpu/nova/core/todo.rst

@@ -44,25 +44,6 @@ automatically generates the corresponding mappings between a value and a number.
 | Complexity: Beginner
 | Link: https://docs.rs/num/latest/num/trait.FromPrimitive.html
 
-Conversion from byte slices for types implementing FromBytes [TRSM]
--------------------------------------------------------------------
-
-We retrieve several structures from byte streams coming from the BIOS or loaded
-firmware. At the moment converting the bytes slice into the proper type require
-an inelegant `unsafe` operation; this will go away once `FromBytes` implements
-a proper `from_bytes` method.
-
-| Complexity: Beginner
-
-CoherentAllocation improvements [COHA]
---------------------------------------
-
-`CoherentAllocation` needs a safe way to write into the allocation, and to
-obtain slices within the allocation.
-
-| Complexity: Beginner
-| Contact: Abdiel Janulgue
-
 Generic register abstraction [REGA]
 -----------------------------------
 
@@ -153,17 +134,6 @@ A `num` core kernel module is being designed to provide these operations.
 | Complexity: Intermediate
 | Contact: Alexandre Courbot
 
-Delay / Sleep abstractions [DLAY]
----------------------------------
-
-Rust abstractions for the kernel's delay() and sleep() functions.
-
-FUJITA Tomonori plans to work on abstractions for read_poll_timeout_atomic()
-(and friends) [1].
-
-| Complexity: Beginner
-| Link: https://lore.kernel.org/netdev/20250228.080550.354359820929821928.fujita.tomonori@gmail.com/ [1]
-
 IRQ abstractions
 ----------------
 

MAINTAINERS

@@ -8264,6 +8264,7 @@ S:	Supported
 W:	https://drm.pages.freedesktop.org/maintainer-tools/drm-rust.html
 T:	git https://gitlab.freedesktop.org/drm/rust/kernel.git
 F:	drivers/gpu/drm/nova/
+F:	drivers/gpu/drm/tyr/
 F:	drivers/gpu/nova-core/
 F:	rust/kernel/drm/
 

drivers/gpu/drm/drm_gpuvm.c

@@ -877,6 +877,31 @@ __drm_gpuvm_bo_list_add(struct drm_gpuvm *gpuvm, spinlock_t *lock,
 	cond_spin_unlock(lock, !!lock);
 }
 
+/**
+ * drm_gpuvm_bo_is_zombie() - check whether this vm_bo is scheduled for cleanup
+ * @vm_bo: the &drm_gpuvm_bo
+ *
+ * When a vm_bo is scheduled for cleanup using the bo_defer list, it is not
+ * immediately removed from the evict and extobj lists. Therefore, anyone
+ * iterating these lists should skip entries that are being destroyed.
+ *
+ * Checking the refcount without incrementing it is okay as long as the lock
+ * protecting the evict/extobj list is held for as long as you are using the
+ * vm_bo, because even if the refcount hits zero while you are using it, freeing
+ * the vm_bo requires taking the list's lock.
+ *
+ * Zombie entries can be observed on the evict and extobj lists regardless of
+ * whether DRM_GPUVM_RESV_PROTECTED is used, but they remain on the lists for a
+ * longer time when the resv lock is used because we can't take the resv lock
+ * during run_job() in immediate mode, meaning that they need to remain on the
+ * lists until drm_gpuvm_bo_deferred_cleanup() is called.
+ */
+static bool
+drm_gpuvm_bo_is_zombie(struct drm_gpuvm_bo *vm_bo)
+{
+	return !kref_read(&vm_bo->kref);
+}
+
 /**
  * drm_gpuvm_bo_list_add() - insert a vm_bo into the given list
  * @__vm_bo: the &drm_gpuvm_bo
@@ -1082,6 +1107,8 @@ drm_gpuvm_init(struct drm_gpuvm *gpuvm, const char *name,
 	INIT_LIST_HEAD(&gpuvm->evict.list);
 	spin_lock_init(&gpuvm->evict.lock);
 
+	init_llist_head(&gpuvm->bo_defer);
+
 	kref_init(&gpuvm->kref);
 
 	gpuvm->name = name ? name : "unknown";
@@ -1123,6 +1150,8 @@ drm_gpuvm_fini(struct drm_gpuvm *gpuvm)
 		 "Extobj list should be empty.\n");
 	drm_WARN(gpuvm->drm, !list_empty(&gpuvm->evict.list),
 		 "Evict list should be empty.\n");
+	drm_WARN(gpuvm->drm, !llist_empty(&gpuvm->bo_defer),
+		 "VM BO cleanup list should be empty.\n");
 
 	drm_gem_object_put(gpuvm->r_obj);
 }
@@ -1218,6 +1247,9 @@ drm_gpuvm_prepare_objects_locked(struct drm_gpuvm *gpuvm,
 
 	drm_gpuvm_resv_assert_held(gpuvm);
 	list_for_each_entry(vm_bo, &gpuvm->extobj.list, list.entry.extobj) {
+		if (drm_gpuvm_bo_is_zombie(vm_bo))
+			continue;
+
 		ret = exec_prepare_obj(exec, vm_bo->obj, num_fences);
 		if (ret)
 			break;
@@ -1461,6 +1493,9 @@ drm_gpuvm_validate_locked(struct drm_gpuvm *gpuvm, struct drm_exec *exec)
 
 	list_for_each_entry_safe(vm_bo, next, &gpuvm->evict.list,
 				 list.entry.evict) {
+		if (drm_gpuvm_bo_is_zombie(vm_bo))
+			continue;
+
 		ret = ops->vm_bo_validate(vm_bo, exec);
 		if (ret)
 			break;
@@ -1561,6 +1596,7 @@ drm_gpuvm_bo_create(struct drm_gpuvm *gpuvm,
 
 	INIT_LIST_HEAD(&vm_bo->list.entry.extobj);
 	INIT_LIST_HEAD(&vm_bo->list.entry.evict);
+	init_llist_node(&vm_bo->list.entry.bo_defer);
 
 	return vm_bo;
 }
@@ -1622,6 +1658,126 @@ drm_gpuvm_bo_put(struct drm_gpuvm_bo *vm_bo)
 }
 EXPORT_SYMBOL_GPL(drm_gpuvm_bo_put);
 
+/*
+ * drm_gpuvm_bo_into_zombie() - called when the vm_bo becomes a zombie due to
+ * deferred cleanup
+ *
+ * If deferred cleanup is used, then this must be called right after the vm_bo
+ * refcount drops to zero. Must be called with GEM mutex held. After releasing
+ * the GEM mutex, drm_gpuvm_bo_defer_zombie_cleanup() must be called.
+ */
+static void
+drm_gpuvm_bo_into_zombie(struct kref *kref)
+{
+	struct drm_gpuvm_bo *vm_bo = container_of(kref, struct drm_gpuvm_bo,
+						  kref);
+
+	if (!drm_gpuvm_resv_protected(vm_bo->vm)) {
+		drm_gpuvm_bo_list_del(vm_bo, extobj, true);
+		drm_gpuvm_bo_list_del(vm_bo, evict, true);
+	}
+
+	list_del(&vm_bo->list.entry.gem);
+}
+
+/*
+ * drm_gpuvm_bo_defer_zombie_cleanup() - adds a new zombie vm_bo to the
+ * bo_defer list
+ *
+ * Called after drm_gpuvm_bo_into_zombie(). GEM mutex must not be held.
+ *
+ * It's important that the GEM stays alive for the duration in which we hold
+ * the mutex, but the instant we add the vm_bo to bo_defer, another thread
+ * might call drm_gpuvm_bo_deferred_cleanup() and put the GEM. Therefore, to
+ * avoid kfreeing a mutex we are holding, the GEM mutex must be released
+ * *before* calling this function.
+ */
+static void
+drm_gpuvm_bo_defer_zombie_cleanup(struct drm_gpuvm_bo *vm_bo)
+{
+	llist_add(&vm_bo->list.entry.bo_defer, &vm_bo->vm->bo_defer);
+}
+
+static void
+drm_gpuvm_bo_defer_free(struct kref *kref)
+{
+	struct drm_gpuvm_bo *vm_bo = container_of(kref, struct drm_gpuvm_bo,
+						  kref);
+
+	drm_gpuvm_bo_into_zombie(kref);
+	mutex_unlock(&vm_bo->obj->gpuva.lock);
+	drm_gpuvm_bo_defer_zombie_cleanup(vm_bo);
+}
+
+/**
+ * drm_gpuvm_bo_put_deferred() - drop a struct drm_gpuvm_bo reference with
+ * deferred cleanup
+ * @vm_bo: the &drm_gpuvm_bo to release the reference of
+ *
+ * This releases a reference to @vm_bo.
+ *
+ * This might take and release the GEMs GPUVA lock. You should call
+ * drm_gpuvm_bo_deferred_cleanup() later to complete the cleanup process.
+ *
+ * Returns: true if vm_bo is being destroyed, false otherwise.
+ */
+bool
+drm_gpuvm_bo_put_deferred(struct drm_gpuvm_bo *vm_bo)
+{
+	if (!vm_bo)
+		return false;
+
+	drm_WARN_ON(vm_bo->vm->drm, !drm_gpuvm_immediate_mode(vm_bo->vm));
+
+	return !!kref_put_mutex(&vm_bo->kref,
+				drm_gpuvm_bo_defer_free,
+				&vm_bo->obj->gpuva.lock);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_bo_put_deferred);
+
+/**
+ * drm_gpuvm_bo_deferred_cleanup() - clean up BOs in the deferred list
+ * deferred cleanup
+ * @gpuvm: the VM to clean up
+ *
+ * Cleans up &drm_gpuvm_bo instances in the deferred cleanup list.
+ */
+void
+drm_gpuvm_bo_deferred_cleanup(struct drm_gpuvm *gpuvm)
+{
+	const struct drm_gpuvm_ops *ops = gpuvm->ops;
+	struct drm_gpuvm_bo *vm_bo;
+	struct drm_gem_object *obj;
+	struct llist_node *bo_defer;
+
+	bo_defer = llist_del_all(&gpuvm->bo_defer);
+	if (!bo_defer)
+		return;
+
+	if (drm_gpuvm_resv_protected(gpuvm)) {
+		dma_resv_lock(drm_gpuvm_resv(gpuvm), NULL);
+		llist_for_each_entry(vm_bo, bo_defer, list.entry.bo_defer) {
+			drm_gpuvm_bo_list_del(vm_bo, extobj, false);
+			drm_gpuvm_bo_list_del(vm_bo, evict, false);
+		}
+		dma_resv_unlock(drm_gpuvm_resv(gpuvm));
+	}
+
+	while (bo_defer) {
+		vm_bo = llist_entry(bo_defer, struct drm_gpuvm_bo, list.entry.bo_defer);
+		bo_defer = bo_defer->next;
+		obj = vm_bo->obj;
+		if (ops && ops->vm_bo_free)
+			ops->vm_bo_free(vm_bo);
+		else
+			kfree(vm_bo);
+
+		drm_gpuvm_put(gpuvm);
+		drm_gem_object_put(obj);
+	}
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_bo_deferred_cleanup);
+
 static struct drm_gpuvm_bo *
 __drm_gpuvm_bo_find(struct drm_gpuvm *gpuvm,
 		    struct drm_gem_object *obj)
@@ -1949,6 +2105,40 @@ drm_gpuva_unlink(struct drm_gpuva *va)
 }
 EXPORT_SYMBOL_GPL(drm_gpuva_unlink);
 
+/**
+ * drm_gpuva_unlink_defer() - unlink a &drm_gpuva with deferred vm_bo cleanup
+ * @va: the &drm_gpuva to unlink
+ *
+ * Similar to drm_gpuva_unlink(), but uses drm_gpuvm_bo_put_deferred() and takes
+ * the lock for the caller.
+ */
+void
+drm_gpuva_unlink_defer(struct drm_gpuva *va)
+{
+	struct drm_gem_object *obj = va->gem.obj;
+	struct drm_gpuvm_bo *vm_bo = va->vm_bo;
+	bool should_defer_bo;
+
+	if (unlikely(!obj))
+		return;
+
+	drm_WARN_ON(vm_bo->vm->drm, !drm_gpuvm_immediate_mode(vm_bo->vm));
+
+	mutex_lock(&obj->gpuva.lock);
+	list_del_init(&va->gem.entry);
+
+	/*
+	 * This is drm_gpuvm_bo_put_deferred() except we already hold the mutex.
+	 */
+	should_defer_bo = kref_put(&vm_bo->kref, drm_gpuvm_bo_into_zombie);
+	mutex_unlock(&obj->gpuva.lock);
+	if (should_defer_bo)
+		drm_gpuvm_bo_defer_zombie_cleanup(vm_bo);
+
+	va->vm_bo = NULL;
+}
+EXPORT_SYMBOL_GPL(drm_gpuva_unlink_defer);
+
 /**
  * drm_gpuva_find_first() - find the first &drm_gpuva in the given range
  * @gpuvm: the &drm_gpuvm to search in

drivers/gpu/drm/nova/Kconfig

@@ -1,9 +1,11 @@
 config DRM_NOVA
 	tristate "Nova DRM driver"
+	depends on 64BIT
 	depends on DRM=y
 	depends on PCI
 	depends on RUST
 	select AUXILIARY_BUS
+	select NOVA_CORE
 	default n
 	help
 	  Choose this if you want to build the Nova DRM driver for Nvidia