# SPDX-License-Identifier: GPL-2.0-only
menuconfig LIBNVDIMM
tristate "NVDIMM (Non-Volatile Memory Device) Support"
depends on PHYS_ADDR_T_64BIT
depends on HAS_IOMEM
depends on BLK_DEV
select MEMREGION
help
Generic support for non-volatile memory devices including
ACPI-6-NFIT defined resources. On platforms that define an
NFIT, or otherwise can discover NVDIMM resources, a libnvdimm
bus is registered to advertise PMEM (persistent memory)
namespaces (/dev/pmemX). A PMEM namespace refers to a
memory resource that may span multiple DIMMs and support DAX
(see CONFIG_DAX).
if LIBNVDIMM
config BLK_DEV_PMEM
tristate "PMEM: Persistent memory block device support"
default LIBNVDIMM
select DAX
select ND_BTT if BTT
select ND_PFN if NVDIMM_PFN
help
Memory ranges for PMEM are described by either an NFIT
(NVDIMM Firmware Interface Table, see CONFIG_NFIT_ACPI), a
non-standard OEM-specific E820 memory type (type-12, see
CONFIG_X86_PMEM_LEGACY), or it is manually specified by the
'memmap=nn[KMG]!ss[KMG]' kernel command line (see
Documentation/admin-guide/kernel-parameters.rst). This driver converts
these persistent memory ranges into block devices that are
capable of DAX (direct-access) file system mappings. See
Documentation/driver-api/nvdimm/nvdimm.rst for more details.
Say Y if you want to use an NVDIMM
config ND_CLAIM
bool
config ND_BTT
tristate
config BTT
bool "BTT: Block Translation Table (atomic sector updates)"
default y if LIBNVDIMM
select ND_CLAIM
help
The Block Translation Table (BTT) provides atomic sector
update semantics for persistent memory devices, so that
applications that rely on sector writes not being torn (a
guarantee that typical disks provide) can continue to do so.
The BTT manifests itself as an alternate personality for an
NVDIMM namespace, i.e. a namespace can be in raw mode pmemX,
or 'sectored' mode.
Select Y if unsure
config ND_PFN
tristate
config NVDIMM_PFN
bool "PFN: Map persistent (device) memory"
default LIBNVDIMM
depends on ZONE_DEVICE
select ND_CLAIM
help
Map persistent memory, i.e. advertise it to the memory
management sub-system. By default persistent memory does
not support direct I/O, RDMA, or any other usage that
requires a 'struct page' to mediate an I/O request. This
driver allocates and initializes the infrastructure needed
to support those use cases.
Select Y if unsure
config NVDIMM_DAX
bool "NVDIMM DAX: Raw access to persistent memory"
default LIBNVDIMM
depends on NVDIMM_PFN
help
Support raw device dax access to a persistent memory
namespace. For environments that want to hard partition
persistent memory, this capability provides a mechanism to
sub-divide a namespace into character devices that can only be
accessed via DAX (mmap(2)).
Select Y if unsure
config OF_PMEM
tristate "Device-tree support for persistent memory regions"
depends on OF
default LIBNVDIMM
help
Allows regions of persistent memory to be described in the
device-tree.
Select Y if unsure.
config NVDIMM_KEYS
def_bool y
depends on ENCRYPTED_KEYS
depends on (LIBNVDIMM=ENCRYPTED_KEYS) || LIBNVDIMM=m
config NVDIMM_KMSAN
bool
depends on KMSAN
help
KMSAN, and other memory debug facilities, increase the size of
'struct page' to contain extra metadata. This collides with
the NVDIMM capability to store a potentially
larger-than-"System RAM" size 'struct page' array in a
reservation of persistent memory rather than limited /
precious DRAM. However, that reservation needs to persist for
the life of the given NVDIMM namespace. If you are using KMSAN
to debug an issue unrelated to NVDIMMs or DAX then say N to this
option. Otherwise, say Y but understand that any namespaces
(with the page array stored pmem) created with this build of
the kernel will permanently reserve and strand excess
capacity compared to the CONFIG_KMSAN=n case.
Select N if unsure.
config NVDIMM_TEST_BUILD
tristate "Build the unit test core"
depends on m
depends on COMPILE_TEST && X86_64
default m if COMPILE_TEST
help
Build the core of the unit test infrastructure. The result of
this build is non-functional for unit test execution, but it
otherwise helps catch build errors induced by changes to the
core devm_memremap_pages() implementation and other
infrastructure.
config NVDIMM_SECURITY_TEST
bool "Enable NVDIMM security unit tests"
depends on NVDIMM_KEYS
help
The NVDIMM and CXL subsystems support unit testing of their device
security state machines. The NVDIMM_SECURITY_TEST option disables CPU
cache maintenance operations around events like secure erase and
overwrite. Also, when enabled, the NVDIMM subsystem core helps the unit
test implement a mock state machine.
Select N if unsure.
endif
