Messages in this thread | | | Date | Tue, 31 Oct 2023 18:38:31 +0100 | Subject | Re: [PATCH drm-misc-next v7 4/7] drm/gpuvm: add an abstraction for a VM / BO combination | From | Danilo Krummrich <> |
| |
On 10/31/23 11:32, Thomas Hellström wrote: > On Mon, 2023-10-23 at 22:16 +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@amd.com> >> Signed-off-by: Danilo Krummrich <dakr@redhat.com> >> --- >> drivers/gpu/drm/drm_gpuvm.c | 335 +++++++++++++++++++++-- >> -- >> drivers/gpu/drm/nouveau/nouveau_uvmm.c | 64 +++-- >> include/drm/drm_gem.h | 32 +-- >> include/drm/drm_gpuvm.h | 188 +++++++++++++- >> 4 files changed, 533 insertions(+), 86 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_gpuvm.c >> b/drivers/gpu/drm/drm_gpuvm.c >> index c03332883432..7f4f5919f84c 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_resv_object_alloc(). >> + * >> + * In order to connect a struct drm_gpuva its backing >> &drm_gem_object each >> + * &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; >> * } >> * >> @@ -774,6 +809,194 @@ 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 > > Still needs s/Returns:/Return:/g > >> failure >> + */ >> +struct drm_gpuvm_bo * >> +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; >> + drm_gem_object_get(obj); >> + >> + kref_init(&vm_bo->kref); >> + INIT_LIST_HEAD(&vm_bo->list.gpuva); >> + INIT_LIST_HEAD(&vm_bo->list.entry.gem); >> + >> + 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); >> + >> + if (!lock) >> + drm_gpuvm_resv_assert_held(gpuvm); >> + >> + drm_gem_gpuva_assert_lock_held(obj); >> + list_del(&vm_bo->list.entry.gem); >> + >> + if (ops && ops->vm_bo_free) >> + ops->vm_bo_free(vm_bo); >> + else >> + kfree(vm_bo); >> + >> + drm_gem_object_put(obj); >> +} >> + >> +/** >> + * 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); >> + >> + drm_gem_gpuva_assert_lock_held(obj); >> + list_add_tail(&vm_bo->list.entry.gem, &obj->gpuva.list); >> + >> + 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; >> + } >> + >> + drm_gem_gpuva_assert_lock_held(obj); >> + list_add_tail(&__vm_bo->list.entry.gem, &obj->gpuva.list); >> + >> + return __vm_bo; >> +} >> +EXPORT_SYMBOL_GPL(drm_gpuvm_bo_obtain_prealloc); >> + >> static int >> __drm_gpuva_insert(struct drm_gpuvm *gpuvm, >> struct drm_gpuva *va) >> @@ -864,24 +1087,33 @@ 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 >> - * 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; >> + struct drm_gpuvm *gpuvm = va->vm; >> >> if (unlikely(!obj)) >> return; >> >> - drm_gem_gpuva_assert_lock_held(obj); >> + drm_WARN_ON(gpuvm->drm, obj != vm_bo->obj); >> >> - list_add_tail(&va->gem.entry, &obj->gpuva.list); >> + va->vm_bo = drm_gpuvm_bo_get(vm_bo); >> + >> + drm_gem_gpuva_assert_lock_held(obj); >> + list_add_tail(&va->gem.entry, &vm_bo->list.gpuva); >> } >> EXPORT_SYMBOL_GPL(drm_gpuva_link); >> >> @@ -892,20 +1124,31 @@ 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; >> >> 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); >> >> @@ -1050,10 +1293,10 @@ 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); >> @@ -1695,9 +1938,8 @@ 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. >> @@ -1714,15 +1956,14 @@ >> 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) >> @@ -1730,8 +1971,8 @@ 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; >> @@ -1745,10 +1986,10 @@ 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 ed439bf4032f..1e95b0a1b047 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 47cbacb244b9..466fdd76c71a 100644 >> --- a/include/drm/drm_gpuvm.h >> +++ b/include/drm/drm_gpuvm.h >> @@ -25,6 +25,7 @@ >> * OTHER DEALINGS IN THE SOFTWARE. >> */ >> >> +#include <linux/dma-resv.h> >> #include <linux/list.h> >> #include <linux/rbtree.h> >> #include <linux/types.h> >> @@ -33,6 +34,7 @@ >> #include <drm/drm_gem.h> >> >> struct drm_gpuvm; >> +struct drm_gpuvm_bo; >> struct drm_gpuvm_ops; >> >> /** >> @@ -73,6 +75,12 @@ 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 >> */ >> @@ -108,7 +116,7 @@ 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; >> @@ -141,7 +149,7 @@ 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, >> @@ -188,10 +196,16 @@ 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 = BIT(0), >> + >> /** >> * @DRM_GPUVM_USERBITS: user defined bits >> */ >> - DRM_GPUVM_USERBITS = BIT(0), >> + DRM_GPUVM_USERBITS = BIT(1), >> }; >> >> /** >> @@ -280,6 +294,19 @@ bool drm_gpuvm_interval_empty(struct drm_gpuvm >> *gpuvm, u64 addr, u64 range); >> struct drm_gem_object * >> drm_gpuvm_resv_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 >> @@ -298,6 +325,12 @@ drm_gpuvm_resv_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__)) >> >> @@ -382,6 +415,128 @@ __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. This pointer is >> not >> + * reference counted. >> + * >> + * A struct drm_gpuvm_bo is not allowed to out-live its >> &drm_gpuvm >> + * context. Implicitly, this is ensured by the fact that the >> driver is >> + * responsible to ensure the VM doesn't contain mappings once >> it's >> + * freed, since a struct drm_gpuvm_bo should be freed once >> the last >> + * mapping being backed by the corresponding buffer object is >> unmapped. >> + */ > > > I don't think the above is completely true. Let's assume in the > !RESV_PROTECTED case that a reference is grabbed on the drm_gpuvm_bo > during an iteration over a list. Then user-space closes the vm and all > vmas are unlinked, but this reference remains but the vm pointer > becomes stale. In the RESV_PROTECTED case this is ensured not to happen > if by the vm->resv being grabbed during unlink, but in the > !RESV_PROTECTED case, the above wording isn't sufficient. The caller > needs to ensure the vm stays alive using some sort of similar rule or > use kref_get_unless_zero() on the vm under the spinlock if > dereferenced.
The list is part of the GPUVM. Hence, the caller *must* either already hold a reference to the GPUVM or otherwise ensure it's not freed while iterating this list. All the drm_gpuvm_bo structures within this list can't have a pointer to another VM than this one by definition.
Anyway, I recognize that this isn't very obvious. Hence, I think we should probably reference count GPUVMs as well. I'd think of the same way we do it with drm_gem_objects. However, I'd prefer to introduce this with a subsequent patch.
> >> + struct drm_gpuvm *vm; >> + >> + /** >> + * @obj: The &drm_gem_object being mapped in @vm. This is a >> reference >> + * counted pointer. >> + */ >> + struct drm_gem_object *obj; >> + >> + /** >> + * @kref: The reference count for this &drm_gpuvm_bo. >> + */ >> + struct kref kref; >> + >> + /** >> + * @list: Structure containing all &list_heads. >> + */ >> + struct { >> + /** >> + * @gpuva: The list of linked &drm_gpuvas. >> + */ >> + struct list_head gpuva; > > Still missing doc on how the @gpuva stays alive during iteration over > the list?
Thanks for pointing this out again, I missed that one.
- Danilo
> > > > 8<------------------------------------------------------------- > > Thanks, > Thomas >
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