c91d713630
Commit6e9f05dc66("libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE") ...updated MAX_STRUCT_PAGE_SIZE to account for sizeof(struct page) potentially doubling in the case of CONFIG_KMSAN=y. Unfortunately this doubles the amount of capacity stolen from user addressable capacity for everyone, regardless of whether they are using the debug option. Revert that change, mandate that MAX_STRUCT_PAGE_SIZE never exceed 64, but allow for debug scenarios to proceed with creating debug sized page maps with a compile option to support debug scenarios. Note that this only applies to cases where the page map is permanent, i.e. stored in a reservation of the pmem itself ("--map=dev" in "ndctl create-namespace" terms). For the "--map=mem" case, since the allocation is ephemeral for the lifespan of the namespace, there are no explicit restriction. However, the implicit restriction, of having enough available "System RAM" to store the page map for the typically large pmem, still applies. Fixes:6e9f05dc66("libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE") Cc: <stable@vger.kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Marco Elver <elver@google.com> Reported-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Yu Zhao <yuzhao@google.com> Link: https://lore.kernel.org/r/167467815773.463042.7022545814443036382.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
4.8 KiB
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