UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity
OpenCloudOS-Kernel/drivers/cxl/Kconfig

158 lines
5.8 KiB
Plaintext
Raw Normal View History

cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints The CXL.mem protocol allows a device to act as a provider of "System RAM" and/or "Persistent Memory" that is fully coherent as if the memory was attached to the typical CPU memory controller. With the CXL-2.0 specification a PCI endpoint can implement a "Type-3" device interface and give the operating system control over "Host Managed Device Memory". See section 2.3 Type 3 CXL Device. The memory range exported by the device may optionally be described by the platform firmware memory map, or by infrastructure like LIBNVDIMM to provision persistent memory capacity from one, or more, CXL.mem devices. A pre-requisite for Linux-managed memory-capacity provisioning is this cxl_mem driver that can speak the mailbox protocol defined in section 8.2.8.4 Mailbox Registers. For now just land the initial driver boiler-plate and Documentation/ infrastructure. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: David Rientjes <rientjes@google.com> (v1) Cc: Jonathan Corbet <corbet@lwn.net> Link: https://www.computeexpresslink.org/download-the-specification Link: https://lore.kernel.org/r/20210217040958.1354670-2-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-17 12:09:50 +08:00
# SPDX-License-Identifier: GPL-2.0-only
menuconfig CXL_BUS
tristate "CXL (Compute Express Link) Devices Support"
depends on PCI
cxl: fix CONFIG_FW_LOADER dependency When FW_LOADER is disabled, cxl fails to link: arm-linux-gnueabi-ld: drivers/cxl/core/memdev.o: in function `cxl_memdev_setup_fw_upload': memdev.c:(.text+0x90e): undefined reference to `firmware_upload_register' memdev.c:(.text+0x93c): undefined reference to `firmware_upload_unregister' In order to use the firmware_upload_register() function, both FW_LOADER and FW_UPLOAD have to be enabled, which is a bit confusing. In addition, the dependency is on the wrong symbol, as the caller is part of the cxl_core.ko module, not the cxl_mem.ko module. Fixes: 9521875bbe005 ("cxl: add a firmware update mechanism using the sysfs firmware loader") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20230703112928.332321-1-arnd@kernel.org Reviewed-by: Xiao Yang <yangx.jy@fujitsu.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2023-07-03 19:29:13 +08:00
select FW_LOADER
select FW_UPLOAD
cxl/pci: Create PCI DOE mailbox's for memory devices DOE mailbox objects will be needed for various mailbox communications with each memory device. Iterate each DOE mailbox capability and create PCI DOE mailbox objects as found. It is not anticipated that this is the final resting place for the iteration of the DOE devices. The support of switch ports will drive this code into the PCIe side. In this imagined architecture the CXL port driver would then query into the PCI device for the DOE mailbox array. For now creating the mailboxes in the CXL port is good enough for the endpoints. Later PCIe ports will need to support this to support switch ports more generically. Cc: Dan Williams <dan.j.williams@intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Lukas Wunner <lukas@wunner.de> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/20220719205249.566684-5-ira.weiny@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-07-20 04:52:47 +08:00
select PCI_DOE
cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints The CXL.mem protocol allows a device to act as a provider of "System RAM" and/or "Persistent Memory" that is fully coherent as if the memory was attached to the typical CPU memory controller. With the CXL-2.0 specification a PCI endpoint can implement a "Type-3" device interface and give the operating system control over "Host Managed Device Memory". See section 2.3 Type 3 CXL Device. The memory range exported by the device may optionally be described by the platform firmware memory map, or by infrastructure like LIBNVDIMM to provision persistent memory capacity from one, or more, CXL.mem devices. A pre-requisite for Linux-managed memory-capacity provisioning is this cxl_mem driver that can speak the mailbox protocol defined in section 8.2.8.4 Mailbox Registers. For now just land the initial driver boiler-plate and Documentation/ infrastructure. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: David Rientjes <rientjes@google.com> (v1) Cc: Jonathan Corbet <corbet@lwn.net> Link: https://www.computeexpresslink.org/download-the-specification Link: https://lore.kernel.org/r/20210217040958.1354670-2-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-17 12:09:50 +08:00
help
CXL is a bus that is electrically compatible with PCI Express, but
layers three protocols on that signalling (CXL.io, CXL.cache, and
CXL.mem). The CXL.cache protocol allows devices to hold cachelines
locally, the CXL.mem protocol allows devices to be fully coherent
memory targets, the CXL.io protocol is equivalent to PCI Express.
Say 'y' to enable support for the configuration and management of
devices supporting these protocols.
if CXL_BUS
cxl: Rename CXL_MEM to CXL_PCI The cxl_mem module was renamed cxl_pci in commit 21e9f76733a8 ("cxl: Rename mem to pci"). In preparation for adding an ancillary driver for cxl_memdev devices (registered on the cxl bus by cxl_pci), go ahead and rename CONFIG_CXL_MEM to CONFIG_CXL_PCI. Free up the CXL_MEM name for that new driver to manage CXL.mem endpoint operations. Suggested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Link: https://lore.kernel.org/r/164298412409.3018233.12407355692407890752.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-01-24 08:28:44 +08:00
config CXL_PCI
tristate "PCI manageability"
cxl/Kconfig: Default drivers to CONFIG_CXL_BUS CONFIG_CXL_BUS is default 'n' as expected for new functionality. When that is enabled do not make the end user hunt for all the expected sub-options to enable. For example CONFIG_CXL_BUS without CONFIG_CXL_MEM is an odd/expert configuration, so is CONFIG_CXL_MEM without CONFIG_CXL_ACPI (on ACPI capable platforms). Default CONFIG_CXL_MEM and CONFIG_CXL_ACPI to CONFIG_CXL_BUS. Acked-by: Ben Widawsky <ben.widawsky@intel.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325450105.2293126.17046356425194082921.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-10 00:01:41 +08:00
default CXL_BUS
cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints The CXL.mem protocol allows a device to act as a provider of "System RAM" and/or "Persistent Memory" that is fully coherent as if the memory was attached to the typical CPU memory controller. With the CXL-2.0 specification a PCI endpoint can implement a "Type-3" device interface and give the operating system control over "Host Managed Device Memory". See section 2.3 Type 3 CXL Device. The memory range exported by the device may optionally be described by the platform firmware memory map, or by infrastructure like LIBNVDIMM to provision persistent memory capacity from one, or more, CXL.mem devices. A pre-requisite for Linux-managed memory-capacity provisioning is this cxl_mem driver that can speak the mailbox protocol defined in section 8.2.8.4 Mailbox Registers. For now just land the initial driver boiler-plate and Documentation/ infrastructure. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: David Rientjes <rientjes@google.com> (v1) Cc: Jonathan Corbet <corbet@lwn.net> Link: https://www.computeexpresslink.org/download-the-specification Link: https://lore.kernel.org/r/20210217040958.1354670-2-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-17 12:09:50 +08:00
help
cxl: Rename CXL_MEM to CXL_PCI The cxl_mem module was renamed cxl_pci in commit 21e9f76733a8 ("cxl: Rename mem to pci"). In preparation for adding an ancillary driver for cxl_memdev devices (registered on the cxl bus by cxl_pci), go ahead and rename CONFIG_CXL_MEM to CONFIG_CXL_PCI. Free up the CXL_MEM name for that new driver to manage CXL.mem endpoint operations. Suggested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Link: https://lore.kernel.org/r/164298412409.3018233.12407355692407890752.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-01-24 08:28:44 +08:00
The CXL specification defines a "CXL memory device" sub-class in the
PCI "memory controller" base class of devices. Device's identified by
this class code provide support for volatile and / or persistent
memory to be mapped into the system address map (Host-managed Device
Memory (HDM)).
cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints The CXL.mem protocol allows a device to act as a provider of "System RAM" and/or "Persistent Memory" that is fully coherent as if the memory was attached to the typical CPU memory controller. With the CXL-2.0 specification a PCI endpoint can implement a "Type-3" device interface and give the operating system control over "Host Managed Device Memory". See section 2.3 Type 3 CXL Device. The memory range exported by the device may optionally be described by the platform firmware memory map, or by infrastructure like LIBNVDIMM to provision persistent memory capacity from one, or more, CXL.mem devices. A pre-requisite for Linux-managed memory-capacity provisioning is this cxl_mem driver that can speak the mailbox protocol defined in section 8.2.8.4 Mailbox Registers. For now just land the initial driver boiler-plate and Documentation/ infrastructure. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: David Rientjes <rientjes@google.com> (v1) Cc: Jonathan Corbet <corbet@lwn.net> Link: https://www.computeexpresslink.org/download-the-specification Link: https://lore.kernel.org/r/20210217040958.1354670-2-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-17 12:09:50 +08:00
cxl: Rename CXL_MEM to CXL_PCI The cxl_mem module was renamed cxl_pci in commit 21e9f76733a8 ("cxl: Rename mem to pci"). In preparation for adding an ancillary driver for cxl_memdev devices (registered on the cxl bus by cxl_pci), go ahead and rename CONFIG_CXL_MEM to CONFIG_CXL_PCI. Free up the CXL_MEM name for that new driver to manage CXL.mem endpoint operations. Suggested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Link: https://lore.kernel.org/r/164298412409.3018233.12407355692407890752.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-01-24 08:28:44 +08:00
Say 'y/m' to enable a driver that will attach to CXL memory expander
devices enumerated by the memory device class code for configuration
and management primarily via the mailbox interface. See Chapter 2.3
Type 3 CXL Device in the CXL 2.0 specification for more details.
cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints The CXL.mem protocol allows a device to act as a provider of "System RAM" and/or "Persistent Memory" that is fully coherent as if the memory was attached to the typical CPU memory controller. With the CXL-2.0 specification a PCI endpoint can implement a "Type-3" device interface and give the operating system control over "Host Managed Device Memory". See section 2.3 Type 3 CXL Device. The memory range exported by the device may optionally be described by the platform firmware memory map, or by infrastructure like LIBNVDIMM to provision persistent memory capacity from one, or more, CXL.mem devices. A pre-requisite for Linux-managed memory-capacity provisioning is this cxl_mem driver that can speak the mailbox protocol defined in section 8.2.8.4 Mailbox Registers. For now just land the initial driver boiler-plate and Documentation/ infrastructure. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: David Rientjes <rientjes@google.com> (v1) Cc: Jonathan Corbet <corbet@lwn.net> Link: https://www.computeexpresslink.org/download-the-specification Link: https://lore.kernel.org/r/20210217040958.1354670-2-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-17 12:09:50 +08:00
If unsure say 'm'.
cxl/mem: Add a "RAW" send command The CXL memory device send interface will have a number of supported commands. The raw command is not such a command. Raw commands allow userspace to send a specified opcode to the underlying hardware and bypass all driver checks on the command. The primary use for this command is to [begrudgingly] allow undocumented vendor specific hardware commands. While not the main motivation, it also allows prototyping new hardware commands without a driver patch and rebuild. While this all sounds very powerful it comes with a couple of caveats: 1. Bug reports using raw commands will not get the same level of attention as bug reports using supported commands (via taint). 2. Supported commands will be rejected by the RAW command. With this comes new debugfs knob to allow full access to your toes with your weapon of choice. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> (v2) Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Ariel Sibley <Ariel.Sibley@microchip.com> Link: https://lore.kernel.org/r/20210217040958.1354670-6-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-17 12:09:54 +08:00
config CXL_MEM_RAW_COMMANDS
bool "RAW Command Interface for Memory Devices"
cxl: Rename CXL_MEM to CXL_PCI The cxl_mem module was renamed cxl_pci in commit 21e9f76733a8 ("cxl: Rename mem to pci"). In preparation for adding an ancillary driver for cxl_memdev devices (registered on the cxl bus by cxl_pci), go ahead and rename CONFIG_CXL_MEM to CONFIG_CXL_PCI. Free up the CXL_MEM name for that new driver to manage CXL.mem endpoint operations. Suggested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Link: https://lore.kernel.org/r/164298412409.3018233.12407355692407890752.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-01-24 08:28:44 +08:00
depends on CXL_PCI
cxl/mem: Add a "RAW" send command The CXL memory device send interface will have a number of supported commands. The raw command is not such a command. Raw commands allow userspace to send a specified opcode to the underlying hardware and bypass all driver checks on the command. The primary use for this command is to [begrudgingly] allow undocumented vendor specific hardware commands. While not the main motivation, it also allows prototyping new hardware commands without a driver patch and rebuild. While this all sounds very powerful it comes with a couple of caveats: 1. Bug reports using raw commands will not get the same level of attention as bug reports using supported commands (via taint). 2. Supported commands will be rejected by the RAW command. With this comes new debugfs knob to allow full access to your toes with your weapon of choice. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> (v2) Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Ariel Sibley <Ariel.Sibley@microchip.com> Link: https://lore.kernel.org/r/20210217040958.1354670-6-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-17 12:09:54 +08:00
help
Enable CXL RAW command interface.
The CXL driver ioctl interface may assign a kernel ioctl command
number for each specification defined opcode. At any given point in
time the number of opcodes that the specification defines and a device
may implement may exceed the kernel's set of associated ioctl function
numbers. The mismatch is either by omission, specification is too new,
or by design. When prototyping new hardware, or developing / debugging
the driver it is useful to be able to submit any possible command to
the hardware, even commands that may crash the kernel due to their
potential impact to memory currently in use by the kernel.
If developing CXL hardware or the driver say Y, otherwise say N.
cxl/acpi: Introduce the root of a cxl_port topology While CXL builds upon the PCI software model for enumeration and endpoint control, a static platform component is required to bootstrap the CXL memory layout. Similar to how ACPI identifies root-level PCI memory resources, ACPI data enumerates the address space and interleave configuration for CXL Memory. In addition to identifying host bridges, ACPI is responsible for enumerating the CXL memory space that can be addressed by downstream decoders. This is similar to the requirement for ACPI to publish resources via the _CRS method for PCI host bridges. Specifically, ACPI publishes a table, CXL Early Discovery Table (CEDT), which includes a list of CXL Memory resources, CXL Fixed Memory Window Structures (CFMWS). For now, introduce the core infrastructure for a cxl_port hierarchy starting with a root level anchor represented by the ACPI0017 device. Follow on changes model support for the configurable decode capabilities of cxl_port instances, i.e. CXL switch support. Co-developed-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325449515.2293126.15303270193010154608.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-10 00:01:35 +08:00
config CXL_ACPI
tristate "CXL ACPI: Platform Support"
depends on ACPI
cxl/Kconfig: Default drivers to CONFIG_CXL_BUS CONFIG_CXL_BUS is default 'n' as expected for new functionality. When that is enabled do not make the end user hunt for all the expected sub-options to enable. For example CONFIG_CXL_BUS without CONFIG_CXL_MEM is an odd/expert configuration, so is CONFIG_CXL_MEM without CONFIG_CXL_ACPI (on ACPI capable platforms). Default CONFIG_CXL_MEM and CONFIG_CXL_ACPI to CONFIG_CXL_BUS. Acked-by: Ben Widawsky <ben.widawsky@intel.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325450105.2293126.17046356425194082921.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-10 00:01:41 +08:00
default CXL_BUS
cxl/acpi: Convert CFMWS parsing to ACPI sub-table helpers The cxl_acpi driver originally open-coded its table parsing since the ACPI subtable helpers were marked __init and only used in early NUMA initialization. Now that those helpers have been exported for driver usage replace the open-coded solution with the common one. Cc: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/163553710810.2509508.14686373989517930921.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-10-30 03:51:48 +08:00
select ACPI_TABLE_LIB
cxl/acpi: Introduce the root of a cxl_port topology While CXL builds upon the PCI software model for enumeration and endpoint control, a static platform component is required to bootstrap the CXL memory layout. Similar to how ACPI identifies root-level PCI memory resources, ACPI data enumerates the address space and interleave configuration for CXL Memory. In addition to identifying host bridges, ACPI is responsible for enumerating the CXL memory space that can be addressed by downstream decoders. This is similar to the requirement for ACPI to publish resources via the _CRS method for PCI host bridges. Specifically, ACPI publishes a table, CXL Early Discovery Table (CEDT), which includes a list of CXL Memory resources, CXL Fixed Memory Window Structures (CFMWS). For now, introduce the core infrastructure for a cxl_port hierarchy starting with a root level anchor represented by the ACPI0017 device. Follow on changes model support for the configurable decode capabilities of cxl_port instances, i.e. CXL switch support. Co-developed-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325449515.2293126.15303270193010154608.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-10 00:01:35 +08:00
help
Enable support for host managed device memory (HDM) resources
published by a platform's ACPI CXL memory layout description. See
Chapter 9.14.1 CXL Early Discovery Table (CEDT) in the CXL 2.0
specification, and CXL Fixed Memory Window Structures (CEDT.CFMWS)
(https://www.computeexpresslink.org/spec-landing). The CXL core
consumes these resource to publish the root of a cxl_port decode
hierarchy to map regions that represent System RAM, or Persistent
Memory regions to be managed by LIBNVDIMM.
cxl/pmem: Add initial infrastructure for pmem support Register an 'nvdimm-bridge' device to act as an anchor for a libnvdimm bus hierarchy. Also, flesh out the cxl_bus definition to allow a cxl_nvdimm_bridge_driver to attach to the bridge and trigger the nvdimm-bus registration. The creation of the bridge is gated on the detection of a PMEM capable address space registered to the root. The bridge indirection allows the libnvdimm module to remain unloaded on platforms without PMEM support. Given that the probing of ACPI0017 is asynchronous to CXL endpoint devices, and the expectation that CXL endpoint devices register other PMEM resources on the 'CXL' nvdimm bus, a workqueue is added. The workqueue is needed to run bus_rescan_devices() outside of the device_lock() of the nvdimm-bridge device to rendezvous nvdimm resources as they arrive. For now only the bus is taken online/offline in the workqueue. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162379909706.2993820.14051258608641140169.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-16 07:18:17 +08:00
If unsure say 'm'.
config CXL_PMEM
tristate "CXL PMEM: Persistent Memory Support"
depends on LIBNVDIMM
default CXL_BUS
help
In addition to typical memory resources a platform may also advertise
support for persistent memory attached via CXL. This support is
managed via a bridge driver from CXL to the LIBNVDIMM system
subsystem. Say 'y/m' to enable support for enumerating and
provisioning the persistent memory capacity of CXL memory expanders.
cxl/acpi: Introduce the root of a cxl_port topology While CXL builds upon the PCI software model for enumeration and endpoint control, a static platform component is required to bootstrap the CXL memory layout. Similar to how ACPI identifies root-level PCI memory resources, ACPI data enumerates the address space and interleave configuration for CXL Memory. In addition to identifying host bridges, ACPI is responsible for enumerating the CXL memory space that can be addressed by downstream decoders. This is similar to the requirement for ACPI to publish resources via the _CRS method for PCI host bridges. Specifically, ACPI publishes a table, CXL Early Discovery Table (CEDT), which includes a list of CXL Memory resources, CXL Fixed Memory Window Structures (CFMWS). For now, introduce the core infrastructure for a cxl_port hierarchy starting with a root level anchor represented by the ACPI0017 device. Follow on changes model support for the configurable decode capabilities of cxl_port instances, i.e. CXL switch support. Co-developed-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325449515.2293126.15303270193010154608.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-10 00:01:35 +08:00
If unsure say 'm'.
cxl/port: Add a driver for 'struct cxl_port' objects The need for a CXL port driver and a dedicated cxl_bus_type is driven by a need to simultaneously support 2 independent physical memory decode domains (cache coherent CXL.mem and uncached PCI.mmio) that also intersect at a single PCIe device node. A CXL Port is a device that advertises a CXL Component Register block with an "HDM Decoder Capability Structure". >From Documentation/driver-api/cxl/memory-devices.rst: Similar to how a RAID driver takes disk objects and assembles them into a new logical device, the CXL subsystem is tasked to take PCIe and ACPI objects and assemble them into a CXL.mem decode topology. The need for runtime configuration of the CXL.mem topology is also similar to RAID in that different environments with the same hardware configuration may decide to assemble the topology in contrasting ways. One may choose performance (RAID0) striping memory across multiple Host Bridges and endpoints while another may opt for fault tolerance and disable any striping in the CXL.mem topology. The port driver identifies whether an endpoint Memory Expander is connected to a CXL topology. If an active (bound to the 'cxl_port' driver) CXL Port is not found at every PCIe Switch Upstream port and an active "root" CXL Port then the device is just a plain PCIe endpoint only capable of participating in PCI.mmio and DMA cycles, not CXL.mem coherent interleave sets. The 'cxl_port' driver lets the CXL subsystem leverage driver-core infrastructure for setup and teardown of register resources and communicating device activation status to userspace. The cxl_bus_type can rendezvous the async arrival of platform level CXL resources (via the 'cxl_acpi' driver) with the asynchronous enumeration of Memory Expander endpoints, while also implementing a hierarchical locking model independent of the associated 'struct pci_dev' locking model. The locking for dport and decoder enumeration is now handled in the core rather than callers. For now the port driver only enumerates and registers CXL resources (downstream port metadata and decoder resources) later it will be used to take action on its decoders in response to CXL.mem region provisioning requests. Note1: cxlpci.h has long depended on pci.h, but port.c was the first to not include pci.h. Carry that dependency in cxlpci.h. Note2: cxl port enumeration and probing complicates CXL subsystem init to the point that it helps to have centralized debug logging of probe events in cxl_bus_probe(). Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Co-developed-by: Dan Williams <dan.j.williams@intel.com> Link: https://lore.kernel.org/r/164374948116.464348.1772618057599155408.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-02-02 05:07:51 +08:00
cxl/mem: Add the cxl_mem driver At this point the subsystem can enumerate all CXL ports (CXL.mem decode resources in upstream switch ports and host bridges) in a system. The last mile is connecting those ports to endpoints. The cxl_mem driver connects an endpoint device to the platform CXL.mem protoctol decode-topology. At ->probe() time it walks its device-topology-ancestry and adds a CXL Port object at every Upstream Port hop until it gets to CXL root. The CXL root object is only present after a platform firmware driver registers platform CXL resources. For ACPI based platform this is managed by the ACPI0017 device and the cxl_acpi driver. The ports are registered such that disabling a given port automatically unregisters all descendant ports, and the chain can only be registered after the root is established. Given ACPI device scanning may run asynchronously compared to PCI device scanning the root driver is tasked with rescanning the bus after the root successfully probes. Conversely if any ports in a chain between the root and an endpoint becomes disconnected it subsequently triggers the endpoint to unregister. Given lock depenedencies the endpoint unregistration happens in a workqueue asynchronously. If userspace cares about synchronizing delayed work after port events the /sys/bus/cxl/flush attribute is available for that purpose. Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> [djbw: clarify changelog, rework hotplug support] Link: https://lore.kernel.org/r/164398782997.903003.9725273241627693186.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-02-04 23:18:31 +08:00
config CXL_MEM
tristate "CXL: Memory Expansion"
depends on CXL_PCI
default CXL_BUS
help
The CXL.mem protocol allows a device to act as a provider of "System
RAM" and/or "Persistent Memory" that is fully coherent as if the
memory were attached to the typical CPU memory controller. This is
known as HDM "Host-managed Device Memory".
Say 'y/m' to enable a driver that will attach to CXL.mem devices for
memory expansion and control of HDM. See Chapter 9.13 in the CXL 2.0
specification for a detailed description of HDM.
If unsure say 'm'.
cxl/port: Add a driver for 'struct cxl_port' objects The need for a CXL port driver and a dedicated cxl_bus_type is driven by a need to simultaneously support 2 independent physical memory decode domains (cache coherent CXL.mem and uncached PCI.mmio) that also intersect at a single PCIe device node. A CXL Port is a device that advertises a CXL Component Register block with an "HDM Decoder Capability Structure". >From Documentation/driver-api/cxl/memory-devices.rst: Similar to how a RAID driver takes disk objects and assembles them into a new logical device, the CXL subsystem is tasked to take PCIe and ACPI objects and assemble them into a CXL.mem decode topology. The need for runtime configuration of the CXL.mem topology is also similar to RAID in that different environments with the same hardware configuration may decide to assemble the topology in contrasting ways. One may choose performance (RAID0) striping memory across multiple Host Bridges and endpoints while another may opt for fault tolerance and disable any striping in the CXL.mem topology. The port driver identifies whether an endpoint Memory Expander is connected to a CXL topology. If an active (bound to the 'cxl_port' driver) CXL Port is not found at every PCIe Switch Upstream port and an active "root" CXL Port then the device is just a plain PCIe endpoint only capable of participating in PCI.mmio and DMA cycles, not CXL.mem coherent interleave sets. The 'cxl_port' driver lets the CXL subsystem leverage driver-core infrastructure for setup and teardown of register resources and communicating device activation status to userspace. The cxl_bus_type can rendezvous the async arrival of platform level CXL resources (via the 'cxl_acpi' driver) with the asynchronous enumeration of Memory Expander endpoints, while also implementing a hierarchical locking model independent of the associated 'struct pci_dev' locking model. The locking for dport and decoder enumeration is now handled in the core rather than callers. For now the port driver only enumerates and registers CXL resources (downstream port metadata and decoder resources) later it will be used to take action on its decoders in response to CXL.mem region provisioning requests. Note1: cxlpci.h has long depended on pci.h, but port.c was the first to not include pci.h. Carry that dependency in cxlpci.h. Note2: cxl port enumeration and probing complicates CXL subsystem init to the point that it helps to have centralized debug logging of probe events in cxl_bus_probe(). Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Co-developed-by: Dan Williams <dan.j.williams@intel.com> Link: https://lore.kernel.org/r/164374948116.464348.1772618057599155408.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-02-02 05:07:51 +08:00
config CXL_PORT
default CXL_BUS
tristate
PM: CXL: Disable suspend The CXL specification claims S3 support at a hardware level, but at a system software level there are some missing pieces. Section 9.4 (CXL 2.0) rightly claims that "CXL mem adapters may need aux power to retain memory context across S3", but there is no enumeration mechanism for the OS to determine if a given adapter has that support. Moreover the save state and resume image for the system may inadvertantly end up in a CXL device that needs to be restored before the save state is recoverable. I.e. a circular dependency that is not resolvable without a third party save-area. Arrange for the cxl_mem driver to fail S3 attempts. This still nominaly allows for suspend, but requires unbinding all CXL memory devices before the suspend to ensure the typical DRAM flow is taken. The cxl_mem unbind flow is intended to also tear down all CXL memory regions associated with a given cxl_memdev. It is reasonable to assume that any device participating in a System RAM range published in the EFI memory map is covered by aux power and save-area outside the device itself. So this restriction can be minimized in the future once pre-existing region enumeration support arrives, and perhaps a spec update to clarify if the EFI memory map is sufficent for determining the range of devices managed by platform-firmware for S3 support. Per Rafael, if the CXL configuration prevents suspend then it should fail early before tasks are frozen, and mem_sleep should stop showing 'mem' as an option [1]. Effectively CXL augments the platform suspend ->valid() op since, for example, the ACPI ops are not aware of the CXL / PCI dependencies. Given the split role of platform firmware vs OS provisioned CXL memory it is up to the cxl_mem driver to determine if the CXL configuration has elements that platform firmware may not be prepared to restore. Link: https://lore.kernel.org/r/CAJZ5v0hGVN_=3iU8OLpHY3Ak35T5+JcBM-qs8SbojKrpd0VXsA@mail.gmail.com [1] Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Len Brown <len.brown@intel.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/165066828317.3907920.5690432272182042556.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-04-23 06:58:11 +08:00
config CXL_SUSPEND
def_bool y
depends on SUSPEND && CXL_MEM
cxl/region: Add region creation support CXL 2.0 allows for dynamic provisioning of new memory regions (system physical address resources like "System RAM" and "Persistent Memory"). Whereas DDR and PMEM resources are conveyed statically at boot, CXL allows for assembling and instantiating new regions from the available capacity of CXL memory expanders in the system. Sysfs with an "echo $region_name > $create_region_attribute" interface is chosen as the mechanism to initiate the provisioning process. This was chosen over ioctl() and netlink() to keep the configuration interface entirely in a pseudo-fs interface, and it was chosen over configfs since, aside from this one creation event, the interface is read-mostly. I.e. configfs supports cases where an object is designed to be provisioned each boot, like an iSCSI storage target, and CXL region creation is mostly for PMEM regions which are created usually once per-lifetime of a server instance. This is an improvement over nvdimm that pre-created "seed" devices that tended to confuse users looking to determine which devices are active and which are idle. Recall that the major change that CXL brings over previous persistent memory architectures is the ability to dynamically define new regions. Compare that to drivers like 'nfit' where the region configuration is statically defined by platform firmware. Regions are created as a child of a root decoder that encompasses an address space with constraints. When created through sysfs, the root decoder is explicit. When created from an LSA's region structure a root decoder will possibly need to be inferred by the driver. Upon region creation through sysfs, a vacant region is created with a unique name. Regions have a number of attributes that must be configured before the region can be bound to the driver where HDM decoder program is completed. An example of creating a new region: - Allocate a new region name: region=$(cat /sys/bus/cxl/devices/decoder0.0/create_pmem_region) - Create a new region by name: while region=$(cat /sys/bus/cxl/devices/decoder0.0/create_pmem_region) ! echo $region > /sys/bus/cxl/devices/decoder0.0/create_pmem_region do true; done - Region now exists in sysfs: stat -t /sys/bus/cxl/devices/decoder0.0/$region - Delete the region, and name: echo $region > /sys/bus/cxl/devices/decoder0.0/delete_region Signed-off-by: Ben Widawsky <bwidawsk@kernel.org> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165784333909.1758207.794374602146306032.stgit@dwillia2-xfh.jf.intel.com [djbw: simplify locking, reword changelog] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 01:28:34 +08:00
config CXL_REGION
cxl/region: Enable CONFIG_CXL_REGION to be toggled Add help text and a label so the CXL_REGION config option can be toggled. This is mainly to enable compile testing without region support. Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Gregory Price <gregory.price@memverge.com> Tested-by: Fan Ni <fan.ni@samsung.com> Link: https://lore.kernel.org/r/167601998765.1924368.258370414771847699.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-02-10 17:06:27 +08:00
bool "CXL: Region Support"
cxl/region: Add region creation support CXL 2.0 allows for dynamic provisioning of new memory regions (system physical address resources like "System RAM" and "Persistent Memory"). Whereas DDR and PMEM resources are conveyed statically at boot, CXL allows for assembling and instantiating new regions from the available capacity of CXL memory expanders in the system. Sysfs with an "echo $region_name > $create_region_attribute" interface is chosen as the mechanism to initiate the provisioning process. This was chosen over ioctl() and netlink() to keep the configuration interface entirely in a pseudo-fs interface, and it was chosen over configfs since, aside from this one creation event, the interface is read-mostly. I.e. configfs supports cases where an object is designed to be provisioned each boot, like an iSCSI storage target, and CXL region creation is mostly for PMEM regions which are created usually once per-lifetime of a server instance. This is an improvement over nvdimm that pre-created "seed" devices that tended to confuse users looking to determine which devices are active and which are idle. Recall that the major change that CXL brings over previous persistent memory architectures is the ability to dynamically define new regions. Compare that to drivers like 'nfit' where the region configuration is statically defined by platform firmware. Regions are created as a child of a root decoder that encompasses an address space with constraints. When created through sysfs, the root decoder is explicit. When created from an LSA's region structure a root decoder will possibly need to be inferred by the driver. Upon region creation through sysfs, a vacant region is created with a unique name. Regions have a number of attributes that must be configured before the region can be bound to the driver where HDM decoder program is completed. An example of creating a new region: - Allocate a new region name: region=$(cat /sys/bus/cxl/devices/decoder0.0/create_pmem_region) - Create a new region by name: while region=$(cat /sys/bus/cxl/devices/decoder0.0/create_pmem_region) ! echo $region > /sys/bus/cxl/devices/decoder0.0/create_pmem_region do true; done - Region now exists in sysfs: stat -t /sys/bus/cxl/devices/decoder0.0/$region - Delete the region, and name: echo $region > /sys/bus/cxl/devices/decoder0.0/delete_region Signed-off-by: Ben Widawsky <bwidawsk@kernel.org> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165784333909.1758207.794374602146306032.stgit@dwillia2-xfh.jf.intel.com [djbw: simplify locking, reword changelog] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 01:28:34 +08:00
default CXL_BUS
cxl/region: Allocate HPA capacity to regions After a region's interleave parameters (ways and granularity) are set, add a way for regions to allocate HPA (host physical address space) from the free capacity in their parent root-decoder. The allocator for this capacity reuses the 'struct resource' based allocator used for CONFIG_DEVICE_PRIVATE. Once the tuple of "ways, granularity, [uuid], and size" is set the region configuration transitions to the CXL_CONFIG_INTERLEAVE_ACTIVE state which is a precursor to allowing endpoint decoders to be added to a region. Co-developed-by: Ben Widawsky <bwidawsk@kernel.org> Signed-off-by: Ben Widawsky <bwidawsk@kernel.org> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165784335630.1758207.420216490941955417.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-04-26 02:43:44 +08:00
# For MAX_PHYSMEM_BITS
depends on SPARSEMEM
cxl/region: Add region creation support CXL 2.0 allows for dynamic provisioning of new memory regions (system physical address resources like "System RAM" and "Persistent Memory"). Whereas DDR and PMEM resources are conveyed statically at boot, CXL allows for assembling and instantiating new regions from the available capacity of CXL memory expanders in the system. Sysfs with an "echo $region_name > $create_region_attribute" interface is chosen as the mechanism to initiate the provisioning process. This was chosen over ioctl() and netlink() to keep the configuration interface entirely in a pseudo-fs interface, and it was chosen over configfs since, aside from this one creation event, the interface is read-mostly. I.e. configfs supports cases where an object is designed to be provisioned each boot, like an iSCSI storage target, and CXL region creation is mostly for PMEM regions which are created usually once per-lifetime of a server instance. This is an improvement over nvdimm that pre-created "seed" devices that tended to confuse users looking to determine which devices are active and which are idle. Recall that the major change that CXL brings over previous persistent memory architectures is the ability to dynamically define new regions. Compare that to drivers like 'nfit' where the region configuration is statically defined by platform firmware. Regions are created as a child of a root decoder that encompasses an address space with constraints. When created through sysfs, the root decoder is explicit. When created from an LSA's region structure a root decoder will possibly need to be inferred by the driver. Upon region creation through sysfs, a vacant region is created with a unique name. Regions have a number of attributes that must be configured before the region can be bound to the driver where HDM decoder program is completed. An example of creating a new region: - Allocate a new region name: region=$(cat /sys/bus/cxl/devices/decoder0.0/create_pmem_region) - Create a new region by name: while region=$(cat /sys/bus/cxl/devices/decoder0.0/create_pmem_region) ! echo $region > /sys/bus/cxl/devices/decoder0.0/create_pmem_region do true; done - Region now exists in sysfs: stat -t /sys/bus/cxl/devices/decoder0.0/$region - Delete the region, and name: echo $region > /sys/bus/cxl/devices/decoder0.0/delete_region Signed-off-by: Ben Widawsky <bwidawsk@kernel.org> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165784333909.1758207.794374602146306032.stgit@dwillia2-xfh.jf.intel.com [djbw: simplify locking, reword changelog] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 01:28:34 +08:00
select MEMREGION
cxl/region: Allocate HPA capacity to regions After a region's interleave parameters (ways and granularity) are set, add a way for regions to allocate HPA (host physical address space) from the free capacity in their parent root-decoder. The allocator for this capacity reuses the 'struct resource' based allocator used for CONFIG_DEVICE_PRIVATE. Once the tuple of "ways, granularity, [uuid], and size" is set the region configuration transitions to the CXL_CONFIG_INTERLEAVE_ACTIVE state which is a precursor to allowing endpoint decoders to be added to a region. Co-developed-by: Ben Widawsky <bwidawsk@kernel.org> Signed-off-by: Ben Widawsky <bwidawsk@kernel.org> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165784335630.1758207.420216490941955417.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-04-26 02:43:44 +08:00
select GET_FREE_REGION
cxl/region: Enable CONFIG_CXL_REGION to be toggled Add help text and a label so the CXL_REGION config option can be toggled. This is mainly to enable compile testing without region support. Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Gregory Price <gregory.price@memverge.com> Tested-by: Fan Ni <fan.ni@samsung.com> Link: https://lore.kernel.org/r/167601998765.1924368.258370414771847699.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-02-10 17:06:27 +08:00
help
Enable the CXL core to enumerate and provision CXL regions. A CXL
region is defined by one or more CXL expanders that decode a given
system-physical address range. For CXL regions established by
platform-firmware this option enables memory error handling to
identify the devices participating in a given interleaved memory
range. Otherwise, platform-firmware managed CXL is enabled by being
placed in the system address map and does not need a driver.
If unsure say 'y'
cxl/region: Add region creation support CXL 2.0 allows for dynamic provisioning of new memory regions (system physical address resources like "System RAM" and "Persistent Memory"). Whereas DDR and PMEM resources are conveyed statically at boot, CXL allows for assembling and instantiating new regions from the available capacity of CXL memory expanders in the system. Sysfs with an "echo $region_name > $create_region_attribute" interface is chosen as the mechanism to initiate the provisioning process. This was chosen over ioctl() and netlink() to keep the configuration interface entirely in a pseudo-fs interface, and it was chosen over configfs since, aside from this one creation event, the interface is read-mostly. I.e. configfs supports cases where an object is designed to be provisioned each boot, like an iSCSI storage target, and CXL region creation is mostly for PMEM regions which are created usually once per-lifetime of a server instance. This is an improvement over nvdimm that pre-created "seed" devices that tended to confuse users looking to determine which devices are active and which are idle. Recall that the major change that CXL brings over previous persistent memory architectures is the ability to dynamically define new regions. Compare that to drivers like 'nfit' where the region configuration is statically defined by platform firmware. Regions are created as a child of a root decoder that encompasses an address space with constraints. When created through sysfs, the root decoder is explicit. When created from an LSA's region structure a root decoder will possibly need to be inferred by the driver. Upon region creation through sysfs, a vacant region is created with a unique name. Regions have a number of attributes that must be configured before the region can be bound to the driver where HDM decoder program is completed. An example of creating a new region: - Allocate a new region name: region=$(cat /sys/bus/cxl/devices/decoder0.0/create_pmem_region) - Create a new region by name: while region=$(cat /sys/bus/cxl/devices/decoder0.0/create_pmem_region) ! echo $region > /sys/bus/cxl/devices/decoder0.0/create_pmem_region do true; done - Region now exists in sysfs: stat -t /sys/bus/cxl/devices/decoder0.0/$region - Delete the region, and name: echo $region > /sys/bus/cxl/devices/decoder0.0/delete_region Signed-off-by: Ben Widawsky <bwidawsk@kernel.org> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165784333909.1758207.794374602146306032.stgit@dwillia2-xfh.jf.intel.com [djbw: simplify locking, reword changelog] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 01:28:34 +08:00
cxl/region: Manage CPU caches relative to DPA invalidation events A "DPA invalidation event" is any scenario where the contents of a DPA (Device Physical Address) is modified in a way that is incoherent with CPU caches, or if the HPA (Host Physical Address) to DPA association changes due to a remapping event. PMEM security events like Unlock and Passphrase Secure Erase already manage caches through LIBNVDIMM, so that leaves HPA to DPA remap events that need cache management by the CXL core. Those only happen when the boot time CXL configuration has changed. That event occurs when userspace attaches an endpoint decoder to a region configuration, and that region is subsequently activated. The implications of not invalidating caches between remap events is that reads from the region at different points in time may return different results due to stale cached data from the previous HPA to DPA mapping. Without a guarantee that the region contents after cxl_region_probe() are written before being read (a layering-violation assumption that cxl_region_probe() can not make) the CXL subsystem needs to ensure that reads that precede writes see consistent results. A CONFIG_CXL_REGION_INVALIDATION_TEST option is added to support debug and unit testing of the CXL implementation in QEMU or other environments where cpu_cache_has_invalidate_memregion() returns false. This may prove too restrictive for QEMU where the HDM decoders are emulated, but in that case the CXL subsystem needs some new mechanism / indication that the HDM decoder is emulated and not a passthrough of real hardware. Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/166993222098.1995348.16604163596374520890.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-12-02 06:03:41 +08:00
config CXL_REGION_INVALIDATION_TEST
bool "CXL: Region Cache Management Bypass (TEST)"
depends on CXL_REGION
help
CXL Region management and security operations potentially invalidate
cxl: fix spelling mistakes Correct spelling mistakes (reported by codespell). Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Alison Schofield <alison.schofield@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Ben Widawsky <bwidawsk@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: linux-cxl@vger.kernel.org Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Link: https://lore.kernel.org/r/20230125032221.21277-1-rdunlap@infradead.org Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-01-25 11:22:21 +08:00
the content of CPU caches without notifying those caches to
cxl/region: Manage CPU caches relative to DPA invalidation events A "DPA invalidation event" is any scenario where the contents of a DPA (Device Physical Address) is modified in a way that is incoherent with CPU caches, or if the HPA (Host Physical Address) to DPA association changes due to a remapping event. PMEM security events like Unlock and Passphrase Secure Erase already manage caches through LIBNVDIMM, so that leaves HPA to DPA remap events that need cache management by the CXL core. Those only happen when the boot time CXL configuration has changed. That event occurs when userspace attaches an endpoint decoder to a region configuration, and that region is subsequently activated. The implications of not invalidating caches between remap events is that reads from the region at different points in time may return different results due to stale cached data from the previous HPA to DPA mapping. Without a guarantee that the region contents after cxl_region_probe() are written before being read (a layering-violation assumption that cxl_region_probe() can not make) the CXL subsystem needs to ensure that reads that precede writes see consistent results. A CONFIG_CXL_REGION_INVALIDATION_TEST option is added to support debug and unit testing of the CXL implementation in QEMU or other environments where cpu_cache_has_invalidate_memregion() returns false. This may prove too restrictive for QEMU where the HDM decoders are emulated, but in that case the CXL subsystem needs some new mechanism / indication that the HDM decoder is emulated and not a passthrough of real hardware. Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/166993222098.1995348.16604163596374520890.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-12-02 06:03:41 +08:00
invalidate the affected cachelines. The CXL Region driver attempts
to invalidate caches when those events occur. If that invalidation
fails the region will fail to enable. Reasons for cache
invalidation failure are due to the CPU not providing a cache
invalidation mechanism. For example usage of wbinvd is restricted to
bare metal x86. However, for testing purposes toggling this option
can disable that data integrity safety and proceed with enabling
regions when there might be conflicting contents in the CPU cache.
If unsure, or if this kernel is meant for production environments,
say N.
perf: CXL Performance Monitoring Unit driver CXL rev 3.0 introduces a standard performance monitoring hardware block to CXL. Instances are discovered using CXL Register Locator DVSEC entries. Each CXL component may have multiple PMUs. This initial driver supports a subset of types of counter. It supports counters that are either fixed or configurable, but requires that they support the ability to freeze and write value whilst frozen. Development done with QEMU model which will be posted shortly. Example: $ perf stat -a -e cxl_pmu_mem0.0/h2d_req_snpcur/ -e cxl_pmu_mem0.0/h2d_req_snpdata/ -e cxl_pmu_mem0.0/clock_ticks/ sleep 1 Performance counter stats for 'system wide': 96,757,023,244,321 cxl_pmu_mem0.0/h2d_req_snpcur/ 96,757,023,244,365 cxl_pmu_mem0.0/h2d_req_snpdata/ 193,514,046,488,653 cxl_pmu_mem0.0/clock_ticks/ 1.090539600 seconds time elapsed Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20230526095824.16336-5-Jonathan.Cameron@huawei.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-05-26 17:58:23 +08:00
config CXL_PMU
tristate "CXL Performance Monitoring Unit"
default CXL_BUS
depends on PERF_EVENTS
help
Support performance monitoring as defined in CXL rev 3.0
section 13.2: Performance Monitoring. CXL components may have
one or more CXL Performance Monitoring Units (CPMUs).
Say 'y/m' to enable a driver that will attach to performance
monitoring units and provide standard perf based interfaces.
If unsure say 'm'.
cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints The CXL.mem protocol allows a device to act as a provider of "System RAM" and/or "Persistent Memory" that is fully coherent as if the memory was attached to the typical CPU memory controller. With the CXL-2.0 specification a PCI endpoint can implement a "Type-3" device interface and give the operating system control over "Host Managed Device Memory". See section 2.3 Type 3 CXL Device. The memory range exported by the device may optionally be described by the platform firmware memory map, or by infrastructure like LIBNVDIMM to provision persistent memory capacity from one, or more, CXL.mem devices. A pre-requisite for Linux-managed memory-capacity provisioning is this cxl_mem driver that can speak the mailbox protocol defined in section 8.2.8.4 Mailbox Registers. For now just land the initial driver boiler-plate and Documentation/ infrastructure. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: David Rientjes <rientjes@google.com> (v1) Cc: Jonathan Corbet <corbet@lwn.net> Link: https://www.computeexpresslink.org/download-the-specification Link: https://lore.kernel.org/r/20210217040958.1354670-2-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-17 12:09:50 +08:00
endif