commit	4c6e6c38d2835b7f6cbd973f3159627f1dbe9966	[log] [tgz]
author	Dave Jiang <dave.jiang@intel.com>	Wed Sep 17 16:50:56 2025 -0700
committer	Alison Schofield <alison.schofield@intel.com>	Wed Sep 24 13:46:17 2025 -0700
tree	0bfe542380224330dfc0dbdf6d1d728aba6b05df
parent	b4caae2ed720d2ba51eabf449fd1e1105bd07dd1 [diff]

tree: 0bfe542380224330dfc0dbdf6d1d728aba6b05df

README.md

ndctl

Utility library for managing the libnvdimm (non-volatile memory device) sub-system in the Linux kernel

Build

meson setup build;
meson compile -C build;

Optionally, to install:

meson install -C build

There are a number of packages required for the build steps that may not be installed by default. For information about the required packages, see the “BuildRequires:” lines in ndctl.spec.in.

https://github.com/pmem/ndctl/blob/main/ndctl.spec.in

Documentation

See the latest documentation for the NVDIMM kernel sub-system here:

https://www.kernel.org/doc/html/latest/driver-api/nvdimm/index.html

A getting started guide is also available on the kernel.org nvdimm wiki:

https://nvdimm.wiki.kernel.org/start

Unit Tests

The unit tests run by meson test require the nfit_test.ko module to be loaded. To build and install nfit_test.ko:

Obtain the kernel source. For example,
git clone -b libnvdimm-for-next git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git
Skip to step 3 if the kernel version is >= v4.8. Otherwise, for kernel versions < v4.8, configure the kernel to make some memory available to CMA (contiguous memory allocator). This will be used to emulate DAX.
```
CONFIG_DMA_CMA=y
CONFIG_CMA_SIZE_MBYTES=200
```
or
cma=200M on the kernel command line.

Apply the fragment below to your kernel config or use it to verify that the options required to run the NDCTL unit tests are correctly enabled.

CONFIG_X86_PMEM_LEGACY=m
CONFIG_ZONE_DEVICE=y
CONFIG_LIBNVDIMM=m
CONFIG_BLK_DEV_PMEM=m
CONFIG_BTT=y
CONFIG_NVDIMM_PFN=y
CONFIG_NVDIMM_DAX=y
CONFIG_DEV_DAX_PMEM=m
CONFIG_FS_DAX=y
CONFIG_EXT4_FS=m
CONFIG_XFS_FS=m
CONFIG_DAX=m
CONFIG_DEV_DAX=m
CONFIG_ENCRYPTED_KEYS=y
CONFIG_NVDIMM_SECURITY_TEST=y
CONFIG_STRICT_DEVMEM=y
CONFIG_IO_STRICT_DEVMEM=y
CONFIG_ACPI_NFIT=m
CONFIG_NFIT_SECURITY_DEBUG=y
CONFIG_MEMORY_FAILURE=y
CONFIG_MEMORY_HOTPLUG=y
CONFIG_MEMORY_HOTREMOVE=y
CONFIG_TRANSPARENT_HUGEPAGE=y

Install the following packages, (Fedora instructions):

dnf install e2fsprogs xfsprogs parted jq trace-cmd hostname fio fio-engine-dev-dax

Build and install the unit test enabled libnvdimm modules in the following order. The unit test modules need to be in place prior to the depmod that runs during the final modules_install
```
make M=tools/testing/nvdimm
sudo make M=tools/testing/nvdimm modules_install
sudo make modules_install
```

CXL test

The unit tests will also run CXL tests by default. In order to make these work, we need to install the cxl_test.ko as well.

Obtain the CXL kernel source(optional). For example, git clone -b pending git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git

Apply the fragment below to your kernel config or use it to verify that the options required to run the CXL unit tests are correctly enabled.

CONFIG_CXL_BUS=m
CONFIG_CXL_PCI=m
CONFIG_CXL_ACPI=m
CONFIG_LIBNVDIMM=m
CONFIG_CXL_PMEM=m
CONFIG_CXL_MEM=m
CONFIG_CXL_PORT=m
CONFIG_CXL_REGION=y
CONFIG_CXL_REGION_INVALIDATION_TEST=y
CONFIG_CXL_FEATURES=y
CONFIG_DAX=m
CONFIG_TRANSPARENT_HUGEPAGE=y
CONFIG_DEV_DAX=m
CONFIG_DEV_DAX_CXL=m
CONFIG_MEMORY_HOTPLUG=y
CONFIG_MEMORY_HOTREMOVE=y
CONFIG_NVDIMM_SECURITY_TEST=y
CONFIG_ENCRYPTED_KEYS=y
CONFIG_NVDIMM_KEYS=y

Install cxl_test and related mock modules.

make M=tools/testing/cxl
sudo make M=tools/testing/cxl modules_install
sudo make modules_install

Now run meson test -C build in the ndctl source directory, or ndctl test, if ndctl was built with -Dtest=enabled as a configuration option to meson.
To run the ‘destructive’ set of tests that may clobber existing pmem configurations and data, configure meson with the destructive option after the meson setup step:
```
meson configure -Dtest=enabled -Ddestructive=enabled build;
```

Troubleshooting

The unit tests will validate that the environment is set up correctly before they try to run. If the platform is misconfigured, i.e. the unit test modules are not available, or the test versions of the modules are superseded by the “in-tree/production” version of the modules meson test will skip tests and report a message like the following in build/meson-logs/testlog.txt

SKIP: libndctl
==============
test/init: nfit_test_init: nfit.ko: appears to be production version: /lib/modules/4.8.8-200.fc24.x86_64/kernel/drivers/acpi/nfit/nfit.ko.xz
__ndctl_test_skip: explicit skip test_libndctl:2684
nfit_test unavailable skipping tests

If the unit test modules are indeed available in the modules ‘extra’ directory the default depmod policy can be overridden by adding a file to /etc/depmod.d with the following contents:

override nfit * extra
override device_dax * extra
override dax_pmem * extra
override dax_pmem_core * extra
override dax_pmem_compat * extra
override libnvdimm * extra
override nd_btt * extra
override nd_e820 * extra
override nd_pmem * extra

The nfit_test module emulates pmem with memory allocated via vmalloc(). One of the side effects is that this breaks ‘physically contiguous’ assumptions in the driver. Use the '--align=4K option to ‘ndctl create-namespace’ to avoid these corner case scenarios.