Now that everything in UVMM knows about the variable page shift, we can select larger values.
The proposed approach relies on nouveau_bo::page unless if it would cause alignment issues (in which case we fall back to searching for an appropriate shift) Signed-off-by: Mary Guillemard <[email protected]> Co-developed-by: Mohamed Ahmed <[email protected]> Signed-off-by: Mohamed Ahmed <[email protected]> Reviewed-by: Lyude Paul <[email protected]> Reviewed-by: James Jones <[email protected]> --- drivers/gpu/drm/nouveau/nouveau_uvmm.c | 60 ++++++++++++++++++++++++++++++++-- 1 file changed, 58 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c b/drivers/gpu/drm/nouveau/nouveau_uvmm.c index 2cd0835b05e8..f10809115c56 100644 --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c @@ -454,6 +454,62 @@ op_unmap_prepare_unwind(struct drm_gpuva *va) drm_gpuva_insert(va->vm, va); } +static bool +op_map_aligned_to_page_shift(const struct drm_gpuva_op_map *op, u8 page_shift) +{ + u64 non_page_bits = (1ULL << page_shift) - 1; + + return (op->va.addr & non_page_bits) == 0 && + (op->va.range & non_page_bits) == 0 && + (op->gem.offset & non_page_bits) == 0; +} + +static u8 +select_page_shift(struct nouveau_uvmm *uvmm, struct drm_gpuva_op_map *op) +{ + struct nouveau_bo *nvbo = nouveau_gem_object(op->gem.obj); + + /* nouveau_bo_fixup_align() guarantees that the page size will be aligned + * for most cases, but it can't handle cases where userspace allocates with + * a size and then binds with a smaller granularity. So in order to avoid + * breaking old userspace, we need to ensure that the VA is actually + * aligned before using it, and if it isn't, then we downgrade to the first + * granularity that will fit, which is optimal from a correctness and + * performance perspective. + */ + if (op_map_aligned_to_page_shift(op, nvbo->page)) + return nvbo->page; + + struct nouveau_mem *mem = nouveau_mem(nvbo->bo.resource); + struct nvif_vmm *vmm = &uvmm->vmm.vmm; + int i; + + /* If the given granularity doesn't fit, let's find one that will fit. */ + for (i = 0; i < vmm->page_nr; i++) { + /* Ignore anything that is bigger or identical to the BO preference. */ + if (vmm->page[i].shift >= nvbo->page) + continue; + + /* Skip incompatible domains. */ + if ((mem->mem.type & NVIF_MEM_VRAM) && !vmm->page[i].vram) + continue; + if ((mem->mem.type & NVIF_MEM_HOST) && + (!vmm->page[i].host || vmm->page[i].shift > PAGE_SHIFT)) + continue; + + /* If it fits, return the proposed shift. */ + if (op_map_aligned_to_page_shift(op, vmm->page[i].shift)) + return vmm->page[i].shift; + } + + /* If we get here then nothing can reconcile the requirements. This should never + * happen. + */ + drm_WARN_ONCE(op->gem.obj->dev, 1, "Could not find an appropriate page size.\n"); + + return PAGE_SHIFT; +} + static void nouveau_uvmm_sm_prepare_unwind(struct nouveau_uvmm *uvmm, struct nouveau_uvma_prealloc *new, @@ -506,7 +562,7 @@ nouveau_uvmm_sm_prepare_unwind(struct nouveau_uvmm *uvmm, if (vmm_get_range) nouveau_uvmm_vmm_put(uvmm, vmm_get_start, vmm_get_range, - PAGE_SHIFT); + select_page_shift(uvmm, &op->map)); break; } case DRM_GPUVA_OP_REMAP: { @@ -599,7 +655,7 @@ op_map_prepare(struct nouveau_uvmm *uvmm, uvma->region = args->region; uvma->kind = args->kind; - uvma->page_shift = PAGE_SHIFT; + uvma->page_shift = select_page_shift(uvmm, op); drm_gpuva_map(&uvmm->base, &uvma->va, op); -- 2.51.1
