Set version to 0.10.1

* Set version to 0.10.1.dev0

* Add `__version__` attribute to top-level module

This is needed for doc generation.

.github/workflows/build_documentation.yaml

@@ -0,0 +1,17 @@
+name: Build documentation
+
+on:
+  push:
+    branches:
+      - main
+      - doc-builder*
+      - v*-release
+
+jobs:
+  build:
+    uses: huggingface/doc-builder/.github/workflows/build_main_documentation.yml@main
+    with:
+      commit_sha: ${{ github.sha }}
+      package: kernels
+    secrets:
+      hf_token: ${{ secrets.HF_DOC_BUILD_PUSH }}

.github/workflows/build_pr_documentation.yaml

@@ -0,0 +1,15 @@
+name: Build PR Documentation
+
+on: pull_request
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    uses: huggingface/doc-builder/.github/workflows/build_pr_documentation.yml@main
+    with:
+      commit_sha: ${{ github.event.pull_request.head.sha }}
+      pr_number: ${{ github.event.number }}
+      package: kernels

.github/workflows/lint.yml

@@ -8,3 +8,24 @@ jobs:
       - uses: actions/checkout@v4
       - name: Run ruff
         uses: astral-sh/ruff-action@v3
+
+  black:
+    name: Run black check
+    runs-on: ubuntu-latest
+    env:
+      UV_PYTHON_PREFERENCE: only-managed
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install uv and set the python version
+        uses: astral-sh/setup-uv@v5
+        with:
+          python-version: 3.12
+
+      - name: Install black
+        run: uv pip install black
+
+      - name: Check formatting
+        run: |
+          uv run black --check src
+          uv run black --check tests

.github/workflows/upload_pr_documentation.yaml

@@ -0,0 +1,16 @@
+name: Upload PR Documentation
+
+on:
+  workflow_run:
+    workflows: ["Build PR Documentation"]
+    types:
+      - completed
+
+jobs:
+  build:
+    uses: huggingface/doc-builder/.github/workflows/upload_pr_documentation.yml@main
+    with:
+      package_name: kernels
+    secrets:
+      hf_token: ${{ secrets.HF_DOC_BUILD_PUSH }}
+      comment_bot_token: ${{ secrets.COMMENT_BOT_TOKEN }}

README.md

@@ -56,10 +56,13 @@ the Hub.
 
 ## 📚 Documentation
 
-- [Using layers](docs/layers.md)
-- [Locking kernel versions](docs/locking.md)
-- [Environment variables](docs/env.md)
-- [Using kernels in a Docker container](docs/docker.md)
-- [Kernel requirements](docs/kernel-requirements.md)
-- [Frequently Asked Questions](docs/faq.md)
+- [Introduction](docs/source/index.md)
+- [Installation](docs/source/installation.md)
+- [Basic usage](docs/source/basic-usage.md)
+- [Using layers](docs/source/layers.md)
+- [Locking kernel/layer versions](docs/source/locking.md)
+- [Environment variables](docs/source/env.md)
+- [Using kernels in a Docker container](docs/source/docker.md)
+- [Kernel requirements](docs/source/kernel-requirements.md)
+- [Frequently Asked Questions](docs/source/faq.md)
 - [Writing kernels](https://github.com/huggingface/kernel-builder/blob/main/docs/writing-kernels.md) using [kernel-builder](https://github.com/huggingface/kernel-builder/)

docs/docker.md

@@ -1,8 +0,0 @@
-# Using kernels in a Docker container
-
-build and run the reference [examples/basic.py](examples/basic.py) in a Docker container with the following commands:
-
-```bash
-docker build --platform linux/amd64 -t kernels-reference -f docker/Dockerfile.reference .
-docker run --gpus all -it --rm -e HF_TOKEN=$HF_TOKEN kernels-reference
-```

docs/source/_toctree.yml

@@ -0,0 +1,28 @@
+- sections:
+    - local: index
+      title: Introduction
+    - local: installation
+      title: Installation
+  title: Getting started
+- sections:
+    - local: basic-usage
+      title: Basic Usage
+    - local: layers
+      title: Using Layers
+    - local: locking
+      title: Locking Kernel Versions
+    - local: env
+      title: Environment Variables
+    - local: faq
+      title: FAQ
+  title: Usage Guide
+- sections:
+    - local: api/kernels
+      title: Kernels
+    - local: api/layers
+      title: Layers
+  title: API Reference
+- sections:
+    - local: kernel-requirements
+      title: Kernel Requirements
+  title: Developer Guide

docs/source/api/kernels.md

@@ -0,0 +1,21 @@
+# Kernels API Reference
+
+## Main Functions
+
+### get_kernel
+
+[[autodoc]] kernels.get_kernel
+
+### has_kernel
+
+[[autodoc]] kernels.has_kernel
+
+## Loading locked kernels
+
+### load_kernel
+
+[[autodoc]] kernels.load_kernel
+
+### get_locked_kernel
+
+[[autodoc]] kernels.get_locked_kernel

docs/source/api/layers.md

@@ -0,0 +1,41 @@
+# Layers API Reference
+
+## Making layers kernel-aware
+
+### use_kernel_forward_from_hub
+
+[[autodoc]] kernels.use_kernel_forward_from_hub
+
+### replace_kernel_forward_from_hub
+
+[[autodoc]] kernels.replace_kernel_forward_from_hub
+
+## Registering kernel mappings
+
+### use_kernel_mapping
+
+[[autodoc]] kernels.use_kernel_mapping
+
+### register_kernel_mapping
+
+[[autodoc]] kernels.register_kernel_mapping
+
+## Kernelizing a model
+
+### kernelize
+
+[[autodoc]] kernels.kernelize
+
+## Classes
+
+### Device
+
+[[autodoc]] kernels.Device
+
+### Mode
+
+[[autodoc]] kernels.Mode
+
+### LayerRepository
+
+[[autodoc]] kernels.LayerRepository

docs/source/basic-usage.md

@@ -0,0 +1,34 @@
+# Basic Usage
+
+## Loading Kernels
+
+Here is how you would use the [activation](https://huggingface.co/kernels-community/activation) kernels from the Hugging Face Hub:
+
+```python
+import torch
+from kernels import get_kernel
+
+# Download optimized kernels from the Hugging Face hub
+activation = get_kernel("kernels-community/activation")
+
+# Create a random tensor
+x = torch.randn((10, 10), dtype=torch.float16, device="cuda")
+
+# Run the kernel
+y = torch.empty_like(x)
+activation.gelu_fast(y, x)
+
+print(y)
+```
+
+## Checking Kernel Availability
+
+You can check if a specific kernel is available for your environment:
+
+```python
+from kernels import has_kernel
+
+# Check if kernel is available for current environment
+is_available = has_kernel("kernels-community/activation")
+print(f"Kernel available: {is_available}")
+```

docs/source/faq.md

@@ -2,9 +2,9 @@
 
 ## Why is the kernelization step needed?
 
-In earlier versions of `kernels`, a layer's `forward` was replaced by
-`use_kernel_forward_from_hub` and `replace_kernel_forward_from_hub`. The
-new `forward` would dispatch to a kernel based on the device type,
+In earlier versions of `kernels`, a layer's `forward` method was replaced
+by `use_kernel_forward_from_hub` and `replace_kernel_forward_from_hub`.
+The new `forward` would dispatch to a kernel based on the device type,
 whether a model was training, etc. However, this approach was
 fundamentally incompatible with `torch.compile` since it relied
 on data-dependent branching.

docs/source/index.md

@@ -0,0 +1,20 @@
+# Kernels
+
+<div align="center">
+<img src="https://github.com/user-attachments/assets/64a652f3-0cd3-4829-b3c1-df13f7933569" width="450" height="450" alt="kernel-builder logo">
+</div>
+
+The Kernel Hub allows Python libraries and applications to load compute
+kernels directly from the [Hub](https://hf.co/). To support this kind
+of dynamic loading, Hub kernels differ from traditional Python kernel
+packages in that they are made to be:
+
+- **Portable**: a kernel can be loaded from paths outside `PYTHONPATH`.
+- **Unique**: multiple versions of the same kernel can be loaded in the
+  same Python process.
+- **Compatible**: kernels must support all recent versions of Python and
+  the different PyTorch build configurations (various CUDA versions
+  and C++ ABIs). Furthermore, older C library versions must be supported.
+
+You can [search for kernels](https://huggingface.co/models?other=kernel) on
+the Hub.

docs/source/installation.md

@@ -0,0 +1,16 @@
+# Installation
+
+Install the `kernels` package with `pip` (requires `torch>=2.5` and CUDA):
+
+```bash
+pip install kernels
+```
+
+# Using kernels in a Docker container
+
+Build and run the reference `examples/basic.py` in a Docker container with the following commands:
+
+```bash
+docker build --platform linux/amd64 -t kernels-reference -f docker/Dockerfile.reference .
+docker run --gpus all -it --rm -e HF_TOKEN=$HF_TOKEN kernels-reference
+```

docs/source/layers.md

@@ -84,12 +84,6 @@ model = kernelize(model, mode=Mode.INFERENCE | Mode.TORCH_COMPILE)
 model = kernelize(model, mode=Mode.TRAINING | Mode.TORCH_COMPILE)
 ```
 
-When the `mode` argument is not specified,
-`Mode.TRAINING | Mode.TORCH_COMPILE` is used as the default. This mode
-aligns most closely with pure PyTorch layers which also support training
-and `torch.compile`. However, to select the most performant kernels, it
-is often good to make the mode specific as possible.
-
 ### Kernel device
 
 Kernels can be registered per device type. For instance, separate `cuda` and
@@ -107,7 +101,7 @@ model = kernelize(model, device="cuda", mode=Mode.INFERENCE)
 
 If the `TRAINING` and/or `TORCH_COMPILE` modes are used, but a registered
 kernel does not support backward passes or `torch.compile` respectively,
-`kernenize` will fall back to the original, non-kernelized, layer. You
+`kernelize` will fall back to the original, non-kernelized, layer. You
 can let `kernelize` raise an exception instead by using `use_fallback=False`:
 
 ```python
@@ -135,6 +129,10 @@ kernel_layer_mapping = {
         "cuda": LayerRepository(
             repo_id="kernels-community/activation",
             layer_name="SiluAndMul",
+        ),
+        "rocm": LayerRepository(
+            repo_id="kernels-community/activation",
+            layer_name="SiluAndMul",
         )
     }
 }
@@ -153,7 +151,7 @@ used with the `use_kernel_mapping` context manager:
 ```python
 with use_kernel_mapping(kernel_layer_mapping):
     # Use the layer for which the mapping is applied.
-    model = kernelize(model)
+    model = kernelize(model, mode=Mode.TRAINING | Mode.TORCH_COMPILE)
 ```
 
 This ensures that the mapping is not active anymore outside the
@@ -261,7 +259,6 @@ Capabilities behave as follows:
   an existing kernel, the new kernel will replace the old kernel.
 - When there are multiple kernels that support a capability, the kernel
   with the smaller capability interval will be used. E.g. given:
-
   - `KernelA` with `min_capability=80` and `max_capability=89`;
   - `KernelB` with `min_capability=75` and `max_capability=89`;
   - `kernelize` runs on a system with capability 8.6.
@@ -270,3 +267,30 @@ Capabilities behave as follows:
   than 75..89. The motivation is that kernels with smaller ranges
   tend to be more optimized for a specific set of GPUs. **This behavior
   might still change in the future.**
+
+### Registering kernels for specific ROCm capabilities
+
+Registering kernels for the ROCm architecture follows the exact same
+pattern as CUDA kernels, using `min_capability` and `max_capability` to restrict
+a kernel to a range of ROCm capabilities.
+
+### Loading from a local repository for testing
+
+The `LocalLayerRepository` class is provided to load a repository from
+a local directory. For example:
+
+```python
+with use_kernel_mapping(
+    {
+        "SiluAndMul": {
+            "cuda": LocalLayerRepository(
+                repo_path="/home/daniel/kernels/activation",
+                package_name="activation",
+                layer_name="SiluAndMul",
+            )
+        }
+    },
+    inherit_mapping=False,
+):
+    kernelize(linear, mode=Mode.INFERENCE)
+```

docs/source/locking.md

@@ -1,4 +1,4 @@
-# Locking kernel versions
+# Locking kernel/layer versions
 
 Projects that use `setuptools` can lock the kernel versions that should be
 used. First specify the accepted versions in `pyproject.toml` and make
@@ -26,6 +26,24 @@ activation = get_locked_kernel("kernels-community/activation")
 **Note:** the lock file is included in the package metadata, so it will only be visible
 to `kernels` after doing an (editable or regular) installation of your project.
 
+## Locked kernel layers
+
+Locking is also supported for kernel layers. To use locked layers, register them
+with the `LockedLayerRepository` class:
+
+```python
+kernel_layer_mapping = {
+    "SiluAndMul": {
+        "cuda": LockedLayerRepository(
+            repo_id="kernels-community/activation",
+            layer_name="SiluAndMul",
+        )
+    }
+}
+
+register_kernel_mapping(kernel_layer_mapping)
+```
+
 ## Pre-downloading locked kernels
 
 Locked kernels can be pre-downloaded by running `kernels download .` in your

flake.lock

@@ -58,11 +58,11 @@
         "nixpkgs": "nixpkgs"
       },
       "locked": {
-        "lastModified": 1750775451,
-        "narHash": "sha256-HiGqtwzIgUH7Xkh+wgpvHRZGooqrW0z663E6nauczA4=",
+        "lastModified": 1754038838,
+        "narHash": "sha256-oHigCT4z0ayyLyEuxdZooSXRAZP8lfOkZHzY1lx1U50=",
         "owner": "huggingface",
         "repo": "hf-nix",
-        "rev": "5943c3169e861618a6634bc8dbdb498e413ab9b7",
+        "rev": "336f781fa284e193baa3d4c3ce3f95fb34e9ffad",
         "type": "github"
       },
       "original": {
@@ -73,17 +73,17 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1747820358,
-        "narHash": "sha256-fTqsZsUX6M3yeEvgyQvXcbGmT2CaRVyVwsi8eK29Oj4=",
-        "owner": "danieldk",
+        "lastModified": 1752785354,
+        "narHash": "sha256-Y33ryUz7MPqKrZwlbQcsYCUz2jAJCacRf8jbs0tYUlA=",
+        "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "d3c1681180717528068082103bf323147de6ab0b",
+        "rev": "d38025438a6ee456758dc03188ca6873a415463b",
         "type": "github"
       },
       "original": {
-        "owner": "danieldk",
-        "ref": "cudatoolkit-12.9-kernel-builder",
+        "owner": "nixos",
         "repo": "nixpkgs",
+        "rev": "d38025438a6ee456758dc03188ca6873a415463b",
         "type": "github"
       }
     },

flake.nix

@@ -26,6 +26,10 @@
         formatter = pkgs.nixfmt-tree;
         devShells = with pkgs; rec {
           default = mkShell {
+            nativeBuildInputs = [
+              # For hf-doc-builder.
+              nodejs
+            ];
             buildInputs =
               [
                 black
@@ -36,6 +40,7 @@
               ++ (with python3.pkgs; [
                 docutils
                 huggingface-hub
+                mktestdocs
                 pytest
                 pytest-benchmark
                 pyyaml

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "kernels"
-version = "0.8.0.dev0"
+version = "0.10.1"
 description = "Download compute kernels"
 authors = [
   { name = "OlivierDehaene", email = "olivier@huggingface.co" },
@@ -24,16 +24,20 @@ build-backend = "setuptools.build_meta"
 
 [dependency-groups]
 dev = [
-  "mypy >= 1.15.0",
-  "pytest >=8",
+  "mktestdocs>=0.2.5",
+  "mypy>=1.15.0",
+  "pytest>=8",
   # Whatever version is compatible with pytest.
   "pytest-benchmark",
-  "torch >=2.5",
+  "torch>=2.5",
   "types-pyyaml"
 ]
 
 [project.optional-dependencies]
 torch = ["torch"]
+docs = [
+  "hf-doc-builder",
+]
 
 [project.scripts]
 kernels = "kernels.cli:main"

pytest.ini

@@ -1,4 +1,5 @@
 [pytest]
 markers =
+    cuda_only: marks tests that should only hosts with CUDA GPUs
+    rocm_only: marks tests that should only run on hosts with ROCm GPUs
     darwin_only: marks tests that should only run on macOS
-    linux_only: marks tests that should only run on Linux

src/kernels/__init__.py

@@ -1,7 +1,13 @@
+import importlib.metadata
+
+__version__ = importlib.metadata.version("kernels")
+
 from kernels.layer import (
     CUDAProperties,
     Device,
     LayerRepository,
+    LocalLayerRepository,
+    LockedLayerRepository,
     Mode,
     kernelize,
     register_kernel_mapping,
@@ -19,9 +25,12 @@ from kernels.utils import (
 )
 
 __all__ = [
+    "__version__",
     "CUDAProperties",
     "Device",
     "LayerRepository",
+    "LocalLayerRepository",
+    "LockedLayerRepository",
     "Mode",
     "get_kernel",
     "get_local_kernel",

src/kernels/_versions.py

@@ -1,4 +1,4 @@
-from typing import Dict
+from typing import Dict, Optional
 
 from huggingface_hub import HfApi
 from huggingface_hub.hf_api import GitRefInfo
@@ -37,3 +37,16 @@ def resolve_version_spec_as_ref(repo_id: str, version_spec: str) -> GitRefInfo:
         )
 
     return versions[accepted_versions[-1]]
+
+
+def select_revision_or_version(
+    repo_id: str, revision: Optional[str], version: Optional[str]
+) -> str:
+    if revision is not None and version is not None:
+        raise ValueError("Either a revision or a version must be specified, not both.")
+    elif revision is None and version is None:
+        revision = "main"
+    elif version is not None:
+        revision = resolve_version_spec_as_ref(repo_id, version).target_commit
+    assert revision is not None
+    return revision

src/kernels/layer.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import functools
 import inspect
 import logging
 import os
@@ -8,27 +9,34 @@ import warnings
 from abc import ABC, abstractmethod
 from contextvars import ContextVar
 from copy import deepcopy
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from enum import Flag, auto
 from functools import lru_cache
-from types import MethodType
+from pathlib import Path
+from types import MethodType, ModuleType
 from typing import (
     TYPE_CHECKING,
     Dict,
     Optional,
+    Protocol,
     Tuple,
     Type,
     Union,
 )
 
 from ._interval_tree import IntervalTree
-from .utils import get_kernel
+from ._versions import select_revision_or_version
+from .utils import (
+    _get_caller_locked_kernel,
+    _get_locked_kernel,
+    get_kernel,
+    get_local_kernel,
+)
 
 if TYPE_CHECKING:
     import torch
     from torch import nn
 
-
 _DISABLE_KERNEL_MAPPING: bool = bool(int(os.environ.get("DISABLE_KERNEL_MAPPING", "0")))
 
 
@@ -36,17 +44,19 @@ class Mode(Flag):
     """
     Kernelize mode
 
-    The `Mode` flag is used by `kernelize` to select kernels for the given
-    mode. Mappings can be registered for specific modes.
+    The `Mode` flag is used by [`kernelize`] to select kernels for the given mode. Mappings can be registered for
+    specific modes.
 
-    * `INFERENCE`: The kernel is used for inference.
-    * `TRAINING`: The kernel is used for training.
-    * `TORCH_COMPILE`: The kernel is used with `torch.compile`.
-    * `FALLBACK`: In a kernel mapping, this kernel is used when no other mode
-       matches.
+    Attributes:
+        INFERENCE: The kernel is used for inference.
+        TRAINING: The kernel is used for training.
+        TORCH_COMPILE: The kernel is used with `torch.compile`.
+        FALLBACK: In a kernel mapping, this kernel is used when no other mode matches.
+
+    Note:
+        Different modes can be combined. For instance, `INFERENCE | TORCH_COMPILE` should be used for layers that
+        are used for inference *with* `torch.compile`.
 
-    Different modes can be combined. For instance, `INFERENCE | TORCH_COMPILE`
-    should be used for layers that are used for inference *with* `torch.compile`.
     """
 
     _NONE = 0
@@ -69,6 +79,36 @@ class Mode(Flag):
 
 @dataclass(frozen=True)
 class Device:
+    """
+    Represents a compute device with optional properties.
+
+    This class encapsulates device information including device type and optional device-specific properties
+    like CUDA capabilities.
+
+    Args:
+        type (`str`):
+            The device type (e.g., "cuda", "mps", "rocm").
+        properties ([`CUDAProperties`], *optional*):
+            Device-specific properties. Currently only [`CUDAProperties`] is supported for CUDA devices.
+
+    Example:
+        ```python
+        from kernels import Device, CUDAProperties
+
+        # Basic CUDA device
+        cuda_device = Device(type="cuda")
+
+        # CUDA device with specific capability requirements
+        cuda_device_with_props = Device(
+            type="cuda",
+            properties=CUDAProperties(min_capability=75, max_capability=90)
+        )
+
+        # MPS device for Apple Silicon
+        mps_device = Device(type="mps")
+        ```
+    """
+
     type: str
     properties: Optional[CUDAProperties] = None
 
@@ -81,6 +121,8 @@ class Device:
         """Create an appropriate repository set for this device type."""
         if self.type == "cuda":
             return _CUDARepos()
+        elif self.type == "rocm":
+            return _ROCMRepos()
         elif self.type == "mps":
             return _MPSRepos()
         else:
@@ -97,6 +139,34 @@ class Device:
 
 @dataclass(frozen=True)
 class CUDAProperties:
+    """
+    CUDA-specific device properties for capability-based kernel selection.
+
+    This class defines CUDA compute capability constraints for kernel selection, allowing kernels to specify
+    minimum and maximum CUDA compute capabilities they support.
+
+    Args:
+        min_capability (`int`):
+            Minimum CUDA compute capability required (e.g., 75 for compute capability 7.5).
+        max_capability (`int`):
+            Maximum CUDA compute capability supported (e.g., 90 for compute capability 9.0).
+
+    Example:
+        ```python
+        from kernels import CUDAProperties, Device
+
+        # Define CUDA properties for modern GPUs (compute capability 7.5 to 9.0)
+        cuda_props = CUDAProperties(min_capability=75, max_capability=90)
+
+        # Create a device with these properties
+        device = Device(type="cuda", properties=cuda_props)
+        ```
+
+    Note:
+        CUDA compute capabilities are represented as integers where the major and minor versions are concatenated.
+        For example, compute capability 7.5 is represented as 75, and 8.6 is represented as 86.
+    """
+
     min_capability: int
     max_capability: int
 
@@ -112,33 +182,250 @@ class CUDAProperties:
         return hash((self.min_capability, self.max_capability))
 
 
-@dataclass
-class LayerRepository:
+@dataclass(frozen=True)
+class ROCMProperties:
     """
-    Repository and name of a layer.
+    ROCM-specific device properties for capability-based kernel selection.
+
+    This class defines ROCM compute capability constraints for kernel selection, allowing kernels to specify
+    minimum and maximum ROCM compute capabilities they support.
+
+    Args:
+        min_capability (`int`):
+            Minimum ROCM compute capability required (e.g., 75 for compute capability 7.5).
+        max_capability (`int`):
+            Maximum ROCM compute capability supported (e.g., 90 for compute capability 9.0).
+
+    Example:
+        ```python
+        from kernels import ROCMProperties, Device
+
+        # Define ROCM properties for modern GPUs (compute capability 7.5 to 9.0)
+        rocm_props = ROCMProperties(min_capability=75, max_capability=90)
+
+        # Create a device with these properties
+        device = Device(type="rocm", properties=rocm_props)
+        ```
+
+    Note:
+        ROCM compute capabilities are represented as integers where the major and minor versions are concatenated.
+        For example, compute capability 7.5 is represented as 75, and 8.6 is represented as 86.
     """
 
-    layer_name: str = field(
-        metadata={"help": "The name of the layer in the kernel repository."}
-    )
-    repo_id: str = field(metadata={"help": "The kernel hub repository with the layer."})
-    revision: str = field(
-        default="main", metadata={"help": "The revision of the layer."}
-    )
+    min_capability: int
+    max_capability: int
+
+    def __eq__(self, other):
+        if not isinstance(other, ROCMProperties):
+            return NotImplemented
+        return (
+            self.min_capability == other.min_capability
+            and self.max_capability == other.max_capability
+        )
+
+    def __hash__(self):
+        return hash((self.min_capability, self.max_capability))
+
+
+class LayerRepositoryProtocol(Protocol):
+    @property
+    def layer_name(self) -> str: ...
+
+    def load(self) -> ModuleType: ...
+
+
+class LayerRepository:
+    """
+    Repository and name of a layer for kernel mapping.
+
+    Args:
+        repo_id (`str`):
+            The Hub repository containing the layer.
+        layer_name (`str`):
+            The name of the layer within the kernel repository.
+        revision (`str`, *optional*, defaults to `"main"`):
+            The specific revision (branch, tag, or commit) to download. Cannot be used together with `version`.
+        version (`str`, *optional*):
+            The kernel version to download. This can be a Python version specifier, such as `">=1.0.0,<2.0.0"`.
+            Cannot be used together with `revision`.
+
+    Example:
+        ```python
+        from kernels import LayerRepository
+
+        # Reference a specific layer by revision
+        layer_repo = LayerRepository(
+            repo_id="kernels-community/activation",
+            layer_name="SiluAndMul",
+        )
+
+        # Reference a layer by version constraint
+        layer_repo_versioned = LayerRepository(
+            repo_id="kernels-community/activation",
+            layer_name="SiluAndMul",
+            version=">=0.0.3,<0.1"
+        )
+        ```
+    """
+
+    def __init__(
+        self,
+        repo_id: str,
+        *,
+        layer_name: str,
+        revision: Optional[str] = None,
+        version: Optional[str] = None,
+    ):
+        if revision is not None and version is not None:
+            raise ValueError(
+                "Either a revision or a version must be specified, not both."
+            )
+
+        self._repo_id = repo_id
+        self.layer_name = layer_name
+
+        # We are going to resolve these lazily, since we do not want
+        # to do a network request for every registered LayerRepository.
+        self._revision = revision
+        self._version = version
+
+    @functools.lru_cache()
+    def _resolve_revision(self) -> str:
+        return select_revision_or_version(
+            repo_id=self._repo_id, revision=self._revision, version=self._version
+        )
+
+    def load(self) -> ModuleType:
+        return get_kernel(self._repo_id, revision=self._resolve_revision())
 
     def __eq__(self, other):
         return (
             isinstance(other, LayerRepository)
             and self.layer_name == other.layer_name
-            and self.repo_id == other.repo_id
-            and self.revision == other.revision
+            and self._repo_id == other._repo_id
+            and self._revision == other._revision
+            and self._version == other._version
         )
 
     def __hash__(self):
-        return hash((self.layer_name, self.repo_id, self.revision))
+        return hash((self.layer_name, self._repo_id, self._revision, self._version))
+
+    def __str__(self) -> str:
+        return f"`{self._repo_id}` (revision: {self._resolve_revision()}) for layer `{self.layer_name}`"
 
 
-_CACHED_LAYER: Dict[LayerRepository, Type["nn.Module"]] = {}
+class LocalLayerRepository:
+    """
+    Repository from a local directory for kernel mapping.
+
+    Args:
+        repo_path (`Path`):
+            The local repository containing the layer.
+        package_name (`str`):
+            Package name of the kernel.
+        layer_name (`str`):
+            The name of the layer within the kernel repository.
+
+    Example:
+        ```python
+        from pathlib import Path
+
+        from kernels import LocalLayerRepository
+
+        # Reference a specific layer by revision
+        layer_repo = LocalLayerRepository(
+            repo_path=Path("/home/daniel/kernels/activation"),
+            package_name="activation",
+            layer_name="SiluAndMul",
+        )
+        ```
+    """
+
+    def __init__(
+        self,
+        repo_path: Path,
+        *,
+        package_name: str,
+        layer_name: str,
+    ):
+        self._repo_path = repo_path
+        self._package_name = package_name
+        self.layer_name = layer_name
+
+    def load(self) -> ModuleType:
+        return get_local_kernel(self._repo_path, self._package_name)
+
+    def __eq__(self, other):
+        return (
+            isinstance(other, LocalLayerRepository)
+            and self.layer_name == other.layer_name
+            and self._repo_path == other._repo_path
+            and self._package_name == other._package_name
+        )
+
+    def __hash__(self):
+        return hash((self.layer_name, self._repo_path, self._package_name))
+
+    def __str__(self) -> str:
+        return f"`{self._repo_path}` (package: {self._package_name}) for layer `{self.layer_name}`"
+
+
+class LockedLayerRepository:
+    """
+    Repository and name of a layer.
+
+    In contrast to `LayerRepository`, this class uses repositories that
+    are locked inside a project.
+    """
+
+    def __init__(
+        self,
+        repo_id: str,
+        *,
+        lockfile: Optional[Path] = None,
+        layer_name: str,
+    ):
+        """
+        Construct a layer repository.
+
+        Args:
+            repo_id (`str`): The Hub repository containing the layer.
+        """
+        self._repo_id = repo_id
+        self._lockfile = lockfile
+        self.layer_name = layer_name
+
+    @functools.lru_cache()
+    def _resolve_revision(self) -> str:
+        if self._lockfile is None:
+            locked_sha = _get_caller_locked_kernel(self._repo_id)
+        else:
+            with open(self._lockfile, "r") as f:
+                locked_sha = _get_locked_kernel(self._repo_id, f.read())
+
+        if locked_sha is None:
+            raise ValueError(f"Kernel `{self._repo_id}` is not locked")
+
+        return locked_sha
+
+    def load(self) -> ModuleType:
+        return get_kernel(repo_id=self._repo_id, revision=self._resolve_revision())
+
+    def __eq__(self, other):
+        return (
+            isinstance(other, LockedLayerRepository)
+            and self.layer_name == other.layer_name
+            and self._repo_id == other._repo_id
+        )
+
+    def __hash__(self):
+        return hash((self.layer_name, self._repo_id))
+
+    def __str__(self) -> str:
+        return f"`{self._repo_id}` (revision: {self._resolve_revision()}) for layer `{self.layer_name}`"
+
+
+_CACHED_LAYER: Dict[LayerRepositoryProtocol, Type["nn.Module"]] = {}
 
 
 class _DeviceRepos(ABC):
@@ -150,10 +437,10 @@ class _DeviceRepos(ABC):
     @abstractmethod
     def repos(
         self,
-    ) -> Optional[Dict[Mode, LayerRepository]]: ...
+    ) -> Optional[Dict[Mode, LayerRepositoryProtocol]]: ...
 
     @abstractmethod
-    def insert(self, device: Device, repos: Dict[Mode, LayerRepository]):
+    def insert(self, device: Device, repos: Dict[Mode, LayerRepositoryProtocol]):
         """
         Insert a repository for a specific device and mode.
         """
@@ -161,7 +448,7 @@ class _DeviceRepos(ABC):
 
 
 class _MPSRepos(_DeviceRepos):
-    _repos: Dict[Mode, LayerRepository]
+    _repos: Dict[Mode, LayerRepositoryProtocol]
 
     def __init__(self):
         super().__init__()
@@ -170,10 +457,10 @@ class _MPSRepos(_DeviceRepos):
     @property
     def repos(
         self,
-    ) -> Optional[Dict[Mode, LayerRepository]]:
+    ) -> Optional[Dict[Mode, LayerRepositoryProtocol]]:
         return self._repos
 
-    def insert(self, device: Device, repos: Dict[Mode, LayerRepository]):
+    def insert(self, device: Device, repos: Dict[Mode, LayerRepositoryProtocol]):
         if device.type != "mps":
             raise ValueError(f"Device type must be 'mps', got {device.type}")
 
@@ -181,7 +468,7 @@ class _MPSRepos(_DeviceRepos):
 
 
 class _CUDARepos(_DeviceRepos):
-    _repos: IntervalTree[Dict[Mode, LayerRepository]]
+    _repos: IntervalTree[Dict[Mode, LayerRepositoryProtocol]]
 
     def __init__(self):
         super().__init__()
@@ -190,11 +477,11 @@ class _CUDARepos(_DeviceRepos):
     @property
     def repos(
         self,
-    ) -> Optional[Dict[Mode, LayerRepository]]:
+    ) -> Optional[Dict[Mode, LayerRepositoryProtocol]]:
         capability = _find_capability()
         return self.repos_by_capability.find_smallest_interval(capability)
 
-    def insert(self, device: Device, repos: Dict[Mode, LayerRepository]):
+    def insert(self, device: Device, repos: Dict[Mode, LayerRepositoryProtocol]):
         assert device.properties is None or isinstance(
             device.properties, CUDAProperties
         )
@@ -211,6 +498,46 @@ class _CUDARepos(_DeviceRepos):
         self.repos_by_capability.insert(min_capability, max_capability, repos)
 
 
+class _ROCMRepos(_DeviceRepos):
+    _repos: IntervalTree[Dict[Mode, LayerRepositoryProtocol]]
+
+    def __init__(self):
+        super().__init__()
+        self.repos_by_capability = IntervalTree()
+
+    @property
+    def repos(
+        self,
+    ) -> Optional[Dict[Mode, LayerRepositoryProtocol]]:
+        capability = _find_capability()
+        return self.repos_by_capability.find_smallest_interval(capability)
+
+    def insert(self, device: Device, repos: Dict[Mode, LayerRepositoryProtocol]):
+        assert device.properties is None or isinstance(
+            device.properties, ROCMProperties
+        )
+
+        min_capability = (
+            0 if device.properties is None else device.properties.min_capability
+        )
+        max_capability = (
+            sys.maxsize
+            if device.properties is None
+            else device.properties.max_capability
+        )
+
+        self.repos_by_capability.insert(min_capability, max_capability, repos)
+
+
+def _validate_device_type(device_type: str) -> None:
+    """Validate that the device type is supported."""
+    supported_devices = {"cuda", "rocm", "mps"}
+    if device_type not in supported_devices:
+        raise ValueError(
+            f"Unsupported device type '{device_type}'. Supported device types are: {', '.join(sorted(supported_devices))}"
+        )
+
+
 _KERNEL_MAPPING: ContextVar[Dict[str, Dict[str, _DeviceRepos]]] = ContextVar(
     "_KERNEL_MAPPING", default={}
 )
@@ -219,17 +546,65 @@ _KERNEL_MAPPING: ContextVar[Dict[str, Dict[str, _DeviceRepos]]] = ContextVar(
 def use_kernel_mapping(
     mapping: Dict[
         str,
-        Dict[Union[Device, str], Union[LayerRepository, Dict[Mode, LayerRepository]]],
+        Dict[
+            Union[Device, str],
+            Union[LayerRepositoryProtocol, Dict[Mode, LayerRepositoryProtocol]],
+        ],
     ],
     *,
     inherit_mapping: bool = True,
 ):
     """
-    Context manager that sets a mapping for a duration of the context.
+    Context manager that sets a kernel mapping for the duration of the context.
 
-    When `inherit_mapping` is set to `True` the current mapping will be
-    extended by `mapping` inside the context. If it is `False`, only
-    `mapping` is used inside the context.
+    This function allows temporary kernel mappings to be applied within a specific context, enabling different
+    kernel configurations for different parts of your code.
+
+    Args:
+        mapping (`Dict[str, Dict[Union[Device, str], Union[LayerRepositoryProtocol, Dict[Mode, LayerRepositoryProtocol]]]]`):
+            The kernel mapping to apply. Maps layer names to device-specific kernel configurations.
+        inherit_mapping (`bool`, *optional*, defaults to `True`):
+            When `True`, the current mapping will be extended by `mapping` inside the context. When `False`,
+            only `mapping` is used inside the context.
+
+    Returns:
+        Context manager that handles the temporary kernel mapping.
+
+    Example:
+        ```python
+        import torch
+        import torch.nn as nn
+        from torch.nn import functional as F
+
+        from kernels import use_kernel_forward_from_hub
+        from kernels import use_kernel_mapping, LayerRepository, Device
+        from kernels import Mode, kernelize
+
+        # Define a mapping
+        mapping = {
+            "SiluAndMul": {
+                "cuda": LayerRepository(
+                    repo_id="kernels-community/activation",
+                    layer_name="SiluAndMul",
+                )
+            }
+        }
+
+        @use_kernel_forward_from_hub("SiluAndMul")
+        class SiluAndMul(nn.Module):
+            def forward(self, x: torch.Tensor) -> torch.Tensor:
+                d = x.shape[-1] // 2
+                return F.silu(x[..., :d]) * x[..., d:]
+
+        model = SiluAndMul()
+
+        # Use the mapping for the duration of the context.
+        with use_kernel_mapping(mapping):
+            # kernelize uses the temporary mapping
+            model = kernelize(model, mode=Mode.TRAINING | Mode.TORCH_COMPILE, device="cuda")
+
+        # Outside the context, original mappings are restored
+        ```
     """
 
     class ContextManager:
@@ -250,31 +625,64 @@ def use_kernel_mapping(
 def register_kernel_mapping(
     mapping: Dict[
         str,
-        Dict[Union[Device, str], Union[LayerRepository, Dict[Mode, LayerRepository]]],
+        Dict[
+            Union[Device, str],
+            Union[LayerRepositoryProtocol, Dict[Mode, LayerRepositoryProtocol]],
+        ],
     ],
+    inherit_mapping: bool = True,
 ):
     """
-    Allows one to register a mapping between a layer name and the corresponding
-    kernel(s) to use, depending on the device. This should be used in conjunction
-    with `kernelize`.
+    Register a global mapping between layer names and their corresponding kernel implementations.
 
-    Example usage:
+    This function allows you to register a mapping between a layer name and the corresponding kernel(s) to use,
+    depending on the device and mode. This should be used in conjunction with [`kernelize`].
 
-    ```python
-    from kernels import LayerRepository, register_kernel_mapping
+    Args:
+        mapping (`Dict[str, Dict[Union[Device, str], Union[LayerRepositoryProtocol, Dict[Mode, LayerRepositoryProtocol]]]]`):
+            The kernel mapping to register globally. Maps layer names to device-specific kernels.
+            The mapping can specify different kernels for different modes (training, inference, etc.).
+        inherit_mapping (`bool`, *optional*, defaults to `True`):
+            When `True`, the current mapping will be extended by `mapping`. When `False`, the existing mappings
+            are erased before adding `mapping`.
 
-    kernel_layer_mapping = {
-      "LlamaRMSNorm": {
-          "cuda": LayerRepository(
-              repo_id="kernels-community/activation",
-              layer_name="RmsNorm",
-              revision="layers",
-          ),
-      },
-    }
-    register_kernel_mapping(kernel_layer_mapping)
-    ```
+    Example:
+        ```python
+        from kernels import LayerRepository, register_kernel_mapping, Mode
+
+        # Simple mapping for a single kernel per device
+        kernel_layer_mapping = {
+            "LlamaRMSNorm": {
+                "cuda": LayerRepository(
+                    repo_id="kernels-community/activation",
+                    layer_name="RmsNorm",
+                    revision="layers",
+                ),
+            },
+        }
+        register_kernel_mapping(kernel_layer_mapping)
+
+        # Advanced mapping with mode-specific kernels
+        advanced_mapping = {
+            "MultiHeadAttention": {
+                "cuda": {
+                    Mode.TRAINING: LayerRepository(
+                        repo_id="username/training-kernels",
+                        layer_name="TrainingAttention"
+                    ),
+                    Mode.INFERENCE: LayerRepository(
+                        repo_id="username/inference-kernels",
+                        layer_name="FastAttention"
+                    ),
+                }
+            }
+        }
+        register_kernel_mapping(advanced_mapping)
+        ```
     """
+    if not inherit_mapping:
+        _KERNEL_MAPPING.set({})
+
     # Merge with existing mappings.
     for new_kernel, new_device_repos in mapping.items():
         device_repo = _KERNEL_MAPPING.get().setdefault(new_kernel, {})
@@ -283,10 +691,10 @@ def register_kernel_mapping(
                 Device(type=new_device) if isinstance(new_device, str) else new_device
             )
 
-            if isinstance(new_repo, LayerRepository):
-                kernel_options = {Mode.FALLBACK: new_repo}
-            else:
+            if isinstance(new_repo, dict):
                 kernel_options = new_repo
+            else:
+                kernel_options = {Mode.FALLBACK: new_repo}
 
             feature_repos = device_repo.setdefault(device.type, device.create_repo())
             feature_repos.insert(device, kernel_options)
@@ -297,15 +705,20 @@ def replace_kernel_forward_from_hub(
     layer_name: str,
 ):
     """
-    Decorator that prepares a layer class to use a kernel from the Hugging Face Hub.
+    Function that prepares a layer class to use kernels from the Hugging Face Hub.
 
-    This decorator stores the layer name and original forward method, which will be used
-    by the kernelize function to replace the forward implementation with the appropriate
-    kernel from the hub.
+    It is recommended to use [`use_kernel_forward_from_hub`] decorator instead.
+    This function should only be used as a last resort to extend third-party layers,
+    it is inherently fragile since the member variables and `forward` signature
+    of usch a layer can change.
 
-    Args:
-        cls: The layer class to decorate
-        layer_name: The name of the layer to use for kernel lookup
+    Example:
+        ```python
+        from kernels import replace_kernel_forward_from_hub
+        import torch.nn as nn
+
+        replace_kernel_forward_from_hub(nn.LayerNorm, "LayerNorm")
+        ```
     """
     cls.kernel_layer_name = layer_name
 
@@ -338,10 +751,10 @@ _MODE_FALLBACK_PRIORITY = {
 
 
 def _select_repository(
-    repositories: Dict[Mode, LayerRepository],
+    repositories: Dict[Mode, LayerRepositoryProtocol],
     *,
     mode: Mode,
-) -> Optional[Tuple[LayerRepository, Mode]]:
+) -> Optional[Tuple[LayerRepositoryProtocol, Mode]]:
     # Get the fallback priority list for the requested mode
     if mode not in _MODE_FALLBACK_PRIORITY:
         raise ValueError(f"Unsupported mode: {mode}")
@@ -359,30 +772,66 @@ def _select_repository(
 def kernelize(
     model: "nn.Module",
     *,
-    mode: Mode = Mode.TRAINING | Mode.TORCH_COMPILE,
+    mode: Mode,
     device: Optional[Union[str, "torch.device"]] = None,
     use_fallback: bool = True,
 ):
     """
-    Iterate over all modules in the model and replace the `forward` method of
-    extensible layers for which kernels are registered using `register_kernel_mapping`
-    or `use_kernel_mapping`.
+    Replace layer forward methods with optimized kernel implementations.
+
+    This function iterates over all modules in the model and replaces the `forward` method of extensible layers
+    for which kernels are registered using [`register_kernel_mapping`] or [`use_kernel_mapping`].
 
     Args:
-        model: The PyTorch model to kernelize
-        mode: the mode that the kernel is going to be used in (e.g.
-            `Mode.TRAINING | Mode.TORCH_COMPILE` kernelizes the model for training
-            and `torch.compile`).
-        device: The device type to load kernels for. The device type will be inferred
-            from the parameters of the model when not provided.
-        use_fallback: Whether to use the original forward method of modules when no
-            compatible kernel could be found. If set to `False`, an exception will
-            be raised in such cases.
+        model (`nn.Module`):
+            The PyTorch model to kernelize.
+        mode ([`Mode`]): The mode that the kernel is going to be used in. For example,
+            `Mode.TRAINING | Mode.TORCH_COMPILE` kernelizes the model for training with
+            `torch.compile`.
+        device (`Union[str, torch.device]`, *optional*):
+            The device type to load kernels for. Supported device types are: "cuda", "mps", "rocm".
+            The device type will be inferred from the model parameters when not provided.
+        use_fallback (`bool`, *optional*, defaults to `True`):
+            Whether to use the original forward method of modules when no compatible kernel could be found.
+            If set to `False`, an exception will be raised in such cases.
 
     Returns:
-        The kernelized model
+        `nn.Module`: The kernelized model with optimized kernel implementations.
+
+    Example:
+        ```python
+        import torch
+        import torch.nn as nn
+
+        from kernels import kernelize, Mode, register_kernel_mapping, LayerRepository
+        from kernels import use_kernel_forward_from_hub
+
+        @use_kernel_forward_from_hub("SiluAndMul")
+        class SiluAndMul(nn.Module):
+            def forward(self, x: torch.Tensor) -> torch.Tensor:
+                d = x.shape[-1] // 2
+                return F.silu(x[..., :d]) * x[..., d:]
+
+        mapping = {
+            "LayerNorm": {
+                "cuda": LayerRepository(
+                    repo_id="kernels-community/activation",
+                    layer_name="SiluAndMul",
+                )
+            }
+        }
+        register_kernel_mapping(mapping)
+
+        # Create and kernelize a model
+        model = nn.Sequential(
+            nn.Linear(1024, 2048, device="cuda"),
+            SiluAndMul(),
+        )
+
+        # Kernelize for inference
+        kernelized_model = kernelize(model, mode=Mode.TRAINING | Mode.TORCH_COMPILE)
+        ```
     """
-    import torch
 
     if mode == Mode.FALLBACK:
         raise ValueError("Mode.FALLBACK can only be used to register kernel mappings.")
@@ -396,7 +845,8 @@ def kernelize(
     if device is None:
         device_type = _find_device(model)
     elif isinstance(device, str):
-        device_type = Device(type=torch.device(device).type)
+        _validate_device_type(device)
+        device_type = Device(type=device)
     else:
         device_type = Device(device.type)
 
@@ -462,9 +912,7 @@ def kernelize(
 
         repo, repo_mode = repo_with_mode
 
-        logging.info(
-            f"Using layer `{repo.layer_name}` from repo `{repo.repo_id}` (revision: {repo.revision}) for layer `{layer_name}`"
-        )
+        logging.info(f"Using layer `{repo.layer_name}` from repo {repo}")
         logging.debug(f"kernelize mode: {mode}, repo mode: {repo_mode}")
 
         layer = _get_layer_memoize(repo, module_class)
@@ -489,7 +937,41 @@ def kernelize(
 
 def use_kernel_forward_from_hub(layer_name: str):
     """
-    Make a layer extensible using the name `layer_name`.
+    Decorator factory that makes a layer extensible using the specified layer name.
+
+    This is a decorator factory that returns a decorator which prepares a layer class to use kernels from the
+    Hugging Face Hub.
+
+    Args:
+        layer_name (`str`):
+            The name of the layer to use for kernel lookup in registered mappings.
+
+    Returns:
+        `Callable`: A decorator function that can be applied to layer classes.
+
+    Example:
+        ```python
+        import torch
+        import torch.nn as nn
+
+        from kernels import use_kernel_forward_from_hub
+        from kernels import Mode, kernelize
+
+        @use_kernel_forward_from_hub("MyCustomLayer")
+        class MyCustomLayer(nn.Module):
+            def __init__(self, hidden_size):
+                super().__init__()
+                self.hidden_size = hidden_size
+
+            def forward(self, x: torch.Tensor):
+                # original implementation
+                return x
+
+        model = MyCustomLayer(768)
+
+        # The layer can now be kernelized:
+        # model = kernelize(model, mode=Mode.TRAINING | Mode.TORCH_COMPILE, device="cuda")
+        ```
     """
 
     def decorator(cls):
@@ -499,21 +981,17 @@ def use_kernel_forward_from_hub(layer_name: str):
     return decorator
 
 
-def _get_kernel_layer(
-    *, repo_id: str, layer_name: str, revision: str
-) -> Type["nn.Module"]:
+def _get_kernel_layer(repo: LayerRepositoryProtocol) -> Type["nn.Module"]:
     """Get a layer from a kernel."""
 
-    kernel = get_kernel(repo_id, revision=revision)
+    kernel = repo.load()
 
     if getattr(kernel, "layers", None) is None:
-        raise ValueError(
-            f"Kernel `{repo_id}` at revision `{revision}` does not define any layers."
-        )
+        raise ValueError(f"Kernel repo {repo} does not define any layers.")
 
-    layer = getattr(kernel.layers, layer_name, None)
+    layer = getattr(kernel.layers, repo.layer_name, None)
     if layer is None:
-        raise ValueError(f"Layer `{layer_name}` not found in kernel `{repo_id}`.")
+        raise ValueError(f"Layer `{repo.layer_name}` not found in kernel repo {repo}.")
     return layer
 
 
@@ -557,6 +1035,18 @@ def _validate_layer(*, check_cls, cls):
             )
 
 
+def _is_cuda_platform():
+    import torch
+
+    return torch.version.cuda is not None
+
+
+def _is_rocm_platform():
+    import torch
+
+    return torch.version.hip is not None
+
+
 def _find_device(model: "nn.Module") -> Device:
     try:
         param = next(model.parameters())
@@ -565,7 +1055,15 @@ def _find_device(model: "nn.Module") -> Device:
             "Cannot determine model device, provide as `device` argument to `kernelize`."
         )
 
-    return Device(type=param.device.type)
+    dev_type = param.device.type
+    if dev_type == "cuda":
+        # Refine based on actual platform
+        if _is_rocm_platform():
+            return Device(type="rocm")
+        elif _is_cuda_platform():
+            return Device(type="cuda")
+
+    return Device(type=dev_type)
 
 
 @lru_cache
@@ -590,13 +1088,19 @@ def _conditionally_replace_forward(
     # layers registered with the FALLBACK mode never get rejected by
     # _validate_layer_has_mode. For such layers, we want to fall back in
     # case the layer does not support the given mode.
-    needs_fallback = Mode.TORCH_COMPILE in mode and not getattr(
+    needs_fallback_for_compile = Mode.TORCH_COMPILE in mode and not getattr(
         layer, "can_torch_compile", False
     )
-    needs_fallback |= Mode.TRAINING in mode and not getattr(layer, "has_backward", True)
+    needs_fallback_for_backward = Mode.TRAINING in mode and not getattr(
+        layer, "has_backward", True
+    )
 
-    if needs_fallback:
+    if needs_fallback_for_compile or needs_fallback_for_backward:
         if use_fallback:
+            if needs_fallback_for_compile:
+                logging.info("Layer does not support torch.compile, using fallback")
+            if needs_fallback_for_backward:
+                logging.info("Layer does not support backward, using fallback")
             _replace_forward(module, module_class)
         else:
             raise ValueError(f"Available kernel does not support mode: {mode}")
@@ -612,7 +1116,7 @@ def _validate_layer_has_mode(
     *,
     layer_name: str,
     module: Type["nn.Module"],
-    repo: LayerRepository,
+    repo: LayerRepositoryProtocol,
     repo_mode: Mode,
 ):
     """
@@ -621,7 +1125,7 @@ def _validate_layer_has_mode(
 
     if Mode.TRAINING in repo_mode and not getattr(module, "has_backward", True):
         raise ValueError(
-            f"Layer `{repo.layer_name}` ({repo.repo_id}, revision: {repo.revision}) does not support backward.\n"
+            f"Layer `{repo.layer_name}` from repo {repo} does not support backward.\n"
             f"Was registered for `{layer_name}` with mode `{repo_mode}`"
         )
 
@@ -629,7 +1133,7 @@ def _validate_layer_has_mode(
         module, "can_torch_compile", False
     ):
         raise ValueError(
-            f"Layer `{repo.layer_name}` ({repo.repo_id}, revision: {repo.revision}) does not support torch.compile.\n"
+            f"Layer `{repo.layer_name}` from repo {repo} does not support torch.compile.\n"
             f"Was registered for `{layer_name}` with mode `{repo_mode}`"
         )
 
@@ -637,17 +1141,13 @@ def _validate_layer_has_mode(
 
 
 def _get_layer_memoize(
-    repo: LayerRepository, module_class: Type["nn.Module"]
+    repo: LayerRepositoryProtocol, module_class: Type["nn.Module"]
 ) -> Type["nn.Module"]:
     layer = _CACHED_LAYER.get(repo, None)
     if layer is not None:
         return layer
 
-    layer = _get_kernel_layer(
-        repo_id=repo.repo_id,
-        layer_name=repo.layer_name,
-        revision=repo.revision,
-    )
+    layer = _get_kernel_layer(repo)
     _validate_layer(check_cls=module_class, cls=layer)
     _CACHED_LAYER[repo] = layer
 

src/kernels/utils.py

@@ -16,7 +16,7 @@ from typing import Dict, List, Optional, Tuple
 from huggingface_hub import file_exists, snapshot_download
 from packaging.version import parse
 
-from kernels._versions import resolve_version_spec_as_ref
+from kernels._versions import select_revision_or_version
 from kernels.lockfile import KernelLock, VariantLock
 
 
@@ -46,9 +46,12 @@ def build_variant() -> str:
         compute_framework = f"rocm{rocm_version.major}{rocm_version.minor}"
     elif torch.backends.mps.is_available():
         compute_framework = "metal"
+    elif torch.version.xpu is not None:
+        version = torch.version.xpu
+        compute_framework = f"xpu{version[0:4]}{version[5:6]}"
     else:
         raise AssertionError(
-            "Torch was not compiled with CUDA, Metal, or ROCm enabled."
+            "Torch was not compiled with CUDA, Metal, XPU, or ROCm enabled."
         )
 
     torch_version = parse(torch.__version__)
@@ -96,7 +99,20 @@ def install_kernel(
     """
     Download a kernel for the current environment to the cache.
 
-    The output path is validated againt `hash` when set.
+    The output path is validated against the hashes in `variant_locks` when provided.
+
+    Args:
+        repo_id (`str`):
+            The Hub repository containing the kernel.
+        revision (`str`):
+            The specific revision (branch, tag, or commit) to download.
+        local_files_only (`bool`, *optional*, defaults to `False`):
+            Whether to only use local files and not download from the Hub.
+        variant_locks (`Dict[str, VariantLock]`, *optional*):
+            Optional dictionary of variant locks for validation.
+
+    Returns:
+        `Tuple[str, Path]`: A tuple containing the package name and the path to the variant directory.
     """
     package_name = package_name_from_repo_id(repo_id)
     variant = build_variant()
@@ -188,26 +204,34 @@ def get_kernel(
 ) -> ModuleType:
     """
     Load a kernel from the kernel hub.
-    This function downloads a kernel to the local Hugging Face Hub cache
-    directory (if it was not downloaded before) and then loads the kernel.
+
+    This function downloads a kernel to the local Hugging Face Hub cache directory (if it was not downloaded before)
+    and then loads the kernel.
+
     Args:
-        repo_id (`str`): The Hub repository containing the kernel.
-        revision (`str`, *optional*, defaults to `"main"`): The specific
-            revision (branch, tag, or commit) to download.
-            Cannot be used together with `version`.
-        version (`str`, *optional*): The kernel version to download. This
-            can be a Python version specifier, such as `">=1.0.0,<2.0.0"`.
+        repo_id (`str`):
+            The Hub repository containing the kernel.
+        revision (`str`, *optional*, defaults to `"main"`):
+            The specific revision (branch, tag, or commit) to download. Cannot be used together with `version`.
+        version (`str`, *optional*):
+            The kernel version to download. This can be a Python version specifier, such as `">=1.0.0,<2.0.0"`.
             Cannot be used together with `revision`.
+
     Returns:
         `ModuleType`: The imported kernel module.
+
     Example:
         ```python
+        import torch
         from kernels import get_kernel
-        kernel = get_kernel("username/my-kernel")
-        result = kernel.kernel_function(input_data)
+
+        activation = get_kernel("kernels-community/activation")
+        x = torch.randn(10, 20, device="cuda")
+        out = torch.empty_like(x)
+        result = activation.silu_and_mul(out, x)
         ```
     """
-    revision = _revision_or_version(repo_id, revision, version)
+    revision = select_revision_or_version(repo_id, revision, version)
     package_name, package_path = install_kernel(repo_id, revision=revision)
     return import_from_path(package_name, package_path / package_name / "__init__.py")
 
@@ -215,30 +239,55 @@ def get_kernel(
 def get_local_kernel(repo_path: Path, package_name: str) -> ModuleType:
     """
     Import a kernel from a local kernel repository path.
+
+    Args:
+        repo_path (`Path`):
+            The local path to the kernel repository.
+        package_name (`str`):
+            The name of the package to import from the repository.
+
+    Returns:
+        `ModuleType`: The imported kernel module.
     """
-    package_name, package_path = _load_kernel_from_path(repo_path, package_name)
-    return import_from_path(package_name, package_path / package_name / "__init__.py")
+    variant = build_variant()
+    universal_variant = universal_build_variant()
+
+    # Presume we were given the top level path of the kernel repository.
+    for base_path in [repo_path, repo_path / "build"]:
+        # Prefer the universal variant if it exists.
+        for v in [universal_variant, variant]:
+            package_path = base_path / v / package_name / "__init__.py"
+            if package_path.exists():
+                return import_from_path(package_name, package_path)
+
+    # If we didn't find the package in the repo we may have a explicit
+    # package path.
+    package_path = repo_path / package_name / "__init__.py"
+    if package_path.exists():
+        return import_from_path(package_name, package_path)
+
+    raise FileNotFoundError(f"Could not find package '{package_name}' in {repo_path}")
 
 
 def has_kernel(
     repo_id: str, revision: Optional[str] = None, version: Optional[str] = None
 ) -> bool:
     """
-    Check whether a kernel build exists for the current environment
-    (Torch version and compute framework).
+    Check whether a kernel build exists for the current environment (Torch version and compute framework).
 
     Args:
-        repo_id (`str`): The Hub repository containing the kernel.
-        revision (`str`, *optional*, defaults to `"main"`): The specific
-            revision (branch, tag, or commit) to download.
-            Cannot be used together with `version`.
-        version (`str`, *optional*): The kernel version to download. This
-            can be a Python version specifier, such as `">=1.0.0,<2.0.0"`.
+        repo_id (`str`):
+            The Hub repository containing the kernel.
+        revision (`str`, *optional*, defaults to `"main"`):
+            The specific revision (branch, tag, or commit) to download. Cannot be used together with `version`.
+        version (`str`, *optional*):
+            The kernel version to download. This can be a Python version specifier, such as `">=1.0.0,<2.0.0"`.
             Cannot be used together with `revision`.
+
     Returns:
-        `bool`: `true` if a kernel is avaialble for the current environment.
+        `bool`: `True` if a kernel is available for the current environment.
     """
-    revision = _revision_or_version(repo_id, revision, version)
+    revision = select_revision_or_version(repo_id, revision, version)
 
     package_name = package_name_from_repo_id(repo_id)
     variant = build_variant()
@@ -262,8 +311,16 @@ def load_kernel(repo_id: str, *, lockfile: Optional[Path] = None) -> ModuleType:
     """
     Get a pre-downloaded, locked kernel.
 
-    If `lockfile` is not specified, the lockfile will be loaded from the
-    caller's package metadata.
+    If `lockfile` is not specified, the lockfile will be loaded from the caller's package metadata.
+
+    Args:
+        repo_id (`str`):
+            The Hub repository containing the kernel.
+        lockfile (`Path`, *optional*):
+            Path to the lockfile. If not provided, the lockfile will be loaded from the caller's package metadata.
+
+    Returns:
+        `ModuleType`: The imported kernel module.
     """
     if lockfile is None:
         locked_sha = _get_caller_locked_kernel(repo_id)
@@ -308,7 +365,18 @@ def load_kernel(repo_id: str, *, lockfile: Optional[Path] = None) -> ModuleType:
 
 
 def get_locked_kernel(repo_id: str, local_files_only: bool = False) -> ModuleType:
-    """Get a kernel using a lock file."""
+    """
+    Get a kernel using a lock file.
+
+    Args:
+        repo_id (`str`):
+            The Hub repository containing the kernel.
+        local_files_only (`bool`, *optional*, defaults to `False`):
+            Whether to only use local files and not download from the Hub.
+
+    Returns:
+        `ModuleType`: The imported kernel module.
+    """
     locked_sha = _get_caller_locked_kernel(repo_id)
 
     if locked_sha is None:
@@ -420,16 +488,3 @@ def git_hash_object(data: bytes, object_type: str = "blob"):
 
 def package_name_from_repo_id(repo_id: str) -> str:
     return repo_id.split("/")[-1].replace("-", "_")
-
-
-def _revision_or_version(
-    repo_id: str, revision: Optional[str] = None, version: Optional[str] = None
-) -> str:
-    if revision is not None and version is not None:
-        raise ValueError("Either a revision or a version must be specified, not both.")
-    elif revision is None and version is None:
-        revision = "main"
-    elif version is not None:
-        revision = resolve_version_spec_as_ref(repo_id, version).target_commit
-    assert revision is not None
-    return revision

tests/conftest.py

@@ -1,10 +1,24 @@
 import sys
 
 import pytest
+import torch
+
+has_cuda = (
+    hasattr(torch.version, "cuda")
+    and torch.version.cuda is not None
+    and torch.cuda.device_count() > 0
+)
+has_rocm = (
+    hasattr(torch.version, "hip")
+    and torch.version.hip is not None
+    and torch.cuda.device_count() > 0
+)
 
 
 def pytest_runtest_setup(item):
-    if "linux_only" in item.keywords and not sys.platform.startswith("linux"):
-        pytest.skip("skipping Linux-only test on non-Linux platform")
+    if "cuda_only" in item.keywords and not has_cuda:
+        pytest.skip("skipping CUDA-only test on host without CUDA")
+    if "rocm_only" in item.keywords and not has_rocm:
+        pytest.skip("skipping ROCm-only test on host without ROCm")
     if "darwin_only" in item.keywords and not sys.platform.startswith("darwin"):
         pytest.skip("skipping macOS-only test on non-macOS platform")

tests/layer_locking/kernels.lock

@@ -0,0 +1,12 @@
+[
+  {
+    "repo_id": "kernels-test/versions",
+    "sha": "dc142fd6c9920c993d32be6358b78957c58681c3",
+    "variants": {
+      "torch-universal": {
+        "hash": "sha256-35ce0ccfe68e392cbc06feef72268f4c41a74b9920496a2c6ee8978db7f7c17c",
+        "hash_type": "git_lfs_concat"
+      }
+    }
+  }
+]

tests/layer_locking/pyproject.toml

@@ -0,0 +1,2 @@
+[tool.kernels.dependencies]
+"kernels-test/versions" = ">=0.1.0,<0.2.0"

tests/test_basic.py

@@ -10,10 +10,16 @@ def kernel():
 
 
 @pytest.fixture
-def local_kernel():
+def local_kernel_path():
     package_name, path = install_kernel("kernels-community/activation", "main")
     # Path is the build variant path (build/torch-<...>), so the grandparent
     # is the kernel repository path.
+    return package_name, path
+
+
+@pytest.fixture
+def local_kernel(local_kernel_path):
+    package_name, path = local_kernel_path
     return get_local_kernel(path.parent.parent, package_name)
 
 
@@ -34,7 +40,7 @@ def device():
     return "cuda"
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_gelu_fast(kernel, device):
     x = torch.arange(1, 10, dtype=torch.float16, device=device).view(3, 3)
     y = torch.empty_like(x)
@@ -50,7 +56,7 @@ def test_gelu_fast(kernel, device):
     assert torch.allclose(y, expected)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_local_kernel(local_kernel, device):
     x = torch.arange(1, 10, dtype=torch.float16, device=device).view(3, 3)
     y = torch.empty_like(x)
@@ -66,6 +72,39 @@ def test_local_kernel(local_kernel, device):
     assert torch.allclose(y, expected)
 
 
+@pytest.mark.cuda_only
+def test_local_kernel_path_types(local_kernel_path, device):
+    package_name, path = local_kernel_path
+
+    # Top-level repo path
+    # ie: /home/ubuntu/.cache/huggingface/hub/models--kernels-community--activation/snapshots/2fafa6a3a38ccb57a1a98419047cf7816ecbc071
+    kernel = get_local_kernel(path.parent.parent, package_name)
+    x = torch.arange(1, 10, dtype=torch.float16, device=device).view(3, 3)
+    y = torch.empty_like(x)
+
+    kernel.gelu_fast(y, x)
+    expected = torch.tensor(
+        [[0.8408, 1.9551, 2.9961], [4.0000, 5.0000, 6.0000], [7.0000, 8.0000, 9.0000]],
+        device=device,
+        dtype=torch.float16,
+    )
+    assert torch.allclose(y, expected)
+
+    # Build directory path
+    # ie: /home/ubuntu/.cache/huggingface/hub/models--kernels-community--activation/snapshots/2fafa6a3a38ccb57a1a98419047cf7816ecbc071/build
+    kernel = get_local_kernel(path.parent.parent / "build", package_name)
+    y = torch.empty_like(x)
+    kernel.gelu_fast(y, x)
+    assert torch.allclose(y, expected)
+
+    # Explicit package path
+    # ie: /home/ubuntu/.cache/huggingface/hub/models--kernels-community--activation/snapshots/2fafa6a3a38ccb57a1a98419047cf7816ecbc071/build/torch28-cxx11-cu128-x86_64-linux
+    kernel = get_local_kernel(path, package_name)
+    y = torch.empty_like(x)
+    kernel.gelu_fast(y, x)
+    assert torch.allclose(y, expected)
+
+
 @pytest.mark.darwin_only
 @pytest.mark.parametrize("dtype", [torch.float16, torch.float32])
 def test_relu_metal(metal_kernel, dtype):
@@ -74,7 +113,7 @@ def test_relu_metal(metal_kernel, dtype):
     assert torch.allclose(y, torch.relu(x))
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 @pytest.mark.parametrize(
     "kernel_exists",
     [
@@ -110,7 +149,7 @@ def test_version():
         )
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_universal_kernel(universal_kernel):
     torch.manual_seed(0)
     A = torch.randint(-10, 10, (64, 128), dtype=torch.int8, device="cuda")

tests/test_benchmarks.py

@@ -16,21 +16,21 @@ def device():
     return "cuda"
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_gelu_small(kernel, device, benchmark):
     x = torch.randn(32, 32, dtype=torch.float16, device=device)
     y = torch.empty_like(x)
     benchmark(kernel.gelu_fast, y, x)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_gelu_medium(kernel, device, benchmark):
     x = torch.randn(128, 128, dtype=torch.float16, device=device)
     y = torch.empty_like(x)
     benchmark(kernel.gelu_fast, y, x)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_gelu_large(kernel, device, benchmark):
     x = torch.randn(512, 512, dtype=torch.float16, device=device)
     y = torch.empty_like(x)

tests/test_doctest.py

@@ -0,0 +1,49 @@
+import inspect
+
+import pytest
+from mktestdocs import check_docstring, get_codeblock_members
+
+import kernels
+
+
+def all_public_functions():
+    function_list = inspect.getmembers(kernels, inspect.isfunction)
+    return [func for _, func in function_list]
+
+
+def all_public_classes():
+    class_list = inspect.getmembers(kernels, inspect.isclass)
+    return [cls for _, cls in class_list]
+
+
+def all_public_class_members():
+    members = get_codeblock_members(*all_public_classes())
+    return members
+
+
+@pytest.mark.cuda_only
+@pytest.mark.parametrize(
+    "func",
+    all_public_functions(),
+    ids=lambda d: d.__name__,
+)
+def test_func_docstring(func):
+    check_docstring(obj=func)
+
+
+@pytest.mark.cuda_only
+@pytest.mark.parametrize(
+    "cls",
+    all_public_classes(),
+    ids=lambda d: d.__name__,
+)
+def test_class_docstring(cls):
+    check_docstring(obj=cls)
+
+
+@pytest.mark.cuda_only
+@pytest.mark.parametrize(
+    "member", all_public_class_members(), ids=lambda d: d.__qualname__
+)
+def test_member_docstring(member):
+    check_docstring(member)

tests/test_kernel_locking.py

@@ -2,9 +2,17 @@ from dataclasses import dataclass
 from pathlib import Path
 
 import pytest
+import torch.nn as nn
 
 from kernels import load_kernel
 from kernels.cli import download_kernels
+from kernels.layer import (
+    LockedLayerRepository,
+    Mode,
+    kernelize,
+    use_kernel_forward_from_hub,
+    use_kernel_mapping,
+)
 
 
 # Mock download arguments class.
@@ -19,9 +27,34 @@ def test_download_all_hash_validation():
     download_kernels(DownloadArgs(all_variants=True, project_dir=project_dir))
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_load_locked():
     project_dir = Path(__file__).parent / "kernel_locking"
     # Also validates that hashing works correctly.
     download_kernels(DownloadArgs(all_variants=False, project_dir=project_dir))
     load_kernel("kernels-community/activation", lockfile=project_dir / "kernels.lock")
+
+
+def test_layer_locked():
+    project_dir = Path(__file__).parent / "layer_locking"
+
+    @use_kernel_forward_from_hub("Version")
+    class Version(nn.Module):
+        def forward(self) -> str:
+            return "0.0.0"
+
+    version = Version()
+
+    with use_kernel_mapping(
+        {
+            "Version": {
+                "cuda": LockedLayerRepository(
+                    repo_id="kernels-test/versions",
+                    layer_name="Version",
+                    lockfile=project_dir / "kernels.lock",
+                )
+            },
+        }
+    ):
+        version = kernelize(version, device="cuda", mode=Mode.INFERENCE)
+        assert version() == "0.1.1"

tests/test_layer.py

@@ -7,19 +7,21 @@ import torch.nn as nn
 from torch.nn import functional as F
 
 from kernels import (
+    CUDAProperties,
     Device,
     LayerRepository,
+    LocalLayerRepository,
     Mode,
     kernelize,
     register_kernel_mapping,
     use_kernel_forward_from_hub,
+    use_kernel_mapping,
 )
 from kernels.layer import (
     _KERNEL_MAPPING,
-    CUDAProperties,
     _validate_layer,
-    use_kernel_mapping,
 )
+from kernels.utils import install_kernel
 
 kernel_layer_mapping = {
     "SiluAndMul": {
@@ -32,7 +34,11 @@ kernel_layer_mapping = {
         "cuda": LayerRepository(
             repo_id="kernels-test/op-without-fake-test",
             layer_name="SiluAndMul",
-        )
+        ),
+        "rocm": LayerRepository(
+            repo_id="kernels-test/op-without-fake-test",
+            layer_name="SiluAndMul",
+        ),
     },
     "SiluAndMulStringDevice": {
         "cuda": LayerRepository(
@@ -102,29 +108,74 @@ def test_arg_kinds():
     assert arg_kind("foo", "bar", kwarg1="baz", kwarg2=5) == ("foo", "bar", "baz", 5)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 @pytest.mark.parametrize("cls", [SiluAndMulWithKernel, SiluAndMulStringDevice])
-@pytest.mark.parametrize("device", ["cuda", "cpu"])
-def test_hub_forward(cls, device):
+def test_hub_forward(cls):
     torch.random.manual_seed(0)
 
     silu_and_mul = SiluAndMul()
-    X = torch.randn((32, 64), device=device)
+    X = torch.randn((32, 64), device="cuda")
     Y = silu_and_mul(X)
 
-    silu_and_mul_with_kernel = kernelize(cls(), device=device, mode=Mode.INFERENCE)
+    silu_and_mul_with_kernel = kernelize(cls(), device="cuda", mode=Mode.INFERENCE)
     Y_kernel = silu_and_mul_with_kernel(X)
 
     torch.testing.assert_close(Y_kernel, Y)
 
     assert silu_and_mul.n_calls == 1
-    if device == "cuda":
-        assert silu_and_mul_with_kernel.n_calls == 0
-    else:
-        assert silu_and_mul_with_kernel.n_calls == 1
+    assert silu_and_mul_with_kernel.n_calls == 0
 
 
-@pytest.mark.linux_only
+@pytest.mark.rocm_only
+def test_hub_forward_rocm():
+    torch.manual_seed(0)
+
+    silu_and_mul = SiluAndMul()
+    X = torch.randn((32, 64))
+    Y = silu_and_mul(X)
+
+    silu_and_mul_with_kernel = kernelize(
+        SiluAndMulNoCompileKernel(), device="rocm", mode=Mode.INFERENCE
+    )
+    Y_kernel = silu_and_mul_with_kernel(X)
+
+    torch.testing.assert_close(Y_kernel, Y)
+
+    assert silu_and_mul.n_calls == 1
+    # Should use kernel (n_calls == 0) if ROCm kernel is available, otherwise fallback (n_calls == 1)
+    # The exact behavior depends on whether the test kernel exists for ROCm
+    assert silu_and_mul_with_kernel.n_calls in [0, 1]
+
+
+def test_rocm_kernel_mapping():
+    """Test that ROCm shorthand device mapping works correctly."""
+    kernel_layer_mapping = {
+        "SiluAndMul": {
+            "rocm": LayerRepository(
+                repo_id="kernels-community/activation",
+                layer_name="SiluAndMul",
+            )
+        }
+    }
+
+    # Test that the mapping is processed correctly
+    with use_kernel_mapping(kernel_layer_mapping, inherit_mapping=False):
+        mapping = _KERNEL_MAPPING.get()
+
+        # Verify the mapping exists
+        assert "SiluAndMul" in mapping
+        assert "rocm" in mapping["SiluAndMul"]
+
+        # Verify the repository is correctly stored
+        rocm_repos = mapping["SiluAndMul"]["rocm"]
+        assert rocm_repos is not None
+        assert (
+            rocm_repos.repos[Mode.FALLBACK]._repo_id == "kernels-community/activation"
+        )
+        assert rocm_repos.repos[Mode.FALLBACK].layer_name == "SiluAndMul"
+
+
+@pytest.mark.cuda_only
 def test_capability():
     linear = TorchLinearWithCounter(32, 32).to("cuda")
     with use_kernel_mapping(
@@ -183,7 +234,33 @@ def test_layer_fallback_works():
     kernelize(silu_and_mul, device="cuda", mode=Mode.INFERENCE)
 
 
-@pytest.mark.linux_only
+def test_local_layer_repo():
+    # Fetch a kernel to the local cache.
+    package_name, path = install_kernel("kernels-test/backward-marker-test", "main")
+
+    linear = TorchLinearWithCounter(32, 32).to("cuda")
+
+    with use_kernel_mapping(
+        {
+            "Linear": {
+                "cuda": LocalLayerRepository(
+                    # install_kernel will give the fully-resolved path.
+                    repo_path=path.parent.parent,
+                    package_name=package_name,
+                    layer_name="LinearBackward",
+                )
+            }
+        },
+        inherit_mapping=False,
+    ):
+        kernelize(linear, mode=Mode.INFERENCE)
+
+    X = torch.randn(10, 32, device="cuda")
+    linear(X)
+    assert linear.n_calls == 0
+
+
+@pytest.mark.cuda_only
 @pytest.mark.parametrize("cls", [SiluAndMulWithKernel, SiluAndMulNoCompileKernel])
 @pytest.mark.parametrize("device", ["cuda"])
 def test_torch_compile_layer_without_fallback(cls, device):
@@ -214,7 +291,7 @@ def test_torch_compile_layer_without_fallback(cls, device):
     torch.testing.assert_close(Y_compiled, Y)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 @pytest.mark.parametrize("cls", [SiluAndMulWithKernel, SiluAndMulNoCompileKernel])
 @pytest.mark.parametrize("device", ["cuda"])
 def test_torch_compile_layer_with_fallback(cls, device):
@@ -237,8 +314,11 @@ def test_torch_compile_layer_with_fallback(cls, device):
     torch.testing.assert_close(Y_compiled, Y)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_mapping_contexts():
+    # Make sure we start from scratch.
+    register_kernel_mapping(kernel_layer_mapping, inherit_mapping=False)
+
     assert set(_KERNEL_MAPPING.get().keys()) == {
         "SiluAndMul",
         "SiluAndMulStringDevice",
@@ -281,7 +361,9 @@ def test_mapping_contexts():
                 "TestKernel",
             }
             assert (
-                _KERNEL_MAPPING.get()["SiluAndMul"]["cuda"].repos[Mode.FALLBACK].repo_id
+                _KERNEL_MAPPING.get()["SiluAndMul"]["cuda"]
+                .repos[Mode.FALLBACK]
+                ._repo_id
                 == "kernels-community/non-existing"
             )
 
@@ -292,7 +374,7 @@ def test_mapping_contexts():
             "TestKernel",
         }
         assert (
-            _KERNEL_MAPPING.get()["SiluAndMul"]["cuda"].repos[Mode.FALLBACK].repo_id
+            _KERNEL_MAPPING.get()["SiluAndMul"]["cuda"].repos[Mode.FALLBACK]._repo_id
             == "kernels-community/activation"
         )
 
@@ -301,7 +383,9 @@ def test_mapping_contexts():
                 "SiluAndMul",
             }
             assert (
-                _KERNEL_MAPPING.get()["SiluAndMul"]["cuda"].repos[Mode.FALLBACK].repo_id
+                _KERNEL_MAPPING.get()["SiluAndMul"]["cuda"]
+                .repos[Mode.FALLBACK]
+                ._repo_id
                 == "kernels-community/non-existing"
             )
 
@@ -312,7 +396,7 @@ def test_mapping_contexts():
             "TestKernel",
         }
         assert (
-            _KERNEL_MAPPING.get()["SiluAndMul"]["cuda"].repos[Mode.FALLBACK].repo_id
+            _KERNEL_MAPPING.get()["SiluAndMul"]["cuda"].repos[Mode.FALLBACK]._repo_id
             == "kernels-community/activation"
         )
 
@@ -351,7 +435,7 @@ def test_validate_kernel_layer():
         _validate_layer(cls=BadLayer4, check_cls=SiluAndMul)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_invalid_mode_for_mapping_rejected():
     linear = TorchLinearWithCounter(32, 32).to("cuda")
 
@@ -371,7 +455,7 @@ def test_invalid_mode_for_mapping_rejected():
             kernelize(linear, mode=Mode.TRAINING)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_kernel_modes():
     linear = TorchLinearWithCounter(32, 32).to("cuda")
 
@@ -400,11 +484,6 @@ def test_kernel_modes():
         linear(X)
         assert linear.n_calls == 0
 
-        # Same as previous, since TRAINING | TORCH_COMPILE is the default.
-        kernelize(linear)
-        linear(X)
-        assert linear.n_calls == 0
-
     # Case 2: register a kernel just for training. If no base kernel
     #         layer is registered, we fall back to the original layer.
     with use_kernel_mapping(
@@ -434,12 +513,6 @@ def test_kernel_modes():
         # TRAINING | TORCH_COMPILE cannot fall back to TRAINING kernel, so uses original.
         assert linear.n_calls == 1
 
-        # Same as previous, since TRAINING | TORCH_COMPILE is the default.
-        kernelize(linear)
-        linear(X)
-        # TRAINING | TORCH_COMPILE cannot fall back to TRAINING kernel, so uses original.
-        assert linear.n_calls == 2
-
     # Case 3: register a kernel just for training and one for fallback.
     with use_kernel_mapping(
         {
@@ -461,23 +534,17 @@ def test_kernel_modes():
         X = torch.randn(10, 32, device="cuda")
         linear(X)
         # Falls back to TRAINING.
-        assert linear.n_calls == 2
+        assert linear.n_calls == 1
 
         kernelize(linear, mode=Mode.TRAINING)
         linear(X)
         # Falls back to the TRAINING kernel.
-        assert linear.n_calls == 2
+        assert linear.n_calls == 1
 
         kernelize(linear, mode=Mode.TRAINING | Mode.TORCH_COMPILE)
         linear(X)
         # TRAINING | TORCH_COMPILE falls back to FALLBACK kernel.
-        assert linear.n_calls == 2
-
-        # Same as previous, since TRAINING | TORCH_COMPILE is the default.
-        kernelize(linear)
-        linear(X)
-        # TRAINING | TORCH_COMPILE falls back to FALLBACK kernel.
-        assert linear.n_calls == 2
+        assert linear.n_calls == 1
 
     # Case 4: register a kernel with two preferences.
     with use_kernel_mapping(
@@ -497,25 +564,20 @@ def test_kernel_modes():
         X = torch.randn(10, 32, device="cuda")
         linear(X)
         # Falls back to the TRAINING | TORCH_COMPILE kernel.
-        assert linear.n_calls == 2
+        assert linear.n_calls == 1
 
         kernelize(linear, mode=Mode.TRAINING)
         linear(X)
         # TRAINING can fall back to TRAINING | TORCH_COMPILE kernel.
-        assert linear.n_calls == 2
+        assert linear.n_calls == 1
 
         kernelize(linear, mode=Mode.TRAINING | Mode.TORCH_COMPILE)
         linear(X)
         # Uses TRAINING | TORCH_COMPILE kernel.
-        assert linear.n_calls == 2
-
-        kernelize(linear)
-        linear(X)
-        # Same as previous, since TRAINING | TORCH_COMPILE is the default.
-        assert linear.n_calls == 2
+        assert linear.n_calls == 1
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_fallback_used_when_training():
     linear = TorchLinearWithCounter(32, 32).to("cuda")
 
@@ -580,7 +642,7 @@ def test_invalid_mode_rejected():
         kernelize(torch.nn.Linear(32, 32), mode=Mode.TORCH_COMPILE)
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_kernel_modes_inference():
     """Test inference-specific fallback scenarios."""
     linear = TorchLinearWithCounter(32, 32).to("cuda")
@@ -677,7 +739,7 @@ def test_kernel_modes_inference():
         assert linear.n_calls == 4
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_kernel_modes_mixed():
     """Test mixed training and inference kernel scenarios."""
     linear = TorchLinearWithCounter(32, 32).to("cuda")
@@ -767,7 +829,7 @@ def test_kernel_modes_mixed():
         assert linear.n_calls == 2
 
 
-@pytest.mark.linux_only
+@pytest.mark.cuda_only
 def test_kernel_modes_cross_fallback():
     """Test cross-mode fallback scenarios from inference to training modes."""
     linear = TorchLinearWithCounter(32, 32).to("cuda")
@@ -801,7 +863,8 @@ def test_kernel_modes_cross_fallback():
         {
             "Linear": {
                 "cuda": {
-                    Mode.TRAINING | Mode.TORCH_COMPILE: LayerRepository(
+                    Mode.TRAINING
+                    | Mode.TORCH_COMPILE: LayerRepository(
                         repo_id="kernels-test/backward-marker-test",
                         layer_name="LinearBackward",
                     )
@@ -839,7 +902,8 @@ def test_kernel_modes_cross_fallback():
                         repo_id="kernels-test/backward-marker-test",
                         layer_name="LinearBackward",
                     ),
-                    Mode.INFERENCE | Mode.TORCH_COMPILE: LayerRepository(
+                    Mode.INFERENCE
+                    | Mode.TORCH_COMPILE: LayerRepository(
                         repo_id="kernels-test/backward-marker-test",
                         layer_name="LinearBackward",
                     ),
@@ -857,3 +921,95 @@ def test_kernel_modes_cross_fallback():
         linear(X)
         # TRAINING | TORCH_COMPILE should NOT fall back to inference kernels, use original
         assert linear.n_calls == 2
+
+
+def test_layer_versions():
+    @use_kernel_forward_from_hub("Version")
+    class Version(nn.Module):
+        def forward(self) -> str:
+            return "0.0.0"
+
+    version = Version()
+
+    with use_kernel_mapping(
+        {
+            "Version": {
+                Device(type="cuda"): LayerRepository(
+                    repo_id="kernels-test/versions",
+                    layer_name="Version",
+                )
+            }
+        }
+    ):
+        version = kernelize(version, device="cuda", mode=Mode.INFERENCE)
+        assert version() == "0.2.0"
+
+    with use_kernel_mapping(
+        {
+            "Version": {
+                Device(type="cuda"): LayerRepository(
+                    repo_id="kernels-test/versions",
+                    layer_name="Version",
+                    version="<1.0.0",
+                )
+            }
+        }
+    ):
+        version = kernelize(version, device="cuda", mode=Mode.INFERENCE)
+        assert version() == "0.2.0"
+
+    with use_kernel_mapping(
+        {
+            "Version": {
+                Device(type="cuda"): LayerRepository(
+                    repo_id="kernels-test/versions",
+                    layer_name="Version",
+                    version="<0.2.0",
+                )
+            }
+        }
+    ):
+        version = kernelize(version, device="cuda", mode=Mode.INFERENCE)
+        assert version() == "0.1.1"
+
+    with use_kernel_mapping(
+        {
+            "Version": {
+                Device(type="cuda"): LayerRepository(
+                    repo_id="kernels-test/versions",
+                    layer_name="Version",
+                    version=">0.1.0,<0.2.0",
+                )
+            }
+        }
+    ):
+        version = kernelize(version, device="cuda", mode=Mode.INFERENCE)
+        assert version() == "0.1.1"
+
+    with use_kernel_mapping(
+        {
+            "Version": {
+                Device(type="cuda"): LayerRepository(
+                    repo_id="kernels-test/versions",
+                    layer_name="Version",
+                    version=">0.2.0",
+                )
+            }
+        }
+    ):
+        with pytest.raises(ValueError, match=r"No version.*satisfies requirement"):
+            kernelize(version, device="cuda", mode=Mode.INFERENCE)
+
+    with pytest.raises(ValueError, match=r"Either a revision or a version.*not both"):
+        use_kernel_mapping(
+            {
+                "Version": {
+                    Device(type="cuda"): LayerRepository(
+                        repo_id="kernels-test/versions",
+                        layer_name="Version",
+                        revision="v0.1.0",
+                        version="<1.0.0",
+                    )
+                }
+            }
+        )