Hello,
Pinging again re: review and also was asking if we can revert the
select_page_shift() handling back to v1 behavior with a fall-back
path, as it looks like there are some cases where
nouveau_bo_fixup_align() isn't enough;
https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36450#note_3159199.
Thanks!
On Fri, Oct 10, 2025 at 2:39?AM Mohamed Ahmed
<mohamedahmedegypt2001 at gmail.com> wrote:>
> From: Mary Guillemard <mary at mary.zone>
>
> 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 <mary at mary.zone>
> Co-developed-by: Mohamed Ahmed <mohamedahmedegypt2001 at gmail.com>
> Signed-off-by: Mohamed Ahmed <mohamedahmedegypt2001 at gmail.com>
> ---
> drivers/gpu/drm/nouveau/nouveau_uvmm.c | 29 ++++++++++++++++++++++++--
> 1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c
b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> index 2cd0835b05e8..26edc60a530b 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> @@ -454,6 +454,31 @@ 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 page_size = 1ULL << page_shift;
> +
> + return op->va.addr % page_size == 0 && op->va.range %
page_size == 0 &&
> + op->gem.offset % page_size == 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 for us that the page size
will be aligned
> + * but just in case, make sure that it is aligned.
> + */
> + if (op_map_aligned_to_page_shift(op, nvbo->page))
> + return nvbo->page;
> +
> + /* This should never happen, but raise a warning and return 4K if
we get here. */
> + WARN_ON(1);
> + return PAGE_SHIFT;
> +}
> +
> static void
> nouveau_uvmm_sm_prepare_unwind(struct nouveau_uvmm *uvmm,
> struct nouveau_uvma_prealloc *new,
> @@ -506,7 +531,7 @@ 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 +624,7 @@ 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);
>
> --
> 2.51.0
>