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