Re: [PATCH drm-misc-next v6 3/6] drm/gpuvm: add an abstraction for a VM / BO combination
From: Thomas Hellström
Date: Tue Oct 17 2023 - 06:55:36 EST
Hi,
On 10/17/23 11:58, Danilo Krummrich wrote:
On Fri, Oct 13, 2023 at 02:30:29PM +0200, Thomas Hellström wrote:
On Mon, 2023-10-09 at 01:32 +0200, Danilo Krummrich wrote:
Add an abstraction layer between the drm_gpuva mappings of a
particular
drm_gem_object and this GEM object itself. The abstraction represents
a
combination of a drm_gem_object and drm_gpuvm. The drm_gem_object
holds
a list of drm_gpuvm_bo structures (the structure representing this
abstraction), while each drm_gpuvm_bo contains list of mappings of
this
GEM object.
This has multiple advantages:
1) We can use the drm_gpuvm_bo structure to attach it to various
lists
of the drm_gpuvm. This is useful for tracking external and evicted
objects per VM, which is introduced in subsequent patches.
2) Finding mappings of a certain drm_gem_object mapped in a certain
drm_gpuvm becomes much cheaper.
3) Drivers can derive and extend the structure to easily represent
driver specific states of a BO for a certain GPUVM.
The idea of this abstraction was taken from amdgpu, hence the credit
for
this idea goes to the developers of amdgpu.
Cc: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
---
drivers/gpu/drm/drm_gpuvm.c | 332 +++++++++++++++++++++--
--
drivers/gpu/drm/nouveau/nouveau_uvmm.c | 64 +++--
include/drm/drm_gem.h | 32 +--
include/drm/drm_gpuvm.h | 177 ++++++++++++-
4 files changed, 521 insertions(+), 84 deletions(-)
diff --git a/drivers/gpu/drm/drm_gpuvm.c
b/drivers/gpu/drm/drm_gpuvm.c
index 6368dfdbe9dd..28282283ddaf 100644
--- a/drivers/gpu/drm/drm_gpuvm.c
+++ b/drivers/gpu/drm/drm_gpuvm.c
@@ -70,6 +70,18 @@
* &drm_gem_object, such as the &drm_gem_object containing the root
page table,
* but it can also be a 'dummy' object, which can be allocated with
* drm_gpuvm_root_object_alloc().
+ *
+ * In order to connect a struct drm_gpuva its backing
&drm_gem_object each
NIT: Same as previous patch regarding kerneldoc references
I was intentionally using generic references here to make the documentation
more readable while still keeping references to be able to look up the
structure's fields.
+ * &drm_gem_object maintains a list of &drm_gpuvm_bo structures, and
each
+ * &drm_gpuvm_bo contains a list of &&drm_gpuva structures.
+ *
+ * A &drm_gpuvm_bo is an abstraction that represents a combination
of a
+ * &drm_gpuvm and a &drm_gem_object. Every such combination should
be unique.
+ * This is ensured by the API through drm_gpuvm_bo_obtain() and
+ * drm_gpuvm_bo_obtain_prealloc() which first look into the
corresponding
+ * &drm_gem_object list of &drm_gpuvm_bos for an existing instance
of this
+ * particular combination. If not existent a new instance is created
and linked
+ * to the &drm_gem_object.
*/
/**
@@ -395,21 +407,28 @@
/**
* DOC: Locking
*
- * Generally, the GPU VA manager does not take care of locking
itself, it is
- * the drivers responsibility to take care about locking. Drivers
might want to
- * protect the following operations: inserting, removing and
iterating
- * &drm_gpuva objects as well as generating all kinds of operations,
such as
- * split / merge or prefetch.
- *
- * The GPU VA manager also does not take care of the locking of the
backing
- * &drm_gem_object buffers GPU VA lists by itself; drivers are
responsible to
- * enforce mutual exclusion using either the GEMs dma_resv lock or
alternatively
- * a driver specific external lock. For the latter see also
- * drm_gem_gpuva_set_lock().
- *
- * However, the GPU VA manager contains lockdep checks to ensure
callers of its
- * API hold the corresponding lock whenever the &drm_gem_objects GPU
VA list is
- * accessed by functions such as drm_gpuva_link() or
drm_gpuva_unlink().
+ * In terms of managing &drm_gpuva entries DRM GPUVM does not take
care of
+ * locking itself, it is the drivers responsibility to take care
about locking.
+ * Drivers might want to protect the following operations:
inserting, removing
+ * and iterating &drm_gpuva objects as well as generating all kinds
of
+ * operations, such as split / merge or prefetch.
+ *
+ * DRM GPUVM also does not take care of the locking of the backing
+ * &drm_gem_object buffers GPU VA lists and &drm_gpuvm_bo
abstractions by
+ * itself; drivers are responsible to enforce mutual exclusion using
either the
+ * GEMs dma_resv lock or alternatively a driver specific external
lock. For the
+ * latter see also drm_gem_gpuva_set_lock().
+ *
+ * However, DRM GPUVM contains lockdep checks to ensure callers of
its API hold
+ * the corresponding lock whenever the &drm_gem_objects GPU VA list
is accessed
+ * by functions such as drm_gpuva_link() or drm_gpuva_unlink(), but
also
+ * drm_gpuvm_bo_obtain() and drm_gpuvm_bo_put().
+ *
+ * The latter is required since on creation and destruction of a
&drm_gpuvm_bo
+ * the &drm_gpuvm_bo is attached / removed from the &drm_gem_objects
gpuva list.
+ * Subsequent calls to drm_gpuvm_bo_obtain() for the same &drm_gpuvm
and
+ * &drm_gem_object must be able to observe previous creations and
destructions
+ * of &drm_gpuvm_bos in order to keep instances unique.
*/
/**
@@ -439,6 +458,7 @@
* {
* struct drm_gpuva_ops *ops;
* struct drm_gpuva_op *op
+ * struct drm_gpuvm_bo *vm_bo;
*
* driver_lock_va_space();
* ops = drm_gpuvm_sm_map_ops_create(gpuvm, addr, range,
@@ -446,6 +466,10 @@
* if (IS_ERR(ops))
* return PTR_ERR(ops);
*
+ * vm_bo = drm_gpuvm_bo_obtain(gpuvm, obj);
+ * if (IS_ERR(vm_bo))
+ * return PTR_ERR(vm_bo);
+ *
* drm_gpuva_for_each_op(op, ops) {
* struct drm_gpuva *va;
*
@@ -458,7 +482,7 @@
*
* driver_vm_map();
* drm_gpuva_map(gpuvm, va, &op->map);
- * drm_gpuva_link(va);
+ * drm_gpuva_link(va, vm_bo);
*
* break;
* case DRM_GPUVA_OP_REMAP: {
@@ -485,11 +509,11 @@
* driver_vm_remap();
* drm_gpuva_remap(prev, next, &op-
remap);
*
- * drm_gpuva_unlink(va);
* if (prev)
- * drm_gpuva_link(prev);
+ * drm_gpuva_link(prev, va-
vm_bo);
* if (next)
- * drm_gpuva_link(next);
+ * drm_gpuva_link(next, va-
vm_bo);
+ * drm_gpuva_unlink(va);
*
* break;
* }
@@ -505,6 +529,7 @@
* break;
* }
* }
+ * drm_gpuvm_bo_put(vm_bo);
* driver_unlock_va_space();
*
* return 0;
@@ -514,6 +539,7 @@
*
* struct driver_context {
* struct drm_gpuvm *gpuvm;
+ * struct drm_gpuvm_bo *vm_bo;
* struct drm_gpuva *new_va;
* struct drm_gpuva *prev_va;
* struct drm_gpuva *next_va;
@@ -534,6 +560,7 @@
* struct drm_gem_object *obj, u64
offset)
* {
* struct driver_context ctx;
+ * struct drm_gpuvm_bo *vm_bo;
* struct drm_gpuva_ops *ops;
* struct drm_gpuva_op *op;
* int ret = 0;
@@ -543,16 +570,23 @@
* ctx.new_va = kzalloc(sizeof(*ctx.new_va),
GFP_KERNEL);
* ctx.prev_va = kzalloc(sizeof(*ctx.prev_va),
GFP_KERNEL);
* ctx.next_va = kzalloc(sizeof(*ctx.next_va),
GFP_KERNEL);
- * if (!ctx.new_va || !ctx.prev_va || !ctx.next_va) {
+ * ctx.vm_bo = drm_gpuvm_bo_create(gpuvm, obj);
+ * if (!ctx.new_va || !ctx.prev_va || !ctx.next_va ||
!vm_bo) {
* ret = -ENOMEM;
* goto out;
* }
*
+ * // Typically protected with a driver specific GEM
gpuva lock
+ * // used in the fence signaling path for
drm_gpuva_link() and
+ * // drm_gpuva_unlink(), hence pre-allocate.
+ * ctx.vm_bo = drm_gpuvm_bo_obtain_prealloc(ctx.vm_bo);
+ *
* driver_lock_va_space();
* ret = drm_gpuvm_sm_map(gpuvm, &ctx, addr, range, obj,
offset);
* driver_unlock_va_space();
*
* out:
+ * drm_gpuvm_bo_put(ctx.vm_bo);
* kfree(ctx.new_va);
* kfree(ctx.prev_va);
* kfree(ctx.next_va);
@@ -565,7 +599,7 @@
*
* drm_gpuva_map(ctx->vm, ctx->new_va, &op->map);
*
- * drm_gpuva_link(ctx->new_va);
+ * drm_gpuva_link(ctx->new_va, ctx->vm_bo);
*
* // prevent the new GPUVA from being freed in
* // driver_mapping_create()
@@ -577,22 +611,23 @@
* int driver_gpuva_remap(struct drm_gpuva_op *op, void *__ctx)
* {
* struct driver_context *ctx = __ctx;
+ * struct drm_gpuva *va = op->remap.unmap->va;
*
* drm_gpuva_remap(ctx->prev_va, ctx->next_va, &op-
remap);
*
- * drm_gpuva_unlink(op->remap.unmap->va);
- * kfree(op->remap.unmap->va);
- *
* if (op->remap.prev) {
- * drm_gpuva_link(ctx->prev_va);
+ * drm_gpuva_link(ctx->prev_va, va->vm_bo);
* ctx->prev_va = NULL;
* }
*
* if (op->remap.next) {
- * drm_gpuva_link(ctx->next_va);
+ * drm_gpuva_link(ctx->next_va, va->vm_bo);
* ctx->next_va = NULL;
* }
*
+ * drm_gpuva_unlink(va);
+ * kfree(va);
+ *
* return 0;
* }
*
@@ -771,6 +806,194 @@ drm_gpuvm_destroy(struct drm_gpuvm *gpuvm)
}
EXPORT_SYMBOL_GPL(drm_gpuvm_destroy);
+/**
+ * drm_gpuvm_bo_create() - create a new instance of struct
drm_gpuvm_bo
+ * @gpuvm: The &drm_gpuvm the @obj is mapped in.
+ * @obj: The &drm_gem_object being mapped in the @gpuvm.
+ *
+ * If provided by the driver, this function uses the &drm_gpuvm_ops
+ * vm_bo_alloc() callback to allocate.
+ *
+ * Returns: a pointer to the &drm_gpuvm_bo on success, NULL on
Kerneldoc uses "Return:" rather than "Returns:", (This seems to a
common thing throughout the series).
Gonna fix.
failure
+ */
+struct drm_gpuvm_bo *
Any particular reason there's line-break after the function type even
when it fits the ~100 char limit?
Nope, just for consistency thoughout this source file.
+drm_gpuvm_bo_create(struct drm_gpuvm *gpuvm,
+ struct drm_gem_object *obj)
+{
+ const struct drm_gpuvm_ops *ops = gpuvm->ops;
+ struct drm_gpuvm_bo *vm_bo;
+
+ if (ops && ops->vm_bo_alloc)
+ vm_bo = ops->vm_bo_alloc();
+ else
+ vm_bo = kzalloc(sizeof(*vm_bo), GFP_KERNEL);
+
+ if (unlikely(!vm_bo))
+ return NULL;
+
+ vm_bo->vm = gpuvm;
+ vm_bo->obj = obj;
+
+ kref_init(&vm_bo->kref);
+ INIT_LIST_HEAD(&vm_bo->list.gpuva);
+ INIT_LIST_HEAD(&vm_bo->list.entry.gem);
+
+ drm_gem_object_get(obj);
Perhaps group this with the vm_bo->obj assignment to emphasize that
that's the pointer that gets the reference?
Yep, makes sense.
+
+ return vm_bo;
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_bo_create);
+
+static void
+drm_gpuvm_bo_destroy(struct kref *kref)
+{
+ struct drm_gpuvm_bo *vm_bo = container_of(kref, struct
drm_gpuvm_bo,
+ kref);
+ struct drm_gpuvm *gpuvm = vm_bo->vm;
+ const struct drm_gpuvm_ops *ops = gpuvm->ops;
+ struct drm_gem_object *obj = vm_bo->obj;
+ bool lock = !drm_gpuvm_resv_protected(gpuvm);
+
+ drm_gem_gpuva_assert_lock_held(obj);
+ if (!lock)
+ drm_gpuvm_resv_assert_held(gpuvm);
+
+ list_del(&vm_bo->list.entry.gem);
+
+ drm_gem_object_put(obj);
Not sure if we have any drivers utilizing vm_bo_free() yet, but it
might make sense to move the drm_gem_object_put() until after the
freeing below, in case vm_bo_free() wants to use it?
Good point, gonna fix.
+
+ if (ops && ops->vm_bo_free)
+ ops->vm_bo_free(vm_bo);
+ else
+ kfree(vm_bo);
+}
+
+/**
+ * drm_gpuvm_bo_put() - drop a struct drm_gpuvm_bo reference
+ * @vm_bo: the &drm_gpuvm_bo to release the reference of
+ *
+ * This releases a reference to @vm_bo.
+ *
+ * If the reference count drops to zero, the &gpuvm_bo is destroyed,
which
+ * includes removing it from the GEMs gpuva list. Hence, if a call
to this
+ * function can potentially let the reference count to zero the
caller must
+ * hold the dma-resv or driver specific GEM gpuva lock.
+ */
+void
+drm_gpuvm_bo_put(struct drm_gpuvm_bo *vm_bo)
+{
+ if (vm_bo)
+ kref_put(&vm_bo->kref, drm_gpuvm_bo_destroy);
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_bo_put);
+
+static struct drm_gpuvm_bo *
+__drm_gpuvm_bo_find(struct drm_gpuvm *gpuvm,
+ struct drm_gem_object *obj)
+{
+ struct drm_gpuvm_bo *vm_bo;
+
+ drm_gem_gpuva_assert_lock_held(obj);
+
+ drm_gem_for_each_gpuvm_bo(vm_bo, obj)
+ if (vm_bo->vm == gpuvm)
+ return vm_bo;
+
+ return NULL;
+}
+
+/**
+ * drm_gpuvm_bo_find() - find the &drm_gpuvm_bo for the given
+ * &drm_gpuvm and &drm_gem_object
+ * @gpuvm: The &drm_gpuvm the @obj is mapped in.
+ * @obj: The &drm_gem_object being mapped in the @gpuvm.
+ *
+ * Find the &drm_gpuvm_bo representing the combination of the given
+ * &drm_gpuvm and &drm_gem_object. If found, increases the reference
+ * count of the &drm_gpuvm_bo accordingly.
+ *
+ * Returns: a pointer to the &drm_gpuvm_bo on success, NULL on
failure
+ */
+struct drm_gpuvm_bo *
+drm_gpuvm_bo_find(struct drm_gpuvm *gpuvm,
+ struct drm_gem_object *obj)
+{
+ struct drm_gpuvm_bo *vm_bo = __drm_gpuvm_bo_find(gpuvm, obj);
+
+ return vm_bo ? drm_gpuvm_bo_get(vm_bo) : NULL;
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_bo_find);
+
+/**
+ * drm_gpuvm_bo_obtain() - obtains and instance of the &drm_gpuvm_bo
for the
+ * given &drm_gpuvm and &drm_gem_object
+ * @gpuvm: The &drm_gpuvm the @obj is mapped in.
+ * @obj: The &drm_gem_object being mapped in the @gpuvm.
+ *
+ * Find the &drm_gpuvm_bo representing the combination of the given
+ * &drm_gpuvm and &drm_gem_object. If found, increases the reference
+ * count of the &drm_gpuvm_bo accordingly. If not found, allocates a
new
+ * &drm_gpuvm_bo.
+ *
+ * A new &drm_gpuvm_bo is added to the GEMs gpuva list.
+ *
+ * Returns: a pointer to the &drm_gpuvm_bo on success, an ERR_PTR on
failure
+ */
+struct drm_gpuvm_bo *
+drm_gpuvm_bo_obtain(struct drm_gpuvm *gpuvm,
+ struct drm_gem_object *obj)
+{
+ struct drm_gpuvm_bo *vm_bo;
+
+ vm_bo = drm_gpuvm_bo_find(gpuvm, obj);
+ if (vm_bo)
+ return vm_bo;
+
+ vm_bo = drm_gpuvm_bo_create(gpuvm, obj);
+ if (!vm_bo)
+ return ERR_PTR(-ENOMEM);
+
+ list_add_tail(&vm_bo->list.entry.gem, &obj->gpuva.list);
Lockdep check?
Is inherited by drm_gpuvm_bo_find(), but I can also be explicit here.
+
+ return vm_bo;
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_bo_obtain);
+
+/**
+ * drm_gpuvm_bo_obtain_prealloc() - obtains and instance of the
&drm_gpuvm_bo
+ * for the given &drm_gpuvm and &drm_gem_object
+ * @__vm_bo: A pre-allocated struct drm_gpuvm_bo.
+ *
+ * Find the &drm_gpuvm_bo representing the combination of the given
+ * &drm_gpuvm and &drm_gem_object. If found, increases the reference
+ * count of the found &drm_gpuvm_bo accordingly, while the @__vm_bo
reference
+ * count is decreased. If not found @__vm_bo is returned without
further
+ * increase of the reference count.
+ *
+ * A new &drm_gpuvm_bo is added to the GEMs gpuva list.
+ *
+ * Returns: a pointer to the found &drm_gpuvm_bo or @__vm_bo if no
existing
+ * &drm_gpuvm_bo was found
+ */
+struct drm_gpuvm_bo *
+drm_gpuvm_bo_obtain_prealloc(struct drm_gpuvm_bo *__vm_bo)
+{
+ struct drm_gpuvm *gpuvm = __vm_bo->vm;
+ struct drm_gem_object *obj = __vm_bo->obj;
+ struct drm_gpuvm_bo *vm_bo;
+
+ vm_bo = drm_gpuvm_bo_find(gpuvm, obj);
+ if (vm_bo) {
+ drm_gpuvm_bo_put(__vm_bo);
+ return vm_bo;
+ }
+
+ list_add_tail(&__vm_bo->list.entry.gem, &obj->gpuva.list);
Perhaps a lockdep check here?
Same as above.
+
+ return __vm_bo;
+}
+EXPORT_SYMBOL_GPL(drm_gpuvm_bo_obtain_prealloc);
+
static int
__drm_gpuva_insert(struct drm_gpuvm *gpuvm,
struct drm_gpuva *va)
@@ -860,24 +1083,33 @@ EXPORT_SYMBOL_GPL(drm_gpuva_remove);
/**
* drm_gpuva_link() - link a &drm_gpuva
* @va: the &drm_gpuva to link
+ * @vm_bo: the &drm_gpuvm_bo to add the &drm_gpuva to
*
- * This adds the given &va to the GPU VA list of the &drm_gem_object
it is
- * associated with.
+ * This adds the given &va to the GPU VA list of the &drm_gpuvm_bo
and the
+ * &drm_gpuvm_bo to the &drm_gem_object it is associated with.
+ *
+ * For every &drm_gpuva entry added to the &drm_gpuvm_bo an
additional
+ * reference of the latter is taken.
*
* This function expects the caller to protect the GEM's GPUVA list
against
NIT: Referring to a "gem object" as a "GEM" catches my eye every time.
Perhaps that has become common practice? With my "it used to be like.."
hat on, I'd use gem object.
I think this is the way it referred to in a lot of places, e.g. drm_exe.c,
drm_gem.c, etc. Hence, I'd like to stick with that.
- * concurrent access using the GEMs dma_resv lock.
+ * concurrent access using either the GEMs dma_resv lock or a driver
specific
+ * lock set through drm_gem_gpuva_set_lock().
*/
void
-drm_gpuva_link(struct drm_gpuva *va)
+drm_gpuva_link(struct drm_gpuva *va, struct drm_gpuvm_bo *vm_bo)
{
struct drm_gem_object *obj = va->gem.obj;
if (unlikely(!obj))
return;
+ WARN_ON(obj != vm_bo->obj);
Can we use drm_WARN here?
Sure!
drm_gem_gpuva_assert_lock_held(obj);
- list_add_tail(&va->gem.entry, &obj->gpuva.list);
+ drm_gpuvm_bo_get(vm_bo);
+
+ va->vm_bo = vm_bo;
+ list_add_tail(&va->gem.entry, &vm_bo->list.gpuva);
}
EXPORT_SYMBOL_GPL(drm_gpuva_link);
@@ -888,13 +1120,22 @@ EXPORT_SYMBOL_GPL(drm_gpuva_link);
* This removes the given &va from the GPU VA list of the
&drm_gem_object it is
* associated with.
*
+ * This removes the given &va from the GPU VA list of the
&drm_gpuvm_bo and
+ * the &drm_gpuvm_bo from the &drm_gem_object it is associated with
in case
+ * this call unlinks the last &drm_gpuva from the &drm_gpuvm_bo.
+ *
+ * For every &drm_gpuva entry removed from the &drm_gpuvm_bo a
reference of
+ * the latter is dropped.
+ *
* This function expects the caller to protect the GEM's GPUVA list
against
- * concurrent access using the GEMs dma_resv lock.
+ * concurrent access using either the GEMs dma_resv lock or a driver
specific
+ * lock set through drm_gem_gpuva_set_lock().
*/
void
drm_gpuva_unlink(struct drm_gpuva *va)
{
struct drm_gem_object *obj = va->gem.obj;
+ struct drm_gpuvm_bo *vm_bo = va->vm_bo;
if (unlikely(!obj))
return;
@@ -902,6 +1143,9 @@ drm_gpuva_unlink(struct drm_gpuva *va)
drm_gem_gpuva_assert_lock_held(obj);
list_del_init(&va->gem.entry);
+ va->vm_bo = NULL;
+
+ drm_gpuvm_bo_put(vm_bo);
}
EXPORT_SYMBOL_GPL(drm_gpuva_unlink);
@@ -1046,10 +1290,10 @@ drm_gpuva_remap(struct drm_gpuva *prev,
struct drm_gpuva *next,
struct drm_gpuva_op_remap *op)
{
- struct drm_gpuva *curr = op->unmap->va;
- struct drm_gpuvm *gpuvm = curr->vm;
+ struct drm_gpuva *va = op->unmap->va;
+ struct drm_gpuvm *gpuvm = va->vm;
- drm_gpuva_remove(curr);
+ drm_gpuva_remove(va);
if (op->prev) {
drm_gpuva_init_from_op(prev, op->prev);
@@ -1693,9 +1937,8 @@ drm_gpuvm_prefetch_ops_create(struct drm_gpuvm
*gpuvm,
EXPORT_SYMBOL_GPL(drm_gpuvm_prefetch_ops_create);
/**
- * drm_gpuvm_gem_unmap_ops_create() - creates the &drm_gpuva_ops to
unmap a GEM
- * @gpuvm: the &drm_gpuvm representing the GPU VA space
- * @obj: the &drm_gem_object to unmap
+ * drm_gpuvm_bo_unmap_ops_create() - creates the &drm_gpuva_ops to
unmap a GEM
+ * @vm_bo: the &drm_gpuvm_bo abstraction
*
* This function creates a list of operations to perform unmapping
for every
* GPUVA attached to a GEM.
@@ -1712,15 +1955,14 @@
EXPORT_SYMBOL_GPL(drm_gpuvm_prefetch_ops_create);
* Returns: a pointer to the &drm_gpuva_ops on success, an ERR_PTR
on failure
*/
struct drm_gpuva_ops *
-drm_gpuvm_gem_unmap_ops_create(struct drm_gpuvm *gpuvm,
- struct drm_gem_object *obj)
+drm_gpuvm_bo_unmap_ops_create(struct drm_gpuvm_bo *vm_bo)
{
struct drm_gpuva_ops *ops;
struct drm_gpuva_op *op;
struct drm_gpuva *va;
int ret;
- drm_gem_gpuva_assert_lock_held(obj);
+ drm_gem_gpuva_assert_lock_held(vm_bo->obj);
ops = kzalloc(sizeof(*ops), GFP_KERNEL);
if (!ops)
@@ -1728,8 +1970,8 @@ drm_gpuvm_gem_unmap_ops_create(struct drm_gpuvm
*gpuvm,
INIT_LIST_HEAD(&ops->list);
- drm_gem_for_each_gpuva(va, obj) {
- op = gpuva_op_alloc(gpuvm);
+ drm_gpuvm_bo_for_each_va(va, vm_bo) {
+ op = gpuva_op_alloc(vm_bo->vm);
if (!op) {
ret = -ENOMEM;
goto err_free_ops;
@@ -1743,10 +1985,10 @@ drm_gpuvm_gem_unmap_ops_create(struct
drm_gpuvm *gpuvm,
return ops;
err_free_ops:
- drm_gpuva_ops_free(gpuvm, ops);
+ drm_gpuva_ops_free(vm_bo->vm, ops);
return ERR_PTR(ret);
}
-EXPORT_SYMBOL_GPL(drm_gpuvm_gem_unmap_ops_create);
+EXPORT_SYMBOL_GPL(drm_gpuvm_bo_unmap_ops_create);
/**
* drm_gpuva_ops_free() - free the given &drm_gpuva_ops
diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c
b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
index 93ad2ba7ec8b..4e46f850e65f 100644
--- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
@@ -62,6 +62,8 @@ struct bind_job_op {
enum vm_bind_op op;
u32 flags;
+ struct drm_gpuvm_bo *vm_bo;
+
struct {
u64 addr;
u64 range;
@@ -1113,22 +1115,28 @@ bind_validate_region(struct nouveau_job *job)
}
static void
-bind_link_gpuvas(struct drm_gpuva_ops *ops, struct
nouveau_uvma_prealloc *new)
+bind_link_gpuvas(struct bind_job_op *bop)
{
+ struct nouveau_uvma_prealloc *new = &bop->new;
+ struct drm_gpuvm_bo *vm_bo = bop->vm_bo;
+ struct drm_gpuva_ops *ops = bop->ops;
struct drm_gpuva_op *op;
drm_gpuva_for_each_op(op, ops) {
switch (op->op) {
case DRM_GPUVA_OP_MAP:
- drm_gpuva_link(&new->map->va);
+ drm_gpuva_link(&new->map->va, vm_bo);
break;
- case DRM_GPUVA_OP_REMAP:
+ case DRM_GPUVA_OP_REMAP: {
+ struct drm_gpuva *va = op->remap.unmap->va;
+
if (op->remap.prev)
- drm_gpuva_link(&new->prev->va);
+ drm_gpuva_link(&new->prev->va, va-
vm_bo);
if (op->remap.next)
- drm_gpuva_link(&new->next->va);
- drm_gpuva_unlink(op->remap.unmap->va);
+ drm_gpuva_link(&new->next->va, va-
vm_bo);
+ drm_gpuva_unlink(va);
break;
+ }
case DRM_GPUVA_OP_UNMAP:
drm_gpuva_unlink(op->unmap.va);
break;
@@ -1150,10 +1158,18 @@ nouveau_uvmm_bind_job_submit(struct
nouveau_job *job)
list_for_each_op(op, &bind_job->ops) {
if (op->op == OP_MAP) {
- op->gem.obj = drm_gem_object_lookup(job-
file_priv,
- op-
gem.handle);
- if (!op->gem.obj)
+ struct drm_gem_object *obj;
+
+ obj = drm_gem_object_lookup(job->file_priv,
+ op->gem.handle);
+ if (!(op->gem.obj = obj))
return -ENOENT;
+
+ dma_resv_lock(obj->resv, NULL);
+ op->vm_bo = drm_gpuvm_bo_obtain(&uvmm->base,
obj);
+ dma_resv_unlock(obj->resv);
+ if (IS_ERR(op->vm_bo))
+ return PTR_ERR(op->vm_bo);
}
ret = bind_validate_op(job, op);
@@ -1364,7 +1380,7 @@ nouveau_uvmm_bind_job_submit(struct nouveau_job
*job)
case OP_UNMAP_SPARSE:
case OP_MAP:
case OP_UNMAP:
- bind_link_gpuvas(op->ops, &op->new);
+ bind_link_gpuvas(op);
break;
default:
break;
@@ -1511,6 +1527,12 @@ nouveau_uvmm_bind_job_free_work_fn(struct
work_struct *work)
if (!IS_ERR_OR_NULL(op->ops))
drm_gpuva_ops_free(&uvmm->base, op->ops);
+ if (!IS_ERR_OR_NULL(op->vm_bo)) {
+ dma_resv_lock(obj->resv, NULL);
+ drm_gpuvm_bo_put(op->vm_bo);
+ dma_resv_unlock(obj->resv);
+ }
+
if (obj)
drm_gem_object_put(obj);
}
@@ -1776,15 +1798,18 @@ void
nouveau_uvmm_bo_map_all(struct nouveau_bo *nvbo, struct nouveau_mem
*mem)
{
struct drm_gem_object *obj = &nvbo->bo.base;
+ struct drm_gpuvm_bo *vm_bo;
struct drm_gpuva *va;
dma_resv_assert_held(obj->resv);
- drm_gem_for_each_gpuva(va, obj) {
- struct nouveau_uvma *uvma = uvma_from_va(va);
+ drm_gem_for_each_gpuvm_bo(vm_bo, obj) {
+ drm_gpuvm_bo_for_each_va(va, vm_bo) {
+ struct nouveau_uvma *uvma = uvma_from_va(va);
- nouveau_uvma_map(uvma, mem);
- drm_gpuva_invalidate(va, false);
+ nouveau_uvma_map(uvma, mem);
+ drm_gpuva_invalidate(va, false);
+ }
}
}
@@ -1792,15 +1817,18 @@ void
nouveau_uvmm_bo_unmap_all(struct nouveau_bo *nvbo)
{
struct drm_gem_object *obj = &nvbo->bo.base;
+ struct drm_gpuvm_bo *vm_bo;
struct drm_gpuva *va;
dma_resv_assert_held(obj->resv);
- drm_gem_for_each_gpuva(va, obj) {
- struct nouveau_uvma *uvma = uvma_from_va(va);
+ drm_gem_for_each_gpuvm_bo(vm_bo, obj) {
+ drm_gpuvm_bo_for_each_va(va, vm_bo) {
+ struct nouveau_uvma *uvma = uvma_from_va(va);
- nouveau_uvma_unmap(uvma);
- drm_gpuva_invalidate(va, true);
+ nouveau_uvma_unmap(uvma);
+ drm_gpuva_invalidate(va, true);
+ }
}
}
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 16364487fde9..369505447acd 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -580,7 +580,7 @@ int drm_gem_evict(struct drm_gem_object *obj);
* drm_gem_gpuva_init() - initialize the gpuva list of a GEM object
* @obj: the &drm_gem_object
*
- * This initializes the &drm_gem_object's &drm_gpuva list.
+ * This initializes the &drm_gem_object's &drm_gpuvm_bo list.
*
* Calling this function is only necessary for drivers intending to
support the
* &drm_driver_feature DRIVER_GEM_GPUVA.
@@ -593,28 +593,28 @@ static inline void drm_gem_gpuva_init(struct
drm_gem_object *obj)
}
/**
- * drm_gem_for_each_gpuva() - iternator to walk over a list of
gpuvas
- * @entry__: &drm_gpuva structure to assign to in each iteration
step
- * @obj__: the &drm_gem_object the &drm_gpuvas to walk are
associated with
+ * drm_gem_for_each_gpuvm_bo() - iterator to walk over a list of
&drm_gpuvm_bo
+ * @entry__: &drm_gpuvm_bo structure to assign to in each iteration
step
+ * @obj__: the &drm_gem_object the &drm_gpuvm_bo to walk are
associated with
*
- * This iterator walks over all &drm_gpuva structures associated
with the
- * &drm_gpuva_manager.
+ * This iterator walks over all &drm_gpuvm_bo structures associated
with the
+ * &drm_gem_object.
*/
-#define drm_gem_for_each_gpuva(entry__, obj__) \
- list_for_each_entry(entry__, &(obj__)->gpuva.list, gem.entry)
+#define drm_gem_for_each_gpuvm_bo(entry__, obj__) \
+ list_for_each_entry(entry__, &(obj__)->gpuva.list,
list.entry.gem)
/**
- * drm_gem_for_each_gpuva_safe() - iternator to safely walk over a
list of
- * gpuvas
- * @entry__: &drm_gpuva structure to assign to in each iteration
step
- * @next__: &next &drm_gpuva to store the next step
- * @obj__: the &drm_gem_object the &drm_gpuvas to walk are
associated with
+ * drm_gem_for_each_gpuvm_bo_safe() - iterator to safely walk over a
list of
+ * &drm_gpuvm_bo
+ * @entry__: &drm_gpuvm_bostructure to assign to in each iteration
step
+ * @next__: &next &drm_gpuvm_bo to store the next step
+ * @obj__: the &drm_gem_object the &drm_gpuvm_bo to walk are
associated with
*
- * This iterator walks over all &drm_gpuva structures associated
with the
+ * This iterator walks over all &drm_gpuvm_bo structures associated
with the
* &drm_gem_object. It is implemented with
list_for_each_entry_safe(), hence
* it is save against removal of elements.
*/
-#define drm_gem_for_each_gpuva_safe(entry__, next__, obj__) \
- list_for_each_entry_safe(entry__, next__, &(obj__)-
gpuva.list, gem.entry)
+#define drm_gem_for_each_gpuvm_bo_safe(entry__, next__, obj__) \
+ list_for_each_entry_safe(entry__, next__, &(obj__)-
gpuva.list, list.entry.gem)
#endif /* __DRM_GEM_H__ */
diff --git a/include/drm/drm_gpuvm.h b/include/drm/drm_gpuvm.h
index 13539f32c2e2..ddb0b8d323cf 100644
--- a/include/drm/drm_gpuvm.h
+++ b/include/drm/drm_gpuvm.h
@@ -26,12 +26,14 @@
*/
#include <linux/list.h>
+#include <linux/dma-resv.h>
#include <linux/rbtree.h>
#include <linux/types.h>
#include <drm/drm_gem.h>
struct drm_gpuvm;
+struct drm_gpuvm_bo;
struct drm_gpuvm_ops;
/**
@@ -72,6 +74,12 @@ struct drm_gpuva {
*/
struct drm_gpuvm *vm;
+ /**
+ * @vm_bo: the &drm_gpuvm_bo abstraction for the mapped
+ * &drm_gem_object
+ */
+ struct drm_gpuvm_bo *vm_bo;
+
/**
* @flags: the &drm_gpuva_flags for this mapping
*/
@@ -107,7 +115,7 @@ struct drm_gpuva {
struct drm_gem_object *obj;
/**
- * @entry: the &list_head to attach this object to a
&drm_gem_object
+ * @entry: the &list_head to attach this object to a
&drm_gpuvm_bo
*/
struct list_head entry;
} gem;
@@ -140,7 +148,7 @@ struct drm_gpuva {
int drm_gpuva_insert(struct drm_gpuvm *gpuvm, struct drm_gpuva *va);
void drm_gpuva_remove(struct drm_gpuva *va);
-void drm_gpuva_link(struct drm_gpuva *va);
+void drm_gpuva_link(struct drm_gpuva *va, struct drm_gpuvm_bo
*vm_bo);
void drm_gpuva_unlink(struct drm_gpuva *va);
struct drm_gpuva *drm_gpuva_find(struct drm_gpuvm *gpuvm,
@@ -187,10 +195,16 @@ static inline bool drm_gpuva_invalidated(struct
drm_gpuva *va)
* enum drm_gpuvm_flags - flags for struct drm_gpuvm
*/
enum drm_gpuvm_flags {
+ /**
+ * @DRM_GPUVM_RESV_PROTECTED: GPUVM is protected externally
by the
+ * GPUVM's &dma_resv lock
+ */
+ DRM_GPUVM_RESV_PROTECTED = (1 << 0),
+
/**
* @DRM_GPUVM_USERBITS: user defined bits
*/
- DRM_GPUVM_USERBITS = (1 << 0),
+ DRM_GPUVM_USERBITS = (1 << 1),
};
/**
@@ -272,6 +286,19 @@ bool drm_gpuvm_interval_empty(struct drm_gpuvm
*gpuvm, u64 addr, u64 range);
struct drm_gem_object *
drm_gpuvm_root_object_alloc(struct drm_device *drm);
+/**
+ * drm_gpuvm_resv_protected() - indicates whether
&DRM_GPUVM_RESV_PROTECTED is
+ * set
+ * @gpuvm: the &drm_gpuvm
+ *
+ * Returns: true if &DRM_GPUVM_RESV_PROTECTED is set, false
otherwise.
+ */
+static inline bool
+drm_gpuvm_resv_protected(struct drm_gpuvm *gpuvm)
+{
+ return gpuvm->flags & DRM_GPUVM_RESV_PROTECTED;
+}
+
/**
* drm_gpuvm_resv() - returns the &drm_gpuvm's &dma_resv
* @gpuvm__: the &drm_gpuvm
@@ -290,6 +317,12 @@ drm_gpuvm_root_object_alloc(struct drm_device
*drm);
*/
#define drm_gpuvm_resv_obj(gpuvm__) ((gpuvm__)->r_obj)
+#define drm_gpuvm_resv_held(gpuvm__) \
+ dma_resv_held(drm_gpuvm_resv(gpuvm__))
+
+#define drm_gpuvm_resv_assert_held(gpuvm__) \
+ dma_resv_assert_held(drm_gpuvm_resv(gpuvm__))
+
#define drm_gpuvm_resv_held(gpuvm__) \
dma_resv_held(drm_gpuvm_resv(gpuvm__))
@@ -374,6 +407,117 @@ __drm_gpuva_next(struct drm_gpuva *va)
#define drm_gpuvm_for_each_va_safe(va__, next__, gpuvm__) \
list_for_each_entry_safe(va__, next__, &(gpuvm__)->rb.list,
rb.entry)
+/**
+ * struct drm_gpuvm_bo - structure representing a &drm_gpuvm and
+ * &drm_gem_object combination
+ *
+ * This structure is an abstraction representing a &drm_gpuvm and
+ * &drm_gem_object combination. It serves as an indirection to
accelerate
+ * iterating all &drm_gpuvas within a &drm_gpuvm backed by the same
+ * &drm_gem_object.
+ *
+ * Furthermore it is used cache evicted GEM objects for a certain
GPU-VM to
+ * accelerate validation.
+ *
+ * Typically, drivers want to create an instance of a struct
drm_gpuvm_bo once
+ * a GEM object is mapped first in a GPU-VM and release the instance
once the
+ * last mapping of the GEM object in this GPU-VM is unmapped.
+ */
+struct drm_gpuvm_bo {
+
+ /**
+ * @vm: The &drm_gpuvm the @obj is mapped in.
Not refcounted. @vm may potentially be freed under us in the
!RESV_PROTECTED case.
It's the drivers responsibility to ensure the VM is not freed up as long as
VM_BOs with this VM do exist. However, this is nothing drivers need to care
about explicitly, since drivers are responsible to keep the VM alive as long
as mappings exist anyway. And all mappings being gone implies also all VM_BOs
being gone, since the lifetime of a VM_BO goes from the first mapping backed by
a certain object is created to the last mapping backed by this object is
removed. drm_gpuvm_destroy() will also warn if the GPUVM still contains
mappings.
I will document this more explicitly somewhere.
+ */
+ struct drm_gpuvm *vm;
+
+ /**
+ * @obj: The &drm_gem_object being mapped in @vm.
Refcounted pointer.
Guess you want me to document that.
Yes, that'd be good. Especially with internal lower-level locking it
will become crucial to know where we have strong vs weak referencing so
we know where to upgrade with kref_get_unless_zero().
Thanks,
Thomas