fix: reject CP shared KV with HiCache storage

python/sglang/srt/server_args.py

@@ -1586,6 +1586,11 @@ class ServerArgs:
                         "Phase 2 shared KV initially supports NSATokenToKVPool only; "
                         "HiSparseNSATokenToKVPool is not wired yet."
                     )
+                    assert self.hicache_storage_backend is None, (
+                        "enable_nsa_prefill_cp_shared_kv does not support "
+                        "hicache_storage_backend in the host-only CP HiCache stage. "
+                        "Disable hicache_storage_backend or disable CP shared KV."
+                    )
                     if self.disaggregation_mode == "prefill":
                         assert envs.SGLANG_DISAGGREGATION_ALL_CP_RANKS_TRANSFER.get(), (
                             "Phase 2 shared KV with PD disaggregation requires "