Function graph_kv_pull_host 

pub fn graph_kv_pull_host(
    _kv_id: u64,
    _layer: usize,
    _from: usize,
    _to: usize,
    _nkv: usize,
    _hd: usize,
) -> Option<(Vec<f32>, Vec<f32>, usize)>

Rows [from, to) of one wgpu exact-attention mirror in the host cache’s layout (V zero-padded to hd), whatever the mirror’s geometry (narrow V, a sliding layer’s ring). The third value is the first position actually read: a ring returns zeros below it. None: no wgpu mirror holding those rows at (nkv, hd).