[diffusion] feat: support loading peft lora (#35868)

docs/docs/sglang-diffusion/api/cli.mdx

@@ -82,6 +82,7 @@ Use `sglang generate --help` and `sglang serve --help` for the full argument lis
 - `--lora-path {PATH}` and `--lora-nickname {NAME}`: load a LoRA adapter from a local path, Hugging Face repo/subfolder, or exact Hub file URL
 - `--lora-weight-name {FILE}`: select one adapter file from a repository that contains multiple LoRA revisions. The Hub download is filtered to that file plus JSON metadata, so unused weights are not downloaded.
 - `--lora-alpha {N}`: supply the training alpha when a single-file adapter omits both per-layer alpha tensors and `adapter_config.json`. Do not set it when the adapter already records alpha metadata.
+- PEFT `adapter_config.json` semantics are applied automatically for named adapter slots, RSLoRA, and per-layer `alpha_pattern`. Adapters that require unsupported auxiliary parameters or runtime behavior, such as DoRA, fail before weight injection instead of silently using ordinary LoRA math.
 - `--lora-merge-mode {auto|merge|dynamic}`: choose how LoRA is applied. `auto` statically merges regular weights and uses dynamic LoRA for FSDP-sharded weights to avoid full-gather peaks.
 - `--num-gpus {N}`: number of GPUs to use
 - `--performance-mode {manual|auto|speed|memory}` / `--mode`: preset for latency/throughput and memory defaults. `auto` is the default and dispatches residency from selected-GPU headroom and workload type: image DiTs stay resident above the 45 GiB threshold, while video DiT placement remains model-specific. It uses FSDP only for validated DiT-offload replacement paths. `speed` keeps `torch.compile` disabled unless a model-specific deployment config opts in after validation; pass `--enable-torch-compile true` to enable it explicitly. Use `manual` to keep performance-related server args under explicit user control. Explicit offload, FSDP, and parallelism flags take precedence in all modes.

python/sglang/multimodal_gen/runtime/managers/gpu_worker.py

@@ -1093,7 +1093,7 @@ class GPUWorker(GPUWorkerPostTrainingMixin):
         """
         List loaded LoRA adapters and current application status per module.
         """
-        from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import (
+        from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import (
             LoRAPipeline,
         )
 

python/sglang/multimodal_gen/runtime/pipelines/cosmos3_pipeline.py

@@ -11,7 +11,7 @@ import os
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.stages.model_specific_stages.cosmos3 import (
     Cosmos3DecodingStage,
     Cosmos3DenoisingStage,

python/sglang/multimodal_gen/runtime/pipelines/ernie_image.py

@@ -7,7 +7,7 @@ import os
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.stages.input_validation import (
     InputValidationStage,
 )

python/sglang/multimodal_gen/runtime/pipelines/helios_pipeline.py

@@ -9,7 +9,7 @@ using the modular pipeline architecture. Phase 1: T2V only.
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.stages import (
     InputValidationStage,
 )

python/sglang/multimodal_gen/runtime/pipelines/lingbot_video_moe.py

@@ -3,7 +3,7 @@
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.stages import (
     DenoisingStage,
     InputValidationStage,

python/sglang/multimodal_gen/runtime/pipelines/lingbot_world_causal_dmd_pipeline.py

@@ -12,7 +12,7 @@ from sglang.multimodal_gen.runtime.models.schedulers.scheduling_self_forcing_flo
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.stages import (
     AuxiliaryConditionEncodingStage,
     DMDTimestepPreparationStage,

python/sglang/multimodal_gen/runtime/pipelines/ltx_2_pipeline.py

@@ -29,7 +29,7 @@ from sglang.multimodal_gen.runtime.models.schedulers.scheduling_flow_match_euler
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.schedule_batch import Req
 from sglang.multimodal_gen.runtime.pipelines_core.stages import (
     InputValidationStage,

python/sglang/multimodal_gen/runtime/pipelines/minimax_h3_pipeline.py

@@ -9,7 +9,7 @@ from sglang.multimodal_gen.runtime.disaggregation.roles import RoleType
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.stages import InputValidationStage
 from sglang.multimodal_gen.runtime.pipelines_core.stages.model_specific_stages.minimax_h3 import (
     MiniMaxH3AudioEncodingStage,

python/sglang/multimodal_gen/runtime/pipelines/stable_diffusion_3.py

@@ -8,7 +8,7 @@ import torch
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.schedule_batch import Req
 from sglang.multimodal_gen.runtime.pipelines_core.stages import (
     InputValidationStage,

python/sglang/multimodal_gen/runtime/pipelines/wan_causal_dmd_pipeline.py

@@ -10,7 +10,7 @@ This module wires the causal DMD denoising stage into the modular pipeline.
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 
 # isort: off
 from sglang.multimodal_gen.runtime.pipelines_core.stages import (

python/sglang/multimodal_gen/runtime/pipelines/wan_dmd_pipeline.py

@@ -14,7 +14,7 @@ from sglang.multimodal_gen.runtime.models.schedulers.scheduling_flow_match_euler
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.server_args import ServerArgs
 
 # isort: off

python/sglang/multimodal_gen/runtime/pipelines/wan_i2v_dmd_pipeline.py

@@ -14,7 +14,7 @@ from sglang.multimodal_gen.runtime.models.schedulers.scheduling_flow_match_euler
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.stages import DmdDenoisingStage
 from sglang.multimodal_gen.runtime.server_args import ServerArgs
 

python/sglang/multimodal_gen/runtime/pipelines/wan_i2v_pipeline.py

@@ -14,7 +14,7 @@ from sglang.multimodal_gen.runtime.models.schedulers.scheduling_flow_unipc_multi
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.server_args import ServerArgs
 
 

python/sglang/multimodal_gen/runtime/pipelines/wan_pipeline.py

@@ -14,7 +14,7 @@ from sglang.multimodal_gen.runtime.models.schedulers.scheduling_flow_unipc_multi
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.stages import (
     InputValidationStage,
 )

python/sglang/multimodal_gen/runtime/pipelines_core/__init__.py

@@ -13,7 +13,7 @@ from sglang.multimodal_gen.registry import get_model_info
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.pipelines_core.schedule_batch import Req
 from sglang.multimodal_gen.runtime.server_args import ServerArgs
 from sglang.multimodal_gen.runtime.utils.hf_diffusers_utils import (

python/sglang/multimodal_gen/runtime/pipelines_core/lora/__init__.py

@@ -0,0 +1 @@
+"""LoRA loading and pipeline integration."""

python/sglang/multimodal_gen/runtime/pipelines_core/lora/format_adapter.py

@@ -2,11 +2,16 @@ from __future__ import annotations
 
 import logging
 from enum import Enum
-from typing import Dict, Iterable, Mapping, Optional
+from typing import Any, Dict, Iterable, Mapping, Optional
 
 import torch
 from diffusers.loaders import lora_conversion_utils as lcu
 
+from sglang.multimodal_gen.runtime.pipelines_core.lora.peft_adapter import (
+    apply_peft_config,
+    normalize_peft_keys,
+)
+
 logger = logging.getLogger("LoRAFormatAdapter")
 
 
@@ -539,10 +544,13 @@ def convert_lora_state_dict_by_format(
 def normalize_lora_state_dict(
     state_dict: Mapping[str, torch.Tensor],
     logger: Optional[logging.Logger] = None,
+    *,
+    adapter_config: Mapping[str, Any] | None = None,
 ) -> Dict[str, torch.Tensor]:
     """Normalize any supported LoRA format into a single canonical layout."""
     log = logger or globals()["logger"]
 
+    state_dict = normalize_peft_keys(state_dict)
     keys = list(state_dict.keys())
     log.info(
         "[LoRAFormatAdapter] normalize_lora_state_dict called, #keys=%d",
@@ -558,6 +566,7 @@ def normalize_lora_state_dict(
     log.info("[LoRAFormatAdapter] detected format: %s", fmt)
 
     normalized = convert_lora_state_dict_by_format(state_dict, fmt, log)
+    normalized = apply_peft_config(normalized, adapter_config or {})
 
     norm_keys = list(normalized.keys())
     if norm_keys:

python/sglang/multimodal_gen/runtime/pipelines_core/lora/peft_adapter.py

@@ -0,0 +1,211 @@
+"""Adapt PEFT checkpoint semantics to native diffusion LoRA layers."""
+
+from __future__ import annotations
+
+import json
+import math
+import re
+from pathlib import Path
+from typing import Any, Mapping
+
+import torch
+
+_ADAPTER_SLOT = re.compile(r"(\.lora_[AB])\.([^.]+)\.weight$")
+_WRAPPER_PREFIXES = ("peft_model.base_model.model.", "base_model.model.")
+_UNSUPPORTED_CONFIG_FIELDS = (
+    "alora_invocation_tokens",
+    "layer_replication",
+    "modules_to_save",
+    "target_parameters",
+    "trainable_token_indices",
+    "use_bdlora",
+    "use_qalora",
+)
+
+
+def load_peft_config(weight_path: str) -> dict[str, Any]:
+    path = Path(weight_path).with_name("adapter_config.json")
+    if not path.is_file():
+        return {}
+    with path.open(encoding="utf-8") as file:
+        config = json.load(file)
+    if not isinstance(config, dict):
+        raise ValueError("PEFT adapter_config.json must contain a JSON object")
+    return config
+
+
+def get_peft_lora_alpha(config: Mapping[str, Any]) -> int | None:
+    alpha = config.get("lora_alpha")
+    if alpha is None:
+        return None
+    if (
+        isinstance(alpha, bool)
+        or not isinstance(alpha, (int, float))
+        or alpha <= 0
+        or isinstance(alpha, float)
+        and not alpha.is_integer()
+    ):
+        raise ValueError("PEFT lora_alpha must be a positive integer")
+    return int(alpha)
+
+
+def normalize_peft_keys(
+    state_dict: Mapping[str, torch.Tensor],
+) -> dict[str, torch.Tensor]:
+    """Remove a uniform PEFT model wrapper and named adapter slot."""
+    prefix = next(
+        (
+            prefix
+            for prefix in _WRAPPER_PREFIXES
+            if state_dict and all(name.startswith(prefix) for name in state_dict)
+        ),
+        "",
+    )
+    normalized: dict[str, torch.Tensor] = {}
+    slots = set()
+    has_bare_weights = False
+    for name, tensor in state_dict.items():
+        name = name.removeprefix(prefix)
+        match = _ADAPTER_SLOT.search(name)
+        if match is not None:
+            slots.add(match.group(2))
+        elif name.endswith((".lora_A.weight", ".lora_B.weight")):
+            has_bare_weights = True
+        target = _ADAPTER_SLOT.sub(r"\1.weight", name)
+        if target in normalized:
+            raise ValueError(
+                "LoRA checkpoint contains multiple PEFT adapter slots for "
+                f"the same tensor: {target!r}"
+            )
+        normalized[target] = tensor
+    if len(slots) > 1:
+        raise ValueError(
+            f"LoRA checkpoint contains multiple PEFT adapter slots: {sorted(slots)}"
+        )
+    if slots and has_bare_weights:
+        raise ValueError("LoRA checkpoint mixes named and unnamed PEFT adapter slots")
+    return normalized
+
+
+def _validate_peft_features(
+    state_dict: Mapping[str, torch.Tensor], config: Mapping[str, Any]
+) -> None:
+    unsupported = {name for name in _UNSUPPORTED_CONFIG_FIELDS if config.get(name)}
+    if config.get("bias") not in (None, "none"):
+        unsupported.add("bias")
+    unsupported.update(
+        name for name in ("fan_in_fan_out", "lora_bias") if config.get(name, False)
+    )
+    if unsupported:
+        raise ValueError(
+            "PEFT adapter requires unsupported auxiliary/runtime features: "
+            f"{sorted(unsupported)}"
+        )
+    if config.get("use_dora", False) or any(
+        "lora_magnitude_vector" in name or "dora_scale" in name for name in state_dict
+    ):
+        raise ValueError(
+            "DoRA adapters are not supported by the native diffusion LoRA layers"
+        )
+    auxiliary = [
+        name
+        for name in state_dict
+        if any(
+            marker in name
+            for marker in ("lora_embedding_", "modules_to_save", "trainable_tokens")
+        )
+    ]
+    if auxiliary:
+        raise ValueError(
+            f"PEFT adapter contains unsupported auxiliary tensors: {auxiliary[:8]}"
+        )
+
+
+def apply_peft_config(
+    state_dict: dict[str, torch.Tensor], config: Mapping[str, Any]
+) -> dict[str, torch.Tensor]:
+    """Represent PEFT scaling variants with native LoRA tensors and alpha."""
+    _validate_peft_features(state_dict, config)
+    normalized = dict(state_dict)
+    patterns = config.get("alpha_pattern", {})
+    if not isinstance(patterns, dict):
+        raise ValueError("PEFT alpha_pattern must be an object")
+    compiled_patterns = []
+    for pattern, value in patterns.items():
+        if not isinstance(pattern, str):
+            raise ValueError("PEFT alpha_pattern keys must be strings")
+        try:
+            expression = re.compile(rf"(.*\.)?({pattern})$")
+        except re.error as error:
+            raise ValueError(
+                f"Invalid PEFT alpha_pattern expression {pattern!r}: {error}"
+            ) from error
+        alpha = get_peft_lora_alpha({"lora_alpha": value})
+        if alpha is None:
+            raise ValueError(
+                f"PEFT alpha_pattern value for {pattern!r} must be a positive integer"
+            )
+        compiled_patterns.append((expression, alpha))
+
+    suffix = ".lora_A.weight"
+    for name in state_dict:
+        if not name.endswith(suffix):
+            continue
+        base = name[: -len(suffix)]
+        alpha = next(
+            (alpha for pattern, alpha in compiled_patterns if pattern.match(base)), None
+        )
+        if alpha is None:
+            continue
+        alpha_key = f"{base}.alpha"
+        existing = normalized.get(alpha_key)
+        if existing is not None and (
+            existing.numel() != 1 or int(existing.item()) != alpha
+        ):
+            raise ValueError(f"PEFT alpha_pattern conflicts with tensor {alpha_key!r}")
+        normalized[alpha_key] = torch.tensor(alpha)
+
+    use_rslora = config.get("use_rslora", False)
+    if not isinstance(use_rslora, bool):
+        raise ValueError("PEFT use_rslora must be boolean")
+    if not use_rslora:
+        return normalized
+
+    suffix = ".lora_B.weight"
+    pairs = 0
+    for name, weight in state_dict.items():
+        if not name.endswith(suffix):
+            continue
+        lora_a = state_dict.get(f"{name[: -len(suffix)]}.lora_A.weight")
+        if lora_a is None or lora_a.ndim < 2 or lora_a.shape[-2] <= 0:
+            raise ValueError(f"RSLoRA weight {name!r} has no valid rank-bearing A")
+        normalized[name] = weight * math.sqrt(lora_a.shape[-2])
+        pairs += 1
+    if not pairs:
+        raise ValueError("PEFT use_rslora is true, but no LoRA A/B pairs were found")
+    return normalized
+
+
+def scale_fused_sections(
+    a_parts: Mapping[int, torch.Tensor],
+    b_parts: Mapping[int, torch.Tensor],
+    alpha_parts: Mapping[int, torch.Tensor],
+    default_alpha: int | None,
+) -> list[torch.Tensor] | None:
+    """Fold per-section PEFT alpha values into fused LoRA B weights."""
+    if not alpha_parts:
+        return None
+    scaled = []
+    for index in range(len(a_parts)):
+        rank = a_parts[index].shape[0]
+        alpha = float(
+            alpha_parts[index].item()
+            if index in alpha_parts
+            else default_alpha if default_alpha is not None else rank
+        )
+        scale = alpha / rank
+        weight = b_parts[index]
+        scaled.append(
+            weight if scale == 1.0 else (weight.float() * scale).to(weight.dtype)
+        )
+    return scaled

python/sglang/multimodal_gen/runtime/pipelines_core/lora/pipeline.py

@@ -1,7 +1,6 @@
 # Copied and adapted from: https://github.com/hao-ai-lab/FastVideo
 
 # SPDX-License-Identifier: Apache-2.0
-import json
 import os
 from collections import defaultdict
 from collections.abc import Hashable
@@ -26,9 +25,14 @@ from sglang.multimodal_gen.runtime.managers.memory_managers.layerwise_offload im
 from sglang.multimodal_gen.runtime.pipelines_core.composed_pipeline_base import (
     ComposedPipelineBase,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_format_adapter import (
+from sglang.multimodal_gen.runtime.pipelines_core.lora.format_adapter import (
     normalize_lora_state_dict,
 )
+from sglang.multimodal_gen.runtime.pipelines_core.lora.peft_adapter import (
+    get_peft_lora_alpha,
+    load_peft_config,
+    scale_fused_sections,
+)
 from sglang.multimodal_gen.runtime.server_args import LORA_MERGE_MODES, ServerArgs
 from sglang.multimodal_gen.runtime.utils.hf_diffusers_utils import maybe_download_lora
 from sglang.multimodal_gen.runtime.utils.logging_utils import init_logger
@@ -98,11 +102,19 @@ def _store_fused_lora_groups(
             or set(b_parts) != set(range(n))
         ):
             continue
-        a, b, fused_alpha = stack_or_compose_fused_lora(
-            [a_parts[i] for i in range(n)],
-            [b_parts[i] for i in range(n)],
+        a_list = [a_parts[i] for i in range(n)]
+        b_list = [b_parts[i] for i in range(n)]
+        scaled_b = scale_fused_sections(
+            a_parts,
+            b_parts,
+            to_merge_params.get(f"{base}.alpha", {}),
             adapter_alpha,
         )
+        a, b, fused_alpha = stack_or_compose_fused_lora(
+            a_list, scaled_b or b_list, None if scaled_b else adapter_alpha
+        )
+        if scaled_b:
+            fused_alpha = a.shape[-2]
         adapter[str(a_key)] = a.to(device)
         adapter[b_key] = b.to(device)
         if fused_alpha is not None:
@@ -823,16 +835,15 @@ class LoRAPipeline(ComposedPipelineBase):
             lora_local_path = maybe_download_lora(lora_path, weight_name=weight_name)
 
         raw_state_dict = load_file(lora_local_path)
-        lora_state_dict = normalize_lora_state_dict(raw_state_dict, logger=logger)
-        adapter_lora_alpha = lora_alpha
-        adapter_config_path = os.path.join(
-            os.path.dirname(lora_local_path), "adapter_config.json"
+        adapter_config = load_peft_config(lora_local_path)
+        lora_state_dict = normalize_lora_state_dict(
+            raw_state_dict,
+            logger=logger,
+            adapter_config=adapter_config,
         )
-        if adapter_lora_alpha is None and os.path.isfile(adapter_config_path):
-            with open(adapter_config_path, encoding="utf-8") as f:
-                adapter_config = json.load(f)
-            if adapter_config.get("lora_alpha") is not None:
-                adapter_lora_alpha = int(adapter_config["lora_alpha"])
+        adapter_lora_alpha = lora_alpha
+        if adapter_lora_alpha is None:
+            adapter_lora_alpha = get_peft_lora_alpha(adapter_config)
 
         if lora_nickname in self.lora_adapters:
             self.lora_adapters[lora_nickname].clear()

python/sglang/multimodal_gen/runtime/post_training/weights_updater.py

@@ -58,7 +58,7 @@ from sglang.multimodal_gen.runtime.managers.memory_managers.layerwise_offload im
     is_layerwise_offloaded_module,
 )
 from sglang.multimodal_gen.runtime.pipelines.diffusers_pipeline import DiffusersPipeline
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import (
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import (
     LoRAPipeline,
     stack_or_compose_fused_lora,
 )

python/sglang/multimodal_gen/test/unit/test_fused_lora_compose.py

@@ -11,8 +11,9 @@ import torch.nn.functional as F
 from sglang.multimodal_gen.runtime.layers.lora.linear import (
     MergedColumnParallelLinearWithLoRA,
 )
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import (
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import (
     LoRAPipeline,
+    _store_fused_lora_groups,
     stack_or_compose_fused_lora,
 )
 from sglang.multimodal_gen.runtime.post_training.weights_updater import (
@@ -64,6 +65,31 @@ def test_compose_unequal_sections_matches_reference():
     )
 
 
+def test_fused_sections_preserve_per_layer_alpha():
+    a_list, b_list = _make_ab_lists([2, 3, 1])
+    alphas = [2, 6, 1]
+    pending = defaultdict(dict)
+    for index, (lora_a, lora_b, alpha) in enumerate(zip(a_list, b_list, alphas)):
+        pending["attn.qkv.lora_A"][index] = lora_a
+        pending["attn.qkv.lora_B"][index] = lora_b
+        pending["attn.qkv.alpha"][index] = torch.tensor(alpha)
+
+    adapter = {}
+    _store_fused_lora_groups(adapter, pending, adapter_alpha=4, device="cpu")
+
+    x = torch.randn(5, IN_DIM)
+    actual = x @ adapter["attn.qkv.lora_A"].T @ adapter["attn.qkv.lora_B"].T
+    expected = torch.cat(
+        [
+            (x @ lora_a.T @ lora_b.T) * (alpha / lora_a.shape[0])
+            for lora_a, lora_b, alpha in zip(a_list, b_list, alphas)
+        ],
+        dim=-1,
+    )
+    assert adapter["attn.qkv.alpha"].item() == sum(a.shape[0] for a in a_list)
+    torch.testing.assert_close(actual, expected, rtol=1e-5, atol=1e-5)
+
+
 def test_stack_kept_for_equal_sections():
     torch.manual_seed(0)
     a_list = [torch.randn(2, IN_DIM) for _ in range(2)]
@@ -272,7 +298,7 @@ def _make_loader_pipeline() -> _TestLoRAPipeline:
 
 
 def _load_adapter(pipeline, state_dict, lora_alpha=None):
-    loader_mod = "sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline"
+    loader_mod = "sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline"
     with (
         patch(f"{loader_mod}.maybe_download_lora", return_value="/adapter"),
         patch(f"{loader_mod}.load_file", return_value=state_dict),
@@ -344,7 +370,7 @@ def test_apply_composed_adapter_end_to_end():
 
     strength = 2.0
     with patch(
-        "sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline.dist.get_rank",
+        "sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline.dist.get_rank",
         return_value=0,
     ):
         applied = pipeline._apply_lora_to_layers(

python/sglang/multimodal_gen/test/unit/test_gguf_diffusion.py

@@ -702,7 +702,7 @@ class TestGGUFRejectsLoraConversion(unittest.TestCase):
     """The dynamic set_lora path must refuse before replacing any layer."""
 
     def _pipeline_with(self, layer):
-        from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import (
+        from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import (
             LoRAPipeline,
         )
 

python/sglang/multimodal_gen/test/unit/test_lora_format_adapter.py

@@ -16,7 +16,7 @@ import torch
 from huggingface_hub import hf_hub_download
 from safetensors.torch import load_file
 
-from sglang.multimodal_gen.runtime.pipelines_core.lora_format_adapter import (
+from sglang.multimodal_gen.runtime.pipelines_core.lora.format_adapter import (
     LoRAFormat,
     detect_lora_format_from_state_dict,
     normalize_lora_state_dict,

python/sglang/multimodal_gen/test/unit/test_lora_peft.py

@@ -0,0 +1,55 @@
+"""PEFT LoRA normalization and fail-closed capability tests."""
+
+import math
+
+import pytest
+import torch
+
+from sglang.multimodal_gen.runtime.pipelines_core.lora.format_adapter import (
+    normalize_lora_state_dict,
+)
+from sglang.multimodal_gen.runtime.pipelines_core.lora.peft_adapter import (
+    get_peft_lora_alpha,
+)
+
+
+def test_peft_wrapper_slot_and_rslora_scaling_preserve_delta():
+    lora_a = torch.randn(4, 8)
+    lora_b = torch.randn(16, 4)
+    normalized = normalize_lora_state_dict(
+        {
+            "base_model.model.transformer.proj.lora_A.default.weight": lora_a,
+            "base_model.model.transformer.proj.lora_B.default.weight": lora_b,
+        },
+        adapter_config={
+            "use_rslora": True,
+            "lora_alpha": 8,
+            "alpha_pattern": {"transformer.proj": 8},
+        },
+    )
+
+    normalized_b = normalized["transformer.proj.lora_B.weight"]
+    ordinary_delta = (8 / 4) * normalized_b @ lora_a
+    expected_delta = (8 / math.sqrt(4)) * lora_b @ lora_a
+    torch.testing.assert_close(ordinary_delta, expected_delta)
+    assert normalized["transformer.proj.alpha"].item() == 8
+
+
+@pytest.mark.parametrize(
+    ("state_dict", "adapter_config"),
+    [
+        ({}, {"use_dora": True}),
+        ({}, {"modules_to_save": ["head"]}),
+        ({}, {"target_parameters": ["experts.weight"]}),
+        ({}, {"fan_in_fan_out": True}),
+        ({"encoder.lora_embedding_A.weight": torch.ones(2, 2)}, {}),
+    ],
+)
+def test_unsupported_peft_runtime_semantics_fail_closed(state_dict, adapter_config):
+    with pytest.raises(ValueError, match="not supported|unsupported"):
+        normalize_lora_state_dict(state_dict, adapter_config=adapter_config)
+
+
+def test_invalid_peft_lora_alpha_fails_closed():
+    with pytest.raises(ValueError, match="positive integer"):
+        get_peft_lora_alpha({"lora_alpha": 8.5})

python/sglang/multimodal_gen/test/unit/test_lora_pipeline.py

@@ -6,10 +6,10 @@ from unittest.mock import patch
 import torch
 
 from sglang.multimodal_gen.runtime.layers.lora.linear import BaseLayerWithLoRA
-from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import LoRAPipeline
+from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import LoRAPipeline
 from sglang.multimodal_gen.runtime.utils.hf_diffusers_utils import maybe_download_lora
 
-_RANK_PATCH = "sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline.dist.get_rank"
+_RANK_PATCH = "sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline.dist.get_rank"
 
 
 class _TestLoRAPipeline(LoRAPipeline):

python/sglang/multimodal_gen/test/unit/test_ltx2_5_config.py

@@ -564,7 +564,7 @@ class TestLTX25OptionalDecoderLoading(unittest.TestCase):
 
     def test_decoder_is_not_loaded_by_default(self):
         from sglang.multimodal_gen.runtime.pipelines.ltx_2_pipeline import LTX2Pipeline
-        from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import (
+        from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import (
             LoRAPipeline,
         )
 
@@ -578,7 +578,7 @@ class TestLTX25OptionalDecoderLoading(unittest.TestCase):
 
     def test_decoder_load_is_explicit_and_validated(self):
         from sglang.multimodal_gen.runtime.pipelines.ltx_2_pipeline import LTX2Pipeline
-        from sglang.multimodal_gen.runtime.pipelines_core.lora_pipeline import (
+        from sglang.multimodal_gen.runtime.pipelines_core.lora.pipeline import (
             LoRAPipeline,
         )