nouveau creates its drm_gpuvm without DRM_GPUVM_RESV_PROTECTED, so the extobj and evicted lists are protected by internal spinlocks. Every nouveau path but three already touches them with the VM's resv held: drm_gpuvm_exec_lock() and drm_gpuvm_validate() on exec, and TTM moves of private BOs, which share the VM's resv. The remaining three are:
- nouveau_uvmm_bind_job_submit() adds the vm_bo of a MAP op to the extobj list holding no resv at all. Move that into bind_lock_validate(), which now locks the VM's resv as well. - bind_link_gpuvas() unlinks the GPUVAs of UNMAP and REMAP ops, which can drop the last reference of their vm_bo. It runs within the bind job's drm_exec transaction, which the above makes hold the VM's resv. - nouveau_uvmm_bind_job_cleanup() and nouveau_uvmm_fini() can drop the last reference of a vm_bo holding only the object's resv. Lock the VM's resv along with it, through a new nouveau_uvmm_lock_vm_and_obj(). The bind job's fence now always lands in the VM's resv, as BOOKKEEP. This already happened whenever a bind job mapped a private BO. With that the internal spinlocks buy nothing, so set DRM_GPUVM_RESV_PROTECTED. This is also what two-pass locking in drm_gpuvm requires, which a following patch makes use of. Cc: Abhinav Kumar <[email protected]> Cc: Alice Ryhl <[email protected]> Cc: Anna Maniscalco <[email protected]> Cc: Antonino Maniscalco <[email protected]> Cc: Boris Brezillon <[email protected]> Cc: Danilo Krummrich <[email protected]> Cc: David Airlie <[email protected]> Cc: Dmitry Baryshkov <[email protected]> Cc: Jessica Zhang <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Liviu Dudau <[email protected]> Cc: Lyude Paul <[email protected]> Cc: Maarten Lankhorst <[email protected]> Cc: Marijn Suijten <[email protected]> Cc: Maxime Ripard <[email protected]> Cc: Randy Dunlap <[email protected]> Cc: Rob Clark <[email protected]> Cc: Rodrigo Vivi <[email protected]> Cc: Sean Paul <[email protected]> Cc: Shuah Khan <[email protected]> Cc: Simona Vetter <[email protected]> Cc: Steven Price <[email protected]> Cc: Thomas Hellström <[email protected]> Cc: Thomas Zimmermann <[email protected]> Signed-off-by: Matthew Brost <[email protected]> Assisted-by: LLM --- v3: - New patch (Danilo) --- drivers/gpu/drm/nouveau/nouveau_uvmm.c | 49 ++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c b/drivers/gpu/drm/nouveau/nouveau_uvmm.c index 2026fe6b48c6..dae612e56d91 100644 --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c @@ -1187,6 +1187,27 @@ bind_validate_region(struct nouveau_job *job) return 0; } +/* + * Lock the VM's common dma-resv together with the one of @obj, as needed to + * drop what may be the last reference of a &drm_gpuvm_bo. + */ +static void +nouveau_uvmm_lock_vm_and_obj(struct nouveau_uvmm *uvmm, struct drm_exec *exec, + struct drm_gem_object *obj) +{ + int ret; + + drm_exec_init(exec, DRM_EXEC_IGNORE_DUPLICATES, 2); + drm_exec_until_all_locked(exec) { + ret = drm_exec_lock_obj(exec, drm_gpuvm_resv_obj(&uvmm->base)); + if (!ret) + ret = drm_exec_lock_obj(exec, obj); + drm_exec_retry_on_contention(exec); + if (drm_WARN_ON(uvmm->base.drm, ret)) + break; + } +} + static void bind_link_gpuvas(struct bind_job_op *bop) { @@ -1224,12 +1245,24 @@ bind_lock_validate(struct nouveau_job *job, struct drm_exec *exec, unsigned int num_fences) { struct nouveau_uvmm_bind_job *bind_job = to_uvmm_bind_job(job); + struct nouveau_uvmm *uvmm = nouveau_cli_uvmm(job->cli); struct bind_job_op *op; int ret; + /* The VM's dma-resv protects its extobj and evicted lists, and must be + * held by bind_link_gpuvas() in case it drops the last reference of a + * &drm_gpuvm_bo. + */ + ret = drm_gpuvm_prepare_vm(&uvmm->base, exec, num_fences); + if (ret) + return ret; + list_for_each_op(op, &bind_job->ops) { struct drm_gpuva_op *va_op; + if (op->op == OP_MAP) + drm_gpuvm_bo_extobj_add(op->vm_bo); + if (!op->ops) continue; @@ -1288,8 +1321,6 @@ nouveau_uvmm_bind_job_submit(struct nouveau_job *job, dma_resv_unlock(obj->resv); if (IS_ERR(op->vm_bo)) return PTR_ERR(op->vm_bo); - - drm_gpuvm_bo_extobj_add(op->vm_bo); } ret = bind_validate_op(job, op); @@ -1603,9 +1634,11 @@ nouveau_uvmm_bind_job_cleanup(struct nouveau_job *job) drm_gpuva_ops_free(&uvmm->base, op->ops); if (!IS_ERR_OR_NULL(op->vm_bo)) { - dma_resv_lock(obj->resv, NULL); + struct drm_exec exec; + + nouveau_uvmm_lock_vm_and_obj(uvmm, &exec, obj); drm_gpuvm_bo_put(op->vm_bo); - dma_resv_unlock(obj->resv); + drm_exec_fini(&exec); } if (obj) @@ -1941,7 +1974,8 @@ nouveau_uvmm_ioctl_vm_init(struct drm_device *dev, mt_init_flags(&uvmm->region_mt, MT_FLAGS_LOCK_EXTERN); mt_set_external_lock(&uvmm->region_mt, &uvmm->mutex); - drm_gpuvm_init(&uvmm->base, cli->name, 0, drm, r_obj, + drm_gpuvm_init(&uvmm->base, cli->name, DRM_GPUVM_RESV_PROTECTED, + drm, r_obj, NOUVEAU_VA_SPACE_START, NOUVEAU_VA_SPACE_END, init->kernel_managed_addr, @@ -1978,6 +2012,7 @@ nouveau_uvmm_fini(struct nouveau_uvmm *uvmm) struct nouveau_uvma_region *reg; struct nouveau_cli *cli = uvmm->vmm.cli; struct drm_gpuva *va, *next; + struct drm_exec exec; nouveau_uvmm_lock(uvmm); drm_gpuvm_for_each_va_safe(va, next, &uvmm->base) { @@ -1989,9 +2024,9 @@ nouveau_uvmm_fini(struct nouveau_uvmm *uvmm) drm_gpuva_remove(va); - dma_resv_lock(obj->resv, NULL); + nouveau_uvmm_lock_vm_and_obj(uvmm, &exec, obj); drm_gpuva_unlink(va); - dma_resv_unlock(obj->resv); + drm_exec_fini(&exec); nouveau_uvma_unmap(uvma); nouveau_uvma_vmm_put(uvma); -- 2.34.1
